乐昌铅锌尾矿的酸化及重金属溶出的淋溶实验研究

利用淋溶实验，研究了乐昌铅锌尾矿的酸化及其对重金属溶出的影响。结果表明：高硫和中硫尾矿因含很高的有效硫（分别为２０．４％和１５．９％），在尾矿的堆放过程中会发生酸化，发生酸化的时间在第５１周左右，低硫尾矿（有效硫为７．２％）在短期内不会发生酸化。尾矿发生酸化后，将促进其中盐份的溶解，从而使得Ｐｂ、Ｚｎ和Ｃｕ等重金属的溶出增高。本研究可为铅锌尾矿的环境管理提供科学依据     

Effects of clay minerals on Cr(VI) reduction by organic compounds

The objective of this study is to examine the effect of clayminerals (illite, montmorillonite, and kaolinite) on chromate (Cr(VI)) reduction by several low molecular weightorganic compounds. Batch experiments at pH ranging from 3.0 to6.0 and 25 °C showed that 2:1 layered clays illite andsmectite catalyzed Cr(VI) reduction by oxalate. The catalyticeffect increased as pH was decreased. The 1:1 clay kaolinite hadno catalytic effect under comparable conditions. Direct Cr(VI)reduction by reactive moieties associated with illite andmontmorillonite was observed, but at a much slower rate than thecatalytic pathway. Cr(VI) reduction by glyoxylic acid, glycolicacid, lactic acid, and mandelic acid was accelerated by illite,although aqueous phase reduction might occur in parallel. Theseresults suggest that Cr(VI) reduction rates in subsurfaceenvironments rich in organic compounds may be elevated throughcatalysis of surface-bound metals and/or soluble species from theclay minerals, and as a result, higher than those expected fromaqueous phase reaction alone. Such rate enhancement for Cr(VI)reduction needs to be accounted for when developing new remedialtechniques for chromium site remediation or assessing its naturalattenuation.     

高吸附量有机聚合物的合成及其对亚甲基蓝吸附性能研究

为开发高效染料吸附剂,以丙烯酸（AA）、2-丙烯酰胺-2-甲基丙磺酸（AMPS）为单体,N,N''-亚甲基双丙烯酰胺为交联剂,γ-甲基丙烯酰氧基丙基三甲氧基硅烷（KH570）为偶联剂合成了一种新型有机聚合物（KAA）,并以红外光谱（FTIR）与扫描电镜（SEM）对其进行表征.选用典型阳离子染料亚甲基蓝（MB）为研究对象,研究KAA对MB的吸附动力学、吸附热力学以及溶液pH值和不同阳离子对吸附的影响.结果表明,实验浓度范围内KAA对亚甲基蓝的最大吸附量为1558 mg·g^-1,能够在1.5 h内达到吸附平衡,吸附动力学符合准一级动力学模型,吸附等温线符合通用等温模型（a general model）,吸附热力学数据表明吸附过程为自发、放热的熵减过程.KAA对亚甲基蓝的吸附具有较宽的pH适用范围,吸附剂具有良好的pH缓冲能力,阳离子对吸附具有较强的抑制作用,抑制作用大小为Al³⁺ > Ca²⁺ > Na⁺.研究表明吸附的主要驱动力为静电作用和π-π相互作用.与其他吸附剂相比,KAA对亚甲基蓝具有超高的吸附量以及酸碱耐受能力,更符合实际应用需求.     

乘用车内空气质量健康风险评估

为研究我国乘用车内空气的污染现状,采用二次热解析-毛细管气相色谱/质谱联用及高效液相色谱法,测定了16个品牌的市售新车车内空气中BTEX(苯、甲苯、乙苯和二甲苯)、苯乙烯、甲醛、乙醛和丙烯醛等8种污染物质量浓度,并对其健康风险进行了评估. 结果表明:8种污染物的质量浓度除乙醛外均低于GB/T 27630—2011《乘用车内空气质量评价指南》中的标准限值,ρ(苯)、ρ(甲苯)、ρ(乙苯)、ρ(二甲苯)、ρ(苯乙烯)、ρ(甲醛)、ρ(乙醛)和ρ(丙烯醛)范围分别为3.00～73.00、69.00～798.00、18.00～469.75、46.00～1 296.42、12.00～46.00、19.00～72.00、43.29～323.00和5.20～7.60 μg/m3. 致癌物质苯、甲醛和甲苯的质量浓度最高值分别为GB/T 27630—2011各自标准限值的66.36%、72.00%和72.55%;二甲苯质量浓度点离散程度较小,分布集中,其平均值为GB/T 27630—2011标准限值(1 500 μg/m3)的11.86%;ρ(乙苯)最大值为其标准限值的1/3左右;而ρ(苯乙烯)和ρ(丙烯醛)远低于各自标准限值. ρ(苯)和ρ(甲醛)对驾乘人员的健康均可能造成致癌风险. 对于男性职业司机,苯和甲醛平均浓度的致癌风险分别为US EPA(美国国家环境保护局)规定的致癌风险基准值(1×10-6)的18.86和60.67倍,而二者对女性职业司机的致癌风险仅比男性降低了12.53%;对于男性普通驾乘人员,苯和甲醛平均浓度的致癌风险分别为基准值的2.83和9.10倍,女性略低于男性. 二甲苯平均浓度的非致癌风险是US EPA规定的基准HI(非致癌风险指数,取1)的1.78倍. 研究表明,为降低车内空气中有害物质对车内乘员的健康危害,需要采用环保的内饰材料,改善车内空气质量.      

