活性艳蓝经多相类芬顿预处理前后对厌氧污泥性能的影响

以蒽醌类染料活性艳蓝为目标污染物,探讨了其对产甲烷菌的抑制机理;分析了其经多相类芬顿预处理前后对厌氧污泥EPS、粒径分布、金属离子含量的影响;同时对活性艳蓝的降解途径进行了探究。结果表明,活性艳蓝对产甲烷菌具有代谢毒性甚至生理性毒性;其进入厌氧反应器后,会造成COD去除率降低;颗粒污泥粒径减少,污泥中钙、镁离子浓度分别由40.5和16.2 mg·L^-1降低到22.5和6.8 mg·L^-1,污泥的稳定性与絮凝性变差。而经多相类芬顿预处理后,COD去除率可达90%以上,厌氧颗粒污泥EPS总量、蛋白质含量、多糖含量分别增大到98.7、69.9和28.8 mg·(g VSS)^-1,为保持颗粒污泥的活性与稳定性提供了保障。多相类芬顿体系所产生的羟基自由基首先攻击活性艳蓝的三嗪基团及不饱和共轭键的蒽醌结构,继而生成邻苯二甲酸、苯甲酸,再被降解为丁酸、草酸、乙酸等小分子羧酸,从而降低了其毒性,有利于后续厌氧生物处理的进行。     

微波诱导粉煤灰-H2O2处理垃圾渗滤液的研究

Fenton和类Fenton试剂广泛用于持久性有机污染物的矿化处理。微波辐射能提高Fenton和类Fen-ton法处理难降解有机废水的效率和处理能力。实验采用粉煤灰吸附分离与微波高级氧化的组合工艺处理垃圾渗滤液,以降低垃圾渗滤液的化学需氧量(COD)浓度。粉煤灰作为有机废水的吸附剂,同时粉煤灰中溶出的铁及其他过渡金属离子能与H2O2形成Fenton类试剂,产生氧化能力极强的羟基自由基(.OH),氧化处理其中的有机物。当粉煤灰量为20 g/L,pH=2,搅拌1 h后过滤分离;每1 L滤液加入2 mL 30%(质量比)的H2O2,入微波炉,设定温度80℃,功率600 W,在微波中作用20 min时,COD的去除率可达69.81%。     

Preparation of CuxO/C composite derived from Cu-MOFs as Fenton-like catalyst by two-step calcination strategy

Cu_xO/C composites were successfully prepared using Cu-MOFs as the template and precursor by a two-step calcination strategy. SEM and TEM observations indicated that the composites had a microstructural prototype of porous cubic frameworks with the attachment of graphitic nanosheets on the surfaces, where the co-existence of CuO and Cu₂O nanoparticles were uniformly encapsulated. The Fenton-like activities of the Cu_xO/C composites were studied by the degradation of Rhodamine B. The sample calcinated firstly at 500?°C in N₂ followed at 300?°C in air achieved the optimal catalytic properties. Approximate 90% contaminant could be degraded within 40?min and the performances was maintained stable after five cycling runs. The superior Fenton-like activities of as-prepared Cu_xO/C composites were attributed to the high specific surface area, good adsorption and enhanced electron transport of well crystallized microstructures.     

黄铁矿烧渣催化H_2O_2氧化废水中难降解污染物

传统Fenton氧化是以Fe2+离子为催化剂进行催化H2O2氧化,以含铁矿物为催化剂的非均相类Fenton反应最近受到重视。以酸性红B染料、苯酚等污染物以及实际工业废水为处理对象,研究了黄铁矿烧渣为催化剂的非均相类Fenton反应。考察了催化剂、H2O2投加量、初始pH、反应时间、催化剂回收重复利用等因素的影响和优化。在烧渣投加量为10g.L-1,双氧水投加量为20ml.L-1,体系pH在1～11范围内,反应6h后,酸性红B染料、苯酚的去除率接近100%,工业废水处理后脱色效果明显,而且BOD5/COD比值能大幅提高。研究表明:黄铁矿烧渣对催化H2O2氧化具有很强的催化活性,是有效的类Fenton反应催化剂,而且相比于单一含铁矿物具有更好的催化性能,反应受pH影响很小,解决了传统Fenton反应需要调节pH的难题。催化剂易于沉淀分离,能回收重复利用。     

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%.     

