An functional magnetic and carbon-based adsorbent, noted as Fe3O4@HTC-NaOH, was synthesized by hydrothermal and NaOH treatment processing. The results of FT-IR spectrum and ξ-potential showed the surface of Fe3O4@HTC-NaOH existed losts of f-lactonic and sodium carboxylic acid (COONa) groups and was relatively negative. The U(VI) adsorption capacities onto the Fe3O4@HTC-NaOH reached the maximum of 761.20 mg/g, showing a high efficiency for removal U(VI) from polluted water. In addition, the adsorption products can be readily separated from contaminated solutions using a magnet. The results indicated that Fe3O4@HTC-NaOH possessed potential application in the remediation of uranium polluted water and soil.
Though the rapid development of nuclear energy was able to effectively relieve the energy shortages caused by excessively using fossile fuels in the past for a long time, it was likely to bring some problems such as environmental pollution and human health due to nuclide radiotoxicity and chemical toxicity [1,2,3,4,5,6,7,8,9]. Therefore the removal of radionuclides from the environment was extensively paid attention all over the world. Until now, a great deal of methods such as solvent extraction, chemical precipitation, adsorption, ion-exchange, washing techniques and so on were used to treat uranium wasted water and soil [2, 3, 5, 10,11,12,13,14,15]. Among the above methods, adsorption has been widely employed as a result of its economy, high efficiency and simple operation [16,17,18].
The common sorbents were classified into carbon-based materials (activated carbon, mesoporous carbon, hydrothermal carbon, grapheme and so on), oxide materials (alumina, molecular sieve, clay, and so on), nano zero valent iron (NZVI) and polymers [19,20,21,22,23,24,25,26,27]. The carbon-based sorbent was preferred to be the candidate to treat nuclear waste because of its good radiation resistance, thermo-stability, and acid–base resistance properties [28,29,30,31]. Among the carbon-based materials, hydrothermal carbon possessed various merits such as synthesis easy, carbon source readily available, low environmental pollution and high production rate [30, 32]. In addition, many oxygen-containing functional groups existed on the surface of hydrothermal carbon spheres, were so easily modified that the adsorption ability to U(VI) was greatly enhanced. For example, the (bis-3,4-dihydroxybenzy)p-phenylen diamine-grafted hydrothermal carbon reported by our team previously possessed good uranium adsorption property and its maximal adsorption capacity reached 272 mg/g . The possible adsorption mechanism could be explained that uranium was coordinated with oxygen-containing and nitrogen-containing groups which were grafted on the surface of modified hydrothermal carbon. The surface area and activated sites are not only effect factors for adsorption properties, but also the hydrophilic of the sorbent surface. For this reason, Zhou has synthesized carboxyl-functional hydrothermal carbon spheres under low temperature (573.15 K) condition to enhance the surface hydrophilicity of sorbent for reduction of interface resistance between uranium and sorbent at aqueous solution . The results showed that U(VI) sorption capacity was increased from 55.0 to 179.95 mg/g after oxidized at 573.15 K for 5 h and the uranium removal selectivity was improved after heat-treatment in the presence of co-existing ions: Na+, Ni2+, Sr2+, Mn2+, Mg2+, and Zn2+. Moreover, Yang et al.  has prepared amidoxime-functionalized hydrothermal carbon material (HTC-AO), possess high adsorption capacity (1.30 mmol/L) and very high uranium selectivity (0.42 mmol/g), for removal of uranium from water. Those results showed that both surface oxidation and functionalization technologies have facilitated the uranium adsorption property of hydrothermal carbon sorbent.
