Fabrication of highly efficient Bi2WO6/CuS composite for visible-light photocatalytic removal of organic pollutants and Cr(VI) from wastewater

• A novel Bi₂WO₆/CuS composite was fabricated by a facile solvothermal method. • This composite efficiently removed organic pollutants and Cr(VI) by photocatalysis. • The DOM could promoted synchronous removal of organic pollutants and Cr(VI). • This composite could be applied at a wide pH range in photocatalytic reactions. • Possible photocatalytic mechanisms of organic pollutants and Cr(VI) were proposed. A visible-light-driven Bi₂WO₆/CuS p-n heterojunction was fabricated using an easy solvothermal method. The Bi₂WO₆/CuS exhibited high photocatalytic activity in a mixed system containing rhodamine B (RhB), tetracycline hydrochloride (TCH), and Cr (VI) under natural conditions. Approximately 98.8% of the RhB (10 mg/L), 87.6% of the TCH (10 mg/L) and 95.1% of the Cr(VI) (15 mg/L) were simultaneously removed from a mixed solution within 105 min. The removal efficiencies of TCH and Cr(VI) increased by 12.9% and 20.4%, respectively, in the mixed solution, compared with the single solutions. This is mainly ascribed to the simultaneous consumption electrons and holes, which increases the amount of excited electrons/holes and enhances the separation efficiency of photogenerated electrons and holes. Bi₂WO₆/CuS can be applied over a wide pH range (2–6) with strong photocatalytic activity for RhB, TCH and Cr(VI). Coexisiting dissolved organic matter in the solution significantly promoted the removal of TCH (from 74.7% to 87.2%) and Cr(VI) (from 75.7% to 99.9%) because it accelerated the separation of electrons and holes by consuming holes as an electron acceptor. Removal mechanisms of RhB, TCH, and Cr(VI) were proposed, Bi₂WO₆/CuS was formed into a p-n heterojunction to efficiently separate and transfer photoelectrons and holes so as to drive photocatalytic reactions. Specifically, when reducing pollutants (e.g., TCH) and oxidizing pollutants (e.g., Cr(VI)) coexist in wastewater, the p-n heterojunction in Bi₂WO₆/CuS acts as a “bridge” to shorten the electron transport and thus simultaneously increase the removal efficiencies of both types of pollutants.     

Deciphering the effect of sodium dodecylbenzene sulfonate on up-flow anaerobic sludge blanket treatment of synthetic sulfate-containing wastewater

• UASB reactor can work efficiently with high COD/SO₄^2- ratios when SDBS exists. • Outcome of the competition between SRB and MPA was affected by SDBS. • Presence of SDBS makes methanogens with H₂/CO₂ as a substrate dominant. • Microbial diversity decreases in the presence of SDBS. In this study, the effects of organic sulfur on anaerobic biological processes were investigated by operating two up-flow anaerobic sludge blanket (UASB) reactors with sodium dodecylbenzene sulfonate (SDBS) as a representative of organic sulfur. The results indicated that the specific methanogenic activity (SMA) and chemical oxygen demand (COD) removal efficiency of R2 (with SDBS added) were higher than those of R1 (without SDBS) when the COD/SO₄²⁻ ratio was above 5.0. However, when the COD/SO₄²⁻ ratio was lower than 5.0, the sulfate reduction efficiency of R2 was higher than that of R1. These results and the observed SDBS transformation efficiency in anaerobic reactors indicate that low concentrations of SDBS accelerate methane production and the continuous accumulation of SDBS does not weaken the reduction of sulfate. Similarly, the calculated electron flux for a COD/SO₄²⁻ ratio of 1.0 indicates that the utilization intensity of electrons by sulfate-reducing bacteria (SRB) in R2 was 36.48% higher than that of SRB in R1 and exceeded that of methane-producing archaea (MPA) under identical working conditions. Moreover, the addition of SDBS in R2 made sulfidogenesis the dominant reaction at low COD/SO₄²⁻, and Methanobacterium and Methanobrevibacter with H₂/CO₂ as the substrate and Desulfomicrobium were the dominant MPA and SRB, respectively. However, methanogenesis was still the dominant reaction in R1, and Methanosaeta with acetic acid as the substrate and Desulfovibrio were the dominant MPA and SRB, respectively.     

