天然沸石吸附低浓度氨氮废水的研究

采用浙江某地天然沸石吸附废水中低浓度氨氮,研究了pH、天然沸石投加量对吸附的影响,分析了吸附等温线和吸附动力学,并进行了动态吸附和脱附研究。结果表明,pH对天然沸石吸附有较大影响,吸附的最佳pH为8.0;随着天然沸石投加量的增加,氨氮的去除率逐渐增大,但吸附量随之减小。Freundlich方程比Langmuir方程更好地描述氨氮在天然沸石上的吸附行为,且此吸附是优惠吸附。假二级方程很好地拟合吸附动力学实验数据,吸附速率常数k2随着天然沸石投加量的增大而增大。装填105g天然沸石吸附柱处理含氨氮20mg/L废水的水量为15L,出水氨氮浓度小于5mg/L。用含氯化钠和氢氧化钠的溶液作为脱附剂,脱附率为95.5%。

Adsorption of Ammonium-nitrogen from Low Concentration Wastewater by Natural Zeolite

The natural zeolite in Zhejiang Province was used to adsorb ammonium-nitrogen from low concentration wastewater. Effects of pH and natural zeolite dose on the adsorption were studied,the adsorption isotherm and kinetics were analyzed,and dynamic adsorption and desorption were conducted. It was found that the adsorption amount significantly depends on pH,the adsorption amount at pH 8.0 is maximum. The adsorption removal rate increases with increasing natural zeolite dose,however,adsorption amount decreases with an increase in the dose. Freundlich equation is better than Langmuir equation in describing the behavior of adsorption NH3-N on natural zeolite,and the adsorption is favorable. The experimental data fit very well the pseudo-second-order kinetic model,and adsorption rate constant increases with increasing natural zeolite dose. 15 liters wastewater containing 20mg/L NH3-N can be treated by the adsorption column with 105g zeolite,and the concentration of NH3-N at the disposed wastewater is less than 5mg/L. The mixed solution of sodium chloride and sodium hydroxide were used as desorption agent of zeolite,with desorption efficiency of 95.5%.