SO2-4/TiO2对SO2-C7H16-TiO2复相光化学反应的影响

研究了TiO2与SO2,C7H16复相光化学反应的光催化活性.在SO2-C7H16-O2-TiO2光催化反应过程中,TiO2表面可形成SO2-4/TiO2结构,它的存在可提高庚烷的光催化氧化速率,利用IR和XPS研究了反应过程中TiO2表面形成的SO2-4/TiO2结构.     

Cu/Cr co-stabilization mechanisms in a simulated Al2O3-Fe2O3-Cr2O3-CuO waste system

• Cu and Cr can be mostly incorporated into CuFe_xAl_yCr_2−x−yO₄ with a spinel structure. • Spinel phase is the most crucial structure for Cu and Cr co-stabilization. • Compared to Al, Fe and Cr are easier to be incorporated into the spinel structure. • ‘Waste-to-resource’ by thermal process at attainable temperatures can be achieved. Chromium slag usually contains various heavy metals, making its safe treatment difficult. Glass-ceramic sintering has been applied to resolve this issue and emerged as an effective method for metal immobilization by incorporating heavy metals into stable crystal structures. Currently, there is limited knowledge about the reaction pathways adopted by multiple heavy metals and the co-stabilization functions of the crystal structure. To study the Cu/Cr co-stabilization mechanisms during thermal treatment, a simulated system was prepared using a mixture with a molar ratio of Al₂O₃:Fe₂O₃:Cr₂O₃:CuO= 1:1:1:3. The samples were sintered at temperatures 600–1300°C followed by intensive analysis of phase constitutions and microstructure development. A spinel phase (CuFe_xAl_yCr_2−x−yO₄) started to generate at 700°C and the incorporation of Cu/Cr into the spinel largely complete at 900°C, although the spinel peak intensity continued increasing slightly at temperatures above 900°C. Fe₂O₃/Cr₂O₃ was more easily incorporated into the spinel at lower temperatures, while more Al₂O₃ was gradually incorporated into the spinel at higher temperatures. Additionally, sintered sample microstructures became more condensed and smoother with increased sintering temperature. Cu / Cr leachability substantially decreased after Cu/Cr incorporation into the spinel phase at elevated temperatures. At 600°C, the leached ratios for Cu and Cr were 6.28% and 0.65%, respectively. When sintering temperature was increased to 1300°C, the leached ratios for all metal components in the system were below 0.2%. This study proposes a sustainable method for managing Cu/Cr co-exist slag at reasonable temperatures.     

Immobilization of Cu2+, Zn2+, Pb2+, and Cd2+ during geopolymerization

The present research explored the application of geopolymerization for the immobilization and solidification of heavy metal added into metakaolinte. The compressive strength of geopolymers was controlled by the dosage of heavy metal cations, and geopolymers have a toleration limit for heavy metals. The influence of alkaline activator dosage and type on the heavy metal ion immobilization efficiency of metakaolinte-based geopolymer was investigated. A geopolymer with the highest heavy metal immobilization efficiency was identified to occur at an intermediate Na₂SiO₃ dosage and the metal immobilization efficiency showed an orderly increase with the increasing Na⁺ dosage. Geopolymers with and without heavy metals were analyzed by the X-ray powder diffraction (XRD) and Fourier transform infrared (FTIR) spectroscopy. No crystalline phase containing heavy metals was detected in geopolymers with heavy metal, suggesting that the crystalline phase containing heavy metals is not produced or most of the phases incorporating heavy metals are amorphous. FTIR spectroscopy showed that, with increasing heavy metal addition, an increase in NO3- peak intensity was observed, which was accompanied by a decrease in the CO32- peak.     

