Abstract
Globally, salinization affects between 100 and 1000 billion m3 a−1 of irrigation water. The discovery that zero valent iron (ZVI, Fe0) could be used to desalinate water (using intra-particle catalysis in a diffusion environment) raises the possibility that large-scale in situ desalination of aquifers could be undertaken to support agriculture. ZVI desalination removes NaCl by an adsorption–desorption process in a multi-stage cross-coupled catalytic process. This study considers the potential application of two ZVI desalination catalyst types for in situ aquifer desalination. The feasibility of using ZVI catalysts when placed in situ within an aquifer to produce 100 m3 d−1 of partially desalinated water from a saline aquifer is considered.
Similar content being viewed by others
Explore related subjects
Discover the latest articles, news and stories from top researchers in related subjects.Avoid common mistakes on your manuscript.
Introduction
About 17% of global arable cropland is irrigated, of which at least 20% is adversely affected by salinization (Lekakis and Antonopoulis 2015). Irrigated crop land accounts for more than 30% of global agricultural production (Lekakis and Antonopoulis 2015) and more than 65% of global anthropogenic water usage (e.g., Knapp and Baerenklau 2006; FAO 2011; Amarasinghe and Smakhtin 2014; Wada and Bierkens 2014; Panta et al. 2014; Lekakis and Antonopoulis 2015).
Globally salinization affects between 100 and 1000 billion m3 a−1 of irrigation water (e.g., Knapp and Baerenklau 2006; FAO 2011; Amarasinghe and Smakhtin 2014; Wada and Bierkens 2014; Panta et al. 2014). Salinized irrigation water adversely affects crop yields and the long-term viability of agricultural land, and the underlying aquifers receiving salinized infiltration water (e.g., Ayers and Westcot 1994). A small decrease in salinity (e.g., 25–50% reduction) can have the potential to increase crop yields (depending on the crop, and initial water salinity) by between 25 and 10,000% (e.g., Ayers and Westcot 1994; Antia 2015b, 2017, 2018a, b, c).
Agricultural crops have a low value ($ ha−1) and can have a high irrigation requirement (m3 ha−1). This irrigation requirement may (depending on crop type and location) fall within the range 100–10,000 m3 ha−1 (e.g., Tabieh et al. 2015; Antia 2015b). It is unlikely that widespread usage, for irrigation, of partially desalinated water, will occur if the delivery cost of the irrigation water is > $0.2 m−3 (e.g., Tabieh et al. 2015; Antia 2015b, 2016a, b, 2017, 2018a, b, c). The economics of irrigation (and increased agricultural crop yields) using partially desalinated water is addressed elsewhere (Antia 2017, 2018a, b, c).
Conventional desalination plants use a physical process (e.g., membrane separation (reverse osmosis), or thermal distillation (e.g., multi-stage flash distillation) to produce desalinated (or partially desalinated) water containing a 50–99% reduction in water salinity. The full cycle cost of producing this desalinated water falls within the range $3 m−3–$5 m−3 for a plant producing about 100,000 m3 d−1 (Antia 2017), but may, in the future, reduce to the range $0.7 m−3–$4 m−3 (Bitar and Ahmad 2017).
In 2010, it was discovered that zero valent iron (Fe0, ZVI) can be used to partially desalinate water (Fronczyk et al. 2010, 2012; Antia 2010, 2015a, b, 2016a, b, 2017, 2018a, b, c; Hwang et al. 2015; Noubactep, 2018). The desalination process is a complex, multi-stage, cross-coupled, catalytic, adsorption and desorption series of reactions which concentrate Na+ and Cl− ions in the vicinity of the ZVI and in related products (Fronczyk et al. 2010, 2012; Antia 2010, 2015a, b, 2016a, b, c, 2017, 2018a, b, c; Hwang et al. 2015). The simplified, desalination, cross-coupled, catalytic process (Antia 2016c) is summarized in Fig. 1. The catalytic process cycles (Fig. 1) between oxidative addition of Fe (i.e., an increase in oxidation number) and reductive elimination (i.e., a decrease in oxidation number). The oxidation number for Fe oscillates within the range − 2 to + 8 during catalysis (Antia 2015a, b, 2016a, 2017, 2018a, b). This cross-coupled catalytic process has been demonstrated to also remove (during desalination) nitrates, nitrites, fluorides, phosphates, sulphates, Fe, Al, Cu, Mg, Mn, As, K, Ca, B, Ba, Sr from water (Antia 2010, 2014, 2015a, b, 2016c). The desalination process has been demonstrated to operate over the temperature range − 10 to 90 °C (Fronczyk et al. 2010, 2012; Antia 2010, 2015a, b, 2016a, b, 2017, 2018a, b, c; Hwang et al. 2015).
In 2013, small-scale trials using a 300 cm2 pressured dead-end filtration cell established that polyether sulphone (PES) membranes impregnated with 5–10% Fe3O4 nanoparticles could achieve NaCl rejection rates of 62–82% from nitrogen-saturated pressured water containing < 2 g NaCl L−1 (Abuhabid et al. 2013; Alam et al. 2013). A control PES membrane with no Fe3O4 nanoparticles showed no NaCl rejection. These trials established that (i) Fe x O y selectively removes NaCl from a flowing body of water, and (ii) NaCl removal is a function of particle size, pore size, particle surface area, porosity, particle concentration, fluid pressure, and gas partial pressure. Similar observations have been made in the ZVI desalination studies (Fronczyk et al. 2010, 2012; Antia 2010, 2015a, b, 2016a, b, 2017, 2018a, b, c; Hwang et al. 2015).
The desalination catalysts are [Fe x O y (OH) z (H2O) r ] n polymers (Antia 2015b, 2018a, b, c). These particles can be charged, \([{\text{Fe}}_{x} {\text{O}}_{y} ({\text{OH}})_{z} ({\text{H}}_{2} {\text{O}})_{r} ]_{n}^{m + / - }\) and can incorporate one or more anions (An), or cations (Ca) (Antia 2015b, 2018a).They exhibit capacitance, and are conductive (Antia 2015b, 2018a). This capacitance can exceed 300 F g−1 (Antia 2015b) and the associated pseudo-capacitance increases as the nano-porosity and surface area increases (Antia 2015b, 2018a). The capacitance increases as the Debye length decreases, the surface area of the reactive surfaces increases (Antia 2018a). The desalination rate constant is a function of the capacitance (Antia 2015b, 2018a). Capacitance increases as the dead-end porosity of the catalyst increases (Antia 2015b, 2018a).
Desalination is associated with capacitor discharge (Antia 2015b, 2018b). The catalyst complex (capacitor) comprises a central metal atom (e.g., Fen+) and neutral molecules or ions attached to it (Antia 2018b, 2018c). In saline water containing Fe, the dominant acids (within the catalyst) include one or more of H+, Na+, K+, Fen+, Can+, Aln+, Mgn+, Cun+, and CO2 (Antia 2015b, 2016a, 2017, 2018b). The dominant bases (within the catalyst) include one or more of H2O, Cl−, \({\text{HCO}}_{3}^{ - } ,\;{\text{O}}_{2}^{ - } ,\) On−, \({\text{C}}_{x} {\text{H}}_{y}^{n - } ,\;{\text{C}}_{x} {\text{H}}_{y} {\text{O}}_{z}^{n - } ,\;{\text{CO}}_{3}^{2 - } ,\;{\text{NO}}_{3}^{ - } ,\) HS−, H− (e−), OH−, \({\text{HO}}_{2}^{ - } ,\) ClO−, ClOn−, \({\text{SO}}_{4}^{2 - } ,\) Fen−, \({\text{N}}_{3}^{ - } ,\;{\text{NO}}_{2}^{ - } ,\;{\text{SO}}_{3}^{2 - } ,\) and CO.
