Department of Environment and Energy, Sejong University, Seoul 05006, South Korea.
Department of Chemistry, Changwon National University, Changwon 51140, South Korea.
Chemosphere. 2019 Jun;224:597-606. doi: 10.1016/j.chemosphere.2019.02.171. Epub 2019 Feb 27.
In this study, the complex degradation behavior of natural organic matter (NOM) was explored using photocatalytic oxidation systems with a novel catalyst based on a hybrid composite of zinc-bismuth oxides and g-CN (ZBO-CN). The photooxidation system demonstrated the effective removal of NOM under low-intensity visible light irradiation, presenting removal rates of 53-74% and 65-88% on the basis of dissolved organic carbon (DOC) and the UV absorption coefficient (UV), respectively, at 1.5 g/L of the catalyst. The NOM removal showed an increasing trend with a higher ZBO-CN dose. Comparative experiments with the hole and OH radical scavengers revealed that the direct oxidation occurring on the catalyst's surface might be the governing photocatalytic mechanism. Fluorescence excitation emission matrix-parallel factor analysis (EEM-PARAFAC) revealed the individual removal behavior of the different constituents in bulk NOM. Different tendencies towards preferential adsorption and subsequent oxidative removal were found among dissimilar fluorescent components within a bulk terrestrial NOM, following the order of terrestrial humic-like (C1) > humic-like (C2) > microbial humic-like (C3) components. The result suggests the dominant operation of π-π and/or hydrophobic interactions between the NOM and the catalyst. The discriminative removal behavior was more pronounced in visible light versus UV-activated systems, probably due to the incapability of visible light to excite è - h pairs of ZnO and the triplet state of NOM. The high photoactivity and structural stability of ZBO-CN under visible light implies its potential for an effective, low-cost and energy-saving treatment technology to selectively remove large sized humic-like substances from water.
在这项研究中，使用基于锌铋氧化物和 g-CN（ZBO-CN）杂化复合材料的新型催化剂的光催化氧化系统探索了天然有机物（NOM）的复杂降解行为。该光氧化系统在低强度可见光照射下表现出有效去除 NOM 的能力，在 1.5 g/L 催化剂的基础上，DOC 和 UV 吸收系数（UV）的去除率分别为 53-74%和 65-88%。NOM 的去除率随 ZBO-CN 剂量的增加而呈上升趋势。与空穴和 OH 自由基清除剂的对比实验表明，可能是催化剂表面的直接氧化导致了主要的光催化机制。荧光激发发射矩阵平行因子分析（EEM-PARAFAC）揭示了批量 NOM 中不同成分的个体去除行为。在批量陆地 NOM 中，不同荧光成分之间表现出不同的优先吸附和随后氧化去除的趋势，顺序为陆地腐殖质样（C1）>腐殖质样（C2）>微生物腐殖质样（C3）成分。结果表明，NOM 和催化剂之间存在π-π和/或疏水相互作用。与 UV 激活系统相比，可见光系统中的区分去除行为更为明显，这可能是由于可见光无法激发 ZnO 的 è - h 对和 NOM 的三重态。ZBO-CN 在可见光下的高光活性和结构稳定性意味着其具有从水中有效、低成本和节能地去除大尺寸腐殖质样物质的潜力。