Fe2O3-CeO2-Bi2O3/γ-Al2O3 catalyst in the catalytic wet air oxidation (CWAO) of cationic red GTL under mild reaction conditions

Fe₂O₃-CeO₂-Bi₂O₃/γ-Al₂O₃, an environmental friendly material, was investigated. The catalyst exhibited good catalytic performance in the CWAO of cationic red GTL. The apparent activation energy for the reaction was 79 kJ·mol⁻¹. HO₂· and O₂·⁻ appeared as the main reactive species in the reaction. The Fe₂O₃-CeO₂-Bi₂O₃/γ-Al₂O₃ catalyst, a novel environmental-friendly material, was used to investigate the catalytic wet air oxidation (CWAO) of cationic red GTL under mild operating conditions in a batch reactor. The catalyst was prepared by wet impregnation, and characterized by special surface area (BET measurement), X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS). The Fe₂O₃-CeO₂-Bi₂O₃/γ-Al₂O₃ catalyst exhibited good catalytic activity and stability in the CWAO under atmosphere pressure. The effect of the reaction conditions (catalyst loading, degradation temperature, solution concentration and initial solution pH value) was studied. The result showed that the decolorization efficiency of cationic red GTL was improved with increasing the initial solution pH value and the degradation temperature. The apparent activation energy for the reaction was 79 kJ·mol⁻¹. Hydroperoxy radicals (HO₂·) and superoxide radicals (O₂⁻·) appeared as the main reactive species upon the CWAO of cationic red GTL.     

Catalytic ozonation of organic compounds in water over the catalyst of RuO2/ZrO2-CeO2

This research investigates the performances of RuO₂/ZrO₂-CeO₂ in catalytic ozonation for water treatment. The results show that RuO₂/ZrO₂-CeO₂ was active for the catalytic ozonation of oxalic acid and possessed higher stability than RuO₂/Al₂O₃ and Ru/AC. In the catalytic ozonation of dimethyl phthalate (DMP), RuO₂/ZrO₂-CeO₂ did not enhance the DMP degradation rate but significantly improved the total organic carbon (TOC) removal rate. The TOC removal in catalytic ozonation was 56% more than that in noncatalytic ozonation. However this does not mean the catalyst was very active because the contribution of catalysis to the overall TOC removal was only 30%. The adsorption of the intermediates on RuO₂/ZrO₂-CeO₂ played an important role on the overall TOC removal while the adsorption of DMP on it was negligible. This adsorption difference was due to their different ozonation rates. In the catalytic ozonation of disinfection byproduct precursors with RuO₂/ZrO₂-CeO₂, the reductions of the haloacetic acid and trihalomethane formation potentials (HAAFPs and THMFPs) for the natural water samples were 38%–57% and 50%–64%, respectively. The catalyst significantly promoted the reduction of HAAFPs but insignificantly improved the reduction of THMFPs as ozone reacts fast with the THMs precursors. These results illustrate the good promise of RuO₂/ZrO₂-CeO₂ in catalytic ozonation for water treatment.     

3D flower-like mesoporous Bi4O5I2/MoS2 Z-scheme heterojunction with optimized photothermal-photocatalytic performance

3D flower-like hierarchical mesoporous Bi₄O₅I₂/MoS₂ Z-scheme layered heterojunction photocatalyst was fabricated by oil bath and hydrothermal methods. The heterojunction with narrow band gap of ～1.95 eV extended the photoresponse to near-infrared region, which showed obvious photothermal effect due to the introduction of MoS₂ with broad spectrum response. MoS₂ nanosheets were anchored onto the surface of flower-like hierarchical m...     

