Abstract

A low-cost and eco-friendly sorbent, a woody biomass derived sorbent (biosorbent), has been prepared by chemical modification of wood. To improve the Au(III) sorption performance and economic feasibility for Au recovery from dilute aqueous solution, the preparation process has been optimized by changing the preparation conditions. The Au(III) sorption performance and characterization by Fourier transform infrared spectroscopy and scanning electron microscopy show that sulfuric acid treatment increases the number of active sites and porous structure on the woody biosorbent surface. The woody biosorbent shows considerable Au sorption ability even for very low Au concentration (initial [Au(III)] ≥ 0.025 mmol/L was tested in the present study). Furthermore, visible elemental gold particles form, indicating that Au(III) is subsequently reduced to metallic gold by the redox reaction on the sorbent surface. The adsorption–reduction mechanism is explained for the complete Au(III) sorption process by the results of a kinetic study, the sorption isotherm, and the gold reduction phenomenon. The sorbent is highly selective for Au(III) over other base metals and can recover Au(III) from waste water containing high levels of impurities. Considering its remarkable Au(III) uptake performance, selectivity in dilute solution, and extremely low cost and simple production, the woody biosorbent is a promising candidate for gold recovery from dilute aqueous solution.

摘要

通过对木材进行化学改性，制备了一种低成本、环保的吸附剂，一种木质生物质衍生吸附剂（生物吸附剂）。为了提高从稀水溶液中回收 Au(III) 的 Au(III) 吸附性能和经济可行性，通过改变制备条件优化了制备工艺。Au(III) 吸附性能和傅里叶变换红外光谱和扫描电子显微镜表征表明硫酸处理增加了木质生物吸附剂表面活性位点和多孔结构的数量。即使在非常低的 Au 浓度下（本研究中测试了初始 [Au(III)] ≥ 0.025 mmol/L），木质生物吸附剂也显示出相当大的 Au 吸附能力。此外，形成可见的元素金颗粒，表明 Au(III) 随后通过吸附剂表面的氧化还原反应被还原为金属金。通过动力学研究的结果、吸附等温线和金还原现象解释了完整的 Au(III) 吸附过程的吸附 - 还原机制。该吸附剂对 Au(III) 的选择性高于其他贱金属，并且可以从含有大量杂质的废水中回收 Au(III)。考虑到其显着的 Au(III) 吸收性能、在稀溶液中的选择性以及极低的成本和简单的生产，木质生物吸附剂是从稀水溶液中回收金的有希望的候选者。吸附等温线和金还原现象。该吸附剂对 Au(III) 的选择性高于其他贱金属，并且可以从含有高浓度杂质的废水中回收 Au(III)。考虑到其显着的 Au(III) 吸收性能、在稀溶液中的选择性以及极低的成本和简单的生产，木质生物吸附剂是从稀水溶液中回收金的有希望的候选者。吸附等温线和金还原现象。该吸附剂对 Au(III) 的选择性高于其他贱金属，并且可以从含有大量杂质的废水中回收 Au(III)。考虑到其显着的 Au(III) 吸收性能、在稀溶液中的选择性以及极低的成本和简单的生产，木质生物吸附剂是从稀水溶液中回收金的有希望的候选者。