Adsorption of Cu(II), Cd(II), and Pb(II) Using a Novel Adsorbent Based on Polyvinyl Alcohol Anchoring Citric Acid (PVA-CA)

Heavy metals are widely used in industry. On the other hand, heavy metals cause environmental pollution. One technique for removing heavy metals is adsorption. By reacting polyvinyl alcohol with triethyl citrate, a novel adsorbent based on polyvinyl alcohol attaching citric acid (PVA-CA) has been successfully formed, as shown by FTIR spectra. The adsorption test was carried out under acidic conditions for metal ions, namely Cu(II), Cd(II), and Pb(II). Experimental results on metal ions Cu(II), Cd(II), and Pb(II) obtained that the optimum pH for the adsorption of each metal were 4.64, 3.92, and 4.65, respectively. The adsorption mechanism was ion exchange and was supported by coordination bonds between metal ions and C=O oxygen atom of carboxylic group; the slope value and FTIR measurements confirmed this. SEM-EDX was used to confirm the morphology of the adsorbent and metals adsorbed on the PVA-CA surface. The maximum loading capacity of Cd(II) was higher than Pb(II) and Cu(II), for each metal were 1.33, 0.69, and 0.67 mol/ kg for Cu(II), Cd(II), and Pb(II), respectively. From the capacity value, which was relatively high compared to other adsorbents, PVA-CA has excellent potential as an adsorbent to overcome environmental pollution problems caused by heavy metals such as Cu(II), Cd(II), and Pb(II).