Cu~(2+)、Zn~(2+)、Cd~(2+)、Cr~(6+)和Mn~(2+)对萼花臂尾轮虫联合急性毒性研究

为探究重金属复合污染对轮虫的毒性影响,以萼花臂尾轮虫为受试动物,选择Cu~(2+)、Zn~(2+)、Cd~(2+)、Cr6+和Mn~(2+)等5种重金属,采用水生毒理联合效应相加指数法开展了其24 h联合急性毒性作用的评价研究。结果显示,Cu~(2+)、Zn~(2+)、Cd~(2+)、Cr6+和Mn~(2+)等5种重金属对萼花臂尾轮虫24 h半数致死浓度分别为:0.00616 mg·L~(-1),12.62 mg·L-1,2.89 mg·L-1,17.29 mg·L-1和67.32 mg·L-1。联合急性毒性实验结果显示,等毒性配比的Cu~(2+)-Cr6+(0.00385-10.806 mg·L-1)和等浓度配比的Cu~(2+)-Zn~(2+)(0.0199-0.0199 mg·L-1)、Cu~(2+)-Cd~(2+)(0.0181-0.0181 mg·L-1)、Cu~(2+)-Cr6+(0.0118-0.0118 mg·L~(-1))、Zn~(2+)-Cd~(2+)(3.475-3.475 mg·L-1)二元联合测试液的作用结果显示为拮抗效应,其余二元联合测试液的作用结果则均显示是协同效应。等毒性配比的Cu~(2+)-Cr~(6+)-Mn~(2+)(0.00210-5.902-22.981 mg·L-1)和等浓度配比的Cu~(2+)-Cd~(2+)-Mn~(2+)(0.00727-0.00727-0.00727 mg·L-1)三元联合测试液的作用结果显示为拮抗效应,其余三元联合测试液的作用结果则均显示是协同效应。等浓度配比的Cu~(2+)-Zn~(2+)-Cd~(2+)-Cr6+(0.00907-0.00907-0.00907-0.00907 mg·L-1)、Cu~(2+)-Zn~(2+)-Cd~(2+)-Mn~(2+)(0.00898-0.00898-0.00898-0.00898 mg·L~(-1))、Cu~(2+)-Zn~(2+)-Cr6+-Mn~(2+)(0.00819-0.00819-0.00819-0.00819 mg·L~(-1))四元联合测试液的作用结果显示为拮抗效应,其余四元联合测试液的作用结果的则均显示是协同效应。Cu~(2+)-Zn~(2+)-Cd~(2+)-Cr~(6+)-Mn~(2+)等毒性(0.00074-1.520-0.348-2.082-8.107 mg·L~(-1))和等浓度(0.00582-0.00582-0.00582-0.00582-0.00582 mg·L-1)配比的五元联合测试液作用结果均显示是协同效应。     

KMnO4/H2SO4引发制备淀粉改性絮凝剂的研究

以高锰酸钾为引发剂,制备淀粉-丙烯酰胺接枝共聚物.研究酸浓度、引发剂浓度、单体浓度、温度和加料方式对接枝反应的影响.结果表明,少量KMnO4(0.45mmol·l-1)和H2SO4(0.8mmol·l-1)可有效引发淀粉-丙烯酰胺接枝共聚反应,接枝效率达到90%以上,分子量大大提高,对高岭土的絮凝效果较好.     

Sunlight-controlled CO2 separation resulting from a biomass-based CO2 absorber

Renewable solid sorbents for CO₂ capture and storage have shown great potentials for the sake of gaseous separation, tail gas treatment,environmental regulation and climate governance. However, current existed preparation and reusability of solid sorbents are generally subject to high energy consumption and complicated procedure. Herein, a light-controlled CO₂ separation system with high working temperature resulting from natural sawdust combined with polyethyleneimine is f...     

硅藻土和膨润土对重金属离子Zn~（2＋）、Pb~（2＋）及Cd~（2＋）的吸附特性

以硅藻土和膨润土作为吸附剂,考察微波加热与否条件下,不同吸附时间、不同吸附剂用量和不同pH值对硅藻土和膨润土分别吸附Zn2＋、Pb2＋、Cd2＋重金属离子的影响.实验结果表明,硅藻土和膨润土对3种重金属离子均有很好的吸附效果,吸附时间对去除率影响不大,数分钟即可达到吸附平衡,微波加热、增加吸附剂用量和提高pH值,都有利于提高3种重金属离子的去除率.     

基于T-Hg2+-T结构的Hg2+生物传感器研究进展

Hg²⁺不仅污染环境,还会引发多种疾病,危害人体健康.因此,实现对Hg²⁺的快速灵敏检测十分必要.传统的Hg²⁺检测方法存在一定的局限性,而基于T-Hg²⁺-T结构的汞离子生物传感器具有高特异性、高稳定性的优势,近些年得到广泛研究和应用.本文简要介绍了T-Hg²⁺-T结构的概念和特点,并从荧光型、比色型和电化学型3个方面综述了基于T-Hg²⁺-T结构的汞离子生物传感器的研究进展,对未来的发展前景进行了展望.     

