Xiaolin Li, Yili Wang, Junyi Li, Shuoxun Dong, Haotian Hao, Chenyang Liu, Yao Tong, Yanqing Zhou
The Science of the total environment 2021 Dec 15Phosphate is an important factor for the occurrence of surface water eutrophication, and is also a non-renewable resource which faces a potential depletion crisis. In this study, La(OH)3 loaded magnetic cationic hydrogel composite MCH-La(OH)3-EW was used to absorb low strength phosphate in simulated water and real water. The adsorption amount of MCH-La(OH)3-EW was 39.14 ± 0.31 mg P/g and the equilibrium time was 120 min at the initial phosphate concentration of 2.0 mg P/L. The adsorption process was a spontaneous endothermic reaction. MCH-La(OH)3-EW exhibited a high selectivity towards phosphate within pH of 4.0-10.0 or in the presence of co-existing ions (including Cl-, SO42-, NO3-, HCO3-, SiO32-) and humic acid. After 10 cycles of adsorption-desorption, the adsorption amount of regenerated MCH-La(OH)3-EW still remained at 63.4% of its maximum value. For the real water sample with phosphate concentration of 2.0 mg P/L, the phosphate removal efficiency could achieve 97.65-98.90% and the effluent turbidity was 2.10-4.27 NTU at the MCH-La(OH)3-EW dosage of 0.04 g/L. The adsorption mechanism analysis showed that both quaternary amine groups (-N+(CH3)3) and La(OH)3 of MCH-La(OH)3-EW were involved in the process of phosphate adsorption. The electrostatic interaction between phosphate and -N+(CH3)3 rapidly occurred at the initial stage of adsorption process, then the electrostatic absorbed phosphate migrated to La(OH)3 on the surface of MCH-La(OH)3-EW via ligand exchange to form inner-sphere complex. This phenomenon was conducive to phosphate adsorption kinetics by MCH-La(OH)3-EW. Copyright © 2021 Elsevier B.V. All rights reserved.
Xiaolin Li, Yili Wang, Junyi Li, Shuoxun Dong, Haotian Hao, Chenyang Liu, Yao Tong, Yanqing Zhou. Rapid and selective harvest of low-concentration phosphate by La(OH)3 loaded magnetic cationic hydrogel from aqueous solution: Surface migration of phosphate from -N+(CH3)3 to La(OH)3. The Science of the total environment. 2021 Dec 15;800:149418
PMID: 34426305
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