Green catalysts for Fenton-like oxidation of Procion Red MX-5B: Influence of the activation method and the reaction parameters on dye removal

The catalytic activities of the iron catalysts over activated carbon supports prepared by different activation methods in the heterogeneous Fenton-like oxidation of Procion Red MX-5B were investigated. The activated carbons were prepared from walnut shells by applying physical and three chemical activation methods, including HNO₃, ZnCl₂, and KOH activations to obtain various catalyst supports. KOH-activated carbon catalyst was assessed to be the most efficient one. Under the optimum reaction conditions, 47.5% COD removal, 51.6% degradation, and 91.6% decolorization efficiencies were achieved in the presence of this catalyst. In the kinetic study, the activation energy was evaluated as 47.36 kJ/mol.     

树脂负载高价铁催化H2O2降解橙黄Ⅳ

为提高多相类芬顿反应的速率,采用高价铁氧化合物(FeIVF=O/R)为催化剂,强化H2O2分解降解橙黄IV.探讨初始pH值、温度、过氧化氢初始浓度和橙黄IV初始浓度等对反应速率的影响.结果表明:随着pH值升高,橙黄IV降解率下降.在pH值3～10的范围内,能有效地对橙黄IV进行降解.催化H2O2降解橙黄IV的反应遵循一级反应动力学,反应活化能为59.94kJ/mol.反应速率常数与H2O2的初始浓度及与橙黄IV初始浓度都具有很好的正相关性.催化剂重复使用表明铁在树脂表面负载比较牢固,具有较好的稳定性和耐用性.     

Degradation Effect and Mechanism of Dinitrotoluene Wastewater by Magnetic Nano-Fe3O4/H2O2 Fenton-like

The characteristics and influencing factors for dinitrotoluene degradation by nano-Fe₃O₄-H₂O₂ were studied, and the nano-scale Fe₃O₄ catalyst was prepared by the coprecipitation method, with dinitrotoluene wastewater as the degradation object. The results showed that the catalytic reaction system within the pH value range of 1 to 9 could effectively degrade dinitrotoluene, and the optimal pH value was 3; with the increase of catalyst dosage, the degradation efficiency and the catalytic reaction rate of dinitrotoluene grew as well. The optimal catalyst dosage was 1.0 g/L when the H₂O₂ dosage was within the range of 0 to 0.8 mL/L; the degradation efficiency and reaction rate grew with the increase of H₂O₂ dosage. With further increase of H₂O₂ dosage, degradation efficiency and reaction rate decreased; under the best conditions with the H₂O₂ dosage of 0.8 mL/L, the catalyst concentration of 1 g/L and the pH value of 3 at room temperature (25 °C), the degradation rate of the 100-mg/L dinitrotoluene in 120 min reached 97.6%. Through the use of the probe compounds n-butyl alcohol and benzoquinone, it was proved that the oxidation activity species in the nano-Fe₃O₄-H₂O₂ catalytic system were mainly hydroxyl radical (?OH) and superoxide radicals (HO2 ?), based on which, the reaction mechanism was hypothesized.     

Fe_(78)Si_9B_(13)非晶条带在敌敌畏农药废水处理中的应用

为了降低农药废水对环境和人类健康的危害,研制了一种新型催化剂来降解农药废水.将Fe_(78)Si_9B_(13)非晶条带作为催化剂,采用类芬顿法研究了H2O2浓度、p H值、非晶条带用量和初始敌敌畏浓度对COD去除率的影响.结果表明,当H2O2浓度为0. 82 mol/L、p H值为2、非晶条带用量为3 g/L、初始敌敌畏浓度为600 mg/L时,10 min后COD去除率达到最大值85%,而采用传统芬顿法COD去除率仅为50%.当非晶条带循环使用5次后,其结构保持不变且降解效果未发生明显改变.     

Feasibility of a two-stage reduction/subsequent oxidation for treating Tetrabromobisphenol A in aqueous solutions

A “two-stage reduction/subsequent oxidation” (T-SRO) process consists of Fe-Ag reduction and Fenton-like oxidation under ultrasound (US) radiation. Due to the refractory oxidation of brominated flame retardant, T-SRO was employed to remove Tetrabromobisphenol A (TBBPA) by the combination of first debromination and succeeding oxidation. It indicated that the T-SRO process resulted in a complete decrease in TBBPA concentration and a 99.2% decrease in BPA concentration. The T-SRO process for the removal of TBBPA is much effective than Fenton-like oxidation of TBBPA alone. The result showed that US radiation improved the Fenton-like oxidation rate of BPA solutions. The addition of dissolved iron into the Fenton-like oxidation system could accelerate the first 2 min reaction, but had little effect on the following process. The main intermediate products resulting from TBBPA reduction and BPA oxidation were identified by GC-MS and LC-MS/MS. On the basis of this analysis, reactions with •OH radical were identified as the major chemical pathways during BPA oxidation.     

