Removal of copper from aqueous solution by citric acid modified rice straw

Abstract

The objective of the present study were to convert rice straw, a by-product of rice production to a metal adsorbent and further to investigate the potential of using the adsorbent for the removal of Cu(II) ions. The rice straw was water washed and citric acid (CA) modified to enhance its nature adsorption capacity. Batch adsorption studies of Cu(II) adsorption were carried out under various operating conditions, and found to be pH, initial adsorbate concentration, contact time, and adsorbent dosage. The experimental data were analyzed using the Langmuir and Freudlinch isotherm model, and can be well described by Langmuir isotherm model that supports the assumption that adsorption takes place on homogeneous surfaces. The kinetic studies indicated that the pseudosecond- order kinetic equation provides better correlation data than pseudo-first-order kinetic model. Therefore, CA modified rice straw (CARS) has a considerable potential as a low-cost and highly efficient adsorbent, to be a new singleuse adsorbent for the removal of Cu(II) ions from wastewater.