Evaluation and analysis of heavy metals in iron and steel industrial area

Environment, Development and Sustainability - Heavy metal pollution has attracted more attention due to the toxicity and migration characteristics, which has close relationship with soil...     

潜流湿地填料比选及对氨氮的去除效应研究

为了提高西北地区潜流湿地净化污水中氮的效率,采用吸附动力学和热力学实验,对比研究了6种填料对水中氨氮的吸附特性。结果表明:砾石、生物炭、红砖、瓷砖、无烟煤和混凝土渣对氨氮的吸附平衡时间分别为12、24、17、12、8、12h,吸附量体现为生物炭砾石无烟煤瓷砖混凝土渣红砖。6种填料对氨氮的动力学吸附过程符合准二级动力学模型,吸附过程受到固体颗粒表面液膜影响,并非速率控制单独起作用。溶液浓度和温度升高有利于填料对氨氮的吸附,6种填料对氨氮的吸附过程符合Freundlich模型,表明吸附过程为多分子层吸附且吸附表面不均匀。6种填料对氨氮的吸附以物理吸附为主,吸附为吸热过程、焓推动作用,均不属于自发过程。6种填料都适合作潜流湿地填料,但生物炭对氨氮吸附效果最佳。     

Application of red mud as a basic catalyst for biodiesel production

Red mud was investigated in triglyceride transesterification with a view to determine its viability as a basic catalyst for use in biodiesel synthesis.The effect of calcination temperature on the structure and activity of red mud catalysts was investigated.It was found that highly active catalyst was obtained by simply drying red mud at 200°C.Utilization of red mud as a catalyst for biodiesel production not only provides a cost-effective and environmentally friendly way of recycling this solid red mud waste,significantly reducing its environmental effects,but also reduces the price of biodiesel to make biodiesel competitive with petroleum diesel.     

沸石改良土壤的研究进展

沸石因其独特的晶体结构具有较强的离子交换能力和吸附能力,作为良好的土壤改良剂逐步引起了人们的广泛重视。简要综述了沸石对土壤的理化性质、重金属、植物、微生物和酶的影响及其研究进展。     

电感耦合等离子体质谱法测定地表水中铊的研究

本研究建立了电感耦合等离子体质谱法(ICP-MS)测定地表水中铊的方法。对仪器工作条件进行了优化,用在线内标校正基体效应的干扰,重点考察了样品测定介质、酸度、共存元素干扰等因素对测定结果的影响。在最佳实验条件下,该方法的检出限可达0.003μg/L,线性相关系数不小于0.999 9,加标回收率为93%~110%。与传统的原子吸收法相比,该方法不需要富集等繁琐的前处理过程,具有检出限低、快速、精密度和准确度高等优点。     

ZnO-PMMA复合材料光催化去除水中低浓度氨氮

通过水热法制备纳米ZnO,采用热粘固法成功地将其负载于聚甲基丙烯酸甲酯(PMMA)微球表面,并对ZnO-PMMA复合材料光催化去除水中低浓度氨氮的能力进行了考察.同时,探究了负载比例、初始氨氮浓度、催化剂浓度和pH对低浓度氨氮去除效率的影响.实验结果显示,PMMA改善了纳米ZnO的分散性和光催化能力,ZnO-PMMA能够有效地催化去除氨氮废水.在汞灯照射下,当pH=12、温度为30℃时,1 g·L~(-1)的催化剂(ZnO-PMMA)对50 mg·L~(-1)的氨氮废水去除率达到66%,且反应产物硝氮和亚硝氮含量较低,体现了该催化剂具有将氨氮转化为N2的良好的光催化降解能力.同时,纳米材料可以简单方便地回收,减轻了对环境的潜在影响,符合绿色化学的原则.     