The separation of adsorbent from polluted water, however, existed some problems such as operation complex and time-consuming. For these reason, a simple magnetic separation technique was proposed in solid–liquid phase separation due to its fast and highly efficiency . Das et al.  had testified the sorption of U(VI) on magnetic Fe3O4 particles, but the adsorption capacities were relative small. Therefore, Fe3O4 particles were usually modified with other materials to extend their applications. For example, So many reports proved that uranium could be adsorbed onto the surface of magnetic composed-materials (Fe3O4-composed materials), but the sorption capacity is very poor: 52 mg/g, 252 mg/g, 10.5 mg/g and 151.80 mg/g [37,38,39,40]. Zhang et al.  had synthesized a Fe3O4@C@layered double hydroxide composite (Fe3O4@C@Ni–Al LDH) by two-step layer-by-layer method for uranium extraction from aqueous solution (maximum adsorption capacity reached 174 mg/g). Mohamed E Mahmoud had synthesized magnetic sorbent successfully by surface encapsulation way for treating industrial wastewater containing Pb(II) and Cd(II) . Lately, Mohamed E Mahmoud’s group had created a new magnetic sorbent (Nano-Fe3O4-Urea-AC) for extraction of uranium from aqueous solution . However, Fe3O4 particles complexed with modified hydrothermal carbon is seldom reported until now.
Therefore, this work prepared a novel magnetic-based sorbent (Fe3O4@HTC-NaOH) for removal of uranium from the environment. The hydrothermal process was used to obtain Fe3O4-based material, and then it was modified by the way of NaOH treatment to improve sorption capacity and to ensure the integrity of the magnetic core. The structure and surface property were characterized by fourier transform infrared spectrum (FT-IR) and ζ-potential respectively. The uranium adsorption properties of Fe3O4@HTC-NaOH were investigated by batch experiments, including the effect of pH, contact time and temperature, initial U(VI) concentration as well as adsorption kinetics isotherm models and thermodynamics. The recycle experiment, adsorption mechanism and column test were also explored.
Chemicals and reagents
All used chemicals were analytical grade (AR) without further purification. For the preparation of 10 mg/mL uranium stock solution, 11.794 g U3O8 was put in a 100 mL beaker, and 5 mL HNO3 (65 wt%) and 5 mL H2O2 (36.5 wt%) were added. The solution was heated to wet salt shape then 10 mL HNO3 (65 wt%) was added. The solution was transferred to a 1 L flask. The required uranium solution was diluted by distilled water.
Synthesis of functional magnetic Fe3O4@HTC-NaOH
The preparation process of Fe3O4@HTC-NaOH was shown in Fig. 1. Firstly, the synthesis of Fe3O4 micro-particles was refered as the previous report . Then the Fe3O4 microparticle of 0.4 g was dispersed into 50 mL distilled water which contained 6.67 g sucrose and sonicated for 0.5 h. Subsequently, the mixture was transferred into Teflon-lined stainless-steel autoclave and heated to 453.15 K for 16 h. The obtained black product (Fe3O4@HTC) was rinsed with distilled water and ethanol, and then dried at 328.15 K. Furthermore, 0.2 g Fe3O4@HTC was added into 100 mL flask that contained 50 mL 1 M sodium hydroxide solution, and then refluxed for 4 h. Finally, the materials were washed with distilled water and noted as Fe3O4@HTC-NaOH.
The chemical structures and surface properties of Fe3O4@HTC-NaOH and Fe3O4@HTC-NaOH-U were determined by FTS-65A infrared spectroscopy (Bio-rad, USA). Moreover, the surface electronegativities of obtained materials were measures by ξ-potential mater (Stabino PMX 400, microtrac, USA).
0.01 g Fe3O4@HTC-NaOH spheres were added to 100 mL uranium solution (50 mg/L) and shacked for a while, and then the solution concentration were measured by spectrophotometry using arsenazo III as indicator before and after adsorption. The uranium adsorption capacity was calculated by Eq. (1) :
where qm, C0, Ce, m and V were the adsorption capacity (mg/g), uranium concentration in the initial solution (mg/L), uranium concentration in the equilibrium solution (mg/L), the adsorbent mass (g) and volume of initial uranium solution (L), respectively.
