改性Zr-Na/Zeolite双功能沸石脱除水溶液中氨氮和磷性能研究

采用氯化钠离子交换和氯氧化锆沉积沉淀两步法改性天然沸石，得到具有脱除水中氨氮和磷的双功能锆钠改性天然沸石（Zr-Na/Zeolite），考察了不同pH、溶液初始质量浓度和温度下Zr-Na/Zeolite对氨氮溶液、含磷溶液及氮磷共存溶液的吸附情况。结果表明，Zr-Na/Zeolite能够在保持Na改性沸石（Na/Zeolite）优良的吸附氨氮性能的基础上，极大地提高吸附磷的能力。在不同pH下，Zr-Na/Zeolite 吸附氨氮和磷的效果呈现不同的规律。对于氨氮，水溶液pH在4~8时具有最佳吸附性能，最高吸附量达到4.5 mg/g。对于含磷阴离子，脱磷能力随pH的升高而降低，吸附容量从pH=2时的4.71 mg/g降到pH=10时的2.20 mg/g。溶液初始质量浓度从10 mg/L提高到200 mg/L时，氨氮和磷的单位吸附容量分别从1.42和2.46 mg/g提高到11.6和11.8 mg/g，去除率分别从57.0%和98.2%降低到23.2%和23.6%。溶液温度从25 ℃升高到45 ℃，氨氮的吸附容量提高了10%，磷的吸附容量提高了11%。磷和氨氮的吸附过程符合准二级动力学模型。0.1 mol/L NaOH和1.0 mol/L NaCl混合溶液可以再生Zr-Na/Zeolite，循环吸附14次，吸附效率几乎保持不变。

Study on Removal of Ammonium and Phosphate from aqueous solution by Dual-Functional Zr-Na Modified Zeolite

Sodium and Zirconium modified zeolite (Zr-Na/Zeolite) was made through ion exchange with Na+ and deposition of zirconium hydroxide. Removal of ammonium and/or phosphate from aqueous solution containing ammonium, phosphate, and ammonium& phosphate by Zr-Na /Zeolite under different pH value, initial mass concentration and temperature was investigated. Results showed that the Zr-Na /Zeolite had a significant enhancement on phosphate adsorption while kept good ammonium adsorption efficiency compared with Na /Zeolite. The initial pH of the solution had a difference influence to the adsorption efficiency of ammonium and phosphate. The ammonium adsorption performance was relatively high at pH 4-8 and the maximum adsorption capacity was 4.5 mg/g. The phosphate adsorption performance decreased gradually with the increasing of pH. When the pH value changed from 2 to 10, the adsorption capacity decreased from 4.71 mg/g to 2.20 mg/g. When the initial concentration changed from 10 mg/L to 200 mg/L, the amount of adsorbed ammonium and phosphate increased from 1.42 mg/g to 11.6 mg/g and 2.46 mg/g to 11.8 mg/g, while the removal rate decreased from 57.0% to 23.2% and 98.2% to 23.6%, respectively. When the temperature of solution increased from 25 °C to 45 °C, the adsorption capacity of ammonia nitrogen increased by 10%, and the adsorption capacity of phosphorus increased by 11%. The adsorption procedure was suitable to be described by pseudo-second-order equation. The effective desorption of ammonium and phosphate on modified zeolite could be achieved using a 0.1 mol/L NaOH and 1.0 mol/L NaCl mixed solution and the regenerated modified zeolite almost kept the adsorption efficiency on phosphate within 14 cycle times.