微波紫外耦合辐射降解间硝基苯磺酸钠及活性炭再生

针对活性炭吸附法处理污水所面临的吸附剂物耗大及其所形成的危险废弃物处置难题,采用微波紫外耦合辐射技术对活性炭无害化再生。以活性炭吸附电镀废水中的间硝基苯磺酸钠(3-NBSA)为研究对象,考察了pH对活性炭吸附3-NBSA效果的影响,研究了活性炭的吸附动力学和吸附等温线,最后探讨了微波功率、微波辐照时间、空气流量及再生次数对活性炭再生效果和再生损耗率的影响。实验结果表明,pH在2~8范围内对活性炭吸附效果影响不大,活性炭吸附动力学符合准二级动力学模型,等温吸附特性可用Freundlich等温方程式来描述。活性炭再生实验的最佳工艺条件:微波功率为500 W,微波辐照时间为10 min,空气流量为0.024 m3 /h。最佳工艺条件下活性炭的再生率达到99.62%,且连续再生5次后仍能达到90.02%。实验表明,在微波紫外耦合辐射作用下比只在微波作用下,活性炭的再生效果和3-NBSA的降解效果更好。

Degradation of 3-nitrobenzenesulfonic acid and regeneration of activated carbon under coupled irradiation of microwave and ultraviolet

To solve the problems of high cost and hazardous waste disposal when activated carbon (AC) was used in waste water treatment, the application of coupled irradiation system of microwave (MW) and ultraviolet (UV) for regenerating waste AC and degrading the organic pollutants adsorbed on it were studied. As a typical case, the AC with adsorbed 3-nitrobenzenesulfonic acid (3-NBSA) from electroplating wastewater was treated in the system. In this study, the effect of pH on adsorption efficiency, the adsorption kinetics and adsorption isotherms of 3-NBSA on activated carbon were evaluated. Furthermore, the impact factors of activated carbon regeneration rate and regeneration loss rate were discussed by changing MW power, MW irradiation time, airflow rate, and regeneration times. The results indicated that pH had no obvious influence on the adsorption ability when it ranged from 2 to 8. In addition, the adsorption kinetics was consistent with the pseudo second-order dynamic model and the adsorption isotherms could be described by Freundlich equation. The optimal conditions for the regeneration of activated carbon were MW power of 500 W, MW irradiation time of 10 min and airflow rate of 0.024 m3/h. Under these conditions, the regeneration rate achieved 99.62% and regeneration rate could still reach 90.02% after five full cycles. Activated carbon regeneration rate and the effect of 3-NBSA degradation under the coupled irradiation of MW and UV were better than those under MW irradiation only.