Decomposition of aqueous chlorinated contaminants by UV irradiation with H2O2

In the present study, the decomposition rates of carbon tetrachloride (CCl₄) and 2,4-dichlorophenol (2,4-DCP) in water by the ultraviolet (UV) light irradiation alone and H₂O₂/UV were experimentally investigated. The detailed experimental studies have been conducted for examining treatment capacities of the two different ultraviolet light sources (low and medium pressure Hg arc) in H₂O₂/UV processes. The low or medium UV lamp alone resulted in a 60%–90% decomposition of 2,4-DCP while a slight addition of H₂O₂ resulted in a drastic enhancement of the 2,4-DCP decomposition rate. The decomposition rate of 2,4-DCP with the medium pressure UV lamp alone was about 3–6 times greater than the low pressure UV lamp alone. In the direct photolysis of aqueous CCl₄, the medium pressure UV lamp had advantage over the low pressure UV lamp because the molar extinction coefficient of CCl₄ at shorter wavelength (210–220 nm) is about 20 to 50 times higher than that at 254 nm. However, adding H₂O₂ to the medium pressure UV lamp system rendered a negative oxidation rate because H₂O₂ acted as a UV absorber being competitive with CCl₄ due to negligible reaction between CCl₄ and OH radicals. The results from the present study indicated significant influence of the photochemical properties of the target contaminants on the photochemical treatment characteristics for designing cost-effective UV-based degradation of toxic contaminants.     

Heterostructuring noble-metal-free 1T' phase MoS2 with g-C3N4 hollow nanocages to improve the photocatalytic H2 evolution activity

In this work,we report the preparation of 1T’-MoS₂/g-C₃N₄ nanocage(NC) heterostructure by loading 2D semi-metal noble-metal-free 1T’-MoS₂ on the g-C₃N₄ nanocages(NCs).DFT calculation and experimental data have shown that the 1T’-MoS₂/g-C₃N₄ NC heterostructure has a stronger light absorption capacity and larger specific surface area than pure g-C₃N₄ NCs and g-C₃N     

Hydroxyl radical intensified Cu2O NPs/H2O2 process in ceramic membrane reactor for degradation on DMAc wastewater from polymeric membrane manufacturer

• Cu₂O NPs/H₂O₂ Fenton process was intensified by membrane dispersion. • DMAc removal was enhanced to 98% for initial DMAc of 14000 mg/L. • Analyzed time-resolved degradation pathway of DMAc under ·OH attack. High-concentration industrial wastewater containing N,N-dimethylacetamide (DMAc) from polymeric membrane manufacturer was degraded in Cu₂O NPs/H₂O₂ Fenton process. In the membrane-assisted Fenton process DMAc removal rate was up to 98% with 120 min which was increased by 23% over the batch reactor. It was found that ·OH quench time was extended by 20 min and the maximum ·OH productivity was notably 88.7% higher at 40 min. The degradation reaction rate constant was enhanced by 2.2 times with membrane dispersion (k = 0.0349 min⁻¹). DMAc initial concentration (C₀) and H₂O₂ flux (J_p) had major influence on mass transfer and kinetics, meanwhile, membrane pore size (r_p) and length (L_m) also affected the reaction rate. The intensified radical yield, fast mass transfer and nanoparticles high activity all contributed to improve pollutant degradation efficiency. Time-resolved DMAc degradation pathway was analyzed as hydroxylation, demethylation and oxidation leading to the final products of CO₂, H₂O and NO₃⁻ (rather than NH₃ from biodegradation). Continuous process was operated in the dual-membrane configuration with in situ reaction and separation. After five cycling tests, DMAc removal was all above 95% for the initial [DMAc]₀ = 14,000 mg/L in wastewater and stability of the catalyst and the membrane maintained well.     

