Department of Chemical and Materials Engineering, PUC-Rio, Rio de Janeiro, Brazil.
Department of Civil, Environmental and Geomatic Engineering, University College London, London, UK.
Environ Technol. 2022 Jul;43(17):2590-2603. doi: 10.1080/09593330.2021.1890838. Epub 2021 Mar 9.
This study investigated for the first time the efficiency of an advanced oxidation process (AOP) zero valent iron/hydrogen peroxide (ZVI/HO) employing iron nails for the removal of Natural Organic Matter (NOM) from natural water of Regent's Park lake, London, UK. The low cost of nails and their easy separation from the water after the treatment make this AOP attractive for water utilities in low- and middle-income countries. The process was investigated as a pre-oxidation step for drinking water treatment. Results showed that UV254 removal in the natural water was lower than that of simulated water containing commercial humic acid (HA), indicating a matrix effect. Statistical analysis confirmed the maximum removal of dissolved organic carbon (DOC) in natural water depends on the initial pH (best at 4.5) and HO dosage (best at 100% excess of stoichiometric dosage). DOC and UV254 removals under this operational condition were 51% and 89%, respectively. Molecular weight (MW) and specific UV absorbance (SUVA254) were significantly reduced to 74% and 78%, respectively. Formation of Chloroform THM in natural water sample after the ZVI/HO process (initial pH 4.5) was below the limit for drinking water, and 48% less than the THM formation in the same water not subjected to pre-oxidation. Characterization of oxidation products on the iron-nail-ZVI surface after the ZVI/HO treatment by SEM, XRD, and XPS identified the formation of magnetite and lepidocrocite. Results suggest that the investigated ZVI/HO process is a promising technology for removing NOM and reducing THM formation during drinking water treatment.
本研究首次考察了高级氧化工艺（AOP）零价铁/过氧化氢（ZVI/HO）在去除英国伦敦摄政公园湖水天然有机物（NOM）方面的效率，该工艺采用铁钉作为氧化剂。由于铁钉成本低廉，且在处理后易于从水中分离，因此对于中低收入国家的水务公司来说，该工艺极具吸引力。该工艺被作为饮用水处理的预氧化步骤进行了研究。结果表明，天然水中的 UV254 去除率低于含有商业腐殖酸（HA）的模拟水中的去除率，表明存在基质效应。统计分析证实，天然水中溶解有机碳（DOC）的最大去除率取决于初始 pH 值（最佳值为 4.5）和 HO 用量（最佳值为化学计量用量的 100%过量）。在该操作条件下，DOC 和 UV254 的去除率分别为 51%和 89%。分子量（MW）和特定紫外吸光度（SUVA254）分别显著降低至 74%和 78%。在 ZVI/HO 工艺（初始 pH 值为 4.5）后，天然水样中三卤甲烷（THM）的生成量低于饮用水的限值，比未经预氧化的相同水样中的 THM 生成量低 48%。通过 SEM、XRD 和 XPS 对 ZVI/HO 处理后铁钉-ZVI 表面的氧化产物进行了表征，确定了磁铁矿和纤铁矿的形成。结果表明，所研究的 ZVI/HO 工艺是一种很有前途的去除 NOM 和减少饮用水处理过程中三卤甲烷形成的技术。
