Biosorption of Cu2+ by a novel modified spent Chrysanthemum：kinetics, isotherm and thermodynamics

The present study explored the ability of a novel spent chrysanthemum adsorbent prepared from acid acetaldehyde for the removal of Cu 2+ from an aqueous solution. The effect of various parameters, including solution pH, adsorbent dosage, contact time and temperature on adsorption of Cu 2+ were studied by batch experiments. According to the experimental results, the optimal pH range and optimum dosage were found to be 3.0–5.0 and 6.0   g/L, respectively. The adsorption amount at equilibrium decreased with the increase of temperature. Freudlich model provided better correlation for the adsorption of Cu 2+ by modified spent Chrysanthemum (MSC) (R   =   0.99)and spent Chrysanthemum (SC)(R   =   0.98). Adsorption capacity of MSC was 692   mg/g at 293   K, but it was 400   mg/g at 293   K for SC. The adsorption process on Cu 2+ proceeded rapidly and almost reached adsorption equilibrium within 20   min. The kinetics data of MSC were analyzed using the pseudo-first-order equations and pseudo-second-order equations. The pseudo-second-order equation fitted the experimental data very well (R   =   0.99). The adsorption amount at equilibrium decreased with the increase of temperature. The thermodynamic parameters showed that the biosorption was exothermic and spontaneous. Experimental results showed that MSC could be used as an effective biosorbent for Cu 2+ removal from aqueous solutions.