CUCO2O4和ZN-CU二元金属氧化物激活过硫酸钾降解苯酚机制的研究
发布时间：2018-11-14 10:53
【摘要】：近年来,二元金属氧化物A_xB_(3-x)O_4在高级氧化过程中受到了广泛的关注,其中CuFe2O_4、CoFe2O_4和CoMn2O_4已被报道可激活过一硫酸钾(PMS)降解有机污染物。然而,截至目前,关于二元金属催化剂激活更加经济的过硫酸钾(PS)的报道还较少。除此之外,双金属催化剂激活PS/PMS过程中,每种金属在其中的催化作用仍然是限制我们深入理解其催化机制的主要问题。研究发现,CuCo_2O_4和Zn-Cu二元金属氧化物在碱性条件下均展现出高催化活性,并且CuCo_2O_4和Zn_1Cu_2的催化活性随着pH的升高而增加;同时,100.0mg L~(-1)的苯酚在30 min可被1.0 g L~(-1) CuCo204和Zn_1Cu_2和1.0 gL~(-1) PS完全去除,其一级反应速率常数分别为1.64×10~(-1)和6.72×10~(-1)min~(-1)。尽管有报道称SO_4·-和·OH对于苯酚的降解起到了主要作用,但我们的研究发现,在CuCo_2O_4激活PS过程中,加入5.0 M甲醇的掩蔽剂后,仍然有60%的苯酚被去除;而EPR分析进一步表明,此条件下并无SO_4·-和·OH自由基的存在,因此非自由基机制对苯酚的降解具有更重要的贡献意义。XPS分析结果进一步指出,在CuCo_2O_4激活PS过程中,Co(Ⅱ)和Cu(Ⅱ)可被PS氧化为Co(Ⅲ)和Cu(Ⅲ),而这两种高价重金属同样可有效氧化苯酚。为进一步理解Co(Ⅲ)和Cu(Ⅲ)在苯酚降解过程中的贡献,我们设计了一系列配位实验、XPS和Raman分析。这些结果表明,被L-半胱氨酸还原后的Co(Ⅲ)或者被EDTA络合的Co(Ⅲ)均明显抑制了 CuCo_2O_4的催化活性,而F-稳定Cu(Ⅲ)后的体系并未增加反应速率,因此我们认为Co(Ⅲ)的贡献意义高于 Cu(Ⅲ)。Zn_1Cu_2激活PS过程中,5.0 M乙醇掩蔽体系在反应60 min后仍出现了SO_4·-和·OH自由基,说明Zn_1Cu_2激活PS体系中,自由基在其中也会起到重要作用。同时,将Zn(Ⅱ)替换为Mg(Ⅱ)和Ca(Ⅱ),我们发现催化剂Mg1Cu_2和Ca1Cu_2均可激活PS降解苯酚。由于Mg(Ⅱ)和Ca(Ⅱ)并无催化活性,因此我们认为,Zn_1Cu_2的催化效果主要源于Cu。结合XPS分析,我们进一步证实了ZniCu_2体系中出现了"Zn(Ⅲ)"和Cu(Ⅲ),而"Zn(Ⅲ)"的存在仅代表了Zn(Ⅱ)与-O-O-结合生成的中间产物,并且Cu(Ⅲ)的贡献高于"Zn(Ⅲ)"。本研究首次发现了CuCo_2O_4和Zn_1Cu_2两类二元金属氧化物在碱性条件下可高效激活PS降解有机物,为碱性废水处理提供了重要的选择;同时,丰富了我们对碱性条件下PS活化机制的理解。
[Abstract]:In recent years, binary metal oxide AxB3-x Os _ 4 has received extensive attention in the process of advanced oxidation, among which CuFe2O_4,CoFe2O_4 and CoMn2O_4 have been reported to activate the degradation of organic pollutants by potassium monosulfate (PMS). However, so far, there have been few reports about the more economical potassium persulfate (PS) activated by binary metal catalysts. In addition, the catalytic action of each metal in bimetallic catalysts during the activation of PS/PMS is still a major problem that limits our understanding of the catalytic mechanism of bimetallic catalysts. It is found that both CuCo_2O_4 and Zn-Cu binary metal oxides exhibit high catalytic activity under alkaline conditions, and the catalytic activities of CuCo_2O_4 and Zn_1Cu_2 increase with the increase of pH. Meanwhile, phenol of 100.0mg L ~ (-1) could be completely removed by 1.0 g L ~ (-1) CuCo204 and Zn_1Cu_2 and 1.0 gL~ (-1) PS at 30 min. The first-order reaction rate constants are 1.64 脳 10 ~ (-1) and 6.72 脳 10 ~ (-1) min~ (-1), respectively. Although it has been reported that SO_4-and OH play a major role in the degradation of phenol, our study shows that 60% of phenol is still removed after the addition of 5. 0M methanol masking agent in the process of PS activation by CuCo_2O_4. EPR analysis further showed that there were no SO_4-and OH free radicals in this condition, so the mechanism of non free radical has a more important contribution to phenol degradation. XPS analysis results further indicated that, , Co (鈪，
本文编号：2330964
[Abstract]:In recent years, binary metal oxide AxB3-x Os _ 4 has received extensive attention in the process of advanced oxidation, among which CuFe2O_4,CoFe2O_4 and CoMn2O_4 have been reported to activate the degradation of organic pollutants by potassium monosulfate (PMS). However, so far, there have been few reports about the more economical potassium persulfate (PS) activated by binary metal catalysts. In addition, the catalytic action of each metal in bimetallic catalysts during the activation of PS/PMS is still a major problem that limits our understanding of the catalytic mechanism of bimetallic catalysts. It is found that both CuCo_2O_4 and Zn-Cu binary metal oxides exhibit high catalytic activity under alkaline conditions, and the catalytic activities of CuCo_2O_4 and Zn_1Cu_2 increase with the increase of pH. Meanwhile, phenol of 100.0mg L ~ (-1) could be completely removed by 1.0 g L ~ (-1) CuCo204 and Zn_1Cu_2 and 1.0 gL~ (-1) PS at 30 min. The first-order reaction rate constants are 1.64 脳 10 ~ (-1) and 6.72 脳 10 ~ (-1) min~ (-1), respectively. Although it has been reported that SO_4-and OH play a major role in the degradation of phenol, our study shows that 60% of phenol is still removed after the addition of 5. 0M methanol masking agent in the process of PS activation by CuCo_2O_4. EPR analysis further showed that there were no SO_4-and OH free radicals in this condition, so the mechanism of non free radical has a more important contribution to phenol degradation. XPS analysis results further indicated that, , Co (鈪，
本文编号：2330964
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