Trends of chemical speciation profiles of anthropogenic volatile organic compounds emissions in China, 2005–2020

This study estimates the detailed chemical profiles of China＇s anthropogenic volatile organic com- pounds （VOCs） emissions for the period of 2005-2020. The chemical profiles of VOCs for seven activity sectors are calculated, based on which the Photochemical Ozone Creation Potential （POCP） of VOCs for these sectors is evaluated. At the national level, the VOCs species emitted in 2005 include alkanes, alkenes and alkynes, aromatic compounds, alcohols, ketones, aldehydes, esters, ethers and halocarbons, accounting for 26.4wt.%, 29.2wt.%, 21.3 wt.%, 4.7 wt.%, 5.4 wt.%, 1.7 wt.%, 2.1 wt.%, 0.7 wt. % and 2.2wt.% of total emissions, respectively. And during 2005-2020, their mass proportions would respec- tively grow or decrease by - 34.7%, -48.6%, 108.5%, 6.9%, -32.7%, 7.3%, 65.3%, 100.5%, and 55.4%. This change would bring about a 13% reduction of POCP for national VOCs emissions in the future. Thus, although the national VOCs emissions are expected to increase by 33% over the whole period, its ozone formation potential is estimated to rise only by 14%. Large discrepancies are found in VOCs speciation emissions among provinces. Compared to western provinces, the eastern provinces with a more developed economy would emit unsaturated hydrocarbons and benzene with lower mix ratios, and aromatic compounds except benzene, oxidized hydrocar- bons and halocarbons with higher mix ratios. Such differences lead to lower POCP of VOCs emitted in eastern provinces, and higher POCP of VOCs emitted in western provinces. However, due to the large VOCs emissions from Chinese eastern region, the ozone forma- tion potential of VOCs emission in eastern provinces would be much higher than those in western provinces by about 156%-235%.     

Simultaneous removal of arsenate and fluoride from water by AI-Fe （hydr）oxides

A1-Fe （hydr）oxides with different A1/Fe molar ratios （4：1, 1：1, 1：4, 0：1） were prepared using a co- precipitation method and were then employed for simultaneous removal of arsenate and fluoride. The 4A1 ： Fe was superior to other adsorbents for removal of arsenate and fluoride in the pH range of 5.0-9.0. The adsorption capacity of the A1-Fe （hydr）oxides for arsenate and fluoride at pH 6.50.3 increased with increasing A1 content in the adsorbents. The linear relationship between the amount of OH released from the adsorbent and the amount of arsenate or fluoride adsorbent by 4A1 ： Fe indicated that the adsorption of arsenate and fluoride by A1- Fe （hydr）oxides was realized primarily through quantita- tive ligand exchange. Moreover, there was a very good correlation between the surface hydroxyl group densities of A1-Fe （hydr）oxides and their adsorption capacities for arsenate or fluoride. The highest adsorption capacity for arsenate and fluoride by 4A1 ： Fe is mainly ascribed to its highest surface hydroxyl group density besides its largest pHpzc. The dosage of adsorbent necessary to remove arsenate and fluoride to meet the drinking water standard was mainly determined by the presence of fluoride since fluoride was generally present in groundwater at much higher concentration than arsenate.     

Process control factors for continuous microbial perchlorate reduction in the presence of zero-valent iron

Process control parameters influencing microbial perchlorate reduction via a flow-through zero-valent iron （ZVI） column reactor were investigated in order to optimize perchlorate removal from water. Mixed perchlorate reducers were obtained from a wastewater treatment plant and inoculated into the reactor without further acclimation. Examined parameters included hydraulic residence time （HRT）, pH, nutrients requirement, and perchlorate reduction kinetics. The minimum HRT for the system was concluded to be 8 hr. The removal efficiency of 10 mg. L-1 influent perchlorate concentration was reduced by 20%-80% without control to the neutral pH （HRT = 8 hr）. Therefore pH was determined to be an important parameter for microbial perchlorate reduction. Furthermore, a viable alternative to pH buffer was discussed. The microbial perchlorate reduction followed the first order kinetics, with a rate constant （K） of 0.761 hr-1. The results from this study will contribute to the implementation of a safe, cost effective, and efficient system for perchlorate reduction to below regulated levels.     

