Abstract:

Waste rice straws were converted into rice straw derived activated carbon(RSAC), which supported ferric oxides(Fe₃O₄, loaded dosage of 14.25%) as ozone catalyst with 1175.1 m²·g^-1 of specific surface area, and efficiency of heterogeneous catalytic ozonation of biologically pretreated paper-making wastewater were investigated.The results indicated that RSAC and catalyst all had the good adsorption capacity of biologically pretreated paper-making wastewater, and the adsorption isotherms fitted well with the Langmuir model(R²>0.99).The addition of the prepared catalyst significantly enhanced the pollutants removal performance of ozonation of raw wastewater, and the COD, BOD₅, NH₄⁺-N and chromaticity in the treated effluent were 46, 17, 5 mg·L^-1 and 18 degree which all met discharge standard paper-making wastewater(GB 3544-2008) with the optimal operating parameters(0.3 g·h^-1 of ozone dosage and 1 g·L^-1 of catalyst dosage and raw wastewater pH).Moreover, the catalyst had superior stability and leaching of metal irons were very few at 20 cycle's utilization.It was deduced that the enhancement of catalytic activity was responsible for generating more radicals by radical scavenger and ESR detection.Thus, the prepared catalyst with efficient, stable and economical advantages was suitable for catalytic ozonation of biologically pretreated paper-making wastewater.

Key words: adsorption, catalytic ozonation, catalyst, radical, waste treatment

摘要：

以农业废弃物水稻秸秆为原料制备了秸秆基活性炭负载金属Fe氧化物的臭氧催化剂，主要特征为负载Fe₃O₄，负载量14.25%，比表面积1175.1 m²·g^-1，研究其强化臭氧深度处理造纸废水的效能。结果表明，制备的秸秆基活性炭和催化剂均对造纸废水污染物具有较高的吸附性能，吸附等温线与Langmuir模型拟合相关性良好（R²>0.99）；催化剂的使用显著强化了臭氧氧化污染物的性能，最佳的运行参数是臭氧和催化剂投加量分别为0.3g·h^-1和1 g·L^-1及原水pH，处理后出水COD、BOD₅、氨氮和色度分别为46、17、5 mg·L^-1和18倍，均低于我国造纸废水污染物排放标准（GB 3544-2008）；重复20次的运行，催化剂具有良好的稳定性，金属离子溶出浓度极少，并通过自由基捕获剂和ESR测试探讨该催化臭氧氧化过程属自由基间接氧化为主导的反应机理。本研究制备的臭氧催化剂具有性能高效稳定和经济节约的特点，适用于造纸废水深度处理的工程化应用。

关键词: 吸附, 催化臭氧化, 催化剂, 自由基, 废物处理