过氧化氢和一氧化氮在小球藻抗阿特拉津胁迫中的作用

过氧化氢(H_2O_2)和一氧化氮(NO)作为信号分子,可调节植物生长、发育以及应对外源性胁迫。利用过氧化氢酶(CAT)以及NO清除剂(PTIO),研究了除草剂阿特拉津(atrazine,100μg·L~(-1))影响小球藻生长的机理,并分析内源性H_2O_2和NO在小球藻抗除草剂胁迫中的作用。研究结果表明,阿特拉津在诱发小球藻细胞死亡的过程中,不同程度促发了H_2O_2和NO生成;外源CAT可通过清除H_2O_2和诱导NO来缓解阿特拉津对小球藻的生长抑制;PTIO与阿特拉津的联合实验进一步证实,小球藻体内的NO诱导与H_2O_2的爆发无关,它们之间的合成没有相关性。因此,除草剂阿特拉津主要通过诱导小球藻体内的H_2O_2爆发来破坏藻细胞,抑制其生长,与NO的信号传递无关。     

Highly effective visible-photocatalytic hydrogen evolution and simultaneous organic pollutant degradation over an urchin-like oxygen-doped MoS2/ZnIn2S4 composite

● An urchin-like OMS/ZIS composite was fabricated by a facile solvothermal method. ● The OMS/ZIS exhibits superior photocatalytic H₂ evolution for organics degradation. ● A probable mechanism of dual-functional photocatalysis was proposed in detail. ● This work provides an inspiration for rational design of dual-functional catalysts. Achieving hydrogen production and simultaneous decomposition of organic pollutants through dual-functional photocatalytic reactions has received increasing attention due to the environmentally friendly and cost-effective characteristics of this approach. In this work, an urchin-like oxygen-doped MoS₂/ZnIn₂S₄ (OMS/ZIS) composite was fabricated for the first time using a simple solvothermal method. The unique microstructure with abundant active sites and fast charge transfer channels further shortened the charge migration distance and compressed carrier recombination. The obtained composite exhibited an efficient H₂ evolution reaction rate of 12.8 mmol/g/h under visible light, which was nearly times higher than pristine ZnIn₂S₄, and the apparent quantum efficiency was 14.9% (420 nm). The results of the simultaneous photocatalytic H₂ evolution and organic pollutant decomposition test were satisfactory, resulting in decomposition efficiencies of resorcinol, tetracycline, and bisphenol A that reached 41.5%, 63.5%, and 53.0% after 4 h, respectively, and the highest H₂ evolution rate was 672.7 μmol/g/h for bisphenol A. Furthermore, natural organic matter (NOM) abundantly found in actual water was adopted as an electron donor for H production under simulated sunlight irradiation, indicating the promising practicability of simultaneous hydrogen evolution and NOM decomposition. Moreover, the mechanisms of the dual-purpose photocatalytic reactions, as well as the synergistic effect between the molecular structures of the organic pollutants and the corresponding adsorption behavior on the photocatalyst surface were illustrated in detail. These obtained results may serve as an inspiration for the rational design of highly efficient, dual-functional photocatalysts in the future.     

Simultaneous removal of NOx and chlorobenzene on V2O5/TiO2 granular catalyst: Kinetic study and performance prediction

• A V₂O₅/TiO₂ granular catalyst for simultaneous removal of NO and chlorobenzene. • Catalyst synthesized by vanadyl acetylacetonate showed good activity and stability. • The kinetic model was established and the synergetic activity was predicted. • Both chlorobenzene oxidation and SCR of NO follow pseudo-first-order kinetics. • The work is of much value to design of multi-pollutants emission control system. The synergetic abatement of multi-pollutants is one of the development trends of flue gas pollution control technology, which is still in the initial stage and facing many challenges. We developed a V₂O₅/TiO₂ granular catalyst and established the kinetic model for the simultaneous removal of NO and chlorobenzene (i.e., an important precursor of dioxins). The granular catalyst synthesized using vanadyl acetylacetonate precursor showed good synergistic catalytic performance and stability. Although the SCR reaction of NO and the oxidation reaction of chlorobenzene mutually inhibited, the reaction order of each reaction was not considerably affected, and the pseudo-first-order reaction kinetics was still followed. The performance prediction of this work is of much value to the understanding and reasonable design of a catalytic system for multi-pollutants (i.e., NO and dioxins) emission control.     

