六铝酸盐催化剂的催化还原脱硫脱硝性能

采用共沉淀法制备Cu和Fe掺杂的六铝酸盐催化剂(SrCuxFe1-xAl11O19-δ,x为0,0.2,0.4,0.5,0.6,0.8,1),通过XRD、TPR、BET等技术方法对催化剂的结构及性质进行了研究,并考察了以CO为还原剂的催化脱硝活性。结果表明,用碳酸铵作为沉淀剂在1 200℃焙烧4 h可以形成完整的六铝酸盐晶型,Cu和Fe能够取代Al3+,很好地促进六铝酸盐晶体结构的形成;SrCuxFe1-xAl11O19-δ催化剂有很好的脱硫脱硝催化活性,此类型的催化剂均使SO2、NO的转化率在空速为6 000 h-1下达到了80%和90%以上。向体系中加入氧气会对催化活性有较大影响。     

Arsenic(III) and iron(II) co-oxidation by oxygen and hydrogen peroxide: Divergent reactions in the presence of organic ligands

Iron-catalyzed oxidation of As(III) to As(V) can be highly effective for toxic arsenic removal via Fenton reaction and Fe(II) oxygenation. However, the contribution of ubiquitous organic ligands is poorly understood, despite its significant role in redox chemistry of arsenic in natural and engineered systems. In this work, selected naturally occurring organic ligands and synthetic ligands in co-oxidation of Fe(II) and As(III) were examined as a function of pH, Fe(II), H₂O₂, and radical scavengers (methanol and 2-propanol) concentration. As(III) was not measurably oxidised in the presence of excess ethylenediaminetetraacetic acid (EDTA) (i.e. Fe(II):EDTA < 1:1), contrasting with the rapid oxidation of Fe(II) by O₂ and H₂O₂ at neutral pH under the same conditions. However, partial oxidation of As(III) was observed at a 2:1 ratio of Fe(II):EDTA. Rapid Fe(II) oxidation in the presence of organic ligands did not necessarily result in the coupled As(III) oxidation. Organic ligands act as both iron speciation regulators and radicals scavengers. Further quenching experiments suggested both hydroxyl radicals and high-valent Fe species contributed to As(III) oxidation. The present findings are significant for the better understanding of aquatic redox chemistry of iron and arsenic in the environment and for optimization of iron-catalyzed arsenic remediation technology.     

Fe3+、PO43-在煤气化废水处理中的应用

针对煤气化废水的特点,通过投加Fe3 、PO43-的方法来强化多阶段水解-好氧工艺处理煤气化废水的能力,不加Fe3 、PO43-时,CODcr总去除率为78 88%,出水CODcr仍高达931mg/l,当投加Fe3 、PO43-后,出水CODcr降到245mg/l,去除率达到93 93%。     

Effect of Fe（Ⅲ） on the bromate reduction by humic substances in aqueous solution

Humic substances are ubiquitous redox-active organic compounds of environment. In this study, experiments were conducted to determine the reduction capacity of humic acid in the man-ix of bromate and Fe（Ⅲ） solutions and the role of Fe（Ⅲ） in this redox process. The results showed that the humic acid regenerated Fe（Ⅱ） and reduced bromate abiotically. The addition of Fe（Ⅲ） could accelerate the bromate reduction rate by forming humic acid-Fe（Ⅲ） complexes. Iron species acts as electron mediator and catalyst for the bromate reduction by humic acid, in which humic acid transfers electrons to the complexed Fe（Ⅲ） to form Fe（Ⅱ）, and the regenerated Fe（Ⅱ） donate the electrons to bromate. The kinetics study on bromate reduction further indicated that bromate reduction by humic acid-Fe（Ⅲ） complexes is pH dependent. The rate decreased by 2-fold with the increase in solution pH by one unit. The reduction capacity of Aldrich humic acid was observed to be lower than that of humic acid or natural organic matter of Suwanne River, indicating that such redox process is expected to occur in the environment.     

酸性条件下Fe3+氧化SO2的脱硫反应机理

讨论酸性条件下Ｆｅ＾３＋液相氧化ＳＯ２的几何可能反应机理,设计了不同的缓冲和非缓冲Ｆｅ＾３＋溶液脱硫试验。通过对不同反应体系ＳＯ２吸收特性的测量,得出了反应符合半导体或过渡态金属的催化机理,液相氧化反应的速率受Ｆｅ＾３＋的老化进程所控制,从而为低浓度Ｆｅ＾３＋溶液烟气脱硫和解释雾水酸化现象提供了理论基础。     

油气田压裂返排液治理技术研究现状

概述了压裂的目的、压裂液以及压裂返排液的来源和和水质特征。综述了近十年来絮凝沉降法、生物及生化法、高级氧化技术和Fe/C微电解组合工艺的水处理作用原理及其在压裂返排液治理中的应用进展。分析并指出了压裂返排液处理技术中存在的问题和今后的主要发展方向。     

