Abstract:The adsorption of phosphate and ammonium from aqueous solution on zirconium modified zeolite (ZrMZ) was investigated using batch experiments. ZrMZ was effective for phosphate and ammonium removal from aqueous solution. The adsorption kinetics data of phosphate and ammonium on ZrMZ could be well described by a pseudo-second-order model. The adsorption equilibrium data of phosphate on ZrMZ fitted well to the Langmuir, Freundlich and Dubinin–Radushkevich (D–R) isotherm models. The adsorption equilibrium data of ammonium onto ZrMZ fitted better to the Langmuir isotherm model than the Freundlich and D-R isotherm models. Based on the Langmuir isotherm, the maximum monolayer phosphate and ammonium adsorption capacities for ZrMZ were 26.2 and 7.82 mg/g at 303 K, respectively. Thermodynamic parameters showed that the adsorption of phosphate on ZrMZ was spontaneous and endothermic in nature. The phosphate adsorption capacity for ZrMZ decreased with increasing pH from 3 to 12. The ammonium adsorption capacity for ZrMZ was relatively high at pH 4~8, and decreased with increasing pH from 8 to 12 or with decreasing pH from 4 to 3. The presence of Cl-, SO42- , HCO3- and NO3- in aqueous solution had a slight effect on phosphate adsorption onto ZrMZ, while coexisting SiO32- reduced the phosphate adsorption capacity for ZrMZ. The presence of Ca2+ and Mg2+ had a slight effect on ammonium adsorption onto ZrMZ, while coexisting Na+ and K+ reduced the ammonium adsorption capacity for ZrMZ. The mechanism for phosphate adsorption onto ZrMZ was ligand exchange. The mechanism for ammonium adsorption into ZrMZ was cation exchange.
林建伟, 詹艳慧, 陆霞. 锆改性沸石对水中磷酸盐和铵的吸附特性[J]. 中国环境科学, 2012, 32(11): 2023-2031.
LIN Jian-Wei, ZHAN Yan-Hui, LU Xia. Adsorption of phosphate and ammonium from aqueous solution on zirconium modified zeolite.. CHINA ENVIRONMENTAL SCIENCECE, 2012, 32(11): 2023-2031.