Preparation Of Materials Based On Silica Or Cornstalk For Selective Adsorption Of Silver

The nickel electrolyte came from Jinchuan Group Co.,Ltd.,and contained 24.75mg L^-1 Ag,0.5 mg L^-1?Pd,Pt,Au?,100.00 g L^-1 Ni,and 50.00 g L^-1 Cu with the acidity 1.0 chlorhydric acid.The high concentration of nickel and copper in the nickel electrolyte not only interferes the recovery of silver,but also the mainly form presence of silver is[AgCl₄]^3-also difficult to separate.This paper was prepared new and efficient adsorbent for improving the recovery of precious metal.Adsorption behaviors of the adsorbents towards silver were systematically investigated in aqueous phase.The experimental results were as follows:We synthesized thiosemicarbazide-functionalized silica as adsorbent?SiO₂-GA-TSC?under the crosslinking action of glutaraldehyde,when the amino group was introduced on the silica surface by the silane coupling agent APTES.SEM?FTIR?EDX and XPS could prove that thiosemicarbazide successfully grafted on the surface of silica.The maximum adsorption capacity of[AgCl₄]^3-was observed to be 187.70mg g^-1 in single system,and 62.60 mg g^-1 in simulated system,respectively,and the adsorption behavior obeys the Langmuir model.Adsorption mechanisms of[AgCl₄]^3-could be attributed to the electrostatic interaction and coordination with protonated thiol groups on the adsorbent.In addition,the SiO₂-GA-TSC adsorbent have good application in recovery of Ag?I?from nickel electrolyte based on the experimental data.S-bearing carbonize corn stalk was simple-prepared by modified epithiochlorohydrine and thiourea onto corn stalks?OCS-ET-TU?,the adsorbent had strong adsorption affinity and selectivity to[AgCl₄]^3-in the nickel electrolyte.Adsorption capacity of the OCS-ET-TU for[AgCl₄]^3-still can reach to 79.94 mg g^-1at the acid concentration of 1.0 mol L^-1 when the concentration of Cu???and Ni???all reached to 10000 mg L^-1.Adsorption mechanisms of[AgCl₄]^3-could be attributed to the electrostatic interaction and coordination with thiol,episulfide,and thion groups.Furthermore,the corn stalk adsorbent showed good stability and selectivity by column studies,which make it a promising for selective recovery of trace level of silver anions from nickel electrolyte by waste biomass.Cellulose derived graphene?CSG?are synthesized by an in suit self-generation template strategy based on the carburized effect of nickel with cornstalks.Cornstalks could coordinate with Ni?II?ions to form the precursor.After carbonization and removal of the catalyst,CSG are obtained.Series experiments indicate that CSG can only be obtained when using a nickel-based catalyst that can generate a carburized phase during the pyrolytic process.The unique structure of CGS exhibit excellent adsorption performance.In addition,three dimensional graphitic carbon nanosheets?3D-CSG?was achieved through the crosslinking of Polyvinyl alcohol?PVA?,the adsorbent has strong adsorption affinity to Ag?I?in waste water.Adsorption capacity of the 3D-CSG for Ag?I?still could reach to 215.00 mg g^-1 at pH 4.The structure and adsorption mechanism of 3D-CSG were evaluated by Raman?XRD?SEM and XPS.Adsorption mechanisms of silver could be attributed to the electrostatic interaction with hydroxyl groups.In addition,the 3D-CSG adsorbent also shows excellent adsorption to Methylene blue?MB?and Rhodamine B?RB?,the maximum adsorption capacity of MB,RB was observed to be 284.60 mg g^-1,and 41.80 mg g^-1,respectively.In addition,the adsorption mechanisms of dye molecules cold be attributed to?-?conjugation between sp2 structure carbon atoms in CSG and the benzene ring structure in dye.Furthermore,the adsorbent showed good stability and greenly,which make it a promising for recovery of trace level of silver and dye molecules?Methylene blue,Rhodamine B?by waste biomass.