In this study,porous silica with high surface area was prepared through selective leaching of thermally activated chlorite in HCl solution.In the process,chlorite was activated by pre-calcining treatment,then activate...In this study,porous silica with high surface area was prepared through selective leaching of thermally activated chlorite in HCl solution.In the process,chlorite was activated by pre-calcining treatment,then activated components(MgO,Al_(2)O_(3),and Fe_(2)O_(3))were selectively leached by acid solution,resulting in the formation of nanopores in situ.The morphology,structure,surface area and pore-size distribution of the material were characterized by XRD,TG/DSC,^(27)Al MAS NMR,SEM,TEM and N2 adsorption−desorption isotherms.The highest specific surface area(SBET=333 m^(2)/g)was obtained by selectively leaching the 600℃ calcined chlorite from 3 mol/L HCl at 90℃ for 2 h.The pore sizes and specific surface areas can be controlled by calcination and leaching conditions.The ^(27)Al MAS NMR spectra of the samples revealed the relationship between structural transformation and the selective acid leaching properties of thermal-activated chlorite,demonstrating that AlVI transfers into AlV when chlorite changes into activated chlorite during thermal activation,and the coordinations of Al has a significant effect on acid solubility of chlorite.The as-prepared porous silica showed favorable adsorption abilities with capacity of 148.79 mg/g for methylene blue at pH of about 7 and temperature of 25℃,indicating its promising potential in adsorption application.展开更多
基金Project(51772153)supported by the National Natural Science Foundation of China。
文摘In this study,porous silica with high surface area was prepared through selective leaching of thermally activated chlorite in HCl solution.In the process,chlorite was activated by pre-calcining treatment,then activated components(MgO,Al_(2)O_(3),and Fe_(2)O_(3))were selectively leached by acid solution,resulting in the formation of nanopores in situ.The morphology,structure,surface area and pore-size distribution of the material were characterized by XRD,TG/DSC,^(27)Al MAS NMR,SEM,TEM and N2 adsorption−desorption isotherms.The highest specific surface area(SBET=333 m^(2)/g)was obtained by selectively leaching the 600℃ calcined chlorite from 3 mol/L HCl at 90℃ for 2 h.The pore sizes and specific surface areas can be controlled by calcination and leaching conditions.The ^(27)Al MAS NMR spectra of the samples revealed the relationship between structural transformation and the selective acid leaching properties of thermal-activated chlorite,demonstrating that AlVI transfers into AlV when chlorite changes into activated chlorite during thermal activation,and the coordinations of Al has a significant effect on acid solubility of chlorite.The as-prepared porous silica showed favorable adsorption abilities with capacity of 148.79 mg/g for methylene blue at pH of about 7 and temperature of 25℃,indicating its promising potential in adsorption application.
