改性海泡石处理水中低质量浓度NO3-的研究

实验制备酸洗及负载纳米零价铁的海泡石,进行改性海泡石吸附及还原水中低质量浓度NO-3的实验研究。结果表明,对于酸洗海泡石(PNS)吸附NO-3,吸附效果高于天然海泡石,Freundlich模型比Langmuir模型更好地拟合NO-3等温吸附曲线,吸附过程为物理吸附非自发过程,吸附为放热反应,温度升高不利于吸附进行;负载纳米零价铁的海泡石(PNS-nZVI)处理水中NO-3符合准一级反应动力学模型。在一定范围内,酸性条件下促进NO-3的去除,质量浓度越大去除效果越好,温度在30℃时去除率达到峰值,最佳条件下去除率可达到95.4%。PNS-nZVI还原NO-3是一个递进过程,初始阶段NO-3先转化成中间产物NO-2和部分NH+4,随着反应进行NO-2逐步转化成NH+4,NH+4在反应产物中所占比重最大。

Research on Treatment of Modified Sepiolite for Low Mass Concentration NO3- in Water

In this research, acid washed and loaded nanoscale zero valent iron sepiolite was used to adsorb and restore low mass concentration NO - 3 in water by modified sepiolite. The results show that the adsorption effect of pickling sepiolite (PNS) on NO - 3 is higher than that of natural sepiolite. The Freundlich model is better than the Langmuir model to fit the NO - 3 isothermal adsorption curve. The adsorption process is a non spontaneous process of physical adsorption, the adsorption is exothermic reaction, and the increase of temperature is not beneficial to the adsorption. For PNS-nZVI loaded with nanoscale zero valent iron, NO - 3 in water treated by PNS-nZVI conforms to the quasi-first-order reaction kinetic model. In a certain range, the removal of NO - 3 is promoted under the acidic condition. The higher the mass concentration, the better the removal efficiency, the removal rate reaches the peak at 30 ℃, and the removal rate under the best condition can reach 95.4%. The reduction of NO - 3 by PNS-nZVI is a progressive process. At the initial stage, NO - 3 is converted into intermediate product NO - 2 and partial NH + 4. As the reaction proceeds, NO - 2 is gradually converted to NH + 4, and NH + 4 accounts for the largest proportion in the reaction products.