壬基酚聚氧乙烯醚暴露下赤子爱胜蚓（Eisenia foetida）的生理损伤

利用急性接触试验和人工土壤试验分别研究了壬基酚聚氧乙烯醚（NPEO）对赤子爱胜蚓（Eisenia foetida）的致死性和氧化损伤.急性接触试验结果显示,NPEO对赤子爱胜蚓的48 h毒性半致死剂量p（48 h,LD50）为0.58 mg·L^-1;人工土壤试验结果显示,NPEO可诱导赤子爱胜蚓CAT酶活力、GST酶活力、GSH含量和氧化产物（MDA）含量上升,暴露28 d时,NPEO浓度与赤子爱胜蚓CAT酶活力、GST酶活力、GSH含量和MDA含量呈正相关,且均存在显著的剂量-效应关系（P＜0.05）,NPEO剂量增加对赤子爱胜蚓SOD酶活性和Cu-Zn SOD酶活性有轻微抑制作用.以上结果表明NPEO在亚致死暴露浓度下＜0.50 mg· kg^-1）会对赤子爱胜蚓产生生理胁迫并导致一定程度的氧化损伤.     

若尔盖高寒沼泽植物群落与环境因子的关系

了解高寒沼泽植物群落与环境因子之间的关系,对揭示物种对生态环境的需求以及高寒沼泽的保护管理有重要意义,然而目前尚不清楚影响若尔盖高寒沼泽植物分布的主要环境因素。作者于2011—2012年间在若尔盖高寒沼泽随机调查32个样地,收集了植被样方数据、土壤理化性质数据、地表水位等实测数据,借助方差分析、CCA分析和相关分析等经典的统计方法,研究高寒沼泽植物群落物种组成和不同地表积水状况下多样性的差异,以及高寒沼泽植物群落与环境因子的关系。结果显示：若尔盖高寒沼泽植物共有151个种,隶属于39科98属;多样性指数随地表积水的减少呈现出增加的趋势。典范对应分析（CCA）结果表明,第一轴与水位、土壤水分含量、土壤有机碳、土壤总氮显著负相关,与土壤容重显著正相关,第二轴与裸斑率和鼠洞数显著相关。前2个轴一共解释了79．8％的物种与环境因子的关系,与环境因子的相关系数均在0．87以上;其中,水分和土壤养分条件是影响物种分布的主导因子,其次是裸斑面及啮齿动物活动。植物多样性指数与土壤水分负相关,与土壤有机碳和土壤全氮显著负相关,与土壤容重显著正相关。若尔盖沼泽植物群落物种多样性除了受土壤水分和养分条件的影响以外,啮齿动物的活动可能是影响若尔盖沼泽物种分布以及促进群落进一步演替的主要因素之一。     

大肠杆菌与水体中U(Ⅵ)的作用行为和产物研究

通过批次吸附实验及介观和谱学等表征方法,研究了大肠杆菌(E.coli)粉末对水体中U(Ⅵ)的富集行为和吸附模型,并对其作用产物进行了详细分析.结果表明:大肠杆菌对初始浓度为50mg/L U(Ⅵ)溶液(pH＝5)的吸附容量可达到276.89mg/g.Langmuir等温模型和准二级动力学方程能较好的描述其吸附过程. FTIR、SEM-EDS、XRD分析结果表明:在与水体中U(VI)作用后,大肠杆菌表面检测出UO₂²⁺的红外特征峰(876.16cm^-1)和U的能谱吸收峰(结合能=2.4~4.4keV).UO₂²⁺主要与菌体表面的烷基、氨基、羧基、分子间氢键发生作用,重点与PO₂-、P(OH)₂、PO₄^3-以及PO₃^-等含P基团进行络合配位,最终产物以CaU(PO₄)₂、Ca(UO₂)₂(PO₄)₂·xH₂O、NaUO₂(PO₃)₃等铀的磷酸盐形式存在.     

