Reactive species in resin supported heterogeneous Fenton-like oxidation of Malachite green solution

During the oxidative degradation of nonbiodegradable Malachite green (MG) by means of H2O2 /FeIIIR (iron supported on ion-exchage resin) in a dynamic column,the binding energy of the Fe(2p3/2) region for XPS spectra was found to be different between the top layer and the bottom layer in this column. Based on the data from XPS spectra and DMPO-OH·signal by EPR spectra,it is shown that the formation of ferryl (IV) is the key step for the oxidation of MG. The ferryl (IV) species can oxidize MG,and its redox potential is about 0. 739 - 0. 803 V measured by cyclic voltammograms (CV) . The catalytic capability of ferryl (IV) species was also evaluated,and it is found that it can promote the decomposition of H2O2 more efficiently than ferric iron. The removal rate of MG mainly depends on the adsorption of catalyst. Both ferryl (IV) and HO·radicals are the reactive species in the system. The oxidation of HO·is only a small part of the overall removal rate. Based on the obtained results,a possible mechanism for a resin-supported Fenton-like oxidation reaction is proposed.     

非均相微波协同类Fenton催化降解废水中的苯酚

通过等体积浸渍法制备了CuO/γ-Al_2O_3催化剂,并对非均相微波协同类Fenton催化降解苯酚溶液进行了实验研究。实验结果表明,在溶液初始pH为6,H_2O_2投加量为4 m L/L,催化剂投加量为4 g/L,微波功率为500 W,反应时间为13 min的条件下,苯酚降解率可达98%,TOC去除率为62%。催化剂重复使用9次后,苯酚降解率为90.88%。通过比较不同氧化体系处理效果及添加·OH捕获剂证实,微波-催化剂-H_2O_2产生了明显的协同作用。     

Fe3+、Co2+、Ni2+、Cu2+参与UV/类Fenton反应动力学研究

以活性艳红X-3B为研究对象,用4种3d轨道过渡金属离子协同UV作催化剂,以H2O2为氧化剂,探讨不同pH值、不同催化剂和氧化剂投入量对色度、COD去除效果的影响;通过改变温度研究4种过渡金属离子进行催化反应的活化能。结果表明,4种过渡金属离子都能发生类Fenton反应,且对活性艳红X-3B的降解速率模型符合二级反应速率模型,通过对反应速率、体系活化能和指前因子的量化研究,得知催化能力的大小顺序为Fe^3＋〉Cu^2＋〉Ni^2＋〉Co^2＋;受温度影响的大小程度排序为：Ni^2＋〉Co^2＋〉Cu^2＋〉Fe^3＋。     

Fe3O4/埃洛石复合材料制备及其对铅锌选矿 废水中有机物降解性能的研究

铅锌有色金属矿选矿废水中残留大量的有机选矿药剂,COD浓度高达165 mg/L,远超废水的国家排放标准,将其直接回用亦会对选矿指标带来不利影响。为降解废水中残留的有机药剂,使其达到排放或回用标准,通过热分解法将四氧化三铁（Fe₃O₄）纳米颗粒负载于埃洛石天然矿物表面,制备得到Fe₃O₄/埃洛石复合材料,并将其作为类芬顿反应的催化剂,用于选矿废水的催化降解。试验考察了Fe₃O₄/埃洛石复合材料制备过程中的升温速率、所制备材料中Fe₃O₄含量,催化反应中初始pH值、反应温度及H₂O₂投加量对选矿废水中COD去除效果的影响。结果表明：在热分解升温速率为2~5 ℃/min、Fe₃O₄含量为35%的条件下合成的复合材料催化性能最佳;在反应温度为30 ℃、初始pH为3、H₂O₂投加量为10 mmol/L、Fe₃O₄/埃洛石复合材料用量0.5 g/L的条件下,铅锌选矿废水中COD由165 mg/L降为39 mg/L,去除率达到76.35%,实现了选矿废水中COD的高效、低成本降解,净化后选矿废水达到一级排放标准。     

