College of Environmental Science and Engineering, Nanjing Tech University, Nanjing 211800, China.
Int J Environ Res Public Health. 2021 May 4;18(9):4906. doi: 10.3390/ijerph18094906.
The effective treatment of membrane concentrate is a major technical challenge faced by the new coal chemical industry. In this study, a supported perovskite catalyst LaCoO/X was prepared by a sol-impregnation two-step method. The feasibility of the supported perovskite catalyst LaCoO/X in the UV-catalytic wet hydrogen peroxide oxidation (UV-CWPO) system for the purification of concentrated liquid of coal chemical wastewater was investigated. The effects of catalyst support, calcination temperature, calcination time, and re-use time on catalytic performance were investigated by batch experiments. The catalysts were characterized by X-ray diffraction (XRD), Scanning electron microscopy (SEM), Brunauer-Emmett-Teller (BET), and X-ray photoelectron spectroscopy (XPS). Experimental results showed that the supported perovskite catalyst LaCoO/CeO prepared using CeO as support, calcination temperature of 800 °C, and calcination time of 8 h had the best catalytic effect. The catalytic performance of the catalyst remained excellent after seven cycles. The best prepared catalyst was used in UV-CWPO of coal chemical wastewater membrane concentrate. The effects of HO dosage, reaction temperature, reaction pressure, and catalyst dosage on UV-CWPO were determined. Under the conditions of HO dosage of 40 mM, reaction temperature of 120 °C, reaction pressure of 0.5 MPa, catalyst dosage of 1 g/L, pH of 3, and reaction time of 60 min, the removal efficiencies of COD, TOC, and UV were 89.7%, 84.6%, and 98.1%, respectively. Under the optimal operating conditions, the oxidized effluent changed from high toxicity to non-toxicity, the BOD/COD increased from 0.02 to 0.412, and the biodegradability of the oxidized effluent was greatly improved. The catalyst has a simple synthesis procedure, excellent catalytic performance, and great potential in the practical application of coal chemical wastewater treatment.
膜浓缩液的有效处理是新型煤化工面临的主要技术挑战。本研究采用两步浸渍法制备了负载型钙钛矿催化剂 LaCoO/X。考察了负载型钙钛矿催化剂 LaCoO/X 在紫外光催化湿式过氧化氢氧化（UV-CWPO）体系中净化煤化工浓液的可行性。通过批实验考察了催化剂载体、煅烧温度、煅烧时间和重复使用时间对催化性能的影响。采用 X 射线衍射（XRD）、扫描电子显微镜（SEM）、BET 和 X 射线光电子能谱（XPS）对催化剂进行了表征。实验结果表明，以 CeO 为载体、煅烧温度 800°C、煅烧时间 8 h 制备的负载型钙钛矿催化剂 LaCoO/CeO 具有最佳的催化效果。催化剂经过 7 次循环后，催化性能仍保持优异。最佳制备的催化剂用于煤化工废水膜浓缩液的 UV-CWPO。考察了 H2O2 用量、反应温度、反应压力和催化剂用量对 UV-CWPO 的影响。在 H2O2 用量 40 mM、反应温度 120°C、反应压力 0.5 MPa、催化剂用量 1 g/L、pH 值 3、反应时间 60 min 的条件下，COD、TOC 和 UV 的去除率分别为 89.7%、84.6%和 98.1%。在最佳操作条件下，氧化后的废水由高毒性变为无毒，BOD/COD 从 0.02 增加到 0.412，氧化后废水的可生化性得到了很大的提高。该催化剂具有合成工艺简单、催化性能优异等特点，在煤化工废水处理的实际应用中具有很大的潜力。