Results and discussion
The FT-IR spectroscopy results of Fe3O4@HTC and Fe3O4@HTC-NaOH were presented in Fig. 2 On the one hand, it was seen from curve a of Fig. 1 that three peaks at 580 cm−1, 1700 cm−1 and 1600 cm−1 were attributed to –Fe–O–, –C=O– and –C=C– stretching vibrations [43, 44], respectively. The result revealed that the material of Fe3O4@HTC was successfully synthesized and the surface of Fe3O4@HTC had been partially carbonized by hydrothermal treatment. On the other hand, as shown in curve b of Fig. 2, the peak of Fe–O stretching vibration was still existed, which elucidated the structure of Fe3O4 microparticle was not destroyed in the NaOH treatment. Besides, two new peaks at 1595 cm−1 and 1410 cm−1 assigned to the stretching vibrations of –COONa and f-lactonic were detected in the material of Fe3O4@HTC-NaOH . These results illustrated that the oxygen-containing functional groups of Fe3O4@HTC greatly increased after NaOH treatment. Therefore, it was speculated that the hydrophilicity of Fe3O4@HTC-NaOH was better than that of Fe3O4@HTC, which probably promoted the U(VI) adsorption.
The surface electronegativity of sorbent was another important effect factor to U(VI) adsorption. For this reason, ζ-potential was indeed used to characterize the electronegativity of materials. The ζ-potentials of HTC and Fe3O4@HTC-NaOH were shown in Fig. 3. It was seen that at low pH values, large numbers of H+ attached to the material surface probably caused positive surface potential. With pH value increasing, the concentration of H+ gradually decreased and the surface potential became more and more negative. The isoelectric point of Fe3O4@HTC-NaOH at pH 2.2 was lower than that of HTC at pH 3.6 as a result of more –COONa and f-lactone groups locating on the surface of Fe3O4@HTC-NaOH. It can be inferred that the negatively charged Fe3O4@HTC-NaOH was easily combined to the positively charged UO22+ cations.
U(VI) adsorption on the Fe3O4@HTC-NaOH
The influence of pH
The initial pH has a great influence on uranium species distribution and surface electronegativity of absorbent. The effect of pH on the U(VI) on Fe3O4@HTC-NaOH was presented in Fig. 4. There were two stages for U(VI) adsorption on Fe3O4@HTC-NaOH. Firstly, the U(VI)adsorption capacity was increased from 98.11 to 451.30 mg/g (maximum) with pH value increasing from 3.0 to 5.5. The possible explanation was that at low pH, the high concentration of H3O+ might occupy the adsorption site of absorbent, causing the prevention of U(VI) adsorption on Fe3O4@HTC-NaOH. Subsequently, the concentration of H3O+ was gradually decreased at high pH, leading to the gradual increase of U(VI) adsorption capacity on Fe3O4@HTC-NaOH. Secondly, the U(VI) adsorption capacity was gradually decreased with pH value further increasing. It was guessed that the negatively charged uranium species such as UO2(OH)53− and UO2(OH)75− were easily generated at high pH, which were repelled with a negative surface of Fe3O4@HTC-NaOH resulted in a decrease of U(VI) adsorption capacity . Therefore, further experiments were conducted at the optimal pH of 5.5.
The effect of contact time and adsorption kinetics
The effect of contact time on the adsorption of U(VI) onto Fe3O4@HTC-NaOH was investigated to determine the kinetic process and the result shown in Fig. 5. It was obviously observed that the U(VI) adsorption capacity rapidly increased within 50 min and then slowly increased until equilibrium was reached at 200 min. The fast adsorption was due to the adsorption sites of Fe3O4@HTC-NaOH unoccupied at initial stage and U(VI) was easily complexed with those sites. As the adsorption continuously proceeding, both of the U(VI) concentration and adsorption sites were gradually reduced, resulting in a slow increase of U(VI) adsorption capacity until saturation.
To investigate the adsorption mechanism of U(VI)onto Fe3O4@HTC-NaOH, two adsorption kinetic models (Pseudo-first-order and Pseudo-second-order) were used to fit the experimental datas. The linear express of the models were listed in following Eqs. (2) and (3) [19, 47]:
where qe (mg/g) and qt (mg/g) are U(VI) adsorption capacity at equilibrium and at time t, respectively; k1 (min−1) and k2 (g/mg/min) are the equilibrium rate constants of Pseudo-first-order model and Pseudo-second-order model, respectively.
