Ultrasound-assisted electrodeposition synthesis of nZVI-Pd/AC toward reductive degradation of methylene blue

Environmental Science and Pollution Research - A novel composite (nZVI/Pd-AC) was prepared by loading nanoscale zero-valent iron (nZVI) and Pd on activated carbon (AC) electrode under...     

1968～2018年洞庭湖江湖连通河道松滋口冲淤变化特征

探究江湖连通河道演变态势是评估重大人类活动事件对江湖关系变化影响的重要环节。以洞庭湖—荆江三口中松滋口河道为研究对象，通过建立其河道长期的水位—流量关系曲线分析其河道的冲淤变化特征，对其河道冲淤变化驱动因素进行分析，并采用实测河道断面资料验证其结果的可靠性。结果表明：水位—流量关系曲线法分析河道地形冲淤演变特征与实测横断面地形资料分析结果一致，松滋口河道同流量下水位下降对应于该时期河道冲刷，同流量下水位上升对应于河道淤积。不同时期松滋口东西分支河道冲淤变化主要驱动因素不同。1968～1981年间，下荆江裁弯引起的河势变化是西支新江口河道冲刷与东支沙道观河道淤积的主要诱因。1981～2003年间，其东西两支河道淤积主要是由于葛洲坝运行后引起的上荆江河道冲刷导致的。2003～2018年间，其河道冲刷主要是由于三峡大坝运行引起的河道水沙比例的大幅改变导致的。     

溶胶凝胶法制备磷钨酸掺杂TiO2薄膜及其光催化性能

以钛酸四丁酯为前驱物,采用溶胶凝胶法制备了磷钨酸掺杂的二氧化钛薄膜.通过XRD、FT-TR对该薄膜进行了表征,研究了薄膜在对氯苯酚光降解中的催化活性.结果表明,当磷钨酸与二氧化钛摩尔比为0.01:1、薄膜烧结温度600℃、对氯苯酚溶液浓度30 mg/L(pH＝5)、光催化8 h的条件下,对氯苯酚的降解率超过90%,且薄膜可以重复使用.磷钨酸对二氧化钛的光催化活性具有明显的促进作用.     

Effect of combined addition amount of nano zero-valent iron and biochar on methane production by anaerobic digestion of corn straw

Environment, Development and Sustainability - Anaerobic digestion (AD) is an attractive straw resource treatment technology as it can improve the utilization efficiency of straw resource. Raw straw...     

Study on cooperative strategies of rural water environment governance PPP project between companies and farmers from the perspective of evolutionary game

Environment, Development and Sustainability - The PPP mode of rural water environment governance was conducive to attracting social capital for giving full play to the decisive role of the market...     

pH值对亚硝酸盐氧化菌动力学及功能基因的影响

为探究pH值对亚硝酸盐氧化菌（NOB）活性动力学影响,本试验采用序批式活性污泥（SBR）反应器,以富含NOB的活性污泥为对象,基于Monod模型考察不同pH值对NOB活性动力学的影响并进行统计学分析.结果表明,Monod方程可较好地反映不同pH值条件下基质底物浓度对NOB比亚硝态氮氧化速率（SNiOR）的影响,且pH=7.0时动力学参数Ks为（6.167mg/L）,r_max为[1.134g/（g·d）],此时NOB活性最好.利用钟形经验模型进行非线性回归拟合,最大比降解速率（r_max）随pH值的增大呈钟形变化,本试验NOB的最佳pH值为（6.9±0.1）,其中r_max维持在r_opt一半以上的pH值范围（ω）为（3.26±0.4）.以亚硝酸盐氧化还原酶类基因（nxrA、nxrB）为引物,基于荧光定量PCR技术分析结果显示,在不同pH值条件下nxrA基因和nxrB基因拷贝数的变化趋势均与动力学参数（Ks、r_max）的规律一致,且nxrA和nxrB基因在系统的降解过程中起协同作用.     

An investigation of changes in water quality throughout the drinking water production/distribution chain using toxicological and fluorescence analyses

Changes in water quality from source water to finished water and tap water at two conventional drinking water treatment plants(DWTPs) were monitored.Beside the routine water quality testing,Caenorhabditis elegans-based toxicity assays and the fluorescence excitation–emission matrices technique were also applied.Both DWTPs supplied drinking water that met government standards.Under current test conditions,both the investigated finished water and tap water samples exhibited stronger lethal,genotoxic and reprotoxic potential than the relative source water sample,and the tap water sample was more lethal but tended to be less genotoxic than the corresponding finished water sample.Meanwhile,the nearly complete removal of tryptophan-like substances and newly generated tyrosine-like substances were observed after the treatment of drinking water,and humic-like substances were identified in the tap water.Based on these findings,toxic pollutants,including genotoxic/reproductive toxicants,are produced in the drinking water treatment and/or distribution processes.Moreover,further studies are needed to clarify the potentially important roles of tyrosine-like and humic-like substances in mediating drinking water toxicity and to identify the potential sources of these contaminants.Additionally,tryptophan-like fluorescence may be adopted as a useful parameter to monitor the treatment performance of DWTPs.Our observations provided insights into the importance of utilizing biotoxicity assays and fluorescence spectroscopy as tools to complement the routine evaluation of drinking water.     

