Adsorption of benzene and toluene from waste gas using activated carbon activated by ZnCl2

A series of activated carbons with high surface area were prepared from walnut shell using chemical activation with ZnCl2. In this research the carbonization stage was carried out at 500℃. The performance of the synthesized carbons evaluated in adsorption of benzene and toluene from waste gas. The influence of impregnation ratio on the characteristics of synthesized activated carbons as well as their adsorption capacity was investigated. The ratio of activation agent to walnut shell was selected in the range of 0.5-2.0 wt/wt. The synthesized activated carbons were characterized using XRD, SEM, BET and FTIR techniques. The highest activated carbon production yield was obtained at impregnation ratio of 1.5 wt/wt. The XRD analysis illustrated that peaks intensity decreased with increasing impregnation ratio showing that amorphous property of samples was increased. The SEM analysis revealed successful pore development in synthesized activated carbons obtained at high impregnation ratios. The surface area of the activated carbons increased with increasing impregnation ratio and its maximum value reached 2643 m2.g 1 at impregnation ratio of 2/1. FTIR analysis indicated that the relative amount of different acidic surface groups on synthesized carbons was a function of impregnation ratio. Experimental results for benzene and toluene adsorption showed a high potential of employing synthesized impregnated activated carbon for treatment of waste gas. Generally, the amount of VOC adsorbed on the surface was affected by physicochemical properties of synthesized activated carbons.     

聚苯乙烯电纺纳米纤维对水中苯系物的吸附性能

采用高效液相色谱法研究了静电纺聚苯乙烯纳米纤维对水中苯系物有机污染物的吸附性能,探究了纳米纤维对苯、对氯苯、硝基苯的吸附容量随浓度和时间的变化规律.通过实验得到静电纺纳米纤维对苯、对氯苯、硝基苯的平衡吸附容量平均值分别为9.82,5.57和4.4mg.g-1,静态吸附4h后基本达到平衡.实验结果表明,静电纺聚苯乙烯纳米纤维能够较好地吸附苯类物质,并能多次重复利用,对水中较低浓度的苯类物质吸附是一种比较合适的吸附材料.     

低温等离子体结合吸附处理含苯废气

以苯废气为降解对象,利用介质阻挡放电(DBD)产生等离子体进行处理,考察了放电频率、停留时间和气体湿度对苯去除效率的影响。研究发现,在一定浓度和电压下,等离子体对苯的去除率随放电频率的增加而升高,随着废气停留时间的增加而升高,随废气湿度的增大先升高后下降,当相对湿度为20%左右时效率最高。在利用介质阻挡放电结合MOF材料吸附处理含苯废气时,控制入口苯质量浓度小于500mg/m^3,可将出口苯质量浓度降解至4 mg/m^3以下,苯去除率保持在98%以上。     

改性聚丙烯纤维的制备及其对苯系物的吸附

分别采用熔融接枝法和共混法制备聚丙烯(PP)/苯乙烯(St)改性纤维(PP-g-St)和聚丙烯/聚苯乙烯(PS)改性纤维(PP/PS),研究了熔融接枝条件对St接枝率的影响,考察了PP纤维、PP/PS纤维和PP-g-St纤维对纯苯系物和水中乳化、溶解态苯系物的吸附性能,并探讨了再生后的重复吸附性能。实验结果表明:PP熔融接枝St的最优配比为w(St)=9%,w(过氧化二异丙苯)=0.5%,此时St接枝率为4.7%,且能顺利纺丝;相比于PP纤维,PP-g-St纤维和PP/PS纤维对纯苯系物和水中乳化、溶解态苯系物的吸附量显著提高;吸油饱和的PP-g-St纤维和PP/PS纤维通过离心法再生5次后吸附性能再生率仍能够分别达到82.0%和87.6%。     

环境风险评价中化学品苯泄漏的大气环境影响研究

以苯泄漏的大气影响为研究对象,模拟一起典型的突发性环境风险事故.依据<建设项目环境风险评价技术导则>,采用导则推荐的伯努利方程、质量蒸发量公式计算物质泄漏的源强,利用多烟团模式模拟计算其对环境的影响,预测出不同时间不同距离处的影响程度.根据这一预测结果,针对性地提出风险防范及应急措施,为环境风险事故的应急处置提供依据.     

