Removal of trivalent chromium from aqueous solutions by amphiphilic core-shell poly(methyl acrylate)/silk sericin nanospheres

Well-defined, core-shell poly(methyl acrylate/silk sericin) (PMA-SS) nanospheres, ranging from 100 to 150 run in diameter, were prepared via a direct graft copolymerisation of methyl acrylate (MA) with silk sericin (SS). The polymerisation was induced by a small amount of tert-butyl hydroperoxide (TBHP) in water at temp. 353 K. The PMA-SS core-shell nanospheres were used as adsorbent in a series of batch adsorption experiments for the removal of trivalent chromium from aqueous solutions. The experimental results showed that PMA-SS nanospheres were an effective adsorbent for trivalent chromium from aqueous solution, and the maximum amount of adsorption reached 4.876 mg Cr3+/g of sorbent within the experimental range. With the increase in pH values of solutions, the adsorption increased obviously, while the addition of electrolyte had a little effect on the adsorption. The adsorption equilibrium was reached after about 3 h. The adsorption of trivalent chromium by PMA-SS nanospheres was significantly higher than that done by SS powder under the same adsorption conditions.