交替冻融对东北典型土壤腐殖质的影响

以受季节性冻融过程影响显著的东北地区的黑土、暗棕壤和水稻土为例,采用实验室模拟的方法,研究交替冻融循环过程（分别在-20℃和20℃下处理）对土壤腐殖质的影响。研究表明：交替冻融后,黑土和暗棕壤松结态腐殖质质量分数分别增加了39%和28%,HA/FA分别上升了45%和35%;水稻土松结态腐殖质质量分数和HA/FA分别下降了18%和31%。三维荧光结果进一步验证,黑土、暗棕壤在交替冻融中土壤芳香化程度增高,HA/FA上升,而水稻土则相反。黑土和暗棕壤松结态腐殖质和HA/FA升高,主要是微生物分解作用和土壤大团聚体破坏等原因造成,水稻土松结态腐殖质和HA/FA降低,主要是水稻土的缺氧环境造成。     

大清河人工快速渗滤系统示范工程效果分析

以滇池流域受污染的大清河为研究对象,开展了人工快速渗滤系统（CRI）示范工程研究,根据气候条件、进水水质和运行工艺分为6个工况,以探索污染负荷和工艺参数对CRI运行性能的影响。实验结果表明：水力负荷2 m.d-1、湿干比1：1是该示范工程运行的最优工艺条件。CRI系统对有机物（COD）的平均去除率范围17.42%～63.75%;对氨氮去除效果受进水水质影响,高、低污染负荷下NH3-N去除率分别为56.71%、85.48%;CRI示范工程硝化作用较强,反硝化能力较弱,对TN的平均去除率范围为10.69%～28.29%;CRI示范工程对TP的平均去除率为27.62%,最佳工艺条件下为50.23%。CRI系统可通过对填料进行优化组合、适当增大饱水带高度,强化除磷脱氮能力。     

城市消防站选址布局优化及对雄安新区的启示

安全是雄安新区建设发展的重要保障和基础底线。消防救援队伍,承担火灾防范、火灾扑救、抢险救援等工作,是提升新区城市救援能力,保障城市安全的有生力量。消防站是消防救援队伍工作（执勤备战）的场所,优化消防站选址布局意义重大。面向雄安新区消防安全提升和应急救援能力提升需求,针对我国目前消防站建设过程中覆盖率低及消防站建设投资巨大等问题,建立位置集合覆盖模型和最大覆盖模型联合使用的选址方法,增加补充性约束条件对模型进行改进,提出基于GIS的选址模型应用流程,并通过实际案例应用研究,提出雄安新区消防站规划建设的启示建议。     

碳化温度对稻壳生物炭的影响及其对Cr(Ⅵ)的吸附性能

以稻壳为原料,在不同的温度(300,500和700℃)下采用限氧碳化法制备了生物炭,并利用扫描电镜(SEM)和红外光谱(FTIR)表征了生物炭的结构和性质,同时考察了pH值对生物炭吸附的影响,初步探讨了吸附机理。结果表明,制备的生物炭官能团种类和总量相近,均含有烷基、芳香基及一些含氧官能团,随着碳化温度的升高芳香族化合物增加,芳香化程度增强。试验条件下稻壳生物炭(RH700)对Cr(Ⅵ)的饱和吸附量达到16.68 mg/g,降低pH值有利于对Cr(Ⅵ)的吸附。稻壳生物炭等温吸附曲线更符合Langmuir模型,对吸附过程中焓(△H)、熵(△S)和吉布斯自由能(△G)的计算表明,稻壳生物炭对Cr(Ⅵ)的吸附是自发的吸热反应,其吸附行为更符合伪二级动力学模型,拟合的qe值与实测值相差小于0.38 mg/g。颗粒内扩散表明膜扩散和颗粒内扩散共同控制着吸附过程。