The Preparation And Application Of Bentonite And Modified Bentonite Modified Carbon Paste Electrode

In twenty-first Century,heavy metal pollution became more and more serious and seriously harmful to human health.Therefore,the detection of heavy metal ions is necessary.At present,there are many test methods for detecting heavy metals.However,these test methods are complex,the test cycle is long,and the testing equipment is very expensive.So,it can not be applied in actual operation on a large scale.Through using portable test equipment,electrochemical analysis can obtain relatively accurate test results,and has good operability in practical applications.The main component of bentonite is montmorillonite.When the bentonite is modified,the pore path will be further enhanced,and its surface activity and adsorbability will be improved,which is a kind of pillared compound.It can be used as electrode modifier widely used in the treatment of heavy metal wastewater and electrochemical analysis.The main contents of this paper are as follows:(1)The modification temperature,pH,dosage of modifier on the modification effect were studied by controlling variables,and the modified bentonite was characterized by IR and XRD methods,and then studied the modification mechanism,determined the rationality and feasibility.For the follow-up study.(2)A new chemically modified carbon paste electrode for the detection of mercury ions was prepared by bentonite.Because bentonite has the characteristics of cavity structure,it can greatly improve the adsorption capacity of mercury ion on the modified electrode surface,and because of the limited reaction space of bentonite,it can effectively eliminate the interference of other ions.(3)Used bentonite modified by sodium dodecyl benzene sulfonate(SDBS)as modifier toprepare a new modified carbon paste electrode,and used cyclic voltammetry to detect the lead ion in the solution.The effects of pH value and modifier content on the reduction peak current were studied.The experimental results show that the bentonite modified by SDBS modified carbon paste electrode has good electrochemical response of lead ion,this is because the bentonite treated by acidification and intercalation modificated,to further expanded the channels,the adsorption ability was enhanced,so it has a certain enrichment effect on lead ion.(4)Preparation of SDBS / DB18C6 modified carbon paste electrodes as working electrodes and application in detection of lead ion in the solution.The effects of pH value and modifier content on the reduction peak current were studied,the optimal detection conditions were determined.The experimental results show that the addition of the new modifier DB18C6,on the one hand,enhanced the specific adsorption capacity of the modified electrode to the lead ion,thus increasing the sensitivity of the electrode;On the other hand,because DB18C6 is sticky,the addition of the DB18C6 can improve the service life of the electrode,which was easy to dissolve in water and easy to fall off.