农田退水中氮磷与吡虫啉的光催化水循环协同净化试验研究

为探究光催化和水循环协同净化氮磷和吡虫啉污染的效果,设计了空白对照、水循环和光催化水循环3组生态浮床系统、6个处理组对2种模拟农田退水(氮磷退水、氮磷和吡虫啉复合污染退水)进行了试验研究。试验结果表明:水体循环能增强浮床系统对氮的去除效果,7.d后氮磷退水的水循环浮床水体中氨氮和硝氮去除率较空白对照浮床分别提升了5.5%和27.1%;增加光催化的净化技术可加快氨氮硝化,氮磷退水的光催化水循环浮床水体中氨氮和硝氮去除率较空白对照浮床分别提升了26.2%和20.3%;吡虫啉会影响水循环浮床系统对氮磷的净化效果,TiO2光催化复合陶粒对吡虫啉有良好的氧化降解效果,同时对氮磷和吡虫啉复合污染有显著净化效果;氮磷和吡虫啉复合污染退水的光催化水循环浮床降解了 58.2%的吡虫啉,水体中氨氮、硝氮和磷酸盐去除率较未添加吡虫啉的水循环浮床分别提升了72.4%、15.0%和14.8%。

Experimental study on photocatalytic water-circulating synergistic purification of nitrogen, phosphorus and imidacloprid in receding water of farmland

To investigate the synergistic purification of photocatalysis and water recycling for nitrogen, phosphorus and imidacloprid pollution, three groups of ecological floating bed systems including the blank control, water circulation and photocatalytic water circulation, and six treatment groups were designed for the purification of two kinds of simulated water(nitrogen-phosphorus (NP) receding water and NP-imidacloprid complex polluted receding water).The experimental results showed that the water circulation enhanced the removal of nitrogen, and the removal rates of ammonia and nitrate nitrogen in the water of the water recirculating floating bed for the receding water purification of nitrogen and phosphorus increased by 5.5% and 27.1%, respectively, compared with the blank control floating bed after 7.d. The addition of photocatalytic purification technology could accelerate the nitrification of ammonia and nitrate nitrogen, and the removal rates of ammonia and nitrate nitrogen in the water of the water recirculating floating bed for the purification of nitrogen and phosphorus retreat water increased by 26.2% and 20.3%, respectively, compared with the blank control floating bed. Imidacloprid affected the purification efficiency of nitrogen and phosphorus in a water circulating floating bed. The TiO2 composite photocatalytic ceramic pellets had a good oxidative degradation effect on imidacloprid and a significant purification effect on the compound pollution of nitrogen, phosphorus and imidacloprid. The photocatalytic water recirculation floating bed purified 58.2% of imidacloprid in the compound polluted return water, and the removal rates of ammonia nitrogen, nitrate nitrogen and phosphate in the water body were increased by 72.4%, 15.0% and 14.8% respectively compared to the water recirculation floating bed without the addition of imidacloprid.