Experimental Study on Treatment of Low Concentration Ammonia Wastewater by Natural Zeolite

以开发经济型低浓度含氨废水的深度处理技术为目标,选用对氨氮有较强的选择性和吸附性的天然斜发沸石作为吸附材料,通过静态试验及连续通水试验,系统地考察了进水氨氮浓度、pH、通水流量及沸石再生次数对氨氮吸附特性的影响.结果表明:天然斜发沸石对氨氮的吸附等温线满足Langmuir方程,即1/q=7.8/C+212.4.氨氮初浓度在100~300mg/L范围内变化,吸附平衡时间约为6 h.在碱性条件下沸石对氨氮的吸附效果较好.采用HCl溶液可使饱和氨氮沸石再生.低氨氮浓度连续通水吸附操作时适宜的氨氮处理流速为0.4 m/h.The objective of this work is to develop an economical process for the treatment of low concentration ammonia wastewater.The natural zeolite was employed as a specific sorbent,which have relatively high selective and adsorptive properties to NH_4~+-N.The effects of NH_4~+-N load,pH value,filtration velocity and regeneration times on the behavior of NH_4~+-N removal were investigated by the batch and continuous column experiments.The adsorption reached an equilibrium at about 6 h.The isotherms fit well in the Langmuir model of adsorption,e.g-1/q=7.8/C+212.4.At the studied concentration range of 100 to 300 mg/L,the adsorption capability increased with the rise of pH value in the pH range from 7.0 to 10.0,as alkaline condition is favorable to NH_4~+-N adsorption.H·rochloric acid was found to be more adapt to regenerate the NH_4~+-N saturated zeolite.The continuous column experiment results showed that the adsorption treatment of NH_4-N by zeolite should be carried out practically at the filtration velocity of 0.4 m/h(HRT =2 h).厦门市科技计划项目(350220031084)资