Study On Chemical Vapor Deposition Modified Attapulgite And Heavy Metal Adsorption

With the continuous development of society,science and technology,a variety of environmental governance problems are also followed,leading to the constantly emergence of various novel materials.Multifunctional nanocomposites can integrate multiple functions and have potential applications in many fields.Attapulgite(ATP)is a kind of natural clay mineral material,which is cheap and environmental friendly.In this study,three ATP based nanocomposites,different C concentrations doped,C/FeS co-doped and C/N/FeS2 co-doped,were prepared by chemical vapor deposition,and their application in heavy metal adsorption are explored as well.The mainly research contents are as follows(1)using ATP as raw material,the concentration of ethanol was changed by chemical vapor deposition method,and the influence of different modification temperature and holding time on the properties of C-modified ATP material was explored.The results showed that under the conditions of ethanol volume fraction of 25%,modified temperature and holding time of 450? and 2 h respectively,the adsorption performance of Cr(VI)was optimal.The relevant characterization and adsorption tests in this study prove the successful doping of C,and it is found that C plays a skeleton role in supporting the occurrence of the whole adsorption reaction system.This study has great reference value for the research on the surface chemistry of C concentrations doped ATP materials and its application in the field of heavy metal adsorption(2)In order to further improve the adsorption capacity of ATP modified materials to heavy metals,functional ATP materials were prepared by chemical vapor deposition method in the tube furnace,the calcination temperature and atmosphere were changed,and the morphology and structure of the materials were regulated by doping modified related elements or groups.The experiment shows that C/FeS co-doping is successfully achieved by the ATP material modified by carbon disulfide(CS2)vapor at 400?.The removal rates of Hg(II)and Cr(VI)were 97.61%and 99.99%respectively,showing an efficient adsorption capacity.Moreover,the material successfully overcame the problem of ATP water absorption and swelling,and was well separated from water.This study is the first to use one-step chemical vapor deposition method to prepare environmentally friendly co-doped C/FeS ATP materials,which provides a new idea for the preparation of adsorbents with simple operation,low valence chromium and high adsorption efficiency,and shows a good application prospect in the field of heavy metal adsorption(3)In order to explore the adsorption behavior of the modified ATP material on the heavy metal Cr(VI)in high concentration,the ATP material modified by anhydrous ethanol was further optimized.Under the condition of room temperature,the ATP material was fully exposed to the acidic saturated ferric nitrate solution 9 hydrate.After freeze drying,the same chemical vapor deposition method was used to conduct the treatment of CS2 vapor under nitrogen at 800?.The results showed that the obtained material was C/N/FeS2 composite ATP functional material,which showed excellent removal ability to high concentration Cr(VI),and the removal rate of 1000 mg·L-1 potassium dichromate solution was still up to 86%.Further exploration of the mechanism revealed that FeS2 played a key role and C and N doping played an auxiliary role.This study provides new ideas and technologies for the treatment of wastewater contaminated by heavy metals.