The oscillation between capacitor discharge and recharge drives the catalytic desalination reaction (Antia 2010, 2015b, 2018b). In acidic water, the basic capacitor discharge reaction is: 2H2O → O2 + 4H+ + 4e−. The associated capacitor recharge reaction is O2 + 4H+ + 4e− → 2H2O. In alkali water, the basic capacitor discharge reaction is: 4OH− → O2 + 2H2O + 4e−. The associated capacitor recharge reaction is O2 + 2H2O + 4e− → 4OH−. Within the recharge–discharge reaction, O2 can be replaced by one or more of CO, CO2, CH4, C x H y , C x H y O z , C x H y O z N a , or C x H y O z N a Cl b , e.g., 2H2O + C → CO2 + 4H+ + 4e−. CO2 + 4H+ + 4e− → 2H2O + C (Antia 2015b, 2018b); 2H2O + CO → H2CO3 + 2H+ + 2e−. H2CO3 + 2H+ + 2e−→ 2H2O + CO (Antia 2015b). CO2 + 8H+ + 8e− → CH4 + 2H2O, CH4 + 2H2O → CO2 + 8H+ + 8e− (Antia 2015b); 2CO + 12H+ + 12e− → 2CH4 + 2H2O (Antia 2011a, 2015b, 2018b).
This oscillating process (Antia 2010, 2014) allows the ZVI catalyst to remove, or transform, a variety of other pollutants within the water (e.g., pesticides, herbicides, fungicides, nitrates, hormonal pollutants, chlorates, phosphates, nitrogenous pollutants, As, B, Ba, Ca, Cu, Cd, Fe, Mg, Mn, Pb, Sr, Se, etc.). A more detailed list of the pollutants that can be removed, or transformed, is provided elsewhere (Antia 2010, 2011a, 2014, 2016c). The removal process includes one or more of direct reaction to an alternative product, precipitation, reduction, oxidation, adsorption, or adsorption/desorption. The removal of pollutants increases with increased contact time in the reaction environment to a new equilibrium level (Pourbaix 1974; Antia 2010). The equilibrium level is a function of the Eh and pH of the product water and the nature of the other components in the water (Pourbaix 1974; Antia 2010, 2011a, b, 2014). The removal process is commonly multi-stage (Antia 2011a, 2016c) with numerous pollutants being removed simultaneously (Antia 2015a, b).
This study considers the potential application of two groups of ZVI desalination catalysts (termed Catalysts A and B) for in situ aquifer desalination.
Type A catalysts (Figs. 2, 3, 4, 5, 6, 7) operate as catalyst pellets (or powders), which are placed in water (Antia 2015b). These catalyst pellets slowly remove NaCl from a water body over a period of 50–1200 d (Antia 2015a, b). The NaCl is concentrated within the dead-end pores within the catalyst as both hypersaline water and halite (Antia 2017, 2018a, b). The salinity of the water is reduced to an equilibrium level which is typically between 5 and 80% of the feed water salinity (Antia 2015a, b, 2016a, b, 2017, 2018a, b, c). The required pellet concentration in the water is in the range 20–100 g Fe L−1 (Antia 2015b), i.e., provision of 10,000 m3 of irrigation water may require 200–1000 t of catalyst pellets.
Type B catalysts (Figs. 8, 9, 10, 11) gradually remove the Cl− and Na+ ions from a batch of water over a period of 1–36 h (Antia 2015b, 2016a, 2017, 2018b, c). The salinity of the water is reduced to an equilibrium level which is typically between 10 and 80% of the feed water salinity (Antia 2017, 2018a, b, c). Each batch of catalyst can be reused for successive batches (e.g., > 50) without loss of activity (Antia 2017, 2018a, b, c). The rate of desalination commonly increases with increasing feed water salinity (Antia 2017, 2018a, b, c). A typical Bronsted relationship (Antia 2018b) is Log10 (ka) = 1.9768 (Ct = 0)0.5 − 5.8078 (n = 40; R2 = 40%; valid for salinities in the range 1–9 g NaCl L−1). The current generation (2018) of Type B catalysts requires < 0.02 t Fe to partially desalinate 10,000 m3 of irrigation water.
The commercial cost of partial desalination (for irrigation) using a surface-based ZVI reactor system processing 100 m3 d−1 was initially estimated at being < $0.1 m−3 (Antia 2015b, 2016a, 2017). Subsequent trialling (2016–2018) of a commercial-scale ZVI desalination reactor train (processing 0.53 m3 d−1) has established (e.g., Antia 2018b, c) that the actual cost (excluding profit, financing, labour, facility/site costs, administration, etc.) approximated to $0.02 m−3 for Type B catalyst, plus a depreciated capital cost of $0.01 m−3 (excluding operating costs, feed and product water storage costs, site cost, financing costs, insurance costs, profit, taxes, administration costs, etc.). These trials have confirmed that a multi-train ZVI reactor system processing 100 m3 d−1 can be expected to reduce the feed water salinity (1–9 g NaCl L−1) by 40–60%, for a target full cycle cost of < $0.2 m−3.
Moving the desalination process from a reactor environment into the aquifer (providing the saline irrigation water) has the potential to further reduce costs.
In situ placement of ZVI within aquifers [either by injection or placement in permeable reactive barriers (PRBs)] has been extensively used to decontaminate aquifers (e.g., Henderson and Desmond 2007; Fu et al. 2014; Guan et al. 2015) and will remove an extensive suite of cations, anions and microbiota from the aquifer (e.g., Antia 2014, 2016c). Placing ZVI in an aquifer will modify the Eh and pH of the surrounding groundwater (e.g., Antia 2010, 2011a, 2014, 2016a) and can create a requirement for an environmental impact assessment and regulatory approval (e.g., Dougherty and Hall 1995; Mak and Lo 2011; Albergaria et al. 2013; Lynch et al. 2014; Jang et al. 2014; Alvarenga et al. 2016).
To date, aquifer-based ZVI environmental impact assessments have focused on freshwater aquifers. ZVI interacts with NaCl to create an oxic intra-particle nano-redox environment (Antia 2018a) which can facilitate the formation of H x Cl y O z species (Antia 2015b, 2016a). ZVI is known to deactivate common aquifer bacteria (e.g., Kim et al. 2010; Tellen et al. 2010; Barzan et al. 2014; Zabetakis et al. 2015). However, the oxidative redox conditions (which can develop within the intra-particle porosity during desalination) can favour the growth of an extensive microbiota (e.g., Barzan et al. 2014; Antia 2018a, b). The predatory iron bacterium Leptothrix discophora can be present in the ZVI catalyst during desalination, and will remove other bacterial species from the product water (Antia 2018a).
Data set and methodology
The non-isothermal ZVI desalination trials (trial identifiers: ST1a–ST5j, E146a–E146q and E147 series Antia 2015b, 2016a, A–K catalysts Antia 2017, 2018a, b, c) were used as the data base for this study. This data set recorded the feed water salinity (1–20 g L−1), the product water salinity, Eh, pH, electrical conductivity (EC), temperature (non-isothermal fluctuating within the range − 10 to 25 °C), pressure (0–0.01 MPa above atmospheric pressure), operating conditions, reactor volumes (0.2–800 L/batch), ZVI composition, ZVI particle size (ai = 44,000–77,000 nm), ZVI particle surface area, ZVI concentration (0.5 to > 100 g L−1) and ZVI treatment. ZVI was held as pellets (Catalyst A), or in cartridges (Catalyst B) (Antia 2015b, 2017, 2018a, b, c).
Catalysts A and B were trialled on synthetic water containing: (i) Catalyst A: Na–Cl, \({\text{Na}}{-}{\text{Cl}}{-}{\text{HCO}}_{3}^{ - } ,\) Na–Cl–NO3–HCO3 and Na–K–Cl–NO3–HCO3, (ii) Catalyst B: Na–K–Cl–Mg–SO4 and Na–K–Cl–Mg–SO4–HCO3 (Antia 2015b, 2016a). The feed water also contained Ca, Mg, Mn, B, Ba, Cu, Si, Sr, Zn (Antia 2016a). The synthetic water was manufactured by adding NaCl to natural spring water (Catalyst A trials) or by adding Zechstein Halite to natural spring water (Catalyst B trials).
pH measurements were calibrated at pH 4, 7, 10 [Equipment manufactured/branded by Hanna Instruments Ltd. (Leighton Buzzard, Bedfordshire, UK), HM-Digital, Inc. (Culver City, CA, USA) and Extech Instruments, Inc., Nashua, NH, USA]; Eh measurements were calibrated to the standard hydrogen electrode using a quinhydrone calibration at pH of 4 and 7. Oxidation–reduction potential (ORP) measurement equipment was manufactured/branded by Hanna, HM-Digital and Extech; direct ion (Na+ and Cl−) concentration measurements were based on ion calibration at 0.001, 0.01, 0.1 and 1.0 mol L−1 (Catalyst B), equipment manufactured by Bante Instruments Ltd., Shanghai, China; salinity measurements were based on EC (Catalyst A) and direct ion analysis. EC measurement equipment was manufactured/branded by Hanna, HM-Digital and Extech.