Green synthesis of bentonite-supported iron nanoparticles as a heterogeneous Fenton-like catalyst: Kinetics of decolorization of reactive blue 238 dye

This study aimed to synthesize green tea nano zero-valent iron (GT-NZVI) and bentonite-supported green tea nano zero-valent iron (B-GT-NZVI) nanoparticles using green tea extracts in an environmentally sustainable way. Bentonite was used as a support material because it disperses and stabilizes GT-NZVI, and it helps to reduce the cost, increase the adsorption capacity of GT-NZVI, and decrease the optimum amount of GT-NZVI used in Fenton-like oxidation. A scanning electron microscope, an atomic force microscope, and a Fourier transform infrared spectroscope were used to characterize GT-NZVI and B-GT-NZVI, while the zeta potential was measured to evaluate the stability of iron nanoparticles. The decolorization kinetics of reactive blue 238 (RB 238) dye in the aqueous phase in the Fenton-like oxidation process were investigated as well. The effects of various experimental conditions such as reaction time, dosages of catalysts, concentration of H₂O₂, temperature, addition of inorganic salts, and other parameters were investigated. The results show that the oxidative degradation efficiencies of RB 238 dye catalyzed by GT-NZVI and B-GT-NZVI were 93.5% and 96.2%, respectively, at the optimum reaction conditions as follows: c(H₂O₂) = 5 mmol/L, ρ(GT-NZVI) = 0.5 g/L or ρ(B-GT-NZVI) = 0.5 g/L, c(RB 238 dye) = 0.05 mmol/L, and pH = 2.5 at 180 min. The best catalytic performance was exhibited when B-GT-NZVI was used. Three kinetic models were employed, and the second-order model was found to be the best model representing the experimental kinetic data of RB 238 dye. The value of activation energy decreased from 38.22 kJ/mol for GT-NZVI to 14.13 kJ/mol for B-GT-NZVI. This indicates that the effect of B-GT-NZVI in decreasing the energy barrier is more pronounced than that of the GT-NZVI catalyst, leading to improved Fenton-like oxidation processes.     

介孔Fe-SiO2复合材料的制备及吸附协同催化性能

采用原位一步合成法,在含有模板剂、AlCl₃和H₂O的弱酸性反应体系中,引入Si源和Fe源,通过原位共沉积的方式,成功制备出Fe修饰的介孔SiO₂（Fe-SiO₂）复合材料。采用XRD、N₂吸附、FTIR、UV-vis、SEM和EDS等手段表征了介孔Fe-SiO₂复合材料样品的结构、形貌和化学组成;将所获得的介孔Fe-SiO₂复合材料用于吸附和协同催化去除水体中有机污染物亚甲基蓝（MB）;考察了Fe源添加量对介孔Fe-SiO₂复合材料结构和性能的影响。研究结果表明:合成体系中rFe:Si ≤ 0.05（摩尔比）时,所得Fe-SiO₂介孔材料保留了介孔孔道的高度有序性和大比表面积（860~889 m2·g-1）,Fe在介孔Fe-SiO₂复合材料中主要以四配位骨架掺杂的形式存在;当rFe:Si=0.1时,其比表面积下降为526 m2·g-1,Fe以骨架内和骨架外氧化物的形式共存于介孔Fe-SiO₂复合材料中。所有介孔Fe-SiO₂复合材料在去除MB的实验中均表现出很大的吸附容量和优良的多相类芬顿催化能力。其中,rFe:Si=0.05时所获得的介孔Fe-SiO₂复合材料样品性能最佳,对高浓度MB（250 mg·L-1）的吸附和催化总量达到213 mgg-1。      

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.     

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.