Characteristics of Cu2+ Adsorption by Modified Rice Straw

In this paper, modified rice straw was investigated for its Cu(2+)removal ability from aqueous solution. The effects of environmental factors on metal biosorption were studied under static state, including initial concentration of metal ions, sorption time, initial pH value and adsordent dosage. In addition, the relevant equilibrium, kinetics were discussed. The results showed that the rice straw which was modified by NaOH had been improved greatly in its Cu2+ removal ability. The rice straw had good effects on adsorption of low concentration of Cu2+ solution. The adsorption data fit Langmuir isotherm model well, the maximum adsorption capacity for Cu2+ reached 8.48 mg.g(-1). The adsorption of Cu2+ on the modified rice straw was a very rapid process, the kinetics fit a pseudo-second-order equation well. The pH value had prominent effect on the removal rate of Cu2+, adsorption efficient could reach over 92% when pH value was between 5 and 6.5. With increasing adsordent dosage, the removal rate of Cu2+ increased.