共查询到20条相似文献,搜索用时 46 毫秒
1.
因暴露于农业和工矿业等来源的各类污染物,地下水资源受到严重威胁。可渗透反应墙(Permeable reactive barrier,PRB)是一种地下水污染原位修复的创新技术,该技术的关键在于选取适宜的墙体反应介质,如广泛研究的零价铁(ZVI)、碳材料、沸石等。介绍了PRB技术的原理、介质材料类型与选取所需考虑的因素;回顾了含铁、含碳和含硅(矿物)组合材料应用于PRB修复地下水污染的研究进展,并聚焦了批量实验和柱试验中目标污染物的去除效果及作用机理。通过固定、表面修饰与混合等方式,组合材料在一定程度上可解决ZVI的聚集或表面钝化现象,并新增作用机制以助力污染物的去除;通过改性或混合等形式,组合材料还可增强含碳或含硅(矿物)材料对某些特定污染物的去除性能。最后,还展望了未来PRB技术中组合材料的开发和应用方向,以期为研发长效和环境友好型PRB反应介质提供参考。 相似文献
2.
《应用化工》2017,(4)
可渗透反应墙(permeable reactive barrier,PRB)技术作为一种经济、简易、高效的原位被动修复技术逐渐被广泛研究和应用。其关键技术是反应介质的研究,修复重金属污染地下水的PRB反应介质材料细分为氧化还原反应介质、吸附反应介质、沉淀反应介质和混合反应介质等四类,对反应介质的去除机理、应用现状和存在问题进行了综述。可渗透反应墙介质材料的选择应在其反应机理的基础上,结合当地水文地质条件、污染特征和经济费用等加以综合考虑,以保证PRB的长效性。未来PRB反应介质的发展主要集中于复合介质和新型反应介质的开发、反应介质的性能研究。同时,我国对PRB修复重金属污染地下水反应介质的研究还处于实验阶段,应进一步加强工程应用。 相似文献
3.
《应用化工》2022,(4)
可渗透反应墙(permeable reactive barrier,PRB)技术作为一种经济、简易、高效的原位被动修复技术逐渐被广泛研究和应用。其关键技术是反应介质的研究,修复重金属污染地下水的PRB反应介质材料细分为氧化还原反应介质、吸附反应介质、沉淀反应介质和混合反应介质等四类,对反应介质的去除机理、应用现状和存在问题进行了综述。可渗透反应墙介质材料的选择应在其反应机理的基础上,结合当地水文地质条件、污染特征和经济费用等加以综合考虑,以保证PRB的长效性。未来PRB反应介质的发展主要集中于复合介质和新型反应介质的开发、反应介质的性能研究。同时,我国对PRB修复重金属污染地下水反应介质的研究还处于实验阶段,应进一步加强工程应用。 相似文献
4.
5.
渗透反应格栅技术(PRB)修复污染地下水的现场模拟是实际工程设计、过程预测及修复效果评价的有效手段.以甲基叔丁基醚(MTBE)为研究对象,在多孔介质流体动力学、传质学、生物降解动力学等基础上,建立了生物渗透反应格栅修复MTBE污染地下水的数学模型.由双柱法的实验结果可知,模型模拟结果与实验数据的平均相对误差为5.74%,说明文中所建模型能够很好地描述MTBE在反应格栅内的降解去除过程;由污染物在格栅及其附近区域的浓度分布可知,由于部分流体从格栅侧面进入,污染物在此流径上得不到充分降解,表现为生物渗透反应格栅系统处理后的地下水区域边缘处的MTBE浓度高于其中心区域浓度,该结果可用于指导现场PRB系统及其附属设施的设计和安装. 相似文献
6.
7.
8.
10.
地下水是人类宝贵的淡水资源,然而随着现代社会工业化进程的不断发展和人类活动的急剧增加,污染程度也不断加重,这将对人类健康和社会发展造成极大危害,因此必须要研究出行之有效的治理方法,以达到最佳的地下水污染修复。该文在大量搜集国内外地下水重金属污染修复技术研究资料的基础上,针对性的对可渗透反应墙(PRB)技术的概念、原理、活性材料的选取、结构类型、国内外应用实例进行了总结,并提出了目前PRB技术存在的问题及前景展望。 相似文献
11.
12.
Summary Two methods of the synthesis of tributyl ammonium derivatives of glycidyl methacrylate — ethylene dimethacrylate copolymers with various contents of the crosslinking agent were examined. While the two-step process which consists in a reaction with dibutyl amine followed by alkylation with butyl bromide gives products with up to 1.5 mmol/g of required groups, in the case of the single-step reaction of the epoxide group with tributyl amine the content does not exceed 0.4 mmol/g. The use of diamines for increasing the distance between the quaternary group and the polymer backbone does not yield a readily definable product, and cannor therefore become the method of choice. 相似文献
13.
14.
A. Kuppermann 《Israel journal of chemistry》1969,7(2):303-314
The present state of a priori calculations of chemical reaction cross sections is reviewed, with emphasis on the hydrogen atom plus hydrogen molecule reaction. Some comparison with experiment is included. 相似文献
15.
Summary It has been found that the three-phase heterogeneous reaction of propane sultone with hydrolyzed macroporous glycidylmethacrylate copolymers in an aqueous alkaline medium proceeds to a higher degree in presence of phase transfer catalyst. The best results were obtained using tetra(n-butyl)ammonium hydroxide. An important finding is the increase in the degree of transformation of the reaction in flow arrangement compared with the batch procedure. The influence of phase transfer catalyst is also more effective. The reaction is discussed with respect to the properties of the products, i.e. of the overall and surface contents of groups introduced into the reaction, of the specific surface area and specific pore volume of sulfopropylated copolymers. 相似文献
16.
In order to identify the major fluid mechanical effects and catalog their domains of influence, an extensive study of flow behavior of reactive polyester resin systems in uniaxial, horizontal rotating systems has been undertaken. Four general flow phenomena are identified: cascading, where resin is withdrawn from the recirculating pool arid drains back; rimming, where resin is taken around the top of the cylinder by viscous forces; stable hydrocyst formation, where rings of fluid perpendicular to the axis of rotation are formed; and solid body rotation, where the resin on the mold wall is quite uniform and time-independent. For most flow conditions, the desired region of solid body rotation apparently can be reached only by passing through each of the other flow regimes. Experimental work on polyester resin systems is compared with theoretical studies on flow stability, hydrocyst formation, and withdrawal from quiescent pools, and suitable correlations are developed. It is noted that the current correlations for stable hydrocyst formation are invalid for polyester resins and a simpler correlation is proposed. 相似文献
17.
This paper addresses some of the general engineering problems in reactive polymer processing: thermal effects on reactor stability and polymer properties due to rapid exothermic polymerization, the formulation of reaction viscosity relationships required in simulations, and the generation of flow and mixing via technology available from both ends of the viscosity spectrum, which is spanned in its entirety when going from monomer to molded polymer. Methods of analysis are discussed and general design concepts are suggested, which can be applied to the construction of innovative future processing equipment. 相似文献
18.
19.
20.
Sándor Nemes János Borbély Jenö Borda György Deak Tibor Kelen 《Polymer Bulletin》1992,29(1-2):135-138
Summary Propylene oligomers with primary-OH, tertiary-0H and,-di-OH end groups have been prepared by converting the isopropenyl-ended oligomers with hydroboration-oxydation, oxymercuration-demercuration and performic acid hydroxylation reactions, respectively. 相似文献