Removal of Copper Ions and Methylene Blue from Aqueous Solution Using Chemically Modified Mixed Hardwoods Powder as a Biosorbent

Abstract

Citric acid modified mixed hardwoods powder (CMH) was prepared as a biosorbent to remove copper ions and methylene blue (MB) from aqueous solution by batch techniques. FT-IR and XRD were used to characterize the biosorbent. The effects of initial pH value, biosorption temperature, contact time, and initial adsorbate concentration on the biosorption capacities and adsorptivity of Cu2+ and MB onto CMH were investigated. The results showed that CMH exhibited excellent biosorption characteristics for Cu2+ and MB. The maximal biosorption capacity of Cu2+ and MB onto CMH was 165.0 and 237.4 mg/g at 20 °C, respectively. The biosorption kinetics studies indicated that Cu2+ and MB biosorption followed the pseudo-second-order model. The biosorption may be controlled by external intraparticle diffusion mass transfer during the whole biosorption process. Furthermore, the biosorption-equilibrium can be well described by Langmuir and Freundlich isotherm models.