Application of surfactant enhanced permanganate oxidation and bidegradation of trichloroethylene in groundwater

Fe-C-TiO(2) photocatalysts were prepared by mechanical mixing of commercial anatase TiO(2) precursor with FeC(2)O(4) and heating at 500-800 degrees C under argon flow. These photocatalysts were tested for dyes decomposition: Methylene Blue (MB), Reactive Black (RB) and Acid Red (AR). The preliminary adsorption of dyes on the photocatalysts surface was performed. Modification of anatase by FeC(2)O(4) caused reducing of zeta potential of the photocatalyst surface from +12 to -7mV and decreasing of their adsorption ability towards RB and AR, which were negatively charged, -46.8 and -39.7, respectively. Therefore, unmodified TiO(2) showed the highest degree of RB and AR decompositions in the combination of dyes adsorption and UV irradiation. Methylene Blue, which had zeta potential of +4.3 in the aqueous solution was poorly adsorbed on all the tested photocatalysts and also slowly decomposed under UV irradiation. The high rate of dyes decomposition was noted on Fe-C-TiO(2) photocatalysts under UV irradiation with addition of H(2)O(2). It was observed, that at lower temperatures of heat treatment such as 500 degrees C higher content of carbon is remained in the sample, blocking the built in of iron into the TiO(2) lattice. This iron is reactive in the photo-Fenton process resulting in high production of OH radicals and also high activity of the photocatalyst. At higher temperatures of heat treatment, less active FeTiO(3) phase is formed, therefore Fe-C-TiO(2) sample prepared at 800 degrees C showed low photocatalytic activity for dyes decomposition. Fe-C-TiO(2) photocatalysts are active under visible light irradiation, however, the efficiency of a dye decomposition is lower than under UV light. In a dark Fenton process there is observed an insignificant generation of OH radicals and very little decomposition of a dye, what suggests the powerful of photo-Fenton process in the dyes decomposition.     

钛网表面Fe3O4/FeS2膜层制备及其类芬顿降解苯酚研究

为了拓宽类芬顿催化剂的pH适用范围、改善其有机污染物降解性能并解决其分离回收难的问题,本文采用易于大规模制备的电沉积法在钛网表面沉积了Fe3O4/FeS2固定化膜层.通过XRD、SEM及XPS等表征手段研究了所合成催化剂的相组成、形貌及表面元素价态.结果 显示,所合成的材料主要由Fe3 O4与FeS2物相组成,且膜层表面呈现由纳米片间相互交联形成的多孔网状结构.类芬顿降解苯酚性能表明,在0.20 mol/L硫源含量下所得膜层于pH 6.0、H2 O2含量6 mmol/L、苯酚初始质量浓度35 mg/L、反应温度30℃的条件下降解60 min,可将98％的苯酚去除.因而,Fe3O4/FeS2固定化膜层催化剂表现出优异的类芬顿催化活性.分析发现:材料较大的比表面积可增强传质,同时提供更多的活性位点参与苯酚降解;而催化剂表面键合的S22-可促进≡Fe3+/≡Fe2+以及Fe3 +/Fe2的氧化还原循环,同时,以硫酸根形式存在的硫物种可为类芬顿反应提供合适的酸性微环境,从而提高羟基自由基的产生速率及产生量,最终显著改善该催化剂在近中性条件下的催化活性.     

微波辅助类芬顿技术处理合成类制药废水

研究了微波辅助类酚顿技术处理合成类制药废水的优势,通过优化实验发现,微波辅助类芬顿技术具有催化剂和过氧化氢用量低(硝酸铜0.8 g/L,过氧化氢15 m L/L)、初始反应体系无需酸化、反应时间短(6 min)、污染物去除效果满意(TOC去除率62.64%)、可生化性改善良好(从0.25升至0.37)、处理后Cu2+离子残余质量浓度低(0.625 5 mg/L)等独特优势.在相同条件下该技术采用铜系催化剂比相同物质的量的铁系催化剂的TOC去除效率更理想,即从51.40%提高到62.64%.     

钼酸铁空心微球的生物模板法制备及其催化性能研究

以酵母细胞为模板,通过生物模板法制得钼酸铁空心微球材料,采用XRD、SEM、FTIR以及氮气吸脱附等手段,对样品的物相、微观形貌及比表面积等进行表征;并以亚甲基蓝模拟染料废水为研究对象,评价了样品的高级氧化催化性能。结果表明:生物模板法得到的钼酸铁空心微球为单斜晶系Fe_2(MoO_4)_3,样品分散度良好,形貌一致,较好地保持了酵母细胞椭圆形的形貌,平均尺寸约为5.6μm×3.7μm,比表面积为14.9m~2/g;钼酸铁空心微球作为类Fenton催化剂应用于亚甲基蓝模拟染料废水处理,表现出优异的高级氧化催化活性,当催化剂用量为1g/L、H_2O_2浓度为300mmol/L、反应温度25℃、pH=5时,反应60min后对100mg/L模拟染料废水中亚甲基蓝的去除率可达98%以上。     

类Fenton试剂法（Fe-H_2O_2）处理餐饮油脂废水

为了处理餐饮油脂废水中难以生物降解的有机物,采用类Fenton试剂（Fe-H2O2）对其进行处理,分别考察了pH值、反应时间、反应温度、H2O2投加量和Fe投加量对CODCr和动植物油去除率的影响,总结得出了H2O2投加量的系列计算公式。结果表明：废水初始CODCr浓度为1 633.52 mg/L,油脂值为349.58 mg/L时,在pH值为2、反应时间30 min、反应温度60℃、H2O2（30%）投加量为5 mL、nH2O2∶nFe=6∶1的最优条件下,CODCr和动植物油的去除率分别达到91.2%和96.47%。