模拟土壤淋洗废液中重金属的选择性去除与淋洗液的回收研究

土壤淋洗废液中污染物的选择性去除是实现淋洗液回收的关键.本文以硫化钠（Na₂S）、乙基黄原酸钾（PEX）、二甲基二硫代氨基甲酸钠（DTC）作为重金属沉淀剂处理电子垃圾污染土壤模拟淋洗废液,在筛选出Na₂S作为理想重金属沉淀剂的基础上,研究初始pH值、反应温度、沉淀剂浓度等因素对Na₂S分离络合态重金属的影响,并通过软件模拟和产物表征等方式推测反应机理.结果表明：Na₂S对柠檬酸络合态重金属的分离顺序依次为Cu、Pb、Cd,符合硫化物溶度积原则;反应温度、初始pH值对Na₂S处理络合态重金属无显著影响,重金属去除率均保持在90%以上,柠檬酸的回收率约为95%;Visual MINTEQ模拟结果显示,S^2-投加前液相中重金属主要以H₂CA^-、HCA^2-和CA^3-结合形式存在,S^2-投加后液相中重金属则以HS^-和S^2-结合形式存在;扫描电镜及能谱（SEM-EDS）表明,S^2-与金属阳离子按物质的量比1：1生成硫化物沉淀物,沉淀主要呈团聚、成簇和圆片状存在;X射线衍射（XRD）分析结果表明,沉淀产物中存在CuS、CdS、PbS和CuPbS₂.本研究结果可为化学沉淀法处理重金属污染土壤淋洗废液提供技术参考.     

Euclidean贴近度水质评价法及其应用

分析了模糊综合评判在水质评价中的缺陷,将模糊数学中的贴近度与经典的Euclidean距离结合,提出Euclidean贴近度水质评价法。结果表明,该评价方法具有科学性、合理性,并且精度高,简单实用。     

水泥窑共处置废物过程中重金属的流向分布

为了探索水泥窑共处置危险废物过程中重金属流向分布规律,研究了不同温度条件下Cr、As、Pb在煅烧熟料、颗粒物和尾气中的残留率。在900、1 000、1 100、1 200、1 300和1 450℃温度条件下,将添加Cr、As和Pb化学试剂的生料分别进行煅烧,模拟重金属在水泥窑内不同温度带的煅烧过程。结果表明,6个温度条件下,Cr主要分布在熟料中并且呈现不规则变化;颗粒物中的Cr在1 200℃条件下分布量最大,所占比例为32.79%(w);在900℃和1450℃条件下,烟气中的Cr分布量最大,所占比例为0.24%(w)。6个温度条件下As主要分布在熟料中并且1 000~1 450℃条件下稳定在81%~83%之间;在900℃条件下,As在熟料中的残留率最大,所占比例为97%(w);在1450℃条件下,As在尾气中的分布达到最大值,所占比例为0.0023%(w)。6个温度条件下,Pb在熟料中的残留率随着温度升高而逐渐减少,挥发颗粒物中的含量呈现相反的趋势;尾气中Pb的含量随着温度的升高逐渐增加。     

Concentrations,atmospheric partitioning,and air–water/soil surface exchange of polychlorinated dibenzo-p-dioxin and dibenzofuran along the upper reaches of the Haihe River basin,North China