The parameters of Pseudo-first-order and Pseudo-second-order kinetic models could be directly obtained from intercepts and slopes shown in Figs. 6 and 7, and the result listed in Table 1. It was clearly seen from Table 1 that the R2-of Pseudo-second-order kinetic was much higher than that of Pseudo-first-order kinetic model. Moreover, the calculated adsorption capacity using Pseudo-second-order-kinetic model (494.26 mg/g) was more closed to the experimental value (451.3 mg/g) in comparison with that using Pseudo-first-order kinetic model. These results suggested that the U(VI) adsorption onto Fe3O4@HTC-NaOH was controlled by a chemical process.
The effect of temperature
The temperature of the experimental system was also a critical factor for U(VI) adsorption. The effect of temperature on the U(VI) sorption on the Fe3O4@HTC-NaOH was shown in Fig. 8. The value of Qe was increased from 406.20 to 465.70 mg/g with increasing temperature from 283.15 to 308.15 K, which suggested that high temperature was beneficial to U(VI) adsorption onto the surface of Fe3O4@HTC-NaOH. Furthermore, the thermodynamic behavior of U(VI) adsorbed onto Fe3O4@HTC-NaOH was investigated. The standard enthalpy change (ΔH) and standard entropy change (ΔS) can be calculated as Eqs. (4) and (5) [19, 47]:
where Kd is the distribution coefficient (mL/g), T and R are the absolute temperature (K) and the gas constant (8.314 J/mol/K), respectively. The values of ΔH and ΔS were derived from the slop and intercept of the curves of lnKd versus T−1 (Fig. 9).
The thermodynamic parameters of ΔH, ΔS and ΔG were listed in Table 2, the positive value of ΔS (165.96 J/mol/K) suggest that the adsorption process is irreversible and the randomness at the solid-solution interface during the adsorption process was increased. The ΔH (21.86 kJ/mol) > 0 and ΔG < 0 under all test condition testified that the process of U(VI) adsorption onto Fe3O4@HTC-NaOH was spontaneous and endothermic. Moreover, the more negative value of ΔG at higher temperature indicated that the bonding between U(VI) and active sites on Fe3O4@HTC-NaOH were more stable and the U(VI) adsorption process was favored at higher temperatures . In summary, the thermodynamic results proved that the adsorption process of U(VI) onto Fe3O4@HTC-NaOH was irreversible, spontaneous and endothermic.
The effect of initial uranium concentration on adsorption
The effect of various initial U(VI) concentrations on the adsorption capacity of Fe3O4@HTC-NaOH and the comparison of uranium adsorption capacity with different sorbents were illustrated in Fig. 10 and Table 3, respectively. As was shown in Fig. 10, the U(VI) adsorption capacity increased from 63.9 to 761.20 mg/g with an increase of initial uranium concentration and reached equilibrium (761.20 mg/g) at 100 mg/L of U(VI) concentration. The possible reason was that the driving force was enhanced at the high initial uranium concentration to overcome the mass transfer resistance between the aqueous phase and solid phase.
The comparison of uranium equilibrium adsorption capacity with previous magnetic materials were listed in Table 3. Fe3O4@HTC-NaOH not just possess maximum equilibrium adsorption capacity, but also the preparation method is simplest. Therefore, Fe3O4@HTC-NaOH could be a very economical sorbent for reparation of uranium contaminated soil and water.
In order to investigate the U(VI) adsorption onto The Fe3O4@HTC-NaOH, two adsorption isothermal models (Langmuir and Freundlich) were used to fit the experiments data. The Langmuir model was based on the theory of monolayer adsorption. However, the theory of muti-layer adsorption was the dominant basis of the Freundlich model. The mathematical expressions of the two models were presented as Eqs. (6) and (7) [1, 19]:
where qe, Ce (mg/L) and qm are equilibrium adsorption capacity, uranium concentration in solution after adsorbed and maximum fitted adsorption capacity (mg/g) , respectively. KL was the constant associated with adsorption energy, and the value of KL is increased with increasing of adsorption affinity; KF and n are the constants of adsorption capacity and adsorption strength, respectively.
