乙酸锌改性稻壳生物炭电容及电吸附Cu2+性能

Capacitance and electroabsorption properties of zinc acetate modified rice husk biochar for Cu2+

摘要:

以稻壳为原料制备生物炭，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RHC和MRHC。通过SEM、BET、XRD对制备的生物炭理化特性进行表征。分析表明，改性炭孔隙结构丰富，比表面积较大，且锌以氧化物颗粒状存在于生物炭表面。将改性前后的稻壳生物炭制成电极，测试其电化学性能。结果表明，与未改性生物炭相比，改性后的炭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时的改性生物炭）比表面积为495 m2/g，孔容为0.214 cm3/g，该电极在2 A/g下充放电2000次后，其电容保持率为92.16%。将MRHC-0.3电极用于电吸附Cu2+实验，发现在0.9 V，pH为5时吸附效果最好，吸附量为9.57 mg/g。在0.9 V，pH为5，Cu2+初始质量浓度为50 mg/L时，去除率可达63.82%。

Abstract:

The biochar was prepared from rice husk and modified with different concentrations of zinc acetate to produce products named RHC and MRHC, respectively. The prepared biochar was characterized by SEM, BET and XRD for its physicochemical properties. The analysis showed that the modified char had rich pore structure and large specific surface area, and the zinc existed on the surface of the biochar in the form of oxide particles. The rice husk biochar before and after modification was made into an electrode and its electrochemical properties were tested. The results showed that the specific capacitance of the modified carbon electrode was greatly improved, the resistance was significantly reduced, and the cycling performance and multiplicative performance were improved compared with the unmodified biochar. MRHC-0.3 (modified biochar at a zinc acetate concentration of 0.3 mol/L) had a specific surface area of 495 m2/g and a pore volume of 0.214 cm3/g. The capacitance retention rate of this electrode was 92.16% after 2000 charge/discharge cycles at 2 A/g. MRHC-0.3 electrode was used for electrosorption of Cu2+ at 0.9 V, pH 5. The MRHC-0.3 electrode was used for electrosorption of Cu2+, and the best adsorption effect was found at 0.9 V, pH 5, with the adsorption amount of 9.57 mg/g. The removal rate could reach 63.82% at 0.9 V, pH 5, and the initial mass concentration of Cu2+ of 50 mg/L.