Preparation And Adsorption Properties Of Dithiocarbamate Adsorbent

The development of new adsorption materials is an important direction to solving the problem of heavy metal ion pollution in water.Dithiocarbamate（DTC）functional groups have strong chelating adsorption properties for heavy metals and are easy to synthesize.Therefore,DTC can be used to modify various adsorbents and enhance adsorption performance.In this study,DTC was used as the functional modification group,and graphene oxide,attapulgite,and cellulose were used as the matrix materials.DTC was modified on the surface of different materials,and the materials that were difficult to recover were compounded with aramid nanofibers（ANFs）with high strength,high modulus,and corrosion resistance.The relationship between p H value,adsorption time,initial ion concentration,temperature,and the adsorption capacity and adsorption rate of the prepared adsorbent was explored.The adsorption mechanism of heavy Cu²⁺on composite adsorbent was analyzed by kinetic equation and isothermal adsorption model.The main conclusions are as follows:（1）The surface of GO was carboxylated by chloroacetic acid（C₂H₃ClO₂）and sodium hydroxide（NaOH）and then reacted with triethylenetetramine（TETA）.The reacted GO was subjected to xanthate acidification and combined with ANFs to prepare a new adsorption material（GO-DTC/ANFs）.Under the optimum adsorption conditions,the maximum adsorption capacity of GO-DTC/ANFs for Cu²⁺is 126.74 mg/g,and the adsorption process conforms to the pseudo-second-order kinetic equation and Langmuir isothermal adsorption model.The adsorption thermodynamic results indicate that the adsorption process is an endothermic reaction and a spontaneous process.（2）In the sodium hydroxide（NaOH）/urea（NH₄N₂O）solvent system,the purchased wood pulp sponge（CS）was treated,and then TETA was modified to the CS surface by epichlorohydrin（C₃H₅ClO）.Finally,the xanthate reaction was carried out to prepare a new adsorption material（CS-DTC）.Under the optimum adsorption conditions,the adsorption capacity of CS-DTC for Cu²⁺is 69.3 mg/g,and the adsorption process conforms to the pseudo-second-order kinetic equation and Langmuir isothermal adsorption model.The adsorption thermodynamic results indicate that the adsorption process is an endothermic reaction and a spontaneous process.（3）Attapulgite was modified by polyethyleneimine（PEI）and triethylenetetramine（TETA）,and then a novel adsorbent（ATP-DTC）was prepared by xanthate reaction.Finally,to facilitate the recovery of adsorbent,a new two-component composite membrane（ATP-DTC/ANFs）was prepared by a simple vacuum assisted filtration-hot pressing molding method combined with ANFs.Under the optimal adsorption conditions,the adsorption capacity of ATP-DTC/ANFs for Cu²⁺was 70.02 mg/g.The adsorption process conformed to the pseudo-second-order kinetic and Freundlich isothermal adsorption models.The adsorption thermodynamic results indicated that the adsorption process was endothermic and spontaneous.ATP-DTC was used to replace heavy metal capture agents in a metallurgical company.The heavy metal contents of copper,cobalt,and nickel in the tailwater were measured to meet the national emission standards.