载铁活性炭对酸性嫩黄G的吸附机理

Mechanism of Iron-Loaded Activated Carbon for Adsorption of Acid Light Yellow G

为获得高效处理酸性嫩黄G(AYG)废水方法,采用浸渍法制备载铁活性炭(Fe-AC)作为吸附剂,并采用傅里叶红外光谱、扫描电镜及比表面积方法对改性前后活性炭进行表征分析。研究采用Box-Behnken Design响应面分析了各因素及其交互作用对AYG的去除影响,并探讨了Fe-AC吸附处理AYG的机理。结果表明:3个因素对AYG去除影响的显著顺序为Fe-AC投加量>处理时间>pH。最佳处理条件:Fe-AC投加量为9.51g/L、处理时间为40.79 min、pH值为4.23。Fe-AC吸附AYG遵循准二级动力学模型,反应速率常数为0.0102~0.6193 g/(mg·min),吸附过程符合Temkin吸附等温模型。机理分析结果表明,Fe-AC含氧官能团增加,表面粗糙,比表面积及单点吸附总孔容增加,裂缝、凹陷丰富,存在多层吸附现象,为其吸附AYG提供了更多结合位点,更利于其与吸附质结合,增加其对AYG吸附量。

In order to obtain an efficient treatment method for acid light yellow G(AYG)wastewater,iron-loaded activated carbon(Fe-AC)was prepared by impregnation method as adsorbent,and the activated carbon before and after modification was characterized and analyzed by FTIR,SEM and BET.The Box-Behnken Design response surface was used to analyze the effects of various factors and their interactions on AYG removal,and the mechanism of Fe-AC adsorption treatment of AYG was discussed.Results showed that the significant order of the effects of three factors on AYG removal was Fe-AC dosage>processing time>pH.Optimal treatment conditions:Fe-AC dosage was 9.51 g/L,treatment time was 40.79 min,and pH value was 4.23.Fe-AC adsorption AYG followed the pseudosecond-order kinetic model,the reaction rate constant was 0.0102~0.6193 g/(mg·min),and the adsorption process conformed to the Temkin adsorption isothermal model.Results of mechanism analysis showed that the oxygen-containing functional groups of Fe-AC increased,the surface was rough,the specific surface area and the total pore volume of single-point adsorption increased,cracks and depressions were abundant,and there were multi-layer adsorption phenomena,which provided more binding sites for its adsorption of AYG,which was more conducive to its combination with adsorbate and increased its adsorption capacity for AYG.