分光光度法测定水的化学需氧量

《分光光度法测定水的化学需氧量》由会员上传分享，免费在线阅读，更多相关内容在教育资源-天天文库。

1、分光光度法测定水的化学需氧量PINGDINGSHANUNIVERSITY毕业论文院(系专业年级:化学2005级化学姓名:朱晓娜学号:051050122指导教师:吴华涛讲师2009年4月30日摘要化学需氧量（COD）是水质监测的一个重要参数。本文利用重铬酸钾在消解过程中被水样中的还原性组分还原而得到Cr(Ⅲ)或Cr(Ⅵ)，溶液中的Cr(Ⅲ)或Cr(Ⅵ)的浓度与其吸光度值成正比，因此可以通过光度法测定水样中COD值。实验中分别采用加热回流和超声波两种方法进行消解并对各自测定的COD含量进行了比较。两种方法的测定结

2、果呈良好线性相关，但是与声化学消解法相比，回流消解法测定标准水样COD结果稍微偏高。声化学消解法又快速、节能、环保等优点，值得在环境监测工作中推广应用。关键词：加热回流，超声波，COD，分光光度法AbstractThechemicaloxygendemand(COD)isanveryimportantparameterofwaterqualitymonitor.PotassiumdichromatecanbereducedtoCr(Ⅲ)orCr(Ⅵ)byreductivesubstancesinwateron

3、digestion.ThecontentofCr(Ⅲ)orCr(Ⅵ)insolutionisproportionaltotheir’sabsorbancevalue,sotheCODinwatercanbedeterminedbyspectrophotometry.Heatingrefluxandultrasonicwaveareintroducedintodigestion,meanwhiletheresultsofCODbytwomethodsofdigestionarecompared.Theresul

4、tsoftwomethodsaregoodlinear.Comparingwithultrasonicwavedigestion,theCODresultsbyheatingrefluxdigestionareslighthigher.Theultrasonicwavedigestionismorefast,energysaving,environmentalthanheatingreflux,somorewidelyappliedintheenvironmentalmonitoringwork.Keywor

5、d:Heatingrefluxdigestion,Ultrasonicwavedigestion,COD,SpectrophotometryII目录1前言······················································································12实验部分················································································32.1实验原理

6、·············································································32.2试剂及仪器·········································································42.2.1仪器············································································42.2.2药品······

7、······································································42.3溶液的配制·········································································42.3.1氧化剂的配制·······························································42.3.2标准COD水样的配制··············

8、···································42.3.3催化剂的配制·······························································42.4实验步骤及数据记录··························································52.4.1加热回流消解法·······