PAMAM dendrimer-enhanced removal of cobalt ions based on multiple-response optimization using response surface methodology

Abstract

This study introduces poly(amidoamine) PAMAM dendrimers as new macromolecular complexation agents for Co(II) removal in polymer-assisted ultrafiltration (PAUF). A five-level three-factor design of experiments (DOE), central composite design type, and response surface methodology (RSM) were used together to find out the interaction effects and optimize three variables, i.e., initial Co(II) concentration ([Co2+]0), PAMAM dendrimer-to-Co(II) ratio (r), and pH of solution. Multiple-response simultaneous optimization was conducted by using desirability function. The goal of 73.6% overall desirability was attained for the removal efficiency (R) and metal retention capacity (q). The predicted results obtained for the simultaneous optimization are R = 76.78% and q = 392.09 mg/g. The optimum conditions derived via RSM were found to be as follows: [Co2+]0 = 4.14 mg/L, r = 2, and pH = 9.0. Verification experiments (R = 75.73% and q = 387.32 mg/g) confirmed the validity of the predicted model. The DOE–RSM-utilized and desirability function-optimized PAMAM dendrimer-enhanced ultrafiltration (PAMAM-DEUF) process was used for the first time in this study. The results are comparable to those provided by the reference PAUF technique.