The efficiency of the desalination process can be measured directly using the observed rate constant, k (Ebbing and Gammon 2005; Kent 2007; Antia 2016a), where
In this study kn is defined as k/(Pw) as both Catalysts A and B are constructed using the same-sized ZVI particles (44,000–77,000 nm). The expected surface area of the resultant catalyst is within the range 20–200 m2 g−1 (Antia 2015b). The charge (C) associated with Cl− removal is (Ebbing and Gammon 2005):
The effective pseudo-specific capacitance (normalised charge) (Psc) associated with desalination is (e.g., Brousse et al. 2015):
The associated current, I (A) is (e.g., Sarkar et al. 2013):
The capacitance, Ca, is (e.g., Kuo et al. 2007; Yagmur et al. 2013; Chen et al. 2013):
Voltage is defined (Shen et al. 2016) as: Voltage = (average Eh (V) − initial Eh (V))/Pw/t. The applied working electrochemical voltage = (average Eh (V) − initial Eh (V)). The change in voltage during desalination is principally due to the effectiveness of the cathodic sites (Shen et al. 2016). The capacitance is a measure of external cell resistance, Rext, where (Shen et al. 2016)
kn increases as the amount of OH in the water increases and as the amount of available electrochemical energy increases (Antia 2015b; Wang et al. 2015). The catalyst effectively operates (e.g., Antia 2014, 2015b, 2016b; Shen et al. 2016) with a cathodic surface, a solid electrolyte transfer surface (ion conductor) and an anodic surface. The interaction of this electrochemical cell with Cl and Na ion species results in the removal of Na+ and Cl− ions (Antia 2015b, 2016a, 2017).
Desalination is a multi-stage, multi-pathway process, involving catalytic adsorption and desorption (Antia 2015a, b, 2016a, 2017, 2018a). This allows catalysts to be designed whose rate constant (i) increases with decreasing temperature, (ii) remains constant with changing temperature, (iii) increases with increasing temperature, (iv) increases with increasing feed water salinity, (v) remains stable with increasing feed water salinity, (vi) decreases with increasing feed water salinity, (vii) increases with increasing catalyst concentration, and (viii) decreases when the catalyst concentration increases beyond a critical level (e.g., Antia 2015b, 2016a, b).
The apparent activation energy, Ea (for a pseudo-first-order reaction) is derived from the slope (s) of a regression line for ln (kn) (or Log (kn) vs. 1/T Ebbing and Gammon 2005). Figure 2 schematically illustrates the relationship between the experimentally measured activation energy (Ea) and the actual activation energy (E2). The observed activation energy is: Ea = E2 − ΔH1 (Revell and Williamson 2013; Antia 2016a).
The cross-coupled desalination catalytic reaction (Fig. 1) can be simplified into a two-stage reaction (Fig. 2), where
-
(i)
Stage 1 is NaCl + Catalyst (S1) → NaClS1;
-
(ii)
Stage 2 is NaClS1→ [Product (C) NaCl] + Catalyst (S1);
-
(iii)
The net reaction is NaCl + Catalyst (S1) → [Product (C) NaCl] + Catalyst (S1).
The observed activation energies (e.g., Antia 2016b) can be positive (Fig. 2a), or negative (Fig. 2b).
Catalyst A
Catalyst A (trial series ST1a–ST5j ZVI Antia 2015b, 2016a): (i) composition: (Antia 2015b), (ii) particle size, ai = 44,000–77,000 nm (Antia 2015b), (iii) principal catalyst characteristics: (Fig. 3), (iv) external energy requirement = none (Antia 2015b), and (v) equilibrium absorbance, qe = 0.30–0.50 g g−1 (Antia 2015b).
The key characteristics of the ST catalyst pellets (illustrated in Antia 2015b, 2016a, 2017, 2018a, b) are (i) a rate constant (k, kn) which increases with increasing feed water salinity (Fig. 3a), (ii) the time required to reduce the water salinity by 50% increases with increasing Pw (Fig. 3b), (iii) k decreases with decreasing catalyst concentration, and there is a range of potential rate constants which are associated with a specific catalyst concentration (Fig. 3c), and (iv) the rate constant data (Fig. 3c) can be used to predict the time required [with a specific catalyst concentration (Pw)] for the aquifer salinity to reduce by 50% (Fig. 3d).
50 trials operated under identical temperature conditions established equilibrium absorbance, g NaCl g−1 Fe, qe, for a Type A catalyst after 70–130 d (Antia 2015b). The trials were continued to give a total duration of 280 d. The kn values in Fig. 3 are based on t = 280 d. Incremental kn values before the equilibrium salinity levels are reached are in the order of 10−8–10−6 (Fig. 4a, b), where kn = ln (C t /Ct + 24 h)/tPw. kn varies with temperature (Fig. 4a, b). The apparent activation energy is calculated, from the data in Fig. 4, using the method described in Ebbing and Gammon (2005) as:
The measured apparent activation energy, Ea, is − 109.9 kJ mol−1 (Fig. 4b).
The principal electrochemical parameters (e.g., capacitance) for Catalyst A are summarized in Fig. 5. The effectiveness of this catalyst is inversely proportional to its capacitance (Fig. 5). A relationship between the standard rate constant, kn, and capacitance, Ca, has been defined (Kisa and Kazmierczak 1991) as:
The relationship between pseudo-specific capacitance (Eq. 3) and kn (Fig. 5a) indicates that kn increases with pseudo-specific capacitance, and that the associated current discharge associated with the ZVI catalyst (Eq. 4) decreases as kn increases (Fig. 5b). The measured residual capacitance [following desalination (Eq. 5)] associated with the ZVI catalyst (Fig. 5c) decreases with increasing kn. This is interpreted (Antia 2015b, 2018b) as indicating that desalination (and kn) is associated with the discharge of capacitance in the ZVI catalysts.
These relationships (Fig. 5) indicate, that for a specific value of Ca, the variation in kn can be attributed to changes in as and kc (if it is assumed that the other parameters are constant). The cathodic rate constant, kc, increases with the increased availability of O2 (Ebbing and Gammon 2005; Shen et al. 2016). kc may increase as Ca decreases. Catalyst B provides an example where kn is increased by increasing kc (Antia 2018a, b, c).
The principal thermodynamic parameters for Catalyst A (ST catalyst) are summarized in Fig. 6. At equilibrium, when C0 is between 8 and 10 g L−1, kn decreases with increasing salinity (Fig. 6a). When C0 is < 8 g L−1, kn increases with increasing salinity (Fig. 3a). At equilibrium (Ebbing and Gammon 2005):
The values of G are negative within the range − 4 to − 9 kJ mol−1, and decrease as C0 increases (Fig. 6b). Negative G values in the range 0 to − 9 kJ mol−1 indicate that the desalination reaction will produce an equilibrium mixture containing both reactants and products (Ebbing and Gammon 2005), i.e., the saline water will only be partially desalinated at equilibrium (e.g., Antia 2015b, 2016a, 2017). The standard potential, ΔEo, is calculated as (Ebbing and Gammon 2005):
ΔEo is related to Eh and pH as (Pourbaix 1974):
ΔEo decreases with increasing feed water salinity (Fig. 6c), decreasing kn (Fig. 6a) and increasing G (Fig. 6b). This change reflects the composite nature of the desalination reaction (Antia 2016a). The Bronsted relationship illustrated in Fig. 6a is: Log10 (k) = − 8.855 (Ct = 0)0.5 − 6.3213. This indicates that the transition state complex [Product (C) NaCl] (Fig. 6d) has a lower charge than the reactants and has a lower stability at higher ionic strengths than the reactants. The observed (Fig. 6a) increase in k with decreasing ionic strength (decreasing salinity) indicates that the transition state complex is formed by two or more ions with a different charge sign.
If the dominant primary reaction is associated with the interaction of ZVI and water (Antia 2014, 2015b, 2016a, b), e.g., Fe0 + 3HO− = Fe(OH)3 + 3e−, ΔH1 = − 134.2 kJ mol−1 (thermodynamic data from Lide 2008), then E2 = − 24.3 kJ mol−1 (Fig. 6d).