Fe3O4-MnO2复合材料催化降解水中有机污染物的研究进展

综述了Fe₃O₄-MnO₂复合材料催化降解水中有机污染物的研究进展,介绍了Fe₃O₄-MnO₂复合材料的负载方式,总结了Fe₃O₄-MnO₂复合材料在催化降解水中有机污染物方面的应用。同时,阐述了Fe₃O₄-MnO₂复合材料催化降解水中有机污染物的机理。指出：Fe₃O₄-MnO₂复合材料未来的研发方向是实现负载方式的多样性和提高复合材料的热稳定性,制备出形貌多样、结晶性能好、稳定性高、经济性好、功能多样的Fe₃O₄-MnO₂复合材料。     

Mechanisms of photochemical release of dissolved organic matter and iron from resuspended sediments

Photochemical reactions can alter the transformation of sedimentary organic matter into dissolved organic matter (DOM) and affect its ultimate fate in water ecosystems. In the present study, the photorelease of DOM and Fe from resuspended lake sediments was investigated under different O₂ and NO₃^? concentration conditions to study the mechanisms of DOM and Fe photorelease. The amount of photoreleased Fe, which ranged from 0.22 to 0.70 μmol/L, was significantly linearly correlated with the amount of photoreleased DOM. O₂ and NO₃^? could promote the photochemical release of DOM and Fe, especially during the initial 4 h irradiation. In general, the order of the photorelease rates of DOM and Fe under different conditions was as follows: NO₃^?/aerobic > aerobic ≈ NO₃^?/anaerobic > anaerobic. The photorelease rates of DOM and Fe were higher for the initial 4 hr irradiation than these for the subsequent 8 hr irradiation. The photorelease of DOM and Fe is thought to proceed via direct photodissolution and indirect processes. The relative contributions of indirect processes (>60%) was much greater than that of direct photodissolution (<40%). The photoproduced H₂O₂ under aerobic and anaerobic conditions indicated that hydroxyl radicals (?OH) are involved in the photorelease of DOM. Using ?OH scavengers, it was found that 38.7%, 53.7%, and 77.6% of photoreleased DOM was attributed to ?OH under anaerobic, aerobic, and NO₃^?/aerobic conditions, respectively. Our findings provide insights for understanding the mechanisms and the important role of ?OH in the DOM and Fe photorelease from resuspended sediments.     

膨润土负载纳米铁/镍还原阿莫西林的环境影响因素研究

采用液相还原法制备膨润土负载纳米铁/镍(Bent-Fe/Ni)用于还原阿莫西林,研究了不同浓度的阴离子(SO2-4、HCO-3)和阳离子(Ca2+、Cu2+)对Bent-Fe/Ni还原阿莫西林的影响.结果表明,SO2-4、HCO-3浓度对Bent-Fe/Ni还原阿莫西林的影响较大,当其浓度分别为0和500mg·L-1时,阿莫西林的去除率分别为93.7%和21.5%(SO2-4),以及93.7%和5.8%(HCO-3);Ca2+对Bent-Fe/Ni还原阿莫西林起到抑制作用,当其浓度为0和500 mg·L-1时,阿莫西林的去除率分别为93.7%和77.8%;低浓度的Cu2+对Bent-Fe/Ni还原阿莫西林起到促进作用,而高浓度的Cu2+对Bent-Fe/Ni还原阿莫西林起到抑制作用,当其浓度为0、10和100 mg·L-1时,阿莫西林的去除率分别为93.7%、94.8%和86.7%.     

Preparation and characterization of Fe2O3-CeO2-TiO2/γ-Al2O3 catalyst for degradation dye wastewater

In order to develop a catalyst with high activity for catalytic wet oxidation （CWO） process at room temperature and atmospheric pressure, Fe2O3-CeO2-TiO2/γ-Al2O3 catalyst was prepared by consecutive impregnation method and the prepared parameters were optimized. The structure of the catalyst was characterized by BET, XRF, SEM and XPS technologies, and the actual wastewater was used to investigate the catalytic activity of Fe2O3-CeO2-TiO2/γ-Al2O3 in CWO process. The experimental results showed that the prepared catalyst exhibited good catalytic activity when the doping amount of Ti was 1.0 wt% （the weight ratio of Ti to carriers）, and the middle product, Fe2O3-CeO2-TiO2/γ-Al2O3, was calcined in 450℃ for 2 h. The CWO experiment for treating actual dye wastewater indicated that the COD, color and TOC of actual wastewater were decreased by 62.23%, 50.12% and 41.26% in 3 h, respectively, and the ratio of BOD5/COD was increased from 0.19 to 0.30.