【摘要】：近年來,二元金屬氧化物A_xB_(3-x)O_4在高級氧化過程中受到了廣泛的關(guān)注,其中CuFe2O_4、CoFe2O_4和CoMn2O_4已被報(bào)道可激活過一硫酸鉀(PMS)降解有機(jī)污染物。然而,截至目前,關(guān)于二元金屬催化劑激活更加經(jīng)濟(jì)的過硫酸鉀(PS)的報(bào)道還較少。除此之外,雙金屬催化劑激活PS/PMS過程中,每種金屬在其中的催化作用仍然是限制我們深入理解其催化機(jī)制的主要問題。研究發(fā)現(xiàn),CuCo_2O_4和Zn-Cu二元金屬氧化物在堿性條件下均展現(xiàn)出高催化活性,并且CuCo_2O_4和Zn_1Cu_2的催化活性隨著pH的升高而增加;同時(shí),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,其一級反應(yīng)速率常數(shù)分別為1.64×10~(-1)和6.72×10~(-1)min~(-1)。盡管有報(bào)道稱SO_4·-和·OH對于苯酚的降解起到了主要作用,但我們的研究發(fā)現(xiàn),在CuCo_2O_4激活PS過程中,加入5.0 M甲醇的掩蔽劑后,仍然有60%的苯酚被去除;而EPR分析進(jìn)一步表明,此條件下并無SO_4·-和·OH自由基的存在,因此非自由基機(jī)制對苯酚的降解具有更重要的貢獻(xiàn)意義。XPS分析結(jié)果進(jìn)一步指出,在CuCo_2O_4激活PS過程中,Co(Ⅱ)和Cu(Ⅱ)可被PS氧化為Co(Ⅲ)和Cu(Ⅲ),而這兩種高價(jià)重金屬同樣可有效氧化苯酚。為進(jìn)一步理解Co(Ⅲ)和Cu(Ⅲ)在苯酚降解過程中的貢獻(xiàn),我們設(shè)計(jì)了一系列配位實(shí)驗(yàn)、XPS和Raman分析。這些結(jié)果表明,被L-半胱氨酸還原后的Co(Ⅲ)或者被EDTA絡(luò)合的Co(Ⅲ)均明顯抑制了 CuCo_2O_4的催化活性,而F-穩(wěn)定Cu(Ⅲ)后的體系并未增加反應(yīng)速率,因此我們認(rèn)為Co(Ⅲ)的貢獻(xiàn)意義高于 Cu(Ⅲ)。Zn_1Cu_2激活PS過程中,5.0 M乙醇掩蔽體系在反應(yīng)60 min后仍出現(xiàn)了SO_4·-和·OH自由基,說明Zn_1Cu_2激活PS體系中,自由基在其中也會(huì)起到重要作用。同時(shí),將Zn(Ⅱ)替換為Mg(Ⅱ)和Ca(Ⅱ),我們發(fā)現(xiàn)催化劑Mg1Cu_2和Ca1Cu_2均可激活PS降解苯酚。由于Mg(Ⅱ)和Ca(Ⅱ)并無催化活性,因此我們認(rèn)為,Zn_1Cu_2的催化效果主要源于Cu。結(jié)合XPS分析,我們進(jìn)一步證實(shí)了ZniCu_2體系中出現(xiàn)了"Zn(Ⅲ)"和Cu(Ⅲ),而"Zn(Ⅲ)"的存在僅代表了Zn(Ⅱ)與-O-O-結(jié)合生成的中間產(chǎn)物,并且Cu(Ⅲ)的貢獻(xiàn)高于"Zn(Ⅲ)"。本研究首次發(fā)現(xiàn)了CuCo_2O_4和Zn_1Cu_2兩類二元金屬氧化物在堿性條件下可高效激活PS降解有機(jī)物,為堿性廢水處理提供了重要的選擇;同時(shí),豐富了我們對堿性條件下PS活化機(jī)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，

本文編號：2330964