Plasmonic silver/silver oxide nanoparticles anchored bismuth vanadate as a novel visible-light ternary photocatalyst for degrading pharmaceutical micropollutants

The degradation of pharmaceutical micropollutants is an intensifying environmental problem and synthesis of efficient photocatalysts for this purpose is one of the foremost challenges worldwide. Therefore, this study was conducted to develop novel plasmonic Ag/Ag₂O/BiVO₄ nanocomposite photocatalysts by simple precipitation and thermal decomposition methods, which could exhibit higher photocatalytic activity for mineralized pharmaceutical micropollutants. Among the different treatments, the best performance was observed for the Ag/Ag₂O/BiVO₄ nanocomposites (5 wt.%; 10 min's visible light irradiation) which exhibited 6.57 times higher photodegradation rate than the pure BiVO₄. Further, the effects of different influencing factors on the photodegradation system of tetracycline hydrochloride (TC-HCl) were investigated and the feasibility for its practical application was explored through the specific light sources, water source and cycle experiments. The mechanistic study demonstrated that the photogenerated holes (h⁺), superoxide radicals (?O₂^?) and hydroxyl radicals (?OH) participated in TC-HCl removal process, which is different from the pure BiVO₄ reaction system. Hence, the present work can provide a new approach for the formation of novel plasmonic photocatalysts with high photoactivity and can act as effective practical application for environmental remediation.     

某垃圾焚烧厂投产前后周边土壤二英类化合物的分布

为研究垃圾焚烧厂运行对周边土壤二英类化合物（PCDD/Fs）含量的影响,采集了珠三角地区某垃圾焚烧厂投产前和投产后周边土壤样品,分析研究了该垃圾焚烧厂运行对周边土壤中PCDD/Fs含量和组分的变化.结果表明:①2012年（投产前）珠三角地区某垃圾焚烧厂周边土壤PCDD/Fs含量较低,范围为163~591 ng/kg（毒性当量范围为0.198~0.863 ng I-TEQ/kg,I-TEQ为国际毒性当量因子折算的毒性当量值）;2017—2019年（投产后）周边土壤PCDD/Fs含量范围为151~1.75×103 ng/kg（毒性当量范围为0.812~3.88 ng I-TEQ/kg）,与其他研究相比处于较低的水平.②投产后,距该垃圾焚烧厂较近（1.5 km）的采样点（S1）土壤PCDD/Fs含量逐年增长,在较远（5.2 km）但人口较密集的采样点（S3）土壤PCDD/Fs含量整体较高,但呈逐年下降趋势.③投产后,土壤中的17种PCDD/Fs单体组分中,毒性当量贡献率最高的单体为八氯二苯并二英（OCDD）和2,3,4,7,8-五氯二苯并呋喃（2,3,4,7,8-PeCDF）,二者毒性当量贡献率范围为15.7%~45.4%.④在同一采样点土壤PCDD/Fs单体组分年间差异不明显,但同一年份不同采样点差异明显.研究显示,目前该垃圾焚烧厂周边土壤PCDD/Fs含量较低,但仍需要长期监测其可能带来的风险.      

水稻秸秆生物炭中铜和镉的形态分布及释放特性

由于目前缺乏对生物质原料来源的管控办法,极有可能用产自受污染农田土壤的秸秆制备出具有高重金属含量的生物炭,因此,研究生物炭中重金属的形态分布及其释放特性对于防控生物炭应用产生的环境风险具有重要意义.基于此,分别采集江西省贵溪铜冶炼厂周边九牛岗污染区和中国科学院鹰潭红壤生态实验站清洁区种植的水稻秸秆制备生物炭（分别记为“九牛岗生物炭”和“红壤站生物炭”）,分析两种生物炭中Cu、Cd的含量及其化学形态分布,考察不同固液比及pH对生物炭中Cu、Cd浸出的影响.结果表明:九牛岗生物炭中Cu、Cd的总量（以w计）分别为119.99、3.83 mg/kg,显著高于红壤站生物炭（19.50、0.96 mg/kg）.尽管九牛岗生物炭中w（酸溶态Cu）、w（酸溶态Cd）显著高于红壤站生物炭,但在形态分布上,九牛岗生物炭中Cu、Cd主要为相对稳定态（可氧化态和残渣态）,二者占比分别为80.3%、76.7%,高于红壤站生物炭（二者占比分别为53.2%、48.0%）.高固液比和低pH可有效增加两种生物炭中Cu、Cd的浸出毒性,其中,九牛岗生物炭在固液比为1:20和1:60时,浸出液中ρ（Cu）、ρ（Cd）均超过GB/T 14848—2017《地下水质量标准》中Ⅱ类标准限值.动力学及累积释放试验表明,两种生物炭中的部分Cu、Cd可在短时间内迅速释放而后逐渐平稳并有上升趋势,且九牛岗生物炭中Cu、Cd释放量显著高于红壤站生物炭.研究显示,来自污染区水稻秸秆生物炭中的Cu、Cd活性显著高于清洁区生物炭,具有更高的环境风险.