土霉素菌渣活性炭吸附处理低浓度含铬废水

Treatment of Low Concentration Chromium Wastewater onto Oxytetracycline Residue Activated Carbon

为有效处置土霉素菌渣,采用活化法制备土霉素菌渣活性炭(菌渣炭),并用于处理低浓度含铬废水。经过组分测定可知,土霉素菌渣含有较高的挥发分,灰分含量较低;元素分析中C、O元素的含量较高,表明土霉素菌渣含有大量的有机物和菌体蛋白;BET测得菌渣炭的比表面积、孔容和孔径都较大,通过扫描电镜可观察出菌渣炭具有较多的微孔和中孔,有利于对Cr(VI)定的吸附。通过单因素实验确定在初始Cr(VI)浓度为2 mg/L时,菌渣炭对Cr(VI)的最佳吸附pH、吸附剂投加量、吸附时间分别为4、0.5 g/L、50 min,Cr(VI)的最高去除率为96.2%。热力学和动力学分析结果表明菌渣炭对Cr(VI)的吸附符合Freundlich等温吸附模型和准二级动力学模型。菌渣炭的饱和吸附量为17.93 mg/g,对Cr(VI)的吸附速率与吸附剂上未被占据的吸附位点的平方成正比。用1 mol/LHCl对菌渣炭进行洗脱再生,经过4次循环实验Cr(VI)的去除率为77.1%,剩余溶液中Cr(VI)浓度为0.459 mg/L,满足污水综合排放标准0.5 mg/L。研究结果为菌渣炭的资源化利用提供一种新的思路。

Oxytetracycline residue activated carbon(Bacterial slag charcoal)was prepared in activation method,which could be controlled efficiently and used to treat low concentration chromium.The content of volatile matter and ash in oxytetracycline residue was low.But C and O elements in the elemenwere,indicating that the oxytetracycline residue contained a large amount of organic matter and bacterial protein.the specific surface area,pore volume and pore diameter of bacterial slag charcoal are larger.Through scanning electron microscope,it can be observed that the bacterial slag carbon has more micropores and mesoporous,which is contributed to the adsorption of Cr(Ⅵ).The optimum adsorption pH,adsorbent dosage and adsorption time were 4,0.5 g/L and 50min,respectively.The percentage removal of Cr(Ⅵ)was 96.2%when the concentration of Cr(Ⅵ)was 2 mg/L.Thermodynamic and kinetic analysis showed that adsorption of Cr(Ⅵ)on bacterial slag charcoal accorded with Freundlich isothermal adsorption model and pseudo-second-order equation.The saturated adsorption capacity of bacterial slag charcoal was 17.93 mg/g,and the adsorption rate of Cr(Ⅵ)was directly proportional to the square of the adsorbed site on the adsorbent.After 4 cycles,which used 1 mol/L HCl as regenerative agent,the removal rate of Cr(Ⅵ)was 77.1%,and the concentration of Cr(Ⅵ)in the remaining solution was 0.459 mg/L,which can meet Integrated wastewater discharge standard.The research findings provided a new idea for reusing bacterial residue charcoal.