氮掺杂活性炭催化湿式氧化—Ca(OH)_2沉淀工艺去除草甘膦废水中的磷

Removal of phosphorus from glyphosate wastewater by catalytic wet oxidation with nitrogen-doped activated carbon-Ca(OH)_2 precipitation process

用30%(w)H_2O_2溶液氧化处理活性炭(AC),再以三聚氰胺为含氮前驱体经高温处理制得氮掺杂AC催化剂。采用催化湿式氧化(CWO)法去除草甘膦废水中的有机磷(OP),将其彻底氧化降解为PO_4^(3-),再利用Ca(OH)_2沉淀法去除总磷(TP)。表征结果显示:氮掺杂改性可在AC表面形成多种含氮碱性官能团,从而提高其对OP的催化氧化活性。实验结果表明:在温和的工艺条件下(130℃,1 MPa),该催化剂对不同来源废水的OP去除率均高于90%;当m(Ca(OH)_2)∶m(TP)为20时,Ca(OH)_2沉淀可有效去除CWO出水中的TP,最终出水TP质量浓度小于5 mg/L,可有效缓解后续生化系统除磷的压力。

The nitrogen-doped activated carbon（AC）catalyst was prepared by oxidation treatment with 30%（w）H2 O2 solution and thermal treatment with melamine as nitrogen-containing precursor. Organic phosphorus（OP）in glyphosate wastewater was removed and degraded deeply into PO4-（3-）by catalytic wet oxidation（CWO）with nitrogen-doped AC,and then the total phosphorus（TP）could be removed by Ca（OH）2 precipitation. The characterization results indicated that a variety of nitrogen-containing basic groups was formed on the surface of AC by nitrogen doping,which enhanced its catalytic activity to OP oxidation. The experimental results showed that：At the mild conditions（130 ℃,1 MPa）,all the removal rates of OP in different wastewaters were above 90%with the catalyst;When m（Ca（OH）2）∶m（TP）was 20,TP in the CWO effluent could be removed effectively by Ca（OH）2 precipitation with lower than 5 mg/L of the effluent TP mass concentration,which relieved the pressure of biological treatment system for phosphorus removal.