An interpretation of the relationship between activation energy, enthalpy and reaction sequencing is provided in Fig. 6d. Catalyst A is suitable for aquifer partial desalination when the aquifer water temperature is in the range 0–90 °C (Antia 2015b).
The primary cathodic reaction (O2 + 4H+ + 4e− = 2H2O) (Pourbaix 1974) is a function of the availability of both O2 and H+. The bulk of the O2 entering the water will react to form OH radicals and ions (i.e., 0.5O2 + H2O = H2O2; H2O2 + 2e− = 2OH− Pourbaix 1974). Catalyst A is present as a layered double hydroxide (LDH) and derives an O2 and OH supply from four sources within the aquifer (Fig. 7): (i) oxygen diffusion across the air–water interface with subsequent OH− formation (Antia 2016a), (ii) dissolved oxygen within the water body with subsequent OH− formation (Antia 2015b), (iii) natural alkalinity within the water body (Antia 2015b), (iv) ZVI catalysed water decomposition to form H+ and OH− (Antia 2014, 2016b).
All water containing ZVI shows a natural oscillation between higher and lower values for both Eh and pH (Antia 2010, 2011a, 2014, 2016c). This Eh and pH oscillation is associated with an oscillation in Fe valency within the range − 2 to + 8 (Antia 2016a, 2017, 2018b). The pH oscillation reflects changes in the H+:OH− ion ratio in the water while the Eh oscillation reflects changes in the O2:On−:OH−:O2H− ratio in the water (Antia 2014, 2016b, 2017, 2018b). During desalination catalysis (Figs. 1, 7), the Fe oxidation number cyclically increases, before cyclically decreasing (Antia 2016a, 2017, 2018b).
Catalyst B
Catalyst B (trial series E146 Catalyst Antia 2015b, 2016a): (i) composition: (Antia 2015b), (ii) ai = 44,000–77,000 nm (Antia 2015b), (iii) principal operating characteristics (Figs. 8, 9, 10, 11), (iv) external energy requirement = < 0.17 kW m−3 (for air compression, Antia 2016a), and (v) qe = potentially > 1 kg NaCl g−1 Fe (Antia 2015b, 2016a, 2018b); treatment is potentially > 52,000 m3 t−1 (Antia 2015b, 2016a); removed NaCl is concentrated in (and on) the ZVI and in the ZVI cartridge (Antia 2016a).
Type B catalysts show a general trend where kn increases with increasing feed water salinity (Fig. 8a). These rate constants indicate (Fig. 8b–d) that a Type B catalyst (with a concentration of < 1 g L−1) could achieve a 50% desalination of a feed water. The measured rate constant can increase, as Pw decreases, with some Type B catalysts, when Pw exceeds a critical level (Antia 2018b).
The electrochemical parameters associated with this catalyst (Fig. 9) demonstrate, like Catalyst A, that kn increases with decreasing pseudo-specific capacitance (Fig. 9a), decreasing current (Fig. 9b), decreasing OH− addition to the water (Fig. 9c), and decreasing residual capacitance (Fig. 9d). The substantially higher values of kn [relative to Catalyst A (Fig. 3)] reflect the substantially higher values of kc resulting from the oxygenation of the water with air. The desalination reaction is driven by the reaction couple 3O2 + 6H2O + 12e− = 6H2O2 = 12OH− (Antia 2015b, 2016a). This also allows (Fig. 10) the formation of secondary products.
Secondary reactions
Cl− and Na+ ions interact with OH− and H+ within the water to form ion adducts and radicals of the form H x Cl y O z , Cl x O y , NaOH (Antia 2015b, 2016a). Their concentration in the water and in ZVI varies with catalyst type and with the operating mode selected. Their presence can allow a microflora to grow in the ZVI. This can require careful handling of both the ZVI and the water. These factors may need to be considered in an environment impact assessment.
The primary reactant is HClO (formed from the anodic reaction: H2O + Cl− = [OH–Cl] + H+ + 2e− Pourbaix 1974). An excess of HClO, or ClO−, is generated in the inter-particle porosity when the water is saturated with air, or CO2 (Antia 2015b). This can result in the basic cross-couple cycle being disrupted (Fig. 11) to produce ClO–OCl dimers (Cl2O2 species) as an initial primary by-product (Antia 2015b).
The ClO–OCl dimer (product from FeIII desorption) decomposes to form ClO2 + 0.5Cl2 (Figs. 10, 11). The ClO2 product is adsorbed by FeI (Fig. 11). This product is then desorbed from FeIII as 0.5Cl2. The O2 product then interacts with water to produce H2O2 and OH. In the presence of excess O2, the OH interacts with FeI to produce \({\text{HO}}_{2}^{ - } .\) The principal product (Antia 2015b) of this cycle is \({\text{HO}}_{2}^{ - } .\)
The primary reaction outcomes from ClO + ClO are (i) Cl2 + O2, (ii) Cl + ClO2, and (iii) ClO–OCl (Mollina and Mollina 1987; von Hobe et al. 2005). ClO–OCl decomposes to produce Cl + ClO2 (Mollina and Mollina 1987; von Hobe et al. 2005). ClO–OCl can react with ClO to produce Cl2O + ClO2 (Zhu and Lin 2011). The catalysed decomposition of ClO2 produces Cl + O2 (Mollina and Mollina 1987; von Hobe et al. 2005). This then initiates the coupled reaction 2O2 + 2OH = 2HO2 + O2 (e.g., Kingston 1987). In an oxygenated environment the O2 will react with water to produce an intermediate product H2O2 (Pourbaix 1974). The H2O2 will decompose to form 2OH (Pourbaix 1974). Some of the H2O2 will react with the ClO (i.e., ClO + H2O2 = HOCl + HO2 Levanov et al. 2015).
The disrupted oxygenated cycle (Fig. 11) dechlorides the water to produce two principal products Cl2(aq) and \({\text{HO}}_{2}^{ - } .\) The equilibrium relationship [2Cl− = Cl2 + 2e− (Eh = 1.395 + 0.295 log (Cl2/(Cl−)2)] is independent of pH (Pourbaix 1974). The Cl2 product can react with water to form one or more of HClO, ClO−, HClO2, \({\text{ClO}}_{2}^{ - } ,\;{\text{ClO}}_{3}^{ - }\) and \({\text{ClO}}_{4}^{ - }\) (Pourbaix 1974). Their equilibria relationships are a function of Eh and pH (Pourbaix 1974).
HClO forms part of the pH-dependent equilibrium continuum (e.g., McElhatton and Marshall 2007; Hu et al. 2010; Lefrou et al. 2012; Lichtfouse et al. 2012; Sandin 2013) from 0.5Cl2 (aq) to Cl− to HClO to ClO−, where (i) pH = 7.49 + Log(ClO−/HClO) (Pourbaix 1974), (ii) Eh = 1.494 − 0.0295 pH + 0.0295 Log (HClO/Cl−) (Pourbaix 1974), and (iii) Eh = 1.494 − 0.0295 pH + 0.0295 Log (ClO−/Cl−) (Pourbaix 1974).
The expected change in the Eh and pH (Hasab et al. 2012; Valenzuela et al. 2013) of the intra-particle porosity in the presence of NaCl (during desalination) is (i) a progressive drop in pH [relative to the situation without NaCl from 11 (e.g., Antia 2010, 2011a, b) to 4–5 (e.g., Antia 2015b, 2016a)], and (ii) an increase in Eh from < 0.6 (e.g., Antia 2015b, 2016a) to > 1.1 V (Pourbaix 1974).
The NaClO product entering the main water body will decompose (e.g., Pourbaix 1974; Falbe 1986) to form the equilibrium relationships [3NaClO = 2NaCl + NaClO3], [2NaClO = NaCl + NaClO2] and [2NaClO = O2 + 2NaCl].
