School of Engineering and Built Environment, Nathan campus, Griffith University, Nathan, QLD 4111, Australia E-mail:
Water Sci Technol. 2020 Feb;81(4):801-812. doi: 10.2166/wst.2020.163.
Electro-assisted adsorption was investigated for Pb, Cu and Ni removal using date seed biochar (DSB-Electro). Compared with pristine biochar, the results showed that DSB-Electro effectively increased the adsorption capacity of Pb, Cu and Ni by 21% to 94%. Significant differences were observed between Pb and Cu adsorption compared with Ni, which could be explained based on ion polarizing power. Under the same voltage, Ni solution shows the highest electric conductivity; thereby more Ni is transported to the biochar anode, giving them a greater chance to interact with the surface groups. Electro-assisted adsorption occurred rapidly as around 88% of Pb and Ni adsorbed within the first 3 h, while 96% of Cu occurred within the first hour of contact. Reversing the polarity did not seem to cause significant desorption of the adsorbed ions as the amount released from reversing polarity was less than 38%, indicating that only a small fraction of the ions was held by the electrostatic charge introduced by the current. It was likely that the enhanced charge facilitated other adsorption mechanisms by bringing the ions in contact with the biochar initially via electrostatic force. Electro-assisted adsorption can improve the biochar economic feasibility for metals removal (particularly Ni) from industrial streams.
采用电化学辅助吸附法（DSB-Electro）研究了枣椰树生物炭对 Pb、Cu 和 Ni 的去除效果。与原始生物炭相比，结果表明 DSB-Electro 可有效将 Pb、Cu 和 Ni 的吸附容量提高 21%至 94%。Pb 和 Cu 的吸附与 Ni 相比存在显著差异，这可以根据离子极化能力来解释。在相同电压下，Ni 溶液具有最高的电导率；因此，更多的 Ni 被输送到生物炭阳极，从而使它们有更大的机会与表面基团相互作用。电辅助吸附过程迅速发生，约 88%的 Pb 和 Ni 在最初 3 h 内被吸附，而 96%的 Cu 在接触的第一个小时内被吸附。改变电极极性似乎不会导致吸附离子大量解吸，因为从反向极性释放的离子量小于 38%，这表明只有一小部分离子被电流引入的静电荷固定。增强的电荷可能通过最初借助静电力使离子与生物炭接触，从而促进了其他吸附机制。电辅助吸附可提高生物炭从工业废水中去除金属（特别是 Ni）的经济可行性。
