Adsorption mechanism for Cu2+ and Zn2+ by modified bagasse
改性甘蔗渣对Cu2+和Zn2+的吸附机理

The adsorption properties including adsorption kinetics and adsorption isotherm of the PMDA and EDTAD modified bagasse for heavy metal ions of Cu2+ and Zn2+ were investigated. Experimental results showed that the adsorption capacity of the PMDA and EDTAD modified bagasse was improved significantly. The adsorption data of the two metal ions both fitted Langmuir adsorption isotherm, which indicating that adsorption for metal ions was a monolayer adsorption. According to Langmuir model, the adsorption capacities of the PMDA and EDTAD modified bagasse for Cu2+ were 60.21 and 33.45 mg/g, and that for Zn2+ were 70.53 and 36.53 mg/g, respectively. Adsorption process could be finished within 30 min, and could be fitted better with pseudo-second-order kinetic model than pseudo-second-order and intra-particle diffusion kinetic model. The adsorbed Cu2+and Zn2+on the modified bagasse could be effectively desorbed in an EDTA solution, and the regenerated bagasse could be reused with little loss of the adsorption capacity.