Polychlorinated dibenzo-p-dioxin and dibenzofuran (PCDD/PCDF) were overall measured and compared in ambient air, water, soils, and sediments along the upper reaches of the Haihe River of North China, so as to evaluate their concentrations, profiles, and to understand the processes of gas–particle partitioning and air–water/soil exchange. The following results were obtained: (1) The average concentrations (toxic equivalents, TEQs) of 2,3,7,8-PCDD/PCDF in air, water, sediment, and soil samples were 4,855 fg/m³, 9.5 pg/L, 99.2 pg/g dry weight (dw), and 56.4 pg/g (203 fg TEQ/m³, 0.46 pg TEQ/L, 2.2 pg TEQ/g dw, and 1.3 pg TEQ/g, respectively), respectively. (2) Although OCDF, 1,2,3,4,6,7,8-HpCDF, OCDD, and 1,2,3,4,6,7,8-HpCDD were the dominant congeners among four environmental sinks, obvious discrepancies of these congener and homologue patterns of PCDD/PCDF were observed still. (3) Significant linear correlations for PCDD/PCDF were observed between the gas–particle partition coefficient (K _p) and the subcooled liquid vapor pressure (P _L ⁰) and octanol–air partition coefficient (K _oa). (4) Fugacity fraction values of air–water exchange indicated that most of PCDD/PCDF homologues were dominated by net volatilization from water into air. The low-chlorinated PCDD/PCDF (tetra- to hexa-) presented a strong net volatilization from the soil into air, while high-chlorinated PCDD/PCDF (hepta- to octa-) were mainly close to equilibrium for air–soil exchange.     

Occurrence, possible sources, and temporal trends of polychlorinated dibenzo-p-dioxins and dibenzofurans in water and sediment from the lower Yangtze River basin, Jiangsu and Shanghai areas of Eastern China

The concentrations, compositional profiles, and possible sources of polychlorinated dibenzo-p-dioxins and polychlorinated dibenzofurans (PCDD/PCDF) in water column and surface sediment samples from the lower reaches of the Yangtze River were investigated, and the potential risks posed by these chemicals were evaluated. Concentrations of the 17 2,3,7,8-substituted PCDD/PCDF in the water and sediment samples ranged from 0.45 to 10.0 pg TEQ/L (mean 2.34 pg TEQ/L) and from 0.31 to 51 pg TEQ/g dw (mean 5.25 pg TEQ/g dw), respectively. Water and sediments from the Nanjing–Nantong sections of the Yangtze River were found to have elevated PCDD/PCDF levels, and the PCDD/PCDF TEQ concentrations in 13 sediment samples exceeded the probable effect levels (PEL), above which adverse biological effects are likely. Multivariate statistical analysis indicated that the principal PCDD/PCDF contamination source for the water and sediment was the production and use of pentachlorophenol (PCP) or sodium pentachlorophenate (PCP-Na). PCDD/PCDF concentrations were stable over time near the Yangtze River Estuary but had increased sharply in recent decades in the Nanjing–Nantong section, which will have been related to the growth in industrial activities and other anthropogenic PCDD/PCDF sources. Total organic carbon (TOC) and PCDD/PCDF concentrations correlated significantly (R?=?0.474, P?<?0.01), suggesting that TOC plays an important role in the transport and re-distribution of PCDD/PCDF in the Yangtze River basin.     

间歇浸取对废物水泥窑共处置产品中Cr和As释放的影响

研究间歇浸取条件下废物水泥窑共处置产品中重金属Cr、As的释放,对水泥产品在实际应用中的环境安全性评价有重要意义.通过模拟煅烧实验制取含Cr和As的水泥熟料,并制取混凝土样品,采用pH影响实验和扩散浸出实验,研究了混凝土中Cr和As的溶解特性及其间歇浸取对混凝土中Cr和As释放的影响.结果表明,浸取方式对浸取液pH有较...     

An integrative analysis of miRNA and mRNA expression in the brains of Alzheimer's disease transgenic mice after real-world PM2.5 exposure

