Removal of Pb (II), Zn (II), Cu (II), and As (III) ions from water using kraft pulp-based carboxymethylated cellulose in a fixed-bed column adsorption process

Carboxymethylated cellulose containing 1.2 mmol -COOH/g was synthesized from kraft pulp (KP) through a carboxymethylation reaction. This carboxymethylated KP was employed as a sustainable adsorbent for the removal of heavy metal ions, including Pb (II), Zn (II), Cu (II), and As (III), from water. The adsorption process was conducted in both single and multi-component systems using a fixed-bed column. The results showed that the adsorbent effectively removed approximately 99 % of each metal ion from water under the following conditions: feed pH of 5.5, feed flow rate of 15 mL/min, and feed concentrations of 10 mg/L (for the single component system) and 2.5 mg/L for each metal ion (for the multi-component system). The metal ion retention capacities of the adsorbent were determined as 101.0 mg/g for Pb (II), 33.7 mg/g for Zn (II), 31.7 mg/g for Cu (II), and 20.0 mg/g for As (II) in the single component system, and 20.3 mg/g for Pb (II), 8.4 mg/g for Zn (II), 7.8 mg/g for Cu (II), and 4.5 mg/g for As (III) in the multi-component system. Moreover, a simple acid treatment using a 0.01 M HCl solution was found to be highly effective in regenerating the adsorbent. Even after the fifth regeneration/reuse cycle, the adsorbent was completely regenerated, demonstrating its potential for repeated use.