全氟辛烷磺酸盐在天然水体沉积物中的吸附-解吸行为

通过平衡振荡试验,探讨了沉积物的理化性质(总有机碳含量、粒度、阳离子交换容量、比表面积)、离子强度和pH值对全氟辛烷磺酸盐(PFOS)吸附-解吸行为的影响.结果表明,在中性环境中PFOS在水和沉积物中有机质之间的分配作用是影响其吸附行为的重要机制,分配系数Kd与沉积物中总有机碳含量呈显著正相关(r=0.96,p＜0.01,n=15).随着离子强度的增加,盯OS在沉积物中的吸附量明显增大,解吸滞后现象更加明显.pH的影响在酸性和碱性条件下(pH 4～8.5)呈现出不同的特点,在酸性条件下随pH值增加,PFOS在沉积物中的吸附量减少;在pH接近中性时达到最小值;在碱性条件下随pH增加,吸附量增加.     

基于碳数分段法的石油烃污染土壤异位热脱附工艺的优化

针对石油烃污染土壤成分复杂、污染严重、修复难度高的问题,采用适用性广、效率高且去除彻底的异位热脱附技术修复石油烃污染土壤。利用碳数分段法及室内模拟实验,探究在热脱附过程中的土壤粒径、含水率和有机质对石油烃及各组分热解吸效率的影响;另外,还采用响应面法对各影响因素进行了优化,以获得异位热脱附修复石油烃污染土壤的最优工艺参数。结果表明,当污染土壤粒径高于1 mm时,石油烃脱附效率均可达90%以上,且粒径越大土壤颗粒中石油烃去除率越高。其中,润滑油段(ORO, C28~C40)组分的脱附效率随粒径变化最为明显。当土壤含水率为15%、脱附时间为50 min时,石油烃脱附效率最大为52.63%。另外,土壤中有机质含量越低,越利于石油烃的脱除,且高温(400~500 ℃)条件下可基本消除土壤中高含量有机质(3.82%)对石油烃脱除的阻碍作用。响应面优化实验得到的最佳工艺参数条件为,粒径2 mm、有机质含量1.44%、含水率为17.68%,在此条件下的石油烃脱附去除效率可达65.32%。该研究结果可为热脱附技术在石油烃污染场地的实际应用提供参考。     

厌氧消化过程中温度骤降对酸化活动抑制性的研究

对于厌氧消化过程的酸化阶段,反应器内温度的快速下降将对碳水化合物的分解和产酸活动产生明显抑制。当温度依次从30℃下降到25、20和15℃时,反应器内厌氧微生物数量呈缓慢减少趋势,受温度影响不大;但是,厌氧酸化过程却明显表现出受到每一次骤然降温的影响,其碳水化合物的平均去除率随温度骤降从92%依次降低为84%、72%和25%,且最低分别达到78%、52%和10%。研究还表明,随着温度的骤降,厌氧酸化活动将立即受到强烈抑制,并需要一定的时间来恢复以适应发酵温度的改变。     

氧化镁烟气脱硫反应特性研究

利用实验室规模的鼓泡式反应装置,对比了碳酸钙、氧化镁和氧化镁/硫酸镁脱硫剂的反应活性,证实脱硫液中高浓度硫酸镁的存在是保证镁法脱硫效率高于钙法的重要因素,并考察了硫酸镁浓度、脱硫剂(氧化镁)浓度、烟气量、SO2浓度和吸收液温度等因素对脱硫效率的影响。结果表明,脱硫反应可以根据pH分为2个不同阶段;反应过程中脱硫效率随着硫酸镁浓度的增加而显著升高;烟气量增加将会导致脱硫效率有所下降;入口SO2浓度升高,脱硫效率下降;氧化镁浓度、温度对脱硫效率影响不显著。结合实验现象进行推断,氧化镁脱硫的反应过程受SO2在气液两相界面的传质扩散和其水解产物在液相的扩散控制。     

壬基酚及其短链聚氧乙烯醚在污泥和土壤中的存在和降解

壬基酚聚氧乙烯醚(NPnEO)是广泛使用的表面活性剂．在污水处理厂中会降解为具有内分泌干扰效应的短链产物和最终产物壬基酚(NP)。剩余污泥是其进入环境的重要途径。介绍了NP和短链NPnEO在污泥中的存在情况、污泥处理过程对其存在的影响、以及这些物质随污泥处置过程进入土壤后的降解。     

胶束强化超滤去除水中双酚A

采用截留分子量(MWCO)为5000 Dalton、1000 Dalton的聚砜超滤膜,MWCO为1 kDa的再生纤维素超滤膜;采用十二烷基苯磺酸钠(SDBS)、曲拉通100(TritonX-100)、吐温80(Tween-80)、烷基多苷(APG)为表面活性剂,用胶团强化超滤工艺去除水中双酚A。研究了不同材质和截留分子量的超滤膜、表面活性剂浓度、膜操作压力、溶液pH和溶液中电解质等因素对该工艺的影响。结果表明,SDBS对双酚A有较好的去除效果,去除率在80%以上。在H+和Na+存在的条件下,双酚A的截留率增加,透过液中SDBS浓度降低。SDBS与非离子表面活性剂的复配可以提高双酚A截留率,降低透过液中SDBS的浓度,复配效果优劣顺序为Tween-80TritonX-100APG。     

