Determination of point of zero charge of natural organic materials
This study evaluates different methods to determine points of zero charge (PZCs) on five organic materials, namely maple sawdust, wood ash, peat moss, compost, and brown algae, used for the passive treatment of contaminated neutral drainage effluents. The PZC provides important information about metal sorption mechanisms. Three methods were used: (1) the salt addition method, measuring the PZC; (2) the zeta potential method, measuring the isoelectric point (IEP); (3) the ion adsorption method, measuring the point of zero net charge (PZNC). Natural kaolinite and synthetic goethite were also tested with both the salt addition and the ion adsorption methods in order to validate experimental protocols. Results obtained from the salt addition method in 0.05 M NaNO3 were the following: 4.72 ± 0.06 (maple sawdust), 9.50 ± 0.07 (wood ash), 3.42 ± 0.03 (peat moss), 7.68 ± 0.01 (green compost), and 6.06 ± 0.11 (brown algae). Both the ion adsorption and the zeta potential methods failed to give points of zero charge for these substrates. The PZC of kaolinite (3.01 ± 0.03) was similar to the PZNC (2.9–3.4) and fell within the range of values reported in the literature (2.7–4.1). As for the goethite, the PZC (10.9 ± 0.05) was slightly higher than the PZNC (9.0–9.4). The salt addition method has been found appropriate and convenient to determine the PZC of natural organic substrates.
KeywordsPoint of zero charge Point of zero net charge Isoelectric point Salt addition method Ion adsorption method Cation exchange capacity Zeta potential Organic materials
This study was funded by the NSERC (Natural Sciences and Engineering Research Council of Canada), grant no. 469489-14, and the industrial partners of the RIME UQAT-Polytechnique Montreal, including Agnico Eagle, Mine Canadian Malartic, Iamgold, Raglan Mine Glencore, and Rio Tinto.
Compliance with ethical standards
Conflict of interest
The authors declare that they have no conflict of interest.
- Anderson MA, Rubin AJ (1981) Adsorption of inorganic at solid liquid interfaces, Chapter 1. Ann Arbor Science Publishers, Ann Arbor, pp 91–160Google Scholar
- Chapman HD (1965) Cation-exchange capacity. In: Black CA, Evans DD, White JL, Ensminger LE, Clark FE (eds) Methods of soil analysis. Part 1.Agronomy monograph 9. ASA, Madison, pp 891–901Google Scholar
- Fernandez M M L, Meijer E L, Buurman P (1990) Variable charge in natural multi-component systems: line instead of point of zero charge, blocking effects. Proceedings of the 14th International Congress. Soil science, Kyoto, JapanGoogle Scholar
- Gallez A, Juo A, Herbillon A (1976) Surface and charge characteristics of selected soils in the tropics. Soil Sci Soc Am J 40(4):601–608. https://doi.org/10.2136/sssaj1976.03615995004000040039x CrossRefGoogle Scholar
- Knappe DRU, Belk RC, Briley DS, Gandy SR, Rastogi N, Rike AH, Glasgow H, Hannon E, Frazier WD, Kohl P, Pugsley S (2004) Algae detection and removal strategies for drinking water treatment plants. AWWA Research Foundation and the Water Resources Research Institute, American Water Works Association, Denver, p 466Google Scholar
- Kyziol-Komosinska J, Barba F, Callejas P, Rosik-Dulewska C (2010) Beidellite and other natural low-cost sorbent to remove chromium and cadmium from water and wastewater. Bol Soc Esp de Ceram V 49(2):121–128Google Scholar
- Lim LBL, Priyantha N, Tennakoon DTB, Hei C, Bandara C (2013) Sorption characteristics of peat of Brunei Darussalam I: characterization of peat and adsorption equilibrium studies of methylene blue—peat interactions. Ceylon J Sci 17:41–51Google Scholar
- Marcano-Martinez E, McBride MB (1989) Comparison of the titration and ion adsorption methods for surface charge measurement in oxisols. Soil Sci Soc Am J 53(4):1040–1045. https://doi.org/10.2136/sssaj1989.03615995005300040009x CrossRefGoogle Scholar
- Maurya R, Ghosh T, Paliwal C, Shrivastav A, Chokshi K, Pancha I, Ghosh A, Mishra S (2014) Biosorption of methylene blue by de-oiled algal biomass: equilibrium, kinetics and artificial neural network modelling. PLoS One 9(10):e109545. https://doi.org/10.1371/journal.pone.0109545 CrossRefGoogle Scholar
- Meijer EL, Buurman P (1987) Salt effect in a multi-component variable charge system: curve of zero salt effect, registered in a pH-stat. J Soil Sci 38(2):239–244. https://doi.org/10.1111/j.1365-2389.1987.tb02141.x CrossRefGoogle Scholar
- Mott CJB (1981) Anion and ligand exchange. In: Greenland DJ, Hayes MHB (eds) The chemistry of soil processes. JohnWiley & Sons, pp 179–219Google Scholar
- Sing J, Mishra NS, Uma, Banerjee S, Sharma YC (2011) Comparative studies of physical characteristics of raw and modified sawdust for their use as adsorbents for removal of acid dye. BioResources 6(3):2732–2743Google Scholar
- Sposito G (1981) The operational definition of the zero-point of charge in soils. Soil Sci Soc Am J 45(2):292–297. https://doi.org/10.2136/sssaj1981.03615995004500020013x CrossRefGoogle Scholar
- Sposito G (2008) The chemistry of soils, 2nd edn. Oxford University Press, New YorkGoogle Scholar
- Stumm W, Morgan JJ (1996) Aquatic chemistry, chemical equilibria and rates in natural waters, 3rd edn. John Wiley & Sons, Inc., New York, p 1022Google Scholar
- Unuabonah EI, Adebowale KO, Olu-Owolabi BI, Yang LZ, Kong LX (2008) Adsorption of Pb (II) and Cd (II) from aqueous solutions onto sodium tetraborate-modified kaolinite clay: equilibrium and thermodynamic studies. Hydrometallurgy 93(1-2):1–9. https://doi.org/10.1016/j.hydromet.2008.02.009 CrossRefGoogle Scholar
- Zelazny LW, He L, Vanwormhoudt A (1996) Charge analysis of soils and anion exchange. In: Sparks DL, Page AL, Helmke PA, Loeppert RH, Soltanpour PN, Tabatabai MA, Johnson CT, Sumer ME (eds) Methods of soil analysis: chemical methods. SSSA, Madison, pp 1231–1253Google Scholar