Fine particulatematter (PM2.5) is associated with increased risks of Alzheimer’s disease (AD),yet the toxicologicalmechanisms of PM2.5 promoting AD remain unclear. In this study,wildtype and APP/PS1 transgenic mice (AD mice) were exposed to either filtered air (FA) or PM2.5 for eight weeks with a real-world exposure system in Taiyuan, China (mean PM2.5 concentration in the cage was 61 μg/m3). We found that PM2.5 exposure could remarkably aggravate AD mice’s ethological and brain ultrastructural damage, along with the elevation of the pro-inflammatory cytokines (IL-6 and TNF-α), Aβ-42 and AChE levels and the decline of ChAT levels in the brains. Based on high-throughput sequencing results, some differentially expressed (DE) mRNAs and DE miRNAs in the brains of AD mice after PM2.5 exposure were screened.Using RT-qPCR, seven DEmiRNAs (mmu-miR-193b-5p, 122b-5p, 466h-3p, 10b-5p, 1895, 384–5p, and 6412) and six genes (Pcdhgb8, Unc13b, Robo3, Prph, Pter, and Tbata) were evidenced the and verified. Two miRNA-target gene pairs (miR-125b-Pcdhgb8 pair and miR-466h-3p-IL-17Rα/TGF-βR2/Aβ-42/AChE pairs) were demonstrated that they were more related to PM2.5-induced brain injury. Results of Gene Ontology (GO) pathways and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathways predicted that synaptic and postsynaptic regulation, axon guidance, Wnt, MAPK, and mTOR pathways might be the possible regulatory mechanisms associated with pathological response. These revealed that PM2.5- elevated pro-inflammatory cytokine levels and PM2.5-altered neurotransmitter levels in AD mice could be the important causes of brain damage and proposed the promising miRNA andmRNA biomarkers and potentialmiRNA-mRNA interaction networks of PM2.5-promoted AD.     

制药废水二级出水中溶解性有机物混凝去除特性研究

制药废水二级出水中溶解性有机物(DOM)由于组成复杂、难去除、具有多异质性和分散性,是污水深度处理与回用的主要去除对象和关键限制因子.本论文以发酵制药废水二级出水的DOM为研究对象,采用投加聚合氯化铝(PAC)混凝剂去除DOM,考察混凝剂投加量和混凝pH值对去除效果的影响,并结合分子量分级、亲疏水性分级以及三维荧光光谱-平行因子分析方法等对DOM进行了系统表征和分析,进一步阐述混凝过程DOM的去除特征.结果表明,PAC投加量为250 mg·L~(-1)、pH=7时,混凝沉淀30 min对DOC、UV_(254)、色度和浊度的去除率分别为13.05%±0.29%、23.65%±0.75%、12.66%±1.34%、63.67%±0.89%;混凝对分子量10 kDa的组分和疏水中性(HON)组分去除效果分别为50.33%±0.98%、21.56%±0.42%,而对分子量1 kDa组分去除率较低为2.26%±0.12%;三维荧光光谱-平行因子分析将制药废水二级出水分为2个类腐殖质组分(C1、C3)和1个类蛋白组分(C2),混凝对类腐殖酸组分(C1)最大荧光强度去除率(F_(max))最高为46.22%,而亲水性的小分子和蛋白类物质混凝去除效果较差.     

不同含碳量天然气脱碳方案选择

分析国内外常用脱碳方法和各油气田不同含碳量天然气脱碳实例,比较各种脱碳方案的操作条件、适用范围以及优缺点,给出不同含碳量天然气的脱碳方案:当含碳量为2%～10%时可选用常规醇胺法、热碳酸钾法、物理-化学吸收法、变压吸附法;当含碳量为10%～30%时可选用活化MDEA法、热碳酸钾法、物理吸收法、物理-化学吸收法;当含碳量为30%～70%时可选用改良热碳酸钾法、物理吸收法、物理-化学吸收法、膜分离法+常规醇胺法、膜分离法+热碳酸钾法;当含碳量大于70%时可选用低温分离法、膜分离法+化学吸收法。     

护听器个人防护值验证技术

本文介绍了关于护听器实际防护值的研究数据,和用于护听器个人防护效果验证的方法,以及3ME-A-RfitTM听力防护验证系统。研究表明,护听器的标称降噪值对其实际防护值的指示性非常差,目前也还没有一个可靠的方法来使用护听器的标称值。3ME-A-RfitTM听力防护验证系统是使用实地真耳内置麦克风(F-MIRE)方法,在实际工作现场中快速、定量地测定护听器在具体使用者身上取得的个人声衰减值(PAR),让安全管理人员对员工实际获得的防护水平有清晰的了解。