基于铁基质高效催化还原污水中硝酸盐氮的实验研究

污水厂排水中硝酸盐氮(\mathrm{N}{\mathrm{O}}_3^{–}-N)浓度偏高，难利用常规生物脱氮工艺实现\mathrm{N}{\mathrm{O}}_3^{–}-N的深度脱除。以铁基质高效催化脱氮载体为污水中\mathrm{N}{\mathrm{O}}_3^{–}-N的脱除材料，探究不同铁基质催化活性、pH和\mathrm{N}{\mathrm{O}}_3^{–}-N浓度等对污水中\mathrm{N}{\mathrm{O}}_3^{–}-N去除的影响及机制。研究结果表明：添加催化剂D的铁基质高效催化脱氮载体可脱除92.23%的\mathrm{N}{\mathrm{O}}_3^{–}-N，调节污水为酸性至中性条件时，其\mathrm{N}{\mathrm{O}}_3^{–}-N去除率均可达到92.09%以上，且氨氮(\mathrm{N}{\mathrm{H}}_4^{+}-N)积累量先升高后降低；当污水为碱性条件时，\mathrm{N}{\mathrm{O}}_3^{–}-N的去除率亦可达86.13%以上，且在碱性条件时无\mathrm{N}{\mathrm{H}}_4^{+}-N积累；原水中\mathrm{N}{\mathrm{O}}_3^{–}-N的浓度变化(20~70 mg·L^-1)对铁基质高效催化脱氮载体的脱氮性能影响较小，\mathrm{N}{\mathrm{O}}_3^{–}-N去除率均达到96.11%以上。与催化剂A、B和C相比，添加催化剂D的铁基质高效催化脱氮载体脱氮速率最快，\mathrm{N}{\mathrm{O}}_3^{–}-N降解反应过程符合一级反应动力学方程，反应速率常数k=0.0170 min^–1。

Experimental study on effective nitrate removal from sewage by ZVI-based catalyzed reduction

It remains difficult to achieve effective nitrate removal with conventional biological nitrogen removal processes, for the high \mathrm{N}{\mathrm{O}}_3^{-}-N concentration and low organic carbon in tail water from WWTP. Thus, ZVI-based catalyzed reduction was developed and applied in this study. The influence of catalytic activity of the catalysts, pH and \mathrm{N}{\mathrm{O}}_3^{-}-N concentration on nitrate reduction by ZVI-based catalyzed reduction was studied, and the reaction mechanisms was investigated. The results show that the high-catalytic catalytic denitrification carrier with catalyst D can remove 92.23% of \mathrm{N}{\mathrm{O}}_3^{-}-N, and the \mathrm{N}{\mathrm{O}}_3^{-}-N removal rate can reach 92.09% when the wastewater is acidic to neutral. The \mathrm{N}{\mathrm{O}}_3^{-}-N removal efficiency of above 86.13% was also achieved even under alkaline conditions, and no \mathrm{N}{\mathrm{H}}_4^{+}-N accumulation was found. Increasing in \mathrm{N}{\mathrm{O}}_3^{-}-N concentration (20—70 mg·L^–1) showed little impact on nitrate reduction efficiency (remaining ≥96.11%). The nitrogen removal efficiency by ZVI-based catalyzed reduction in the presence of catalyst D obtained the highest speed when compared to catalysts A, B and C, and the reduction reaction was in keeping with the first-order kinetics equation with a calculated reaction rate constant of k=0.0170 min^–1.