Department of Separation Science, LUT School of Engineering Science, LUT University, Sammonkatu 12, FI-50130, Mikkeli, Finland; Africa Center of Excellence for Water Management, Addis Ababa University, P.O. Box 1176, Addis Ababa, Ethiopia; Department of Chemical Engineering, Wachemo University, P.O. Box 667, Hossana, Ethiopia.
Africa Center of Excellence for Water Management, Addis Ababa University, P.O. Box 1176, Addis Ababa, Ethiopia; School of Chemical and Bioengineering, Addis Ababa Institute of Technology, Addis Ababa, Ethiopia.
Chemosphere. 2024 Oct;365:143402. doi: 10.1016/j.chemosphere.2024.143402. Epub 2024 Sep 24.
Water contamination with pharmaceuticals has become an evident environmental challenge. Treatment processes such as electrochemical oxidation (EO) and adsorption have limitations in the simultaneous removal of pharmaceuticals from water. Therefore, this study examined the potential of coupled process (EO followed by adsorption) in binary pharmaceuticals (acetaminophen (ACM) + ciprofloxacin (CIP)) removal from water, with an emphasis on coupled process optimization. Consequently, optimized coupled process conditions including current density (22 mA/cm), pH (5.5), EO time (40 min), adsorbent dose (0.1 g/L) and adsorption time (60 min) were obtained. Under optimal conditions, removal efficiencies of 94.6% (ACM)+92% (CIP), 94.07% (ACM)+91.15% (CIP), and > 99.8% (ACM + CIP) were recorded for 20 mg/L (ACM + CIP) removal in EO, adsorption and EO + adsorption, respectively. Further, the coupled process was employed in multiple pharmaceuticals (20 mg/L of ACM + CIP + ATN (atenolol) + AMX (amoxicillin)) removal from water and removal of > 97.56% (ACM + CIP + ATN + AMX) was achieved. Removal efficiencies of ACM (83.35%) + CIP (73.1%) + ATN (68.52%) + AMX (63.05%) and ACM (80.37%) + CIP (66.5%) + ATN (73.07%) + AMX (60.5%) were obtained in EO and adsorption, respectively. The noted lower removal efficiencies in EO and adsorption are associated with the diverse nature of the pharmaceuticals, limited adsorbent active sites, and the shared utilization of reactive oxygen species (ROS) among the pharmaceuticals in EO. The total organic carbon (TOC) removal of 40.24%, and 99% and chemical oxygen demand (COD) removal of 72.45%, and 99.6% were obtained under optimal conditions of EO, and coupled process, respectively. These findings indicate that the pharmaceuticals are only partially mineralized in EO and the subsequent adsorption effectively eliminated the remaining target pharmaceuticals, and degradation by-products from water. Additionally, integrating EO with adsorption reduced the electrical energy consumption of the EO process from 31.6 kWh/m³ to 6 kWh/m³ under optimal conditions. Overall, coupling EO with adsorption offers the utmost advantages when removing multiple pharmaceuticals from complex water matrices.
水体中药物污染已成为一个明显的环境挑战。电化学氧化（EO）和吸附等处理工艺在同时去除水中药物方面存在局限性。因此，本研究考察了耦合工艺（EO 后接吸附）在二元药物（扑热息痛（ACM）+环丙沙星（CIP））去除中的潜力，重点是优化耦合工艺条件。结果得到了优化的耦合工艺条件，包括电流密度（22 mA/cm）、pH 值（5.5）、EO 时间（40 分钟）、吸附剂剂量（0.1 g/L）和吸附时间（60 分钟）。在最佳条件下，EO、吸附和 EO+吸附对 20 mg/L（ACM+CIP）的去除率分别为 94.6%（ACM）+92%（CIP）、94.07%（ACM）+91.15%（CIP）和>99.8%（ACM+CIP）。此外，该耦合工艺还用于从水中去除多种药物（20 mg/L 的 ACM+CIP+ATN（阿替洛尔）+AMX（阿莫西林）），并实现了>97.56%（ACM+CIP+ATN+AMX）的去除率。在 EO 和吸附中分别获得了 ACM（83.35%）+CIP（73.1%）+ATN（68.52%）+AMX（63.05%）和 ACM（80.37%）+CIP（66.5%）+ATN（73.07%）+AMX（60.5%）的去除效率。在 EO 和吸附中较低的去除效率与药物的多样性、有限的吸附活性位点以及 EO 中药物之间共享的活性氧（ROS）利用有关。在 EO 和耦合工艺的最佳条件下，TOC 的去除率分别为 40.24%和 99%，COD 的去除率分别为 72.45%和 99.6%。这些结果表明，药物在 EO 中仅部分矿化，随后的吸附有效地去除了水中剩余的目标药物和降解副产物。此外，在最佳条件下，将 EO 与吸附相结合可将 EO 工艺的电能消耗从 31.6 kWh/m³降低至 6 kWh/m³。总体而言，在从复杂水基质中去除多种药物时，将 EO 与吸附相结合具有最大优势。
