College of Chemistry and Chemical Engineering, Shaanxi University of Science & Technology, Xi'an, 710021, China.
Shaanxi Key Laboratory of Chemical Additives for Industry, Shaanxi University of Science & Technology, Xi'an, 710021, China.
Environ Sci Pollut Res Int. 2022 Nov;29(55):83045-83059. doi: 10.1007/s11356-022-21616-w. Epub 2022 Jun 27.
The incorporation of ZnO into biochar has become a promising way to obtain adsorbents with enhanced adsorption capacity. In this study, a low-cost ZnO-sludge biochar composite (ZBC) was prepared by a simply in situ method using sewage sludge biochar (SBC) and zinc acetate, as well as employed for Cr(VI) adsorption in water. The results of XPS and FT-IR suggested that the ZBC surface had more functional groups such as -COOH, -OH, -C-O, ZnO, etc. Compared with SBC, the BET-specific surface area of the ZBC increased from 8.82 to 41.24 m·g, which provides potential advantages for Cr(VI) uptake. Benefiting from ZnO incorporation, about an 18% increase in Cr(VI) removal efficiency was obtained. The maximum removal efficiency and equilibrium adsorption amount of ZBC for Cr(VI) reached 98.4% and 33.87 mg·g, respectively. The adsorption was spontaneous and endothermic nature, and coincided nicely with pseudo-second-order kinetics and Langmuir isotherm. The analyses indicated that Cr(VI) removal by ZBC was predominantly via electrostatic attraction, surface complexation, ion exchange, and reduction. This study provided valuable insights into the problem of sludge disposal and provided a new and effective method for Cr(VI) removal.
将 ZnO 掺入生物炭中已成为一种获得吸附能力增强的吸附剂的有前途的方法。本研究采用简单的原位法，利用污水污泥生物炭（SBC）和乙酸锌制备了一种低成本的 ZnO-污泥生物炭复合材料（ZBC），并将其用于水中 Cr(VI)的吸附。XPS 和 FT-IR 的结果表明，ZBC 表面具有更多的官能团，如-COOH、-OH、-C-O、ZnO 等。与 SBC 相比，ZBC 的 BET 比表面积从 8.82 增加到 41.24 m·g，这为 Cr(VI)的吸收提供了潜在的优势。得益于 ZnO 的掺入，Cr(VI)的去除效率提高了约 18%。ZBC 对 Cr(VI)的最大去除效率和平衡吸附量分别达到 98.4%和 33.87 mg·g。吸附是自发和吸热的，与伪二级动力学和 Langmuir 等温线吻合较好。分析表明，ZBC 去除 Cr(VI)主要通过静电吸引、表面络合、离子交换和还原。本研究为污泥处理问题提供了有价值的见解，并为 Cr(VI)的去除提供了一种新的有效方法。
