乙酸锌改性稻壳生物炭电容及电吸附Cu^(2+)性能

Capacitance and electroabsorption performance for Cu^(2+) of zinc acetate modified rice husk biochar

以稻壳为原料制备生物炭(稻壳炭),利用不同浓度的乙酸锌对稻壳炭改性,制得产物分别命名为稻壳生物炭(RHC)和改性稻壳生物炭(MRHC)。通过SEM、BET、XRD对制备的生物炭理化特性进行表征。将RHC和MRHC制成电极,测试其电化学性能。结果表明,MRHC孔隙结构丰富,比表面积较大,且锌以颗粒状氧化物形式存在于生物炭表面。与RHC相比,MRHC电极比电容大大提高,电阻显著减小,循环性能和倍率性能均有提升。MRHC-0.3(乙酸锌浓度为0.3 mol/L时的MRHC)比表面积为495 m^(2)/g,孔容为0.214 cm^(3)/g,该电极在2 A/g下充放电2000次后,其比电容保持率为92.16%。电极在0.9 V、p H为5、Cu^(2+)初始质量浓度为100 mg/L条件下,MRHC-0.3对Cu^(2+)的电吸附效果最好,吸附量为9.57 mg/g。在0.9 V、pH为5、200 mL Cu^(2+)初始质量浓度为50 mg/L的条件下,去除率可达63.82%。

Biochar,prepared from rice husk and characterized by SEM,BET and XRD,was modified with different concentrations of zinc acetate to synthesize products named RHC and MRHC,respectively.The RHC and MRHC obtained were then applied into electrodes for electrochemical performance analysis.The results showed that MRHC,with the zinc existed on the surface of the biochar in oxide form,exhibited rich pore structure and large specific surface area.The MRHC electrode displayed significantly improved specific capacitance,reduced resistance,and enhanced cycling and multiplicative performances compared with RHC.MRHC-0.3(MRHC obtained with a zinc acetate concentration of 0.3 mol/L),with a specific surface area of 495 m^(2)/g and a pore volume of 0.214 cm^(3)/g,after 2000 charge-discharge cycles at 2 A/g,the capacitance retention rate was 92.16%.The MRHC-0.3 electrode showed the best electroadsorption effect,with an adsorption capacity of 9.57 mg/g on Cu^(2+)at 0.9 V,pH 5 and Cu^(2+)with an initial mass concentration of 100 mg/L(200 mL).The removal rate of Cu^(2+)with an initial mass concentration of 50 mg/L could reach 63.82%at 0.9 V and pH 5.