The secondary reactions associated with ZVI in fresh water are largely benign and are associated with the removal or inactivation of microbiota (e.g., Antia 2014). In saline water, the secondary reactions produced during desalination can allow microbiota to flourish. The elevated Eh nano-redox conditions (> 0.7 V) within the ZVI intra-particle porosity are suitable for the growth of Escherichia coli, Listeria monocytogenes, Pseudomonas aeruginosa and Staphylococcus aureus (e.g., Deza et al. 2005). These species are natural constituents of many shallow aquifers (e.g., Ridgway et al. 1990; Hossain and Anwar 2009; Feighery et al. 2013; Penny et al. 2015). The sheltered intra-particle nano-environment will, in some aquifers, result in colonies of these species growing within the ZVI during desalination. The Gram-positive bacteria S. aureus, which is inhibited by concentrations of NaClO above 7.5 mM, is not inhibited in water containing NaCl + NaClO3, or in water containing < 7.5 mM NaClO (Melvin et al. 2011). The water within the ZVI can contain an extensive flora of the predatory oxic bacterium L. discophora (Antia 2018a, b). This bacterium operates by releasing acetaldehyde dehydrogenase enzyme and the associated by-product acetaldehyde into the pore waters within, and surrounding the ZVI (Antia 2018a). Therefore, appropriate biological precautions may be required during catalyst changeover, or water sampling from the catalyst bed.
UV–visible absorbance spectra associated with the ZVI nanoparticles produced during desalination (e.g., Antia 2015b) have identified the presence of Cl− (210–220 nm), Cl2O6 (215 nm), Cl2O2 (230 nm), Cl2O4 (230–235 nm), HClO (240 nm), ClO–OCl (240–250 nm), Cl2 (250 nm), ClO (270 nm), ClO− (290 nm), ClO2 (292 nm), \({\text{HO}}_{2}^{ - }\) (225 nm), Na+ (225–230 nm), NaO− (265 nm) and NaClO (294 nm) (Thomas and Burgess 2007; Antia 2015b, 2016a). Therefore, appropriate chemical precautions may be required during catalyst changeover, or water sampling from the catalyst bed.
Aquifer desalination
Aquifer desalination using a Type A catalyst requires a radial treatment zone to be established around an abstraction well (e.g., Huang et al. 2015). The treatment zone contains a number of wells, or infiltration devices, containing ZVI (Fig. 12). The ZVI is held in removable open-ended cartridges, or in removable permeable containers which are placed in the well, or in an infiltration device (e.g., Antia 2015b, 2016a, 2017). The number of wells/infiltration devices required and amount of ZVI (Z1) required are defined by the required level of desalination, Dr, kn and the required abstraction rate, Ar (m3 d−1). Ar is defined by the irrigation requirements for a specific crop. The required Dr is defined by a cost–benefit analysis of Dr versus crop yield. kn is defined by the selected catalyst. There is precedent for the placement of ZVI in aquifers, as ZVI has been widely used in PRBs for > 20 years to decontaminate aquifers (e.g., Wilkin et al. 2014).
Aquifer-specific parameters such as permeability, homogeneity and porosity will affect both the number of wells or infiltration devices and their micro-siting (Antia 2017). Local factors such as land ownership, land usage, aquifer geometry, aquifer distribution and regulatory constraints will also impact on the feasibility of in situ aquifer desalination.
The primary parameter required to undertake in situ aquifer desalination is:
Each crop type (and variety) will have a yield decrement relationship with salinity. The exact relationship is a function of local conditions (e.g., temperature, soil, operating conditions, irrigation, etc.).
Saline water from riparian water, ground water and saline drainage water from irrigated land (salinity = 0.9–9 g L−1) have been used to irrigate crops (e.g., Rhodes 1984; Zaman and Ahmad 2009; Jiang et al. 2010; Wang et al. 2016). A decrease in irrigation water salinity from 5 to 2.5 g NaCl L−1 (Dr = 0.5) would have the potential (Antia 2015b) to increase (depending on the planting strategy, variety and irrigation strategy adopted) soybean seed yields by between 0.8 and 10.8 t ha−1 (e.g., Khan and Khaliq 2004; Ali et al. 2013; AGDM 2016).
The average residence time, tr (s), required for the water within the ZVI-influenced desalination zone (e.g., Ebbing and Gammon 2005; Kent 2007) is:
Increasing Dr reduces the cost of the desalination project by reducing the average residence time required for the water in the reaction environment. The volume of water required within the aquifer in the ZVI-influenced desalination zone, Vw (m3), is:
The amount of ZVI required (t) is:
The required gross rock aquifer volume (AV, m3) is:
The gross area, Ga (m2), encompassed by the aquifer treatment zone is:
The radius, r (m), of the treatment zone around the abstraction well
The land take required for ZVI desalination can be assessed by considering a hypothetical saline aquifer located 2–3 m below the ground surface which is used for irrigation. The hypothetical parameters are provided in Table 1. These are integrated with the catalyst data to provide (Table 1) an indication of the required aquifer sizes required to deliver 100 m3 d−1 of partially desalinated irrigation water. Four desalination strategies are considered.
The first (passive) strategy places Catalyst A in a number of infiltration devices or wells. This strategy is illustrated schematically in Fig. 12. The water is retained within the reaction zone in the aquifer for a period of 60–1200 d while it gradually desalinates (Fig. 12).
The second (active) strategy places Catalyst B in a reactor (Fig. 13) with water storage, which is located in surface-based tanks (Fig. 13). In this strategy, an abstraction well is used to provide saline feed water for the reactor (Fig. 13). A reactor containing a Type B catalyst, processing 100 m3 d−1 of feed water and producing 100 m3 d−1 of product water, would require 150 m3 of water storage (Fig. 13) and could be placed within a standard 6-m-long shipping container. This allows the reactor and water storage units to be both mobile and temporary facilities. In many regulatory jurisdictions these units can be employed without requiring specific regulatory consents.
The third (active) strategy places Catalyst B in a reactor (Fig. 14) with water storage, which is located within an aquifer (Fig. 14). In most regulatory jurisdictions, this strategy will require specific regulatory consents.
The fourth (active) strategy places Catalyst B in a reactor, where each reactor is located within an infiltration (recycle) borehole and the water storage is located within an aquifer (Fig. 15). This strategy will require specific regulatory consents and in some regulatory areas this strategy will require a waiver from existing regulations. This is because the water composition entering the aquifer will be different to the water composition entering the infiltration borehole(s).
In some regulatory environments, permits (with associated regulatory fees) and environmental impact studies will be required to allow a specific aquifer to be partially desalinated.
The principal differences between conventional desalination and ZVI desalination are summarized in Table 2.
Commercial-scale trials (2016–2018) of a reactor train (using a Type B catalyst) operating at 0.53 m3 d−1 have achieved an average desalination in the range 45–55% (Antia 2017, 2018b, c) from a feed water (constructed by dissolving halite in natural spring water) with a salinity which varies within the range 1–9 g L−1 (Figs. 13, 14, 15). These trials (Antia 2017, 2018b, c) indicate that (i) a reactor (Figs. 13, 14, 15) processing 100 m3 d−1 will contain 19.4 kg Fe, and will require about 150 m3 water (including recycle water) to be held in storage within the reaction environment (Figs. 13, 14, 15), (ii) a single catalyst charge (19.4 kg Fe) will be able to catalytically partially desalinate > 54,000 m3 of saline water (i.e., > 2,780,000 m3 t−1 Fe). This compares with the historical (large scale, e.g., 1000–7000 m3 d−1) commercial ZVI municipal water treatment (Anderson process), which established that 1 t Fe could purify > 2,400,000 m3 of feed water (Anon 1889), (iii) the average desalination increases, as the feed water salinity increases (e.g., Figs. 13, 14, 15), when the feed water salinity is < 9 g L−1 (Antia 2018b).
Saline aquifers extend under a large number of neighbouring agricultural holdings. This allows Type A (Fig. 12) and Type B catalysts (Figs. 14, 15) to be potentially used (by co-operatives and state/municipal authorities) to partially desalinate, in situ, large aquifer volumes, e.g., 100,000–10,000,000 m3. These partially desalinated aquifers can be used for irrigation, or to provide a feed stock for conventional desalination plants. This type of large-scale aquifer desalination will be associated with a decrease in the nitrate content of the aquifer water (Antia 2015a, b).
Conclusions
This study has demonstrated that it is technically feasible to use ZVI catalysts to partially desalinate a saline aquifer, using a radial treatment zone, where water is being continuously removed through an abstraction well. The economics is a function of location, water composition, salinity reduction required, aquifer geology and hydrology, crops selected, planting strategy, land management strategy, anticipated increase in crop yield, local cost structures and commodity prices. The initial technical screening indicates that ZVI catalysts could potentially be used to deliver 100 m3 (partially desalinated water) d−1, for a potential cost of < $0.2 m−3, by the in situ treatment of a saline aquifer.
