Modified ginkgo leaves for adsorption of methyl violet and malachite green dyes in their aqueous system

ABSTRACT As a common agriculture waste as well as available biomass resource from ginkgo tree, ginkgo leaves were used as adsorbent to remove two models of cationic dyes methyl violet (MV) and malachite green (MG) after adequate modification. As the result, hydroxylated magnetic ginkgo leaf powder and carboxylated magnetic ginkgo leaf powder were obtained and characterized, respectively, which had the potential to be an environmentally friendly and economically effective biosorbents for the adsorption of dyes. These new biosorbents exhibited high adsorption capacity for dyes, with the maximum adsorption capacity of 450 mg g –1 for MV and 231 mg g –1 for MG. Further investigation confirmed that these adsorption processes were fitted with pseudo-second-order and Langmuir isothermal model. Moreover, these adsorbents with remarkable magnetism could be easily and rapidly recovered by external magnet after their use. The study demonstrated that the promising and reliable modified biosorbents were very suitable for removal of cationic dyes with high concentration at lower cost.