As can be seen from the Table 4, the value of R2 of Langmuir isothermal model is greater than that of the Freundlich isothermal model. Meanwhile, the qm (813.01 mg/g) of Langmuir isothermal model is better fitted to experimental value (761.20 mg/g). These results confirmed that the uranium adsorbed onto Fe3O4@HTC-NaOH is monolayer adsorption.
The reusable was one of the most important indicators for sorbent. 0.5 M HNO3 was used as eluent to study the reusable properties of Fe3O4@HTC-NaOH and the result was showed in Fig. 13. The equilibrium adsorption capacity slowly decreased as the number of cycle increased. After five-cycles, the adsorption capacity still reached 251 mg/g, indicating that Fe3O4@HTC-NaOH could be taken as a candidate material to recover U(VI) from water.
The adsorption mechanism
The adsorption mechanism of Fe3O4@HTC-NaOH-U was researched by FT-IR spectroscopy, as was shown in Fig. 14. It was seen from curve c that the peaks at 1595 cm−1 and 1410 cm−1 were disappeared and a new peak appeared in 917 cm−1 assigned to O=U=O stretching vibration compared to Fe3O4@HTC-NaOH showed in curve b. Based on the above result, it was inferred that the uranium was adsorbed onto Fe3O4@HTC-NaOH by coordinating with O atom of COONa and f-lactonic groups as was presented in Fig. 15.
1 L of simulated uranium-polluted water containing 20 mg uranium, 1 mmol CO32− and 0.25 mmol Ca2+ were used to column test. As was shown in Fig. 16a and b, four columns (I, II, III and IV) were used once only, and all of columns were fixed with 0.1gFe3O4@HTC-NaOH. The simulated uranium-polluted water (the pH values were fixed at 6.5, 7.0, 7.5 and 8.0 respectively) was pumped from beaker to four columns, and the effluents were collected every 20 mL with a test tube. The uranium concentrations of all effluents were detected by spectrophotometer. The results of column test based on different pH value were shown in Fig. 17. Besides, the distribution of uranium species in the simulated solution (c(U) = 20 mg/L, c(Ca) = 0.25 mmol/L, c(CO32−) = 1 mmol/L) at different pH value was shown in Fig. 18. As was seen in Fig. 18, UO2CO3(OH)3−, CaUO2(CO3)32−, UO2(CO3)34−, Ca2UO2(CO3)3(aq), UO2(CO3)22− and UO2CO3(aq) were main species under pH range from 6.0 to 8.5.
The volume of breakthrough point were decreased with an increase of pH value. This phenomenon could be explained that the electrostatic repulsion between sorbent and divalent and trivalent ions higher than univalent ions. The concentration of (UO2)2CO3(OH)3−is decreased when pH values exceed 6.5, on the contrary, the concentration of CaUO2(CO3)32− was increased obviously at the same state that brings about decreasing of breakthrough point volume. In addition, the distribution of UO2(CO3)22−, UO2(CO3)34− and UO2CO3(aq) are very low compared to (UO2)2CO3(OH)3−, CaUO2(CO3)32− and Ca2UO2(CO3)3(aq), so they could not be the dominant control species. (UO2)2CO3(OH)3− and CaUO2(CO3)32− might be the most important effect factors on uranium removal from the environment (Fig. 18).
In this paper, the economical magnetic sorbent Fe3O4@HTC-NaOH with ultra-high uranium adsorption capacity was synthesized successfully by hydrothermal process and NaOH treatment. The chemical structure and surface potential of Fe3O4@HTC-NaOH characterized by the FT-IR and ζ-potential. Show that after Fe3O4@HTC treating with NaOH solution, the magnetic core was still existed and large numbers of -COONa and f-lactonic groups were formed on the surface of Fe3O4@HTC-NaOH. Besides, the isoelectric point of Fe3O4@HTC-NaOH at pH 2.2 was lower than that of HTC at pH 3.6. The batch experiments were conducted to study uranium adsorption properties of Fe3O4@HTC-NaOH. The results indicated that Fe3O4@HTC-NaOH reached the maximal U(VI) sorption capacity of 761.20 mg/g at initial pH and U(VI) concentration of 5.5 and 100 mg/L and contact time of 200 min. And the U(VI) adsorption behavior onto Fe3O4@HTC-NaOH was better fitted to Pseudo-second-order model and Langmuir isothermal model. The thermodynamic result confirmed that the uranium adsorption process onto Fe3O4@HTC-NaOH was spontaneous and endothermic. Moreover, after five cycles experiment, the uranium adsorption capacity still contained 301 mg/g. The column test illustrated that Fe3O4@HTC-NaOH still owned good uranium removal efficiency under continuous dynamic process. Final, the adsorption mechanism was likely that U(VI) was coordinated with O atom of COONa and f-lactonic groups. All in all, the above results implied that Fe3O4@HTC-NaOH possessed potential application in the remediation of uranium wasted water (underground water and surface water) and polluted soil.
