The current study investigates the coupled filtration/adsorption performance of regenerated cellulose (RC) ultrafiltration membranes functionalized with diethylenetriamine (DETA) as a metal-chelating ligand. Lead and copper ions with various concentrations (10–50 ppm) were selected as model adsorbing metals. To investigate the dynamic adsorption performance of the ions, different parameters including initial metal concentration, time of oxidization reaction, ligand concentration, and solution pH were studied. The maximum removal of Pb(II) and Cu(II) proposed by the modified membranes from their single salt solutions were 87% and 83%. Besides, the removal percentages of 56 and 50 were obtained for the competitive adsorption of Pb(II) and Cu(II) ions from their mixed solution, respectively. The selectivity factor was calculated as 1.25 indicating the potential of the process for selective adsorption of the ions. Langmuir and Freundlich isotherms were employed to describe the adsorption equilibria with the first model providing the best fit. Reusability tests showed that the modified membranes can be effectively regenerated by 0.1 M HCl eluting solution and successively reused in dynamic adsorption process.
