资源描述:
《超声波协同铁粉降解氯酚类污染物的研究论文》由会员上传分享,免费在线阅读,更多相关内容在学术论文-天天文库。
1、摘要摘要本文在采用超声波/铁粉(US/Fe)协同降解水中氯酚类(CPs)污染物中,以2,4-二氯酚(2,4-DCP)为代表,考察超声功率、初始浓度、铁粉投加量、pH、催化剂Cu2+的投加量、自由基捕获剂正丁醇等因素对脱氯效率和TOC去除率的影响,并对2,4-二氯酚的脱氯动力学进行了初步探讨。比较了5种不同结构的氯酚类物质的脱氯效率、脱氯速率和TOC去除率。结果表明,超声波与铁粉对2,4-DCP的降解具有明显的协同效应。脱氯效率随超声功率、铁粉投加量和催化剂Cu2+投加量的增大而增大,随初始浓度的增大而减小。pH对2,4-DCP的降解有显著影响,pH为4时,降解效率最高。正丁醇对2,4-DC
2、P的脱氯有明显的抑制作用,而且反应时间越长,正丁醇投加量越大,抑制作用越明显。在相同条件下,2,4-DCP的TOC去除率明显低于脱氯效率,但TOC去除率随超声波功率、铁粉投加量、溶液pH的变化规律与脱氯效率基本一致。US/Fe对2,4-DCP的协同降解符合一级反应动力学规律,降解速率常数为1.52×10-2min-1,与铁粉单独作用和超声单独作用相比,分别提高了约5倍和13倍。超声波协同铁粉对氯酚类物质的降解效果与分子结构中氯原子数量和氯原子取代位置有关。在相同条件下,脱氯效率和脱氯速率均随取代的氯原子数量的增大而降低,即一元氯酚>二元氯酚>三元氯酚。对于取代的氯原子数量相同的一元氯酚,间
3、-氯酚最易脱氯,对-氯酚次之,邻-氯酚最难脱氯。TOC的去除率随氯原子数量的增大而增大,即三元氯酚>二元氯酚>一元氯酚,而对于氯原子数相同的一元氯酚,TOC去除率与氯原子取代位置的关系为:间-氯酚>对-氯酚>邻-氯酚。关键词:氯酚,超声波,铁粉,协同作用,反应动力学 ⅠAbstractABSTRACTUltrasonic/FewasemployedtodegradetheChlorophenols(CPs)inaqueoussolution.Theeffectsofultrasonicpower,initialconcentration,irondosage,initialpH,cata
4、lystCu2+andn-ButanoldosageondechlorinationandTOCremovalrateof2,4-DCPwereinspected.Thedechlorinationkineticslawof2,4-Dilorophenolwasdiscussed.Thedechlorinationrate,TOCremovalrateanddegradationkineticsconstantsoffivekindsofdifferentchlorophenolswerecompared.TheresultsshowthatthesynergiceffectofUS/Fe
5、issignificant.Thedechlorinationrateof2,4-DCPincreaseswiththeincreasingultrasonicpower,irondosageandcatalystCu2+anddecreaseswiththeincreasinginitialconcentrationof2,4-DCPandn-Butanoldosage.TheeffectofinitialpHon2,4-DCPdecompositionisdistinct,theoptimalpHvalueis4.TheTOCremovalrateislowerthandechlori
6、nationrateunderthesamecondition.VariationofTOCremovalratewithultrasonicpower,irondosage,andinitialpHisthesamewiththatofdechlorinationrates.Thedechlorinationof2,4-DCPbyUS/Feconformstofirst-orderreactiondynamicslaw.Thedegradationrateconstantof2,4-DCPis1.52×10-2min-1.Thedechloronationrateconstantof2,
7、4-DCPbyUS/Fewere5timesor13timesthanthatbyFeorbyUS,respectively.ThedechlorinationrateofCPsisrelatedwiththenumberandsubstitutelocationofClinCPs.Underthesamecondition,dechlorinationrateanddegradationrateconstantdecr