CuO@Fe_(3)O_(4)催化NaClO对水中丙烯酸及其酯的矿化去除

Mineralization and removal of acrylic acid and its esters from water by CuO@Fe_(3)O_(4) catalyzed NaClO

为实现污水尾端处理中可溶性小分子有机物的完全去除,以克服因它们的大量存在使水体中总有机碳含量增加而引发的严重环境问题,采用氧化剂NaClO和双金属氧化物CuO@Fe_(3)O_(4)组成的催化氧化体系,对喷水织机废水中典型的极性小分子有机物丙烯酸和丙烯酸甲酯进行矿化去除研究;通过X射线衍射(XRD)、扫描电子显微镜(SEM)、X射线能谱(EDS)和BET分析等方法对催化剂进行结构表征和形貌观察,确定催化剂最佳合成方法,并通过氧化实验考察催化剂双金属组成、氧化剂NaClO浓度、催化剂加入量、溶液初始pH和循环催化氧化等因素对小分子有机污染物矿化去除的效果。结果表明:初始铁铜摩尔比为5∶1时,合成的5CuO@Fe_(3)O_(4)纳米粒子催化活性最高;当5CuO@Fe_(3)O_(4)和NaClO投加量分别为0.48 g·L^(−1)、16 mmol·L^(−1)、pH=8.3时,对0.2 g·L^(−1)丙烯酸的COD去除率可达61%;催化剂经过7次循环操作后,对丙烯酸或丙烯酸甲酯仍能保持48%或45%的COD去除率;EPR实验证明·OH是催化氧化体系中降解丙烯酸和丙烯酸甲酯的主要活性物种。上述研究结果为揭示污染水体中难降解极性小分子有机物的矿化去除规律,实现水体中有机碳的总量控制和减排目标提供了技术支撑。

Small organic molecules are refractory components in sewage treatment.Their presence in large quantities can increase the total organic carbon content in water and cause serious environmental problems.In this study,the activation of NaClO by CuO@Fe_(3)O_(4) was evaluated by modeling the mineralization of polar organic molecules acrylic acid and methyl acrylate in jet loom wastewater.X-ray diffraction(XRD),scanning electron microscopy(SEM),X-ray energy spectroscopy(EDS)and Brunauer-Emmett-Teller(BET)were used to reveal the morphology and microstructure of CuO@Fe_(3)O_(4),and determine the optimized synthesis method.The effects of bimetallic composition,NaClO concentration,amount of CuO@Fe_(3)O_(4),initial pH and cyclic catalytic oxidation on the mineralization of acrylic acid and methyl acrylate were investigated.The results showed that 5CuO@Fe_(3)O_(4) exhibited a strong catalytic activity in the mineralization process at the initial Fe-Cu molar ratio of 5:1.When the dosages of 5CuO@Fe_(3)O_(4) and NaClO were 0.48 g·L^(−1) and 16 mmol·L^(-1) respectively,the removal rate of COD for 0.2 g·L^(−1) acrylic acid was 61%at pH=8.3.After seven cycles of operation,the removal rates of COD of acrylic acid and methyl acrylate acid were still 48%and 45%,respectively.EPR experiments showed that·OH was the main active species for the degradation of acrylic acid and methyl acrylate in the catalytic oxidation system.These results provide a technical support for revealing the rule of mineralization and removal of refractory polar organic molecules in polluted water,so as to achieve the total amount control and emission reduction goal of organic carbon in water.