Preparation Of Thiol-functionalized Materials And Removal Of Arsenic And Mercury

Arsenic and mercury are typical highly toxic heavy metals,which have very high potential harm to human health.Long-term exposure to arsenic and mercury has a high probability of causing pathological changes in the human body.The water pollution of arsenic and mercury has long been an important environmental problem.Developing economical and high efficiency method of removing arsenic and mercury in water is the key to solve the problem.Adsorption method is the most promising technology for the removal of arsenic and mercury in water.The commonly used adsorbents generally face the problems of high price,complex preparation process,slow mass transfer rate and difficult separation from water.Therefore,the preparation of new economical and efficient adsorbent is an important problem to be solved urgently in development of removal technology for arsenic and mercury in water.In this subject,three novel,economical and efficient adsorbents are prepared to achieve the effective removal of arsenic and mercury in water environment.The main content of this study can be divided into three parts:?1?The Zr-modified magnetic carbonaceous particles were prepared by low temperature hydro-thermal and Zr-rich solution immersion methods.The adsorption performance was investigated and it was found that this adsorbent is a good removing arsenic selection with these advantages including broader pH application range of 2⁸,short adsorption equilibration time less than 2h and high adsorption capacity up to 90.91 mg/g.The kinetics and thermodynamics analysis indicated that the adsorption process accord with the pseudo-second-order kinetics and the adsorption is an endothermic and disorder-enhanced process.?2?A novel absorbent,thiol-functionalized polyvinyl alcohol was synthesized by low temperature reaction.The adsorption performance of this absorbent was investigated and found that HS-PVA can efficiently and quickly remove trace mercury in water in a wider pH range.Under the constant temperature conditions of 293K,313K,and 333K,the maximum adsorption capacity is1180.56?g/g,1203.13?g/g and 1373.37?g/g,respectively.Chemisorption and physisorption simultaneously occurred in the process of absorbing trace mercury in water by HS-PVA.The adsorption of mercury by HS-PVA is a multilayer adsorption on heterogeneous surface,which is an exothermic entropy increasing process.The adsorption is spontaneous in the temperature range of 293K to 333K.?3?A new type of thiol functionalized copolymer,HS-P?St-DVB-GMA?,was prepared and used for the removal of mercury in water.HS-P?St-DVB-GMA?can be used to remove mercury quickly and efficiently in a wide ph range.Adsorption of Hg²⁺on HS-P?St-DVB-GMA?is chemisorptions.Under the constant temperature conditions of 293K,313K,and 333K,the maximum adsorption capacity is 202.84mg/g,191.93mg/g and 180.88mg/g,respectively.The adsorption of mercury by HS-P?St-DVB-GMA?is monolayer adsorption on a highly homogeneous surface,which is an exothermic entropy increasing process.The adsorption is non-spontaneous in the temperature range of 293K to 333K.