Modeling the spill in the Songhua River after the explosion in the petrochemical plant in Jilin

An explosion in a petrochemical plant in Jilin in the northeast of China on 13 November 2005 was responsible for the discharge of large quantities of benzene and nitrobenzene into Songhua River. This endangered the water supply of Harbin city and influenced the daily life for millions of people. The dispersion-advection equation was solved analytically and numerically and used to simulate the concentration of benzene and nitrobenzene in the Songhua River after the accident. Both solutions gave practically identical results. The main elimination process for both compounds was volatilization. The model results are quite close to the results obtained by measurements at monitoring stations. Arrival time of the pollutant wave, peak concentrations and end of the pollutant wave at Harbin and along the river were predicted successfully. The peak concentrations of nitrobenzene at Harbin were more than 30 times above the permissible limits for drinking water.     

七种苯的一取代物在小球藻中的积累及其对藻生长的影响

试验合成的有机化合物对藻生长的影响,不仅能对化学品安全评价提供信息,而且对水质富营养化的理论研究和实际治理都有重要意义。Korte教授曾提出把藻对化学品的积累多寡作为评价化学品安全与否的指标之一。西德联邦环境署也推荐了把藻作为水毒理学试验生物之一,并被很多实验室采用了。在上述以藻作为试验生物的实验中,作者们或者是仅仅做积累试验,或者是仅仅做毒性试验,而使用同一化合物进行上述两个试验并比较其结果,以便从中得到有益的启示至今尚未见报道。本文正是基于此想法,试验了一组苯的取代物对小球藻(Chlorella fusca)生长的影响(促进增殖或抑制增殖)以及藻对化合物的积累。     

水中六六六与五氯苯酚的光催化氧化

以高压汞灯不光泊,ＴｉＯ２为催化剂,研究了水中低浓度六六六五与五氯苯酚的光催化氧化。六六六易被光催化氧化,其４种异构体的半衰期十分接近,均在２０ｍｉｎ左右。ＰＨ中性条件下γ六六六的氧化速率较高。六六六光催化氧化存在含氯中物,并可逐渐被氧化去除。五氯苯酚光催化氧化速率明显高于光分解。３０ｍｉｎ之内五氯苯酚即可完全脱氯。随反应过程的继续,五氯苯酚被氧化成简单的小分子直至完全矿化。该法在饮用水深度处理中     

稻田耕层土壤黑碳分布特征及影响因素

为探究我国稻田土壤黑碳含量分布特征及其影响因素,本研究采用苯多羧酸法(Benzene polycarboxylic acid,BPCA)对稻田耕层土壤黑碳(Black carbon,BC)含量及稳定性进行测定与分析,以完善国内农田土壤黑碳研究,并为农业可持续发展提供理论依据.结果表明:(1)黑碳含量为(0.70±0.08)~(4.57±1.63)g·kg-1,平均值为(1.63±0.18)g·kg-1;黑碳储量为(1.55±0.18)~(6.18±2.39)t·h m-2,平均值为(2.71±0.27)t·hm-2.(2)黑碳含量排序:西南区东北区华南区华东区华北区西北区,黑碳储量排序:西南区东北区华北区华南区华东区西北区.(3)在苯多羧酸含量特征方面,西南区表现为苯四甲酸(∑tetracarboxylic acids,B4CAs)苯六甲酸(mellitic acid,B6CA)苯五甲酸(benzenepentacarboxylic acid,B5CA)苯三甲酸(∑tricarboxylic acids,B3CAs),华北区表现为B6CAB4CAsB5CAB3CAs,其它耕作区表现为B6CAB5CAB4CAsB3CAs.B5CA/B6CA、B6CA/B4CAs分别为(0.73±0.06)~(0.98±0.18)、(1.07±0.14)~(1.38±0.10),平均值分别为(0.92±0.02)、(1.23±0.03).研究发现,稻田土壤黑碳分布特征是人为因素、黑碳结构特性及环境因素等综合作用的结果.土壤黑碳主要来自稻田作物燃烧,并且黑碳含量与pH及容重间的相关性不显著,而与土壤有机碳、黏粒呈显著正相关.     

光催化氧化苯酚中间产物的分析与降解途径探讨

采用光催化氧化法降解苯酚溶液,利用液相色谱对苯酚及其中间产物进行了定性、定量分析。考察了投加H2O2对中间产物浓度变化的影响。根据中间产物的产生情况及浓度变化,推测了苯酚光催化降解的反应途径。