改性花生壳炭电极的电容去离子技术对高盐尾水中Cl-的去除性能

Cl-removal performance from high salt tailwater by capacitive deionization based on modified peanut shell carbon electrode and its application

以废弃花生壳为原料,探究了炭化条件和KOH改性对炭材料电吸附性能的影响。利用电容去离子(capacitive deionization,CDI)技术,探究KOH改性炭电极(KBPS)对于青岛污水处理厂高盐尾水中Cl-的去除效果。通过SEM、BET、FTIR、XRD、XPS、接触角手段对炭材料理化性质进行了表征。结果表明,随炭化温度增高,炭材料石墨化程度与有序度提升。KOH改性可改善炭材料的比表面积、石墨化程度和亲水性。电吸附实验结果表明,在1000℃下炭化的KOH改性炭电极(KBPS1000)吸附量为11.097 mg·g^(-1),相比BPS1000提升了30%。在溶液流速为15 mL·min^(-1)、工作电压为1.2 V时KBPS1000的电吸附性能最佳。经过9次吸附-脱附循环后,KBPS1000电极再生率为98.41%,电极再生性能稳定。配制Cl-浓度为2000 mg·L^(-1)的NaCl溶液,以5对电极板为一组循环,经22组循环后,Cl-浓度由2000 mg·L^(-1)降至454 mg·L^(-1),Cl^(-)去除率可达77.3%。

In this study,the effects of carbonization conditions and KOH modification on the electroabsorption performance of carbon materials were investigated using waste peanut shells as raw materials.Capacitive deionization(CDI)was used to investigate the effect of KOH-modified carbon electrode(KBPS)on the removal of Cl-from the high-salt tailwater of Qingdao wastewater treatment plant.The physical and chemical properties of the carbon materials were characterized by SEM,BET,FTIR,XRD,XPS and contact angle.The result showed that the graphitization and orderliness of the carbon materials increased with the increase of carbonization temperature.The KOH modification improved the specific surface area,graphitization and hydrophilicity of the carbon material.The electrosorption experiments showed that the adsorption capacity of KOH modified carbon electrode KBPS1000 carbonized at 1000℃was 11.097 mg·g^(-1),which was 30%over that of BPS1000.The best electrosorption performance was achieved at a solution flow rate of 15 mL·min^(-1)and an operating voltage of 1.2 V.After nine adsorption-desorption cycles,the regeneration rate of KBPS1000 electrode was 98.41%,and the electrode regeneration performance was stable.The NaCl solution with Cl-concentration of 2000 mg·L^(-1)was prepared,and a set of cycle was performed using 5 pairs of electrodes,the Cl-concentration could decrease from 2000 mg·L^(-1)to 454 mg·g^(-1)after 22 sets of cycles,and the Cl^(-)removal rate could reach 77.3%.