Preparation Of Functionalized 2D/3D Mesoporous Silica Materials For The Adsorption Of Rhenium(?)

In this paper,three functionalized mesoporous silica materials were prepared by one-step method,and their structures were characterized.The adsorption behavior of adsorbents with ReO₄^-in aqueous solution was investigated through a series of experiments.The details are as follows:Sodium silicate as the silicon source,chitosan was added in the process of hydrolysis of sodium silicate.With the interaction between-OH on chitosan and Si-OH,the chitosan can be immobilized by adding the glutaraldehyde,and after hydrothermalreaction,thechitosan/silica2Dmesoporousmaterial SS5/5.5-15-CTS2@95 was synthesized by one-step method.The adsorption and dynamic experimental results showed that the good adsorption capacity of the adsorbent for Re?VII?can reach 206.31mg·g^-11 at pH 3,and the process of adsorption conformed to the Langmuir model and pseudo second-order kinetics equations,the adsorption mechanism of SS5/5.5-15-CTS2@95 was determined by the chelating reaction between the C=N-and ReO₄^-through the FT-IR and XPS analysis.The SS5/5.5-15-CTS2@95 can effectively separate Re?VII?from the wastewater containing Cu?II?,Zn?II?and Mn?II?in the range of pH 2³.At last,the elution cycle experimental results show that the SS5/5.5-15-CTS2@95 has good stability and reusability.TEOS as the silicon source,chitosan was added in the process of hydrolysis of TEOS.Then,adding the glutaraldehyde was used to crosslink-NH₂ groups on chitosan.After hydrothermal reaction,the chitosan/silica 3D mesoporous material?TS8.6-15-CTS2@95?was obtained by one-step method.The adsorption experiment results were found that the maximum adsorption capacity of TS8.6-15-CTS2@95 for Re?VII?could reach 232.75 mg·g^-11 at pH 3 and the process of adsorption conformed to the Langmuir model.The TS8.6-15-CTS2@95 can effectively separate Re?VII?from solutions containing Fe?III?,Cu?II?,Zn?II?and Mn?II?at pH 1²(Sel _Re/M>1.5)and it has good selective capacity for Re?VII?from the simulation wastewater containing high concentration Cu?II?at pH 2³.Sodium silicate as the silicon source,the ethanolamine was added in the process of hydrolysis of sodium silicate,the interaction occurred between-OH on ethanolamine and Si-OH,and the ethanolamine could participate in the process of self-assembly of silicate.Adding glutaraldehyde could realize the immobilization of ethanolamine,then,ethanolamine/silica mesoporous material SS-C4M3-15-EA3@95was prepared under microwave hydrothermal conditions.Through the structure analysis,it was found that the synthesis time could be shorten by the microwave method and the pore size of SS-C4M3-15-EA3@95?10.00 nm?was larger than SS-C4C20-KIT-6?9.00 nm?.The adsorption experiment showed that the maximum adsorption capacity of SS-C4M3-15-EA3@95 could reach 111.41 mg?g^-1.The SS-C4M3-15-EA3@95 could realize effectively separate Re?VII?from solutions containing Fe?III?,Cu?II?,Zn?II?and Mn?II?at pH 1³(Sel_Re/M>1.5)and it has good stability and reusability.