Abdeen Z, Akl ZF (2015) Uranium(VI) adsorption from aqueous solutions using poly(Vinyl Alcohol)/carbon nanotube composites. RSC Adv 5:74220–74229
Abney CW, Mayes RT, Saito T, Dai S (2017) Materials for the recovery of uranium from seawater. Chem Rev 117(23):13935–14013
Asselin S, Ingram JC (2014) Uranium leaching from contaminated soil utilizing rhamnolipid, edta, and citric acid. Appl Environ Soil Sci 2014:1–6
Banning A, Benfer M (2017) Drinking water uranium and potential health effects in the German Federal State of Bavaria. Int J Environ Res Public Health 14(8):927
Barrett CA, Chouyyok W, Speakman RJ, Olsen KB, Addleman RS (2017) Rapid extraction and assay of uranium from environmental surface samples. Talanta 173:69–78
Bem H, Bou-Rabee F (2004) Environmental and health consequences of depleted uranium use in the 1991 Gulf War. Environ Int 30:123–134
Bersimbaev RI, Bulgakova O (2015) The health effects of radon and uranium on the population of Kazakhstan. Genes Environ 37(1):18
Caccin Matteo, Giacobbo Francesca, Da Ros Mirko, Besozzi Luigi, Mariani Mario (2013) Adsorption of uranium, cesium and strontium onto coconut shell activated carbon. J Radioanal Nucl Chem 297:9–18
Cantaluppi C, Degetto S (2000) Civilian and military uses of depleted uranium: environmental and health problems. Ann Chim 90:665–676
Shim JW, Park SJ, Ryu SK (2001) Effect of modification with HNO3 and NaOH on metal adsorption by pitch-based activated carbon fibers. Carbon 39(11):1635–1642
Lu BQ, Li M, Zhang XW, Huang CM, Wu XY, Fang Q (2018) Immobilization of uranium into magnetite from aqueous solution by electrodepositing approach. J Hazard Mater 343:255–265
Mahmoud ME, Osman MM, Hafez OF, Elmelegy E (2010) Removal and Preconcentration of lead (II), copper (II), chromium (III) and iron (III) from Wastewaters by surface developed alumina adsorbents with immobilized 1-nitroso-2-naphthol. J Hazard Mater 173:349–357
Saleh Tawfik A, Naeemullah Mustafa Tuzen, Sarı Ahmet (2017) Polyethylenimine modified activated carbon as novel magnetic adsorbent for the removal of uranium from aqueous solution. Chem Eng Res Des 117:218–227
Shao Dadong, Wang Xiangxue, Li Jiaxing, Huang Yongshun, Ren Xuemei, Hou Guangshun, Wang Xiangke (2015) Reductive immobilization of uranium by Paam–Fes/Fe3o4 Magnetic composites. Environ Sci Water Res Technol 1:169–176
Singhal P, Jha SK, Pandey SP, Neogy S (2017) Rapid extraction of uranium from sea water using Fe3o4 and humic acid coated Fe3o4 nanoparticles. J Hazard Mater 335:152–161
Kim J, Tsouris C, Mayes RT, Oyola Y, Saito T, Janke CJ, Dai S, Schneider E, Sachde D (2013) Recovery of uranium from seawater: a review of current status and future research needs. Sep Sci Technol 48:367–387
Nekhunguni PM, Tavengwa NT, Tutu H (2017) Sorption of uranium(VI) onto hydrous ferric oxide-modified zeolite: assessment of the effect of Ph, contact time, temperature, selected cations and anions on sorbent interactions. J Environ Manage 204:571–582
Rezaei A, Khani H, Masterifarahani M, Rofouei MK (2012) A novel extraction and preconcentration of ultra-trace levels of uranium ions in natural water samples using functionalized magnetic-nanoparticles prior to their determination by inductively coupled plasma-optical emission spectrometry. Anal Methods 4(12):4107–4114
