ABSTRACT

This study investigated for the first time the efficiency of an advanced oxidation process (AOP) zero valent iron/hydrogen peroxide (ZVI/H₂O₂) 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 H₂O₂ 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/H₂O₂ 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/H₂O₂ treatment by SEM, XRD, and XPS identified the formation of magnetite and lepidocrocite. Results suggest that the investigated ZVI/H₂O₂ process is a promising technology for removing NOM and reducing THM formation during drinking water treatment.

摘要

本研究首次研究了高级氧化工艺 (AOP) 零价铁/过氧化氢 (ZVI/H ₂ O ₂) 使用铁钉从英国伦敦摄政公园湖的天然水中去除天然有机物质 (NOM)。钉子的低成本及其在处理后容易与水分离，使得这种 AOP 对低收入和中等收入国家的水务公司具有吸引力。该工艺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植酸 (HA) 的模拟水，表明存在基质效应。统计分析证实，天然水中溶解有机碳 (DOC) 的最大去除量取决于初始 pH 值（最好为 4.5）和 H ₂ O ₂剂量（最好超过化学计量剂量的 100%）。这种操作条件下的 DOC 和 UV254 去除率分别为 51% 和 89%。分子量 (MW) 和比紫外吸光度 (SUVA254) 分别显着降低至 74% 和 78%。_{ZVI/H 2} O ₂过程（初始pH 4.5）后天然水样中氯仿THM的形成低于饮用水的限值，比未经预氧化的相同水中的THM形成量少48%。通过 SEM、XRD 和 XPS对 ZVI/H ₂ O ₂处理后的 Iron-nail-ZVI 表面的氧化产物进行表征，确定了磁铁矿和纤铁矿的形成。结果表明，所研究的 ZVI/H ₂ O ₂该工艺是一种有前途的技术，可去除饮用水处理过程中的 NOM 并减少 THM 的形成。