斜发沸石吸附NH_4^+-N的活化与再生方法研究

NH_4^+-N Adsorption and Regeneration of Activated Clinoptilolite

采用实验方法研究了斜发沸石在静态和动态条件下对中低浓度含NH4+-N废水的吸附性能,包括沸石的几种活化方法比较、沸石对NH4+-N的吸附效果和沸石的再生效率。静态吸附实验结果表明,沸石对NH4+-N的快速吸附等温过程符合Langmuir方程,其表达式为q=0.0764Ce(/1+0.0328C)e。几种活化方法比较的结果表明,加热蒸汽活化效果明显,其饱和吸附量较天然沸石提高26.24。汽提的再生方法可以让饱和沸石得以部分再生,一次再生的效率为80.98,二次再生的效率为65.37。动态吸附试验在停留时间30min,水力负荷1.2m.3m-.2h-1,进水浓度为3.5~4mg.L-1的工况下,水土比为25,处理出水满足地表水IV类标准(NH3-N≤0.5mg.L-1),继续运行到水土比为96时吸附能力被穿透。同时比较了水力负荷为1.2、1.8m3.m-.2h-1和不同滤床填料深度条件下的处理效果。一系列实验证明,利用斜发沸石净化低浓度含NH4+-N废水具有良好的应用前景。

A type of suitable clinoptilolite media was used in constructed rapid infiltration system to remove ammonia-N.The mechanisms for ammonia-N adsorption by clinoptilolite,activation of clinoptilolite and regeneration of clinoptilolite were systematically studied.The adsorption isotherm curve of ammonia-N on clinoptilolite was well described by the Langmuir equation：q=0.076 4 Ce/（1＋0.032 8 Ce）.The ammonia-N removal rate of different activation methods on activated clinoptilolite was in the following order：thermalization clinoptilolite Na-type clinoptiloliteP-type clinoptiloliteH-type clinoptilolitenatural clinoptilolite.Compared to other activation methods,thermalization activation resulted in the best adsorption capacity enhancement which was 26.24% higher than non-activated one.Saturated clinoptilolite could be regenerated by stripping without noticeable loss of capacity.The efficiency of desorption of ammonia-N reached 80.98% and 65.37% respectively after twice regeneration,but the efficiency of desorption of ammonia-N sharply decreased after multi-regeneration.Under ratio of water to solid of 25,hydraulic loading of 1.2 m3·m-2·h-1,HRT = 0.5 h and the influent concentration of 3.5~4 mg·L-1,the effluent concentration was better than the class IV of national surface water environmental quality standards（ammonia-N≤0.5 mg·L-1）.When water-soil ratio was 96,the adsorption of ammonia-N was saturated.Effect of different hydraulic loading and different column heights were also systematically studied.The experimental results showed that the clinoptilolite was suitable for the removal of NH4＋-N in wastewater and with good prospects for application.