化学反硝化去除硝酸盐的试验研究

在间歇式完全混合反应器中,以Pd-Cu/γ-Al₂O₃为催化剂,对催化还原硝酸盐进行了实验研究.结果表明:在负载型金属催化剂作用下,硝酸盐能有效地被还原生成N₂,总氮的去除率达80%以上.催化剂的活性和对氮气的选择性受催化剂量、pH值、H₂的流量和压力、初始硝酸盐浓度等反应条件的影响,适当增加催化剂量和提高H₂的流量和压力都有利于提高催化剂的活性;而对于选择性,前者提高,后者则会导致降低,即控制反应扩散性能有利于提高催化选择性.在试验的浓度范围内,其催化还原硝酸盐的反应为一级反应.

Chemical Denitrification of Nitrate from Groundwater

Batch experiments for catalytic reduction of nitrate from groundwater with Pd and/ Cu catalysts were conducted. It was found that Pd-Cu combined catalysts at a ratio of 4 can maximize the nitrate reduction into nitrogen; above 80% total nitrogen removal efficiency was realized in this study. It was also found that the catalytic activity was affected by the amounts of catalysts, hydrogen flow rate and pressure, the initial concentration of nitrate. With an increasing in the amount of the catalysts, both nitrite and ammonia intermediates can be kept at a low level. A high flow rate and pressure of hydrogen was in favor of the catalytic reduction of nitrate, but not benefit for the selectivity. The catalytic reduction followed a first order kinetics in term of the initial nitrate concentration.