接种降解菌对土壤中邻苯二甲酸二异辛酯降解的影响

邻苯二甲酸二异辛酯〔Di-(2-Ethylhexyl)phthalate,DEHP〕是农田土壤中常被检出的有毒有机污染物,在土壤中有较长的持留性,微生物降解是其从土壤中消失的主要途径.本文采用温室盆栽试验研究了接种两株从污水处理厂活性污泥中分离得到的高效DEHP降解菌及其混合菌悬液降解土壤中DEHP污染的效果,以及土壤中添加葡萄糖和种植作物对其降解效率的影响.结果表明,在土壤初始DEHP浓度为100mg kg-1的条件下,接种两种降解菌及其混合菌悬液都可显著提高土壤中DEHP消失的速率,其残留半衰期比不接种对照缩短了32~48d,但在相同条件下接种不同降解菌的处理之间没有显著差异.土壤中添加0.6%的葡萄糖虽然可以强烈地促进土壤微生物的整体活性,但并没有提高修复效率,反而在短期内延缓了降解菌对DEHP的降解,延长了DEHP在土壤中持留的半衰期;植物生长可显著提高降解菌的降解效率,降低土壤中DEHP的残留浓度.研究结果同时也表明,只添加葡萄糖或只种植植物对土壤中DEHP的降解并没有显著的影响.图3表4参14     

Particulate matter pollution in Kunshan High-Tech zone: Source apportionment with trace elements, plume evolution and its monitoring

Particulate matter(PM) in the Kunshan High-Tech zone is studied during a three-month campaign. PM and trace elements are measured by the online pollution monitoring, forecastwarning and source term retrieval system AS3. Hourly measured concentrations of PM_(10), PM_(2.5) and 16 trace elements in the PM_(2.5) section(Ca, Pb, Cu, Cl, V, Cr, Fe, Ti, Mn, Ni, Zn, Ga, As, Se, Sr, Ba)are focused. Source apportionment of trace elements by Positive Matrix Factorization modeling indicates that there are five major sources, including dust, industrial processing, traffic,combustion, and sea salt with contribution rate of 23.68%, 21.66%, 14.30%, 22.03%, and 6.89%,respectively. Prediction of plume dispersion from concrete plant and traffic emissions shows that PM_(10) pollution of concrete plant is three orders of magnitude more than that of the traffic. The influence range can extend to more than 3 km in 1 hr. Because the footprint of the industrial plumes is constantly moving according to the local meteorological conditions, the fixed monitoring sites scattered in a few hundred meters haven't captured the heaviest pollution plume at the local scale of a few km~2. As a more intensive monitoring network is not operationally possible, the use of online modeling gives accurate and quantitative information of plume location, which increases the spatial pollution monitoring capacity and improves the understanding of measurement data. These results indicate that the development of the AS3 system, which combines monitoring equipment and air pollution modeling systems, is beneficial to the real-time pollution monitoring in the industrial zone.     

杨柳街矿区地下水水化学特征及矿井涌水来源分析

杨柳街矿区随意排放的酸性废水对当地生态环境带来严重破坏,为查明矿区地下水水化学特征及矿井出水的来源,系统采集了20个水样。综合运用Piper三线图、相关性分析、离子比值法和系统聚类对常规水化学组分进行了分析。结果表明:煤系地层含硫矿物的氧化作用是矿井酸性废水形成的主要原因;岩溶区碳酸盐岩的溶解作用是形成低总溶解性固体的HCO_3型地下水的主要水文地球化学过程;煤系砂岩水和岩溶水在石炭系含水层发生了混合作用,对茶园水库构成潜在威胁。矿井渗水的直接补给来源为煤系基岩含水层和上覆泥质灰岩含水层,间接来源为地表河水入渗,潜在来源为西部岩溶含水层沿断层补给。     

氯菊酯在不同质地土壤中的光降解动力学规律

为了研究氯菊酯在土壤中的光降解规律,更好地为其在自然环境中的降解提供理论依据,探讨了氯菊酯在不同质地土壤中,不同条件下的光降解动力学规律。结果表明:氯菊酯降解符合准一级动力学规律,氯菊酯的降解受土壤质地的影响较大,在不同土壤中降解率为:壤质砂土砂质壤土壤质黏土,日光比紫外光照射下腐殖酸对氯菊酯的降解影响明显,随着腐殖酸浓度的增加,它对氯菊酯的降解作用先促进后抑制。