Lai Z, Zhang Z, Cao X, Dai Y, Hua R, Le Z, Luo M, Liu Y (2016) Synthesis of novel functional hydrothermal carbon spheres for removal of uranium from aqueous solution. J Radioanal Nucl Chem 310:1335–1344
Han X, Wang Y, Cao X, Dai Y, Liu Y (2019) Adsorptive performance of ship-type nano-cage polyoxometalates for U(VI) in aqueous solution. Appl Surf Sci 484:1035–1040
Zhang Z, Dong Z, Wang X, Ying D (2018) Ordered mesoporous polymer–carbon composites containing amidoxime groups for uranium removal from aqueous solutions. Chem Eng J 341:208–217
Zhang Z, Liu J, Cao X, Luo X (2015) Comparison of U(VI) adsorption onto nanoscale zero-valent iron and red soil in the presence of U(VI)–CO3/Ca–U(VI)–CO3 complexes. J Hazard Mater 300:633–642
Ivanets AI, Shashkova IL, Kitikova NV, Drozdova NV, Saprunova NA, Radkecich AV, Ku’bitskaya LV (2014) Sorption of strontium ions from solutions onto calcium and magnesium phosphates. Radiochemistry 56(1):32–37
Ivanets AI, Prozorovich VG, Kouznetsova TF, Radkevich AV, Krivoshapkin PV, Krivoshapkina EF, Sillanpää M (2018) Sorption behavior of 85Sr onto manganese oxides with tunnel structure. J Radioanal Nucl Chem 316:673–683
Ivanets AI, Prozorovich VG, Kouznetsova TF, Radkevich AV, Zarubo AM (2016) Mesoporous manganese oxides prepared by sol-gel method: synthesis, characterization and sorption properties towards strontium ions. Environ Nanotechnol Monit Manag 6(Complete):S2215153216300897
Ivanets AI, Milutin VV, Prozorovich VG, Kouznetsova TF, Netrasova NA (2019) Adsorption properties of manganese oxides prepared in aqueous-ethanol medium toward Sr(II) ions. J Radioanal Nucl Chem 321:243–253
Kitikova NV, Ivanets AI, Shashkova IL, Radkevich AV, Shemet LV, Kulbitskaya LV, Sillanpää M et al (2017) Batch study of 85 Sr adsorption from synthetic seawater solutions using phosphate sorbents. J Radioanal Nucl Chem 8:1–11
Heinen AW, Peters JA, Bekkum HV (2000) Competitive adsorption of water and toluene on modified activated carbon supports. Appl Catal A Gen 194(99):193–202
Hritcu D, Humelnicu D, Dodi G, Popa MI (2012) Magnetic chitosan composite particles: evaluation of thorium and uranyl ion adsorption from aqueous solutions. Carbohydr Polym 87:1185–1191
Tan L, Liu Q, Jing X, Liu J, Song D, Songxia H, Liu L, Wang J (2015) Removal of uranium(VI) ions from aqueous solution by magnetic cobalt ferrite/multiwalled carbon nanotubes composites. Chem Eng J 273:307–315
Zhang X, Wang J, Li R, Dai Q, Gao R, Liu Q, Zhang M (2013) Preparation of Fe3o4@C@Layered double hydroxide composite for magnetic separation of uranium. Ind Eng Chem Res 52:10152–10159
Li ZJ, Huang ZW, Guo WL, Wang L, Zheng LR, Chai ZF, Shi WQ (2017) Enhanced photocatalytic removal of uranium(VI) from aqueous solution by magnetic Tio2/Fe3o4 and its graphene composite. Environ Sci Technol 51:5666–5674
Zhang Z, Dong Z, Wang X, Dai Y, Cao X, Wang Y (2019) Synthesis of ultralight phosphorylated carbon aerogel for efficient removal of U(VI): batch and fixed-bed column studies. Chem Eng J 370:1376–1387
Yang X, Li J, Liu J (2013) Simple small molecule carbon source strategy for synthesis of functional hydrothermal carbon: preparation of highly efficient uranium selective solid phase extractant. J Mater Chem A 2:1550–1559
