College of Environmental Science and Engineering, Hunan University, Changsha, Hunan, 410082, China; Key Laboratory of Environmental Biology and Pollution Control (Hunan University), Ministry of Education, Changsha, Hunan, 410082, China.
College of Environmental Science and Engineering, Hunan University, Changsha, Hunan, 410082, China; Key Laboratory of Environmental Biology and Pollution Control (Hunan University), Ministry of Education, Changsha, Hunan, 410082, China.
Water Res. 2019 Sep 1;160:238-248. doi: 10.1016/j.watres.2019.05.081. Epub 2019 May 26.
This study investigated the hydrogen peroxide (HO) activation potential of Fe-Mn binary oxides modified bio-char (FeMn/bio-char) for the degradation of naphthalene, the dominant PAHs in drinking water. Results showed that FeMn/bio-char exhibited 80.7- and 2.18-times decomposition rates towards HO than that of pure bio-char and Fe-Mn binary oxides, respectively, and consequently the FeMn/bio-char/HO photo-Fenton system presented highest naphthalene removal efficiency. The enhanced catalytic activity could be ascribed to the synergistic effect of the combination of bio-char and Fe-Mn binary oxides, such as promoting the adsorption capacity towards contaminant, increasing concentration of persistent free radicals (PFRs) and introducing Fe-Mn binary oxides as new activator. According to the batch-scale experiments, FeMn/bio-char/HO photo-Fenton system could degrade naphthalene effectively at a wide pH ranges, and 82.2% of naphthalene was degraded under natural pH of 5.6 within 148 min. Free radicals quenching studies and electron spin resonance (ESR) analyses verified that the dominant free radical within FeMn/bio-char/HO photo-Fenton system was hydroxyl radical (•OH). According to the preliminary analysis, the generation of •OH were ascribed to the activation of HO by Fe (II), Mn (II) and PFRs on the catalyst surface. The mainly degradation intermediates of naphthalene were identified by GC-MS analysis. Consequently, the possible degradation pathways were proposed. Moreover, naphthalene degradation experiments were also conducted in river, tap water, industrial wastewater as well as medical wastewater, and the results indicated that the FeMn/bio-char/HO photo-Fenton system was effective in the treatment of naphthalene in natural waters. This study brings a valuable insight for the potential environmental applications of modified bio-char.
本研究考察了 Fe-Mn 二元氧化物修饰生物炭（FeMn/bio-char）对饮用水中主要多环芳烃萘的降解的过氧化氢（HO）活化潜力。结果表明，FeMn/bio-char 对 HO 的分解速率分别比纯生物炭和 Fe-Mn 二元氧化物高 80.7 倍和 2.18 倍，因此 FeMn/bio-char/HO 光芬顿体系对萘的去除效率最高。增强的催化活性可归因于生物炭和 Fe-Mn 二元氧化物结合的协同效应，例如促进对污染物的吸附能力，增加持久性自由基（PFRs）的浓度，并引入 Fe-Mn 二元氧化物作为新的活化剂。根据批量实验，FeMn/bio-char/HO 光芬顿体系可以在宽 pH 范围内有效地降解萘，在自然 pH 为 5.6 时，148 分钟内可降解 82.2%的萘。自由基猝灭研究和电子顺磁共振（ESR）分析证实，FeMn/bio-char/HO 光芬顿体系中的主要自由基是羟基自由基（•OH）。根据初步分析，•OH 的产生归因于催化剂表面上 Fe（II）、Mn（II）和 PFRs 对 HO 的活化。通过 GC-MS 分析鉴定了萘的主要降解中间产物。因此，提出了可能的降解途径。此外，还在河水、自来水、工业废水和医疗废水中进行了萘降解实验，结果表明 FeMn/bio-char/HO 光芬顿体系在天然水中处理萘是有效的。本研究为改性生物炭的潜在环境应用提供了有价值的见解。
