湿式催化氧化法处理含高浓度甲醛的草甘膦废水

Treatment of Glyphosate Wastewater Containing High Concentration Formaldehyde by the Catalytic Wet Air Oxidation

草甘膦结晶母液经蒸发或纳滤浓缩回收后,产生大量含有高浓度甲醛的废水,常规的废水处理方法难以达到回用或排放要求.以过量溶液浸渍法制备的Pt-Bi-CeO2/AC为催化剂,采用湿式催化氧化法处理2.5%的HCHO溶液,HCHO去除率高达99.9%以上,COD去除率达到96.6%.采用Pt-Bi-CeO2/AC催化剂对含低浓度草甘膦(PMG,50 mg/L)的生产废水直接进行湿式催化氧化处理,催化剂使用23次后,HCHO去除率稳定在85%左右,COD去除率稳定在87%左右,催化剂具有良好的稳定性.湿式催化氧化处理后的废水可直接回用于PMG生产.采用固定床湿式催化氧化装置处理HCHO溶液以及PMG生产废水,处理效果也非常理想,连续使用720 h,催化剂的稳定性能良好.通过XRD、N2吸附-脱附、HRTEM、ICP-OES和XPS等分析手段对催化剂进行了系统表征.

The glyphosate （PMG） content of the treated PMG wastewater by distillation or nanofihration concen- trate was 50 -200 mg/L, but the formaldehyde （HCHO） was not treated, and it has become a serious problem of the PMG production enterprises. The Pt-Bi-CeOJAC catalyst was selected from four kinds of prepared catalysts by impregnation method. The 2.5% HCHO solution was treated by the catalytic wet oxidation, the removal rate of HCHO was above 99.9% , the removal rate of COD was 96.6% , and pH value was 5.50. Waste water with low concentration （50 mg/L） of PMG was directly treated by Pt-Bi-CeOJAC catalyst by the catalytic wet oxidation process, the HCHO removal rate was stable at about 85% , the removal rate of COD was stable at about 87% , and the catalyst exhibited well stability when the catalyst was used for 23 times. The treated PMG wastewater was used for the PMG production. By using the fixed bed apparatus in the treatment of HCHO solution and PMG wastewater, the effect of the treatment was very ideal, and the stability of the catalyst was good using for 720 h. And the charac- terizations of the catalysts were detected by the XRD, N2 adsorption desorption, HRTEM, ICP-OES and XPS anal- ysis methods.