The practical feasibility of using this technology for in situ aquifer remediation will require appropriate regulatory consents and will require pilot testing (e.g., 5–1000 m3 d−1) within an aquifer which is designed to establish and test: (i) ZVI design layouts within the aquifer (including geological/hydrological data requirements), (ii) methods for placing the ZVI in the aquifer (and removing it), (iii) material and equipment requirements (including command and control systems), (iv) personnel requirements, (v) desalination time frame and achievable desalination levels, (vi) safety codes which have to apply during installation and operation, (vii) environmental constraints (including energy conservation), (viii) appropriate installation and operating standards and codes, (ix) resources required, (x) economic constraints (including operating cost structures, administrative cost structures, utility cost structures, supplies and equipment cost structures, capital and operating cost structures, insurance cost structures) and (xi) quality of the product water and its suitability for irrigation.
Abbreviations
- A r :
-
Required aquifer abstraction rate (m3 d−1)
- A V :
-
The gross rock aquifer volume (m3), required to produce Ar
- a:
-
Year
- a i :
-
ZVI particle size (nm)
- a s :
-
ZVI surface area (m2 g−1 or cm2 g−1)
- c :
-
Concentration of Na+ (mol cm−3)
- C :
-
Charge associated with Cl− removal (Coulombs)
- C a :
-
Capacitance (F g−1)
- C(NaCl):
-
Desorbed removed NaCl product
- C e :
-
Concentration of NaCl at equilibrium (g L−1)
- C t = 0 :
-
Feed water salinity (mol L−1)
- C 0 = NaClt = 0 :
-
Concentration of NaCl in the feed water (g L−1)
- C t = 1NaClt = n :
-
Concentration of NaCl in the product water (g L−1)
- d:
-
Day
- D r :
-
Required level of desalination (1 − C t /C0)
- E 1 :
-
Activation energy for Stage 1 (kJ mol−1)
- E 2 :
-
Activation energy for Stage 2 (kJ mol−1)
- E a :
-
Measured apparent activation energy (kJ mol−1)
- EC:
-
Electrical conductivity (mS cm−1)
- ΔE o :
-
Standard potential (V)
- F:
-
Farad
- F :
-
Faraday constant (96,485.33289 C mol−1)
- g:
-
Grams
- G a :
-
The gross area (m2), encompassed by the aquifer treatment zone
- G :
-
Gibbs free energy (kJ mol−1)
- ΔG o :
-
Standard Gibbs free energy (kJ mol−1) = − RT ln(K). ΔGo = ΔH − TΔS (Ebbing and Gammon 2005)
- ha:
-
Hectare
- ΔH :
-
Enthalpy (kJ mol−1)
- ΔH 1 :
-
Enthalpy associated with Stage 1 (kJ mol−1)
- ΔH 2 :
-
Enthalpy associated with Stage 2 (kJ mol−1)
- I :
-
Current associated with desalination (A)
- k :
-
Rate constant = Ln[C0/C t ]/t and is the dimensionless logarithmic change in the ratio Ln[C0/C t ] per unit time
- k a :
-
The observed rate constant associated with a water flow rate of 0.37 L m−1 and a single Type B catalyst charge containing 57.6 g Fe
- k c :
-
Pseudo-first-order cathodic rate constant
- k n :
-
Normalized rate constant. It is calculated as either kn= k/(Pwas) or kn= k/(Pw) (Wilkin and McNeil 2003; Antia 2015b); kn is the rate constant following normalization for the amount of catalyst placed in the reaction environment (Pw), i.e., rate constant per unit volume of water processed (L) per unit weight of ZVI catalyst (g L−1), kn = k/Pw; since catalytic reaction rates can be expressed as a function of the surface area of the catalyst, kn can be expressed (Antia 2015b) in terms of the catalyst surface area (m2) per unit volume of water (L), i.e., kn = k/(Pwas); the actual surface area (as) is not known in most ZVI studies and changes during catalysis (Antia 2015b). Pw is always known and is simple to measure and define (Antia 2015a, b)
- k 1 :
-
Rate constant at temperature T1
- k 2 :
-
Rate constant at temperature T2
- K :
-
Dimensionless equilibrium constant (Ebbing and Gammon 2005) = rate constant forward reactions/rate constant reverse reactions = 1/(NaClequilibrium/NaClt = 0) = 1/(Ce/C0)
- kW:
-
Kilowatt
- kWh:
-
Kilowatt hour
- L:
-
Litres
- LDH:
-
Layered double hydroxide
- m:
-
Minutes
- m :
-
Number of protons transferred
- m3 :
-
Cubic metre
- M w :
-
Molecular weight of [Cl−], 35.453 g mol−1
- n :
-
Number of 0.8 m3 batches of saline water processed by a single Type B catalyst charge
- n e :
-
Number of electrons transferred
- n :
-
Number of samples or trials considered
- NaClS 1 :
-
Catalytic site with adsorbed NaCl
- NaClt = 0 :
-
C 0
- NaClt = n :
-
C t
- NaClaquifer :
-
NaCl concentration in the saline aquifer (g L−1)
- NaClproduct water :
-
Required NaCl concentration in the product water (g L−1)
- N G :
-
Net to gross ratio within the aquifer [i.e., aquifer/(aquifer + aquitard ratio) within the gross aquifer unit]
- ORP:
-
Oxidation–reduction potential [Volts (mV)]. ORP is translated to Eh, V, using the quinhydrone method documented in Antia (2016a, 2017), i.e., Eh, mV = − 65.667 pH + 744.67 + ORP
- P sc :
-
The effective pseudo-specific capacitance (normalized charge) associated with desalination (F g−1)
- P w :
-
ZVI concentration (g L−1)
- PES:
-
Polyether sulphone
- Q :
-
Reaction quotient, e.g., 1/(NaClt = n/NaClt = 0) (Pourbaix 1974; Ebbing and Gammon 2005)
- q e :
-
Equilibrium absorbance of NaCl by ZVI (catalyst), g NaCl g−1 Fe, qe for a Type A catalyst is typically in the range 0 < qe < 0.3 (Antia 2015b), qe for a Type B catalyst is typically in the range 0 < qe < 1000 (Antia 2015b, 2016a, 2017, 2018a, b, c)
- r :
-
The radius (m) of the treatment zone around the abstraction well
- R ext :
-
External cell resistance
- R 2 :
-
Coefficient of determination
- R :
-
Gas constant (8.3144598 J mol−1 K−1)
- ΔS :
-
Entropy (J K−1)
- S 1 :
-
Catalytic site
- S w :
-
Aquifer mobile water saturation
- T, T 1, T 2 :
-
Temperature (K)
- T h :
-
Aquifer thickness (m)
- t :
-
Time spent in the reaction environment (s)
- t r :
-
Time spent in the reaction environment within the aquifer (s)
- t:
-
Tonnes
- V w :
-
The volume of water required within the aquifer in the ZVI-influenced desalination zone (m3)
- W r :
-
Weight of Cl− removed (g L−1, i.e., concentration reduction, g L−1)
- Z 1 :
-
The amount of ZVI catalyst required (t) to desalinate the aquifer
- ZVI:
-
Zero valent iron, Fe0
- $:
-
US dollar
- ϕ :
-
Aquifer porosity
References
Abuhabid AA, Ghasemi M, Mohammad AW, Rahman RA, El-Shafie AH (2013) Desalination of brackish water using nanofiltration: performance comparison of different membranes. Arab J Sci Eng. https://doi.org/10.1007/s13369-013-0616-z
AGDM (2016) Iowa corn and soybean county yields. AG Decision Maker, A1-14 March 2016
Alam J, Dass LA, Ghaasemi M, Alhoshan M (2013) Synthesis and optimization of PES-Fe3O4 mixed matrix nanocomposite membrane: application studies in water purification. Polym Compos 34:1870–1877
Albergaria JT, Petrus H, Nouws A, Delruematos CM (2013) Ecotoxicity of nanoscale zero valent iron particles—a review. Vigil Santitara Debate 1:38–42
Ali A, Iqbal Z, Safdar ME, Aziz AM, Asif M, Mubeen M, Noorka IR, Rehman A (2013) Comparison of yield performance of soybean varieties under semi-arid conditions. J Anim Plant Sci 23:828–832
Alvarenga RAF, de Lins IO, de Neto JAA (2016) Evaluation of abiotic resource LCIA methods. Resources 5:13
Amarasinghe UA, Smakhtin V (2014) Global water demand projections: past, present and future. Report 156. International Water Management Institute (IWMI), Colombo