Catalytic destruction of pentachlorobenzene in simulated flue gas by a V2O5-WO3/TiO2 catalyst

Pentachlorobenzene (PeCB) in simulated flue gas was destructed by a commercial V₂O₅-WO₃/TiO₂ catalyst in this study. The effects of reaction temperature, oxygen concentration, space velocity and some co-existing pollutants on PeCB conversion were investigated. Furthermore, a possible mechanism for the oxidation of PeCB over the vanadium oxide on the catalysts was proposed. Results show that the increase of gas hourly space velocity (GHSV) and the decrease of operating temperature both resulted in the decrease of PeCB removal over the catalyst, while the effect of the oxygen content in the range of 5-20% (v/v) on PeCB conversion was negligible. PeCB decomposition could be obviously affected by the denitration reactions under the conditions because of the positive effect of NO but negative effect of NH₃. The introduction of SO₂ caused the catalyst poisoning, probably due to the sulfur-containing species formed and deposited on the catalyst surface. The PeCB molecules were first adsorbed on the catalyst surface, and then oxidized into the non-aromatic acyclic intermediates, low chlorinated aromatics and maleic anhydride.     

Identification of priority pharmaceuticals in the water environment of China

In recent years, increasing attention has been paid to the trace-level contamination of pharmaceuticals in the water environment all over the world. Considering a large number of pharmaceuticals used, it is crucial to establish a priority list of pharmaceuticals that should be monitored and/or treated first. In the present study, we developed a ranking system based on the pharmaceutical consumption, removal performance in the wastewater treatment plants (WWTPs) and potential ecological effects, and applied to the situation of China. 39 pharmaceuticals, which had available consumption data and also been reported previously in the WWTPs of China, were selected as candidate pharmaceuticals. Among them, seventeen pharmaceuticals were considered as priority pharmaceuticals, out of which, erythromycin, diclofenac acid and ibuprofen, had the high priority. Compared with other literatures, we found that some pharmaceuticals given concerns to globally should also be included in the priority list in China; while some pharmaceuticals, not mentioned in other literatures, such as cefalexin, ketoconazole, should be also given prior consideration in China. Among all the therapeutic classes, antibiotics, which were grossly abused in China, contributed the most to the priority pharmaceuticals. However, priority antibiotics accounted for only 32% of candidate antibiotics, while 71% and 100% of the candidate anti-inflammatory and antilipidemic respectively were identified as the priority pharmaceuticals, indicating that antibiotics might be overanxiously considered in the previous studies on their behaviors in the WWTPs of China.     

简易生活垃圾填埋场综合治理工程设计

随着越来越多标准化生活垃圾填埋场的建成和投入运行,原有简易生活垃圾填埋场的环境综合治理被各级环境管理部门日益重视,成为改善环境急需解决的问题。以西北某市简易生活垃圾填埋场综合整治工程为例,通过分析简易垃圾填埋场存在的主要环境隐患,有针对性地提出了解决垃圾渗沥液、填埋气、边坡安全等环境和安全问题的具体工程措施,尽量将简易垃圾填埋场对周围环境的影响降到最低程度。     

温度对合成钛酸盐纳米材料的影响及其对水中Cd (Ⅱ)的去除效果

为有效去除水中Cd（Ⅱ）,以TiO₂纳米粉和NaOH为原料,调节水热反应温度分别为100、120、150和190℃,制备出了不同形貌的TNs（钛酸盐纳米材料）,分别记为TNs-100、TNs-120、TNs-150和TNs-190,并对其形貌、结构、比表面积、化学组成等物理化学性能进行了表征;通过对水中Cd（Ⅱ）的静态吸附试验,考察了TNs对Cd（Ⅱ）的吸附性能.结果表明:随着合成温度的升高,TNs的形貌逐渐从纳米片演变成纳米管,管长逐渐变长,最后变成纳米棒.TNs-100的晶型结构主要是锐钛矿型;随着温度升高,结晶度逐渐增强;TNs-190出现了部分金红石相.TNs-150对Cd（Ⅱ）的吸附能力最强,最大平衡吸附量为254.66 mg/g,最佳吸附pH为5.0.再生的TNs-150对Cd（Ⅱ）循环吸附6次的去除率和解吸率均可达93%以上.TNs-150对Cd（Ⅱ）的吸附过程符合准二阶动力学方程和Langmuir吸附等温模型,吸附机制主要是TNs层间Na+和H+与溶液中Cd（Ⅱ）的离子交换.研究显示,TNs的饱和吸附量均高于同类吸附剂,能有效去除水中Cd（Ⅱ）.