太原市土壤重金属污染及其潜在生态风险评价

为全面了解太原市土壤重金属含量及其潜在生态危害程度,在研究区内共采集了80个土壤样品,测试了Pb、Cu、Ni、As、Cd、Cr、Hg、Zn共8种重金属元素含量,并采用地积累指数法和潜在生态危害指数法对土壤重金属污染进行了分析和评价.结果表明,太原市土壤环境总体污染程度处于无-中度污染,潜在生态危害处于轻微危害程度.相对...     

阜宁生态县创建难点与生态经济发展分析

简要介绍了阜宁创建生态县的基本情况,分析了创建的优势条件和劣势条件,以及阜宁的环境压力和生态县建设的差距,得出创建的难点与重点;结合对阜宁生态环境基本情况的分析和把握,提出阜宁的生态经济发展方向,并对阜宁县境进行生态经济区的划分,详细介绍了每个生态经济区的基本情况、生态问题及发展建议.     

Preparation and utilization of wheat straw anionic sorbent for the removal of nitrate from aqueous solution

In order to reduce the impact of eutrophication caused by agricultural residues(i.e.,excess nitrate)in aqueous solution,economic and effective anionic sorbents are required.In this article,we prepared anionic sorbent using wheat straw.Its structural characteristics and adsorption properties for nitrate removal from aqueous solution were investigated.The results indicate that the yield of the prepared anionic sorbent,the total exchange capacity,and the maximum adsorption capacity were 350%,2.57 mEq/g,and 2.08 mmol/g, respectively.The Freundlich isotherm mode is more suitable than the Langmuir mode and the adsorption process accords with the first order reaction kinetic rate equation.When multiple anions(SO_4~(2-),H_2PO_4~-,NO_3~-,and NO_2~-)were present,the isotherm mode of prepared anionic sorbent for nitrate was consistent with Freundlich mode;however,the capacity of nitrate adsorption was reduced by 50%.In alkaline solutions,about 90% of adsorbed nitrate ions could be desorbed from prepared anionic sorbent.The results of this study confirmed that the wheat straw anionic sorbent can be used as an excellent nitrate sorbent that removes nitrate from aqueous solutions.     

煤层气开发环境污染特征及防治对策研究

煤层气开发是一个时短、线长、面广的工程活动,具有单井产气量低、井网密度大、降压排水等独特特征,对生态环境有一定的影响。文中分析了煤层气开发过程中钻井废液、排采水等污染物的性质,结果表明,钻井废液中COD浓度较高,为1 985.5 mg/L,As、Cr、Cu、Zn、Mn、Fe、Pb等重金属含量均在污水综合排放二级标准之内;排采水中含有较高的COD、重金属、盐浓度,经自然沉降后,COD、重金属浓度有所降低,而盐浓度变化不大;考察了煤层气开发对土壤环境质量的影响,发现钻井过程对土壤盐渍化没有影响,但土壤中As含量有所增加。在此基础上,提出钻井废液、排采水及污染土壤的具体防治对策,为煤层气开发污染治理提供理论依据与技术支持。     

Al_b形态处理模拟染料废水的效果及机制研究

采用乙醇-丙酮混合沉淀法分离聚合氯化铝(PAC)溶液中的Alb形态.通过对吸光度和Zeta电位的测定,研究了Alb形态的投加量和溶液pH对分散黄棕和直接紫2种模拟染料废水脱色效果的影响,并将其与PAC进行比较.利用光散射颗粒分析仪(PDA2000)和Mastersizer2000型激光粒度仪在线测定絮体粒径的变化情况,结合絮体的Zeta电位,对Alb形态的絮凝机制进行探讨.结果表明,与PAC比较,Alb形态处理模拟染料废水的最佳pH值范围较宽,在实验条件下,Alb形态形成的絮体的密实性较高,沉降性能较好,恢复能力较强.     

基于FDS的高校宿舍火灾数值模拟

采用美国国家标准和美国技术研究院(NIST)开发的FDS软件,建立了高校宿舍火灾模型,对宿舍火灾进行全尺寸模拟,通过模拟试验给出了火灾发生过程中烟气运动、温度变化和氧气浓度变化的规律.     

杭州湾海底管线溢油风险及应急措施

以杭州湾海底管线为例,提出海底输油管线穿孔溢油安全应急措施。海底输油管线穿孔后,利用抽油泵抽吸,使海底管线内产生负压,阻止管线内原油外溢,利用SCADA系统进行了模拟试验,结果显示：用抽油泵抽吸能使海底管线产生-0．038～-0．04MPa压力,理论上能将海水吸入,阻止原油外泄。     

粤北2座不同营养水平水库浮游植物功能类群的季节演替

于2011年1—12月对广东省韶关市白水礤水库和苍村水库这2座中型居民供水水库进行每月1次、为期1a的采样,利用营养状态指数(TSI)进行水质综合评价,将水库中的浮游植物按功能类群进行分类,并结合水库的水文、水质和浮游植物的生境特征,分析全年优势功能类群的演替特点及其主要的环境影响因子。结果表明,白水礤水库为贫营养型水库,苍村水库为低中营养型水库,全年共检出浮游植物7门45属(种),可划分为16个功能类群,其中,白水礤水库全年以适应低营养盐环境的功能类群占优势,耐富营养化的功能类群仅在丰水期有检出;而苍村水库全年都能监测到耐富营养环境的功能类群,且在丰水期明显占优势,但在枯水期和平水期因营养盐含量的降低,演变为以适应低营养盐环境的功能类群为主。营养盐含量的不同是导致2座水库浮游植物功能类群产生差异的根本原因,而因降水季节的变化所致水体环境因子的变化则是造成2座水库浮游植物功能类群演替不可忽视的因素。     

天津地区地表水咸化的水化学证据

为了解天津滨海地区咸/海水入侵的水化学特征,对该区地表水的化学组成进行了全面研究.结果显示,由山前平原到滨海平原,水化学的组成呈明显的地带性分布.研究水体TDS的含量较高,咸化程度明显,由淡水逐渐向卤水演化;同时,水化学类型由HCO3-Ca型,以及其它混合类型逐渐向Cl-Na型演化.Gibbs图解分析表明,蒸发-浓缩作用是控制该区地表水化学组成的主要原因;而咸/海水入侵以及由其导致的阳离子交换反应、碳酸钙的沉淀/溶解等对其也有重要的影响.     

Preparation and characterization of β-FeOOH-coated sand and its adsorption of Cr(VI) from aqueous solutions

Batch adsorption experiments were conducted to explore the adsorption of Cr(VI) in aqueous solutions by β-FeOOH-coated sand. We investigated the key factors which affected the adsorption process such as adsorbent dosage, initial pH, initial Cr(VI) ion concentration, contact time and temperature. The uptake of Cr(VI) was very rapid and 44.3%, 51.6%, 58.9% of the adsorption happened during the first 180 minutes at 293K, 303K and 313K, respectively. The pseudo-second-order rate equation successfully described the adsorption kinetics. To study the adsorption isotherm, two equilibrium models, the Langmuir and Freundlich isotherms, were adopted. At 293K, 303K and 313K, the adsorption capacities obtained from the Langmuir isotherm were 0.060, 0.070 and 0.076 mg Cr(VI) per gram of the adsorbent, respectively. Thermodynamic parameters such as the change of energy, enthalpy and entropy were calculated using the equilibrium constants. The negative value of ΔG0 and the positive value of ΔH0 showed that the adsorption of Cr(VI) in aqueous solutions by β-FeOOH-coated sand was spontaneous, endothermic and occurred by physisorption.