磷酸活化活性炭对Cu2+的吸附特征研究

寻求廉价而高效的吸附材料为目的,研究向日葵秸杆基活性炭对铜离子的吸附性能。以向日葵秸秆为原料,经H3PO4活化制备活性炭,通过静态实验研究了其对水溶液中Cu2+的吸附特性,考察了溶液pH值、吸附温度和离子强度对吸附的影响,探讨了吸附热力学、动力学和吸附机理。结果表明:溶液pH值为5～6时活性炭对Cu2+的去除效果最好;向50 mL 170 mg·L-1的溶液中加入0.5 g活性炭,温度为45℃、吸附时间为1 h时,对Cu2+的去除率可达98.3%;Langmuir方程能更好地描述Cu2+在活性炭上的等温吸附特征,静态吸附容量可达41.03 mg·g-1;吸附过程符合拟二级动力学过程,且为吸热的化学吸附过程,膜扩散为速率控制步骤,离子交换可能在吸附过程中起了重要作用。     

ZnO-MgO/Al2O3吸附-臭氧催化氧化处理难降解有机废水

以活性氧化铝为载体,采用浸渍法制备催化剂,对甲基橙及草酸模拟废水进行处理.在中性条件下,臭氧催化氧化比单独臭氧氧化能提前30 min使得甲基橙溶液褪色,反应105 min时,臭氧催化氧化对TOC的去除率高达96.53%,比单独使用臭氧氧化对甲基橙TOC去除率提高了47.19%,在处理草酸废水时臭氧催化氧化对TOC去除率高达80.59%,比单独使用臭氧氧化对草酸TOC去除率提高了59.14%.在处理甲基橙及草酸的小试实验中催化剂对有机污染物的吸附作用起到了加快反应进行的作用.在对垃圾渗滤液超滤出水时,O₃与COD质量比为1:1时,臭氧催化氧化对COD去除率为49.09%,比单独使用臭氧氧化提高36.37%,臭氧催化氧化对TOC的去除率是单独使用臭氧氧化的2.54倍,在处理垃圾渗滤液纳滤浓水时,臭氧催化氧化对COD去除率高达88.72%,比单独使用臭氧氧化提高37.60%,并且臭氧催化氧化对TOC的去除率是单独臭氧氧化的1.6倍.臭氧催化氧化反应过程中产生的羟基自由基对有机物更快的反应速率.     

Oxidation and biotoxicity assessment of microcystin-LR using different AOPs based on UV,O3 and H2O2

MC-LR removal performances under different AOPs were compared systematically. Higher removal efficiency and synergistic effects were obtained by combined process. The acute biotoxicity raised in different degrees after oxidation. Microcystin-LR attracts attention due to its high toxicity, high concentration and high frequency. The removal characteristics of UV/H₂O₂ and O₃/H₂O₂ advanced oxidation processes and their individual process for MC-LR were investigated and compared in this study. Both the removal efficiencies and rates of MC-LR as well as the biotoxicity of degradation products was analyzed. Results showed that the UV/H₂O₂ process and O₃/H₂O₂ were effective methods to remove MC-LR from water, and they two performed better than UV-, O₃-, H₂O₂-alone processes under the same conditions. The effects of UV intensity, H₂O₂ concentration and O₃ concentration on the removal performance were explored. The synergistic effects between UV and H₂O₂, O₃ and H₂O₂ were observed. UV dosage of 1800 mJ·cm⁻² was required to remove 90% of 100 mg·L⁻¹ MC-LR, which amount significantly decreased to 500 mJ·cm⁻² when 1.7 mg·L⁻¹ H₂O₂ was added. 0.25 mg·L⁻¹ O₃, or 0.125 mg·L⁻¹ O₃ with 1.7 mg·L⁻¹ H₂O₂ was needed to reach 90% removal efficiency. Furthermore, the biotoxicity results about these UV/H₂O₂, O₃/H₂O₂ and O₃-alone processes all present rising trends with oxidation degree of MC-LR. Biotoxicity of solution, equivalent to 0.01 mg·L⁻¹ Zn²⁺, raised to 0.05 mg·L⁻¹ Zn²⁺ after UV/H₂O₂ or O₃/H₂O₂ reaction. This phenomenon may be attributed to the aldehydes and ketones with small molecular weight generated during reaction. Advice about the selection of MC-LR removal methods in real cases was provided.