Zhang X, Wang J, Li R, Dai Q, Liu L (2013) Removal of uranium(VI) from aqueous solutions by surface modified magnetic Fe3o4 particles. New J Chem 37:3914–3919
Das D, Sureshkumar MK, Koley S (2010) Sorption of uranium on magnetite nanoparticles. J Radioanal Nucl Chem 285(3):447–454
Gao Y, Yuan Y, Ma D, Li L, Li Y, Wenhui X, Tao Wei (2014) Removal of aqueous uranyl ions by magnetic functionalized carboxymethylcellulose and adsorption property investigation. J Nucl Mater 453:82–90
Lin J, Sun W, Desmarais J, Chen N, Feng R, Zhang P, Li D, Lieu A, Tse JS, Pan Y (2018) Uptake and speciation of uranium in synthetic gypsum (Caso4*2h2o): applications to radioactive mine tailings. J Environ Radioact 181:8–17
Song Q, Ma L, Liu J, Bai C, Geng J, Wang H, Li B, Wang L, Li S (2012) Preparation and adsorption performance of 5-azacytosine-functionalized hydrothermal carbon for selective solid-phase extraction of uranium. J Colloid Interface Sci 386:291–299
Zhou L, Zou H, Jin J, Liu Z, Luo T (2016) Preparation of phosphonic acid-functionalized silica magnetic microspheres for uranium(VI) adsorption from aqueous solutions. J Radioanal Nucl Chem 310(3):1155–1163
Mahmoud ME, Khalifa MA, El Wakeel YM, Header MS, Abdel-Fattah MT (2017) Engineered nano-magnetic iron oxide-urea-activated carbon nanolayer sorbent for potential removal of uranium (VI) from aqueous solution. J Nucl Mater 487:13–22
Meng F, Yuan G, Larson SL, Ballard JH, Waggoner CA, Arslan Z, Han FX (2017) Removing uranium (VI) from aqueous solution with insoluble humic acid derived from leonardite. J Environ Radioact 180:1–8
Jing C, Li YL, Landsberger S (2016) Review of soluble uranium removal by nanoscale zero valent iron. J Environ Radioact 164:65–72
Corlin L, Rock T, Cordova J, Woodin M, Durant JL, Gute DM, Ingram J, Brugge D (2016) Health effects and environmental justice concerns of exposure to uranium in drinking water. Curr Environ Health Rep 3:434–442
Elsayed AA (2008) Kinetics and thermodynamics of adsorption of trace amount of uranium on activated carbon. Radiochim Acta 96:481–486
Gopalan A, Philips MF, Jeong JH, Lee KP (2014) Synthesis of novel poly(amidoxime) grafted multiwall carbon nanotube gel and uranium adsorption. J Nanosci Nanotechnol 14(3):2451–2458
Fan FL, Qin Z, Bai J, Rong WD, Fan FY, Tian W, Wu XL, Wang Y, Zhao L (2012) Rapid removal of uranium from aqueous solutions using magnetic Fe3o4@Sio2 composite particles. J Environ Radioact 106:40–46
Chen L, Zhao D, Chen S, Wang X, Chen C (2016) One-step fabrication of amino functionalized magnetic graphene oxide composite for uranium(VI) removal. J Colloid Interface Sci 472:99–107
This work was financially supported by the National Natural Science Foundation of China (21561002, 21866004) and the Science & Technology Support Program of Jiangxi Province (Grant No. 2018ACB21007).
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Lai, Z., Xuan, Z., Yu, S. et al. Synthesis of magnetic-carbon sorbent for removal of U(VI) from aqueous solution. J Radioanal Nucl Chem 322, 2079–2089 (2019). https://doi.org/10.1007/s10967-019-06907-w
- Magnetic sorbents