Sorption of Ag~+, Cu~(2+) on thiol-functionalized poly (acrylic acid)/SiO_2 composite nanofiber membranes

摘要

Thiol-functionalized poly (acrylic acid)/SiO_2 (PAA/SiO_2) composite nanofiber membranes have been fabricated by a sol-gel electrospinning method and their adsorption capacity for Ag~+, Cu~(2+) was investigated. Results showed the PAA/SiO_2 fibers had a diameter between 300 nm-700 nm. FTIR results demonstrated that the mercapto groups have been introduced into the silica skeleton. The adsorption of Ag~+, Cu~(2+) on the membranes fit the Redlich-Peterson isotherm model best. The equilibrium adsorption capacity of Ag~+ (575.64 mg/g) on PAA/SiO_2 nanofiber membranes is higher than Cu~(2+) (331.52 mg/g). The desorption rate reached 98% in 30 min. The removal rate of Ag~+, Cu~(2+) still maintained above 75% after six regeneration cycles. Adsorption kinetics of Ag~+, Cu~(2+) followed a pseudo-second-order model.