Anon (1889) Purification of river water and sewage effluent and the entire removal of colour from water containing peat or clay by means of agitation with metallic iron. Revolving Purifier Company Ltd., London
Antia DDJ (1986) Kinetic method for modeling vitrinite reflectance. Geology 14:606–608
Antia DDJ (2010) Sustainable zero-valent metal (ZVM) water treatment associated with diffusion, infiltration, abstraction and recirculation. Sustainability 2:2988–3073
Antia DDJ (2011a) Modification of aquifer pore water by static diffusion using nano-zero-valent metals. Water 3:79–112
Antia DDJ (2011b) Hydrocarbon formation in immature sediments. Adv Pet Explor Dev 1:1–13
Antia DDJ (2014) Chapter 1: groundwater water remediation by static diffusion using nano-zero valent metals [ZVM] (Fe0, Cu0, Al0), n-FeHn+, n-Fe(OH)x, n-FeOOH, n-Fe–[OxHy](n+/−). In: Kharisov BI, Kharissova OV, Dias HVR (eds) Nanomaterials for environmental protection, 1st edn. Wiley, Inc., Hoboken, pp 3–25
Antia DDJ (2015a) Desalination of groundwater and impoundments using nano-zero valent iron, Fe0. Meteorol Hydrol Water Manag 3:21–38
Antia DDJ (2015b) Desalination of water using ZVI, Fe0. Water 7:3671–3831
Antia DDJ (2016a) ZVI (Fe0) desalination: stability of product water. Resources 5:15
Antia DDJ (2016b) Chapter 28: desalination of irrigation water, livestock water and reject brine using n-ZVM (Fe0, Cu0, Al0). In: Hussain CM, Kharisov BI (eds) Advanced environmental analysis: application of nanomaterials. RSC detection science series no. 10, 1st edn, vol 2. Royal Society of Chemistry, London, p 237–272
Antia DDJ (2016c) Chapter 84: water remediation—water remediation using nano-zero-valent metals (n-ZVM). In: Kharisov BI, Kharissova OV, Ortiz-Mendez U (eds) CRC concise encyclopedia of nanotechnology, 1st edn. CRC Press, Taylor and Francis Group, Boca Raton, pp 1103–1120
Antia DDJ (2017) Provision of desalinated irrigation water by the desalination of groundwater within a saline aquifer. Hydrology 4:1
Antia DDJ (2018a) Chapter 26: irrigation water desalination using PVP (polyvinylpyrrolidone) coated n-Fe0 (ZVI, zero valent iron). In: Hussain CM, Mishra A (eds) New polymer nanocomposites for environmental remediation, 1st edn. Elsevier, Amsterdam, pp 541–600
Antia DDJ (2018b) Chapter 8: direct synthesis of air-stable metal complexes for desalination (and water treatment). In: Kharisov BI (ed) Direct synthesis of metal complexes, 1st edn. Elsevier, Amsterdam, pp 341–367
Antia DDJ (2018c) Chapter 122: partial desalination of saline irrigation water using [FexOy(OH)z(H2O)m]n+/−. In: Martinez LMT, Kharissova OV, Kharisov BI (eds) Handbook of ecomaterials, 1st edn. Springer, Basel, pp 1–30
Ayers RS, Westcot DW (1994) Water quality for agriculture. Irrigation and drainage paper no. 29, Rev. 1, Reprinted 1989, 1994. Food and Agriculture Organization of the United Nations, Rome
Barzan E, Mehrabian S, Irian S (2014) Antimicrobial and genotoxicity effects of zero-valent iron nanoparticles. Jundishapur J Microbiol 7:e10054
Bitar RW, Ahmad A (2017) Solar vs. nuclear: which is cheaper for water desalination? Policy Brief #2/2017. Abu Policy Institute, American University of Beirut, Riad el-Solh, Beirut
Brousse T, Belanger D, Long JW (2015) To be or not to be pseudocapacitive? J Electrochem Soc 162:AS185–AS189
Chen PC, Hsieh SJ, Chen CC, Zou J (2013) The microstructure and capacitance characterizations of anodic titanium based alloy oxide nanotube. J Nanomater. https://doi.org/10.1155/2013/157494
Deza MA, Araujo M, Garrido MJ (2005) Inactivation of Escherichia coli, Listeria monocytogenes, Pseudomonas aeruginosa and Staphylococcus aureus on stainless steel and glass surfaces by neutral electrolysed water. Lett Appl Microbiol 40:5
Dougherty TC, Hall AW (1995) Environmental impact assessment of irrigation and drainage projects. FAO Irrigation and Drainage Paper 53, 8th edn. Food and Agricultural Organization of the United Nations, Rome
Ebbing DD, Gammon SD (2005) General chemistry, 8th edn. Houghton Mifflin Co., Boston
Falbe J (1986) Surfactants in consumer products. Theory, technology and application, 8th edn. Springer, Heidelberg
FAO (2011) The state of the world’s land and water resources for food and agriculture (SOLAW)—managing systems at risk. Food and Agricultural Organization of the United Nations and Earth Scan, Abingdon
Feighery J, Mailloux BJ, Feruson AS, Ahmed KM, van Geen A, Culligan PJ (2013) Transport of E. coli in aquifer sediments of Bangladesh: implications for widespread microbial contamination of groundwater. Water Resour Res 49:3897–3911
Fronczyk J, Pawluk K, Michniak M (2010) Application of permeable reactive barriers near roads for chloride ions removal. Ann Wars Univ Life Sci SGGW Land Reclam 42:249–259
Fronczyk J, Pawluk K, Garbulewski K (2012) Multilayer PRBs—effective technology for protection of the groundwater environment in traffic infrastructures. Chem Eng Trans 28:67–72
Fu F, Dionysiou DD, Liu H (2014) The use of zero valent iron for groundwater remediation and wastewater treatment. A review. J Hazard Mater 267:194–205
Guan X, Sun Y, Qin H, Li J, Lo IMC, He D, Dong H (2015) The limitations of applying zero valent iron technology in contaminants sequestration and the corresponding countermeasures: the development of zero-valent iron technology in the last two decades (1994–2004). Water Res 75:224–248
Hasab MG, Rashchi F, Raygan S (2012) Chloride–hypochlorite oxidation and leaching of refractory sulphide gold concentrate. Physicochem Probl Miner Process 49:61–70
Henderson AD, Desmond AH (2007) Long term performance of zero valent iron permeable reactive barriers. A critical review. Environ Sci Eng 24:401–423
Hossain MZ, Anwar MN (2009) Characterization of microorganisms from Sitakunda Hot Spring. Chittagong Univ J Biol Sci 4:107–117
Hu C, Su S, Li B, Liu M-F (2010) A new online detecting apparatus of the residual chlorine in disinfectant for vegetables. In: Computer and computing technologies in agriculture III. Springer, Heidelberg, p 153–160
Huang CS, Yang S-Y, Yeh H-D (2015) Approximate solution of transient drawdown for constant flux pumping at a partially penetrating well in a radial two-zone confined aquifer. Hydrol Earth Syst Sci 19:2639–2647
Hwang Y, Kim D, Shin H-S (2015) Inhibition of nitrate reduction by NaCl adsorption on a nano-zero valent iron surface during concentrate treatment for water reuse. Environ Technol 36:1178–1187
Jang M-H, Lim M, Hwang YS (2014) Potential environmental implications of nanoscale zero-valent iron particles for environmental remediation. Environ Health Toxicol 29:e2014022
Jiang J, Feng S, Huo Z, Wang Y, Sun Z (2010) Effect of irrigation with saline water on soil water-salt dynamics and maize yield in Arid Northwest China. Wuhan Univ J Nat Sci 15:85–92
Kent JA (2007) Kent and Riegel’s handbook of industrial chemistry and biotechnology, 11th edn. Springer, New York
Khan MB, Khaliq A (2004) Production of soybean (Glycine max L.) as cotton based intercrop. J Res (Sci) Bahauddin Zakariya Univ 15:79–84
Kim JY, Park H-J, Lee C, Nelson KL, Sedlak DL, Yoon J (2010) Inactivation of Escherichia coli by nanoparticulate zerovalent iron and ferrous iron. Appl Environ Microbiol 76:7668–7670