铁柱撑膨润土与H_2O_2联合处理酸性大红模拟染料废水

以天然膨润土为载体,采用离子交换法制备了铁柱撑膨润土(Fe-Bent)催化剂,并与H_2O_2组成类芬顿体系,对酸性大红模拟染料废水进行降解处理;考察了Fe-Bent催化剂用量、H_2O_2浓度、溶液pH、反应温度和反应时间对酸性大红去除率的影响,并对Fe-Bent催化剂进行了XRD表征。表征结果显示,Fe-Bent催化剂中铁以α-Fe_2O_3的形态存在。实验结果表明,在Fe-Bent催化剂用量1.0 g、H_2O_2的浓度6 mmol/L、溶液pH 3.0、反应温度60℃、反应时间80 min的适宜条件下,处理100 mL质量浓度为20 mg/L的酸性大红模拟染料废水,酸性大红的去除率可达94.87%。Fe-Bent催化剂的稳定性较好,循环使用4次后仍具有较高活性。     

Azo-dye Orange II degradation by heterogeneous Fenton-like reaction using carbon-Fe catalysts

In this work, the degradation and mineralization of the non-biodegradable azo dye Orange II (OII) was studied, making use of a heterogeneous Fenton-like oxidation process. For that, hydrogen peroxide activation was achieved by means of two different carbon-based catalysts, which have been impregnated with 7 wt% of iron. The carbon supports employed are quite different, one of them being an activated carbon prepared from agricultural by-products (olive stone), while the other one is a carbon aerogel, prepared by carbonization of an organic resorcinol–formaldehyde polymer. The solids have been characterized using several techniques, namely N₂ and CO₂ adsorption at −196 and 0 °C, respectively, mercury porosimetry, scanning electron microscopy (SEM), high-resolution transmission electron microscopy (HRTEM), x-ray diffraction (XRD) and x-ray photoelectron spectroscopy (XPS). Then, the catalyst's performance in the Fenton-like oxidation of OII was compared, and the effects of the most relevant operating conditions (pH, catalyst concentration, H₂O₂ concentration and temperature) analyzed for the most promising one (the carbon aerogel based catalyst). In this catalyst, characterization data point for a very good iron dispersion on the carbon surface. This sample showed very good catalytic performances, with mineralization degrees as high as 90%. However, iron leaching from the support is also considerable leading to a progressive deactivation in consecutive reaction cycles.     

钼酸铁在邻苯二甲酸氧化降解中的催化性能研究

研究了钼酸铁作为类Fenton试剂对邻苯二甲酸的催化氧化性能。考察了催化剂用量、H2O2浓度和反应温度对邻苯二甲酸去除率的影响。结果表明,当催化剂用量为1000 mg/L,H2O2浓度为4.995 mg/L,反应温度40℃时,反应90 min后,邻苯二甲酸的去除率可达92.36%。     

磁性树脂催化H_2O_2降解盐酸黄连素制药废水的研究

通过化学合成法制备出磁性大孔树脂类Fenton催化剂,研究其催化降解盐酸黄连素制药废水的效能,同时考察了pH值、H_2O_2投加量、催化剂投加量及废水初始浓度对其降解效能和反应速率的影响。结果表明:在盐酸黄连素的初始质量浓度为800 mg/L、催化剂投加量为15 g/L、H_2O_2投加量为297 mmol/L、pH值为4、室温(25.0±0.5)℃的条件下,盐酸黄连素的降解率为84.4%,达到最高。研究表明,该非均相类Fenton反应体系对pH值的使用范围广,且催化剂易于分离,反应数次后依然具有较高的催化活性,重复利用率高。     

Fe~(2+)/活性炭在类Fenton体系降解苯酚废水中的应用

以浸渍法制备了系列Fe~(2+)/活性炭材料,X射线衍射、X射线光电子能谱和扫描电子电镜分析结果表明,形貌未变的活性炭载体负载了铁离子。将所制材料应用于类Fenton体系降解废水中苯酚的实验研究,结果表明,在焙烧温度为500℃,铁离子负载量为0.49 mmol/g条件下制备的Fe~(2+)/活性炭材料的催化活性最高,其与双氧水组成的类Fenton体系在60 min内对苯酚的降解率为83%。该材料在循环使用时稳定性好,经5次使用后其活性仅下降8%。