School of Civil and Environmental Engineering, University of Technology Sydney, P.O. Box 123, Broadway, Ultimo, NSW 2007, Australia.
School of Chemical Engineering, Chonnam National University, 77 Yongbong-ro, Gwangju 61186, Republic of Korea.
Sci Total Environ. 2019 Dec 20;697:134070. doi: 10.1016/j.scitotenv.2019.134070. Epub 2019 Aug 23.
Selective copper (Cu) recovery from wastewater mitigates environmental pollution and is economically valuable. Mesoporous silica adsorbents, SBA-15, with amine-grafting (SBA-15-NH) and manganese loading along with amine-grafting (Mn-SBA-15-NH) were fabricated using KMnO and 3-aminopropyltriethoxysilane. The characteristics of the synthesized adsorbents were evaluated in detail in terms of its crystal structure peaks, surface area and pore size distribution, transmission electron microscope and X-ray photoelectron spectroscopy. The results established the 2.08mmol/g of Cu adsorption capacity on Mn-SBA-15-NH. Furthermore, in a mixed heavy metal solution, high selective Cu adsorption capacity on Mn-SBA-15-NH (2.01mmol/g) was achieved while maintaining 96% adsorption amount as that of a single Cu solution. Comparatively, Cu adsorption on SBA-15-NH decreased by half due to high competition with other heavy metals. Optimal Cu adsorption occurred at pH5. This pH condition enabled grafted amine group in Mn-SBA-15-NH to form strong chelating bonds with Cu, avoiding protonation of amine group (below pH5) as well as precipitation (above pH5). The adsorption equilibrium well fitted to Langmuir and Freundlich isotherm models, while kinetic results were represented by models of linear driving force approximation (LDFA) and pore diffusion model (PDM). High regeneration and reuse capacity of Mn-SBA-15-NH were well established by its capacity to maintain 90% adsorption capacity in a multiple adsorption-desorption cycle. Cu was selectively extracted from Mn-SBA-15-NH with an acid solution.
从废水中选择性回收铜 (Cu) 可以减轻环境污染，具有经济价值。采用 KMnO 和 3-氨丙基三乙氧基硅烷制备了介孔硅吸附剂 SBA-15，其表面进行了胺接枝 (SBA-15-NH) 和锰负载以及胺接枝 (Mn-SBA-15-NH)。详细评估了合成吸附剂的晶体结构峰、表面积和孔径分布、透射电子显微镜和 X 射线光电子能谱等特性。结果表明，Mn-SBA-15-NH 的 Cu 吸附容量为 2.08mmol/g。此外，在混合重金属溶液中，Mn-SBA-15-NH 对 Cu 具有高选择性吸附容量（2.01mmol/g），同时保持 96%的吸附量与单一 Cu 溶液相同。相比之下，由于与其他重金属的高竞争，SBA-15-NH 上的 Cu 吸附量减少了一半。最佳 Cu 吸附发生在 pH5。在这种 pH 条件下，Mn-SBA-15-NH 中的接枝胺基能够与 Cu 形成强螯合键，避免了胺基的质子化（低于 pH5）和沉淀（高于 pH5）。吸附平衡很好地符合 Langmuir 和 Freundlich 等温模型，而动力学结果则由线性驱动力近似（LDFA）和孔扩散模型（PDM）表示。Mn-SBA-15-NH 在多次吸附-解吸循环中保持 90%的吸附容量，证明了其具有高的再生和再利用能力。Cu 可以用酸溶液从 Mn-SBA-15-NH 中选择性提取。