Association between population density and infection rate suggests the importance of social distancing and travel restriction in reducing the COVID-19 pandemic

Environmental Science and Pollution Research - Currently, 2019-nCoV has spread to most countries of the world. Understanding the environmental factors that affect the spread of the disease COVID-19...     

Error estimations of dry deposition velocities of air pollutants using bulk sea surface temperature under common assumptions

It is well known that skin sea surface temperature (SSST) is different from bulk sea surface temperature (BSST) by a few tenths of a degree Celsius. However, the extent of the error associated with dry deposition (or uptake) estimation by using BSST is not well known. This study tries to conduct such an evaluation using the on-board observation data over the South China Sea in the summers of 2004 and 2006. It was found that when a warm layer occurred, the deposition velocities using BSST were underestimated within the range of 0.8–4.3%, and the absorbed sea surface heat flux was overestimated by 21 W m^?2. In contrast, under cool skin only conditions, the deposition velocities using BSST were overestimated within the range of 0.5–2.0%, varying with pollutants and the absorbed sea surface heat flux was underestimated also by 21 W m^?2. Scale analysis shows that for a slightly soluble gas (e.g., NO₂, NO and CO), the error in the solubility estimation using BSST is the major source of the error in dry deposition estimation. For a highly soluble gas (e.g., SO₂), the error in the estimation of turbulent heat fluxes and, consequently, aerodynamic resistance and gas-phase film resistance using BSST is the major source of the total error. In contrast, for a medium soluble gas (e.g., O₃ and CO₂) both the errors from the estimations of the solubility and aerodynamic resistance are important. In addition, deposition estimations using various assumptions are discussed. The largest uncertainty is from the parameterizations for chemical enhancement factors. Other important areas of uncertainty include: (1) various parameterizations for gas-transfer velocity; (2) neutral-atmosphere assumption; (3) using BSST as SST, and (4) constant pH value assumption.     

Causes of the elevated nitrate aerosol levels during episodic days in Taichung urban area,Taiwan

The purpose of this study is to explore the possible reasons accounting for elevated nitrate aerosol levels during high particulate days (HPD) in Taichung urban area of central Taiwan. To achieve this goal, simultaneous measurements of particulate and gaseous pollutants were carried out from September 2004 to April 2005 using an annular denuder system (ADS). The formation rate of NO₂ to nitrate aerosol, calculated using the relevant chemical reactions, was employed to interpret enhanced nitrate aerosol concentrations during HPD. The observations showed that nitrate concentration during HPD was 14 times higher than that during low particulate days (LPD). The average formation rate during HPD was 4.0% h^?1, which was 3.1 times higher than that during LPD. The quantitative analysis showed that the formation rate was mainly influenced by temperature and relative humidity. Lower temperature and higher relative humidity led much nitrate aerosol formation in HPD. Moreover, the residence time analysis of air masses staying over the studied area showed that the slow-motion air retained high nitrate concentrations due to more nitrate aerosol converted from the precursors in NOx-rich areas.     

改性膨润土对废水中六价铬的吸附过程研究

以广西宁明膨润土为原料,利用微波干法制备钠化膨润土和有机膨润土,并用制备的改性膨润土对含Cr（Ⅵ）模拟废水进行吸附实验。结果表明,在pH=5．6（为废水初始pH）,加土量为2g／L,吸附时间为30min的条件下,有机膨润土对含50mg／L的Cr（Ⅵ）废水的去除率达95％。有机膨润土吸附Cr（Ⅵ）的机理主要为离子交换吸附及络合物沉淀吸附,钠化膨润土对Cr（Ⅵ）主要为表面吸附。     

Enhancing capacity building to climate adaptation and water conservation among Chinese young people

Environmental Science and Pollution Research - Capacity development has been regarded as one of many measures to empower the abilities of nations to adapt to a changing climate. Promoting public...     

Application of passive sampling on assessment of concentration distribution and health risk of volatile organic compounds at a high-tech science park

The objectives of this study are to investigate the volatile organic compound (VOC) distribution using passive samplers and to assess the resulting health risks in a high-tech science industrial park. With the advantages of passive sampling techniques, long-term and wide-area samples are collected. The results show TVOC concentrations in summer, fall, winter, and spring are 7.14?±?5.66 ppb, 18.17?±?5.81 ppb, 10.30?±?3.54 ppb, and 14.56?±?4.53 ppb, respectively; those on weekdays and weekends are 14.36?±?6.80 ppb and 9.87?±?4.86 ppb, respectively; and those in industrial and residential zones are 12.97?±?0.39 ppb and 11.13?±?0.68 ppb, respectively. Based on concentration variations, and benzene, toluene, ethylbenzene, and xylene ratios, we can resolve the source origins. Health risks are assessed based on the resulting concentrations. In the case of non-cancer chronic effects, long-term exposure to these concentrations does not support there is a risk of adverse health effects. However, potential cancer risks of exposure to these concentrations may occur, especially to carbon tetrachloride and benzene. By applying this study’s procedures, information on VOC concentration distribution, source identification, and health assessment can be obtained and they are applicable to similar studies.