Kingston AE (1987) Recent studies in atomic and molecular processes. Plenum Press, New York
Kisa A, Kazmierczak J (1991) Kinetics of electrode reactions on metallic electrodes in pure molten chlorides. Chem Pap 45:187–194
Knapp KC, Baerenklau KA (2006) Ground water quantity and quality management: agricultural production and aquifer salinization over long time scales. J Agric Resour Econ 31:616–641
Kortvelysi Z, Gordon G (2004) Chlorite ion interference in the spectrophotometric measurement of chlorine dioxide. J AWWA 96(9):81–87
Kuo S-L, Lee J-F, Wu N-L (2007) Study on pseudocapacitance mechanism of aqueous MnFe2O4 supercapacitor. J Electrochem Soc 154:A34–A38
Lefrou C, Fabray P, Pognet J-C (2012) Electrochemistry. The basics with examples. Springer, Heidelberg
Lekakis EH, Antonopoulis VZ (2015) Modelling the effects of different irrigation salinity on soil water movement, uptake and multicomponent solute transport. J Hydrol 530:431–446
Levanov AV, Isaykina OY, Amirova NK, Antipenko EE, Lunin VV (2015) Photochemical oxidation of chloride ion by ozone in acid aqueous solution. Environ Sci Pollut Res Int 22:16554–16569
Lichtfouse E, Schwarzbauer J, Robert D (2012) Environmental chemistry for a sustainable world, vol 2. Springer, Heidelberg
Lide D (2008) CRC handbook of chemistry and physics, 89th edn. CRC Press, Boca Raton
Lynch SFL, Batty LC, Byrne P (2014) Environmental risk of metal mining contaminated river bank sediment at redox-transitional zones. Minerals 4:52–73
Mak MSH, Lo IMC (2011) Environmental life cycle assessment of permeable reactive barriers: effects of construction methods, reactive materials and groundwater construction. Environ Sci Technol 45:10148–10154
McElhatton A, Marshall RJ (2007) Food safety, a practical and case study approach. Springer, Heidelberg
Melvin JA, Murphy CF, Dubois LG, Thompson JW, Moseley MA, McCafferty DG (2011) Staphylococcus aureus sortase A contributes to the Trojan Horse mechanism of immune defense evasion with its intrinsic resistance to Cys184 oxidation. Biochemistry 50:7591–7599
Mollina LT, Mollina MJ (1987) Production of Cl2O2 from the self-reaction of the ClO radical. J Phys Chem 91:433–436
Noubactep C (2018) Metallic iron for environmental remediation: how experts maintain a comfortable status quo. Fresenius Environ Bull 27:1379–1393
Panta S, Flowers T, Lane P, Doyle R, Haros G, Shaala S (2014) Halophyte agriculture: success stories. Environ Exp Bot 107:71–83
Penny C, Gruffaz C, Nadalig T, Cauchie H-M, Vuilleumier S, Bringel F (2015) Tetrachloromethane-degrading bacterial enrichment cultures and isolates from a contaminated aquifer. Microorganisms 3:327–343
Pourbaix M (1974) Atlas of electrochemical equilibria in aqueous solutions, 1st edn. NACE International, Cebelcor, Houston
Revell LE, Williamson BE (2013) Why are some reactions slower at high temperatures? J Chem Educ 90:1024–1027
Rhodes JD (1984) Use of saline water for irrigation. Calif Agric (October), 42–43
Ridgway HF, Safarik J, Phipps D, Carl P, Clark D (1990) Identification and catabolic activity of well derived gasoline degrading bacteria from a contaminated aquifer. Appl Environ Microbiol 56:3565–3575
Sandin S (2013) Homogenous and heterogeneous decomposition of hypochlorite—a study of the oxygen evolving side reaction using mass spectrometry. PhD Thesis, KTH Royal Institute of Technology, University of Stockholm, Sweden
Sarkar D, Khan GG, Singh AK, Mandal K (2013) High performance pseudocapacitor electrodes based on α-Fe2O3/MnO2 core–shell nanowire heterostructure arrays. J Phys Chem 117:15523–15531
Shen PK, Wang C-Y, Jiang SP, Sun X, Zhang J (2016) Electrochemical energy: advanced materials and technology. CRC Press, Boca Raton
Tabieh M, Al-Karablieh E, Salman A, Al-Qudah H (2015) Farmers’ ability to pay for irrigation water in Jordan Valley. J Water Resour Prot 7:1157–1173
Tellen V, Nkeng G, Dentel S (2010) Improved filtration technology for pathogen reduction in rural water supplies. Water 2:285–306
Thomas O, Burgess G (2007) UV–visible spectrophotometry of water and waste water. Elsevier, Amsterdam
Valenzuela A, Valenzuela JL, Parga JR (2013) Effect of pre-treatment of sulphide refractory concentrate with sodium hypochlorite, followed by extraction of gold by pressure cyanidation, on gold removal. Adv Chem Eng Sci 3:171–177
Von Hobe M, Grooβ J-U, Muller R, Hrechanyy S, Winkler U, Stroh F (2005) A re-evaluation of the ClO/Cl2O2 equilibrium constant based on stratospheric in situ observations. Atmos Chem Phys 5:693–702
Von Hobe M, Salawitch RJ, Canty T, Keller-Rudek H, Moortgat GK, Grooβ J-U, Muller R, Stroh F (2006) Understanding the kinetics of the ClO dimer cycle. Atmos Chem Phys Discuss 6:7905–7944
Wada Y, Bierkens MFP (2014) Sustainability of global water use: past reconstruction and future projections. Environ Res Lett 9:104003
Wang X, Chandrabose RS, Chun S-E, Zhang T, Evanko B, Jian Z, Boettcher SW, Stucky GD, Ji X (2015) High energy density aqueous electrochemical capacitors with a KI–KOH electrolyte. ACS Appl Mater Interfaces 7:19978–19985
Wang Q, Huo Z, Zhang L, Wang J, Zhao Y (2016) Impact of saline water irrigation on water use efficiency and soil salt accumulation for spring maize in arid areas of China. Agric Water Manag 163:125–138
Wilkin RT, McNeil MS (2003) Laboratory evaluation of zero-valent iron to treat water impacted by acid mine drainage. Chemosphere 53:715–725
Wilkin RT, Acree SD, Ross RR, Puls RW, Lee TR, Woods LL (2014) Fifteen-year assessment of a permeable barrier for treatment of chromate and trichloroethylene in groundwater. Sci Total Environ 468–469:186–194
Yagmur V, Atalay FE, Kaya H, Avcu D, Aydogmus E (2013) Electrochemical capacitance of cobalt oxide nanotubes on nickel foam. Acta Phys Pol A 123:215–217
Zabetakis KM, de Guzman GTN, Torents A, Yarwood S (2015) Toxicity of zero valent iron nanoparticles to a trichloroethylene degrading groundwater microbial community. J Environ Sci Health A 50:794–805
Zaman SB, Ahmad S (2009) Economic loss of gross value of agricultural production by salinity and water logging in the Indus Basin of Pakistan. NRD Pak Agric Res Counc Res Brief 1:4
Zhu RS, Lin MC (2011) Ab initio chemical kinetics for reactions of ClO with Cl2O2 isomers. J Chem Phys 134:054307
Acknowledgements
This study was funded by DCA Consultants Ltd.
Author information
Authors and Affiliations
Corresponding author
Additional information
Publisher’s Note
Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.
Rights and permissions
Open Access This article is distributed under the terms of the Creative Commons Attribution 4.0 International License (http://creativecommons.org/licenses/by/4.0/), which permits unrestricted use, distribution, and reproduction in any medium, provided you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license, and indicate if changes were made.
About this article
Cite this article
Antia, D.D.J. ZVI (Fe0) desalination: catalytic partial desalination of saline aquifers. Appl Water Sci 8, 71 (2018). https://doi.org/10.1007/s13201-018-0702-1
Received:
Accepted:
Published:
DOI: https://doi.org/10.1007/s13201-018-0702-1