土壤中有机污染物的气相色谱-四极杆飞行时间质谱非靶标筛查

本文基于气相色谱-四极杆飞行时间质谱(GC-QTOF/MS)对宜昌某化学工业园区内的土壤进行潜在有机污染物的非靶标筛查.根据已有高分辨数据库和保留时间信息,采用精确质量数提取筛查流程识别出样品中96种污染物,主要以多环芳烃及其代谢产物、氯苯类和农药为主.进一步通过未知物分析软件解卷积功能和质谱NIST数据库的匹配,发现了如二氯苯胺、9-芴酮、3-甲基二苯并噻吩等更多的污染物.该方法能够快速筛查和识别出样品中潜在有机污染物,为当地污染物的风险管控提供借鉴意义.     

有机热载体炉大气污染物的适用排放标准

介绍了有机热载体炉的分类和工作原理，并对有机热载体炉与蒸气锅炉的基本特性及其烟尘测试的主要特点进行了比较，提出有机热载体炉大气污染物的适用排放标准应按照GB13271-2001《锅炉大气污染物排放标准》执行。     

几种常用总氮总磷有机分析方法的结果比较

论述了几种常用总氮、总磷分析方法的原理和特点,运用准确度和精密度检验,比较了它们各自对不同有机氮、磷物质和有机污染水体的分析结果。实验结论表明,加和法和还原法不能满足一般方法要求;氧化法具有较高的准确度和精密度,实用性强,建议推广。      

固相萃取剂在富集检测极性有机污染物领域的应用研究进展

介绍了常用固相萃取剂的类型与适用范围,综述了近年来在极性有机污染物富集检测中获得应用的新型固相萃取剂,包括具有高比表面积和亲水表面的聚合物萃取剂,以及利用分子印迹和免疫亲和技术制备的新型萃取剂。     

有机肥释放面源污染物的危害与调控对策

有机肥是一把“双刃剑”,其施用不当也是引发面源污染的重要源头。本文分析了有机肥的主要来源,重点阐述了有机肥释放面源污染物对水体、大气、土壤、农作物以及人畜健康所带来的危害。在此基础上,提出控制有机肥释放面源污染物的措施,即合理施用有机肥、规范养殖污染管理、提高畜禽粪肥的还田利用率、有机肥资源商品化及发展有机农业。     

Chemical and olfactive impacts of organic matters on odor emission patterns from the simulated construction and demolition waste landfills

The explosive increase of construction and demolition waste (CDW) caused the insufficient source separation and emergency disposal at domestic waste landfills in many developing countries. Some organic fractions were introduced to the CDW landfill process and resulted in serious odor pollution. To comprehensively explore the impacts of organic matters on odor emission patterns, five CDW landfills (OIL), with organic matters/ inert CDW components (O/I) from 5% to 30%, and the control group only with inert components (IL) or organics (OL) were simulated at the laboratory. The chemical and olfactive characters of odors were evaluated using the emission rate of 94 odorants content (ER_total), theory odor concentration (TOC_total), and e-nose concentration (ER_ENC), and their correlations with waste properties were also analyzed. It was found that the main contributors to ER_total (IL: 93.0% NH₃; OIL: 41.6% sulfides, 31.0% NH₃, 25.9% oxygenated compounds) and TOC total (IL: 64.1% CH₃SH, 28.2% NH₃; OIL: 71.7% CH₃SH, 24.8% H₂S) changed significantly. With the rise of O/I, ER_total, TOC_total, and ER_ENC increased by 10.9, 20.6, and 2.1 times, respectively. And the organics content in CDW should be less than 10% (i.e., DOC<101.3 mg/L). The good regressions between waste properties (DOC, DN, pH) and ${\mathrm{ER}}_{\stackrel{?}{\mathrm{ENC}}}$ (r=0.86, 0.86, -0.88, p<0.05), ${\mathrm{TOC}}_{\stackrel{?}{\mathrm{total}}}$ (r=0.82, 0.79, -0.82, p<0.05) implied that the carbon sources and acidic substances relating to organics degradation might result in that increase. Besides, the correlation analysis results (${\mathrm{ER}}_{\stackrel{?}{\mathrm{ENC}}}$ vs. ${\mathrm{TOC}}_{\stackrel{?}{\mathrm{total}}}$, r=0.96, p<0.01; vs. ${\mathrm{ER}}_{\stackrel{?}{\mathrm{total}}}$, r=0.86, p<0.05) indicated that e-nose perhaps was a reliable odor continuous monitoring tool for CDW landfills.     

人工湿地在农业面源污染控制方面的应用

简述了人工湿地的类型及去除氮，磷，有机物的主要机理，人工湿地内植物的作用及其它一些问题，从而说明了人工湿地作为一种造价低，运行简单及管理方便的农业面源污染控制系统在我国尤其是广大城镇和农村地区具有良好的应用前景。