Study On The Synthesis Of Sulfhydryl Functionalized Materials And The Adsorption Performance Of Heavy Metal Cd(?)

The pollution of heavy metals Hg,Cd,and Pb is an important environmental issue.Heavy metal pollution has the characteristics of multi-source,strong concealment,high toxicity,complex chemical behavior and ecological effects,etc.It is easy to migrate into the water body and atmosphere,and exists in trace amounts.A consensus has been formed in numerous studies.Guizhou is a central area of low-temperature mineralization in China.The pollution characteristics are reflected in the high background values of Hg,Cd,and Pb in the karst region.The characteristics of compound and symbiotic are often exhibited.The total amount of trace Hg,Cd,and Pb in the water body is studied and developed.The detection method has regional characteristics.The analysis of trace amounts of Hg,Cd,Pb in water and the establishment of trace in-situ detection methods are the need for monitoring of water environment in Guizhou karst area.Due to the high enrichment factor of the thiol-functionalized nanomaterials,it is suitable for different volume samples,the adsorbent can be used for regeneration,and it is easy to realize on-line separation.It has attracted more and more attention and has been widely used.This topic uses 3-mercapto-propyl-trimethoxysilane?MPTMS?,butyl titanate?TBT?,as a precursor,and adopts a sol-gel method for copolymerization and condensation,and controls the surface hydroxyl of nano-TiO₂ by controlling the calcination temperature.Density was regulated and the amount of modifier used was changed to prepare thiol-functionalized TiO₂ nanomaterials enriched in heavy metals Hg,Cd,and Pb.SEM-EDS,FT-IR,BET,XRD,Raman and other methods were used to characterize the microstructure of thiolated TiO₂ nanomaterials.In this paper,flame atomic absorption spectrometry?FAAS?was used as a detection method to systematically study the thiol-functionalized nano-TiO₂ pair metals.Adsorption properties of ions,to explore its use for trace heavy metals enrichment/separation,affecting the main factors such as adsorption performance.The main research content is:?1?TiO₂ was prepared by sol-gel method.The density of hydroxyl groups on the surface of TiO₂ was increased by controlling the calcination temperature.The density of hydroxyl groups on the surface was 14.09 DOH/nm² after calcined at 400?for 6h.?2?In order to obtain high-performance thiol-based TiO₂ nano-adsorption materials,the effect of modifier concentration and ethanol/water ratio on material properties during the material preparation process was investigated,and the material preparation process was optimized.Adsorption kinetics showed that the material reached equilibrium in 40 minutes,and the removal rate of cadmium ions was more than 98%.?3?Flame atomic absorption spectrometry?FAAS?was used as a detection tool to investigate the adsorption behavior of thiolated nano-TiO₂ on Cd?II?,Hg?II?,and Pb?II?and the main factors affecting the adsorption and coexistence of ions.The effect of thiolated nano-TiO₂ on Cd?II?,Hg?II?,Pb?II?adsorption capacity and adsorption rate was investigated.Adsorption kinetics showed that the adsorption material reached equilibrium in 40 min,and the removal rate of heavy metal ions was more than 98%.The mass transfer of cadmium ions in the adsorbent particles was studied.With 2.0 mol/L hydrochloric acid as the release agent,Cd?II?,Hg?II?,Pb?II?adsorbed on thiolated nano-TiO₂ can be eluted.The detection limits of Cd²⁺,Hg²⁺,and Pb²⁺were 2.3ng/L,3.9ng/L,and 4.2ng/L,respectively.The use of thiolated TiO₂nanomaterials can effectively enrich trace heavy metal ions in samples,which plays an important role in improving the sensitivity and accuracy of detection of trace cadmium.