Removal of lead ions from aqueous solutions <i>via</i> polyelectrolyte enhanced ultrafiltration and nanofiltration: efficacy evaluation of chitosan, polyethylenimine, and polyacrylic acid

Abstract

Abstract BACKGROUND Lead contamination in wastewater is a significant environmental issue, necessitating effective removal methods. This study evaluates the performance of polyelectrolyte‐enhanced ultrafiltration (PEUF) and nanofiltration (NF) processes for removing lead ions from aqueous solutions. The objective was to assess the effectiveness of various polyelectrolytes (chitosan, polyethylenimine, and polyacrylic acid) in conjunction with ultrafiltration and to investigate the influence of experimental parameters on lead retention and permeate flux. RESULTS In the PEUF process, a polyethersulfone membrane with a pore size of 10 kDa (PES10) was used. The maximum lead ion rejection of 97% was achieved with polyacrylic acid (PAA) at a concentration of 600 ppm and a transmembrane pressure of 4 bar. Increasing the feed pH enhanced lead retention but reduced permeate flux. Higher ionic strength negatively affected both lead retention and permeate flux. Over time, permeate flux decreased from 553 to 221 L/h/m 2 due to solute accumulation and polymer aggregation. For the NF process, the maximum lead retention of 68% occurred at a transmembrane pressure of 6 bar. Lead retention increased at lower pH (73% at pH 2) but decreased at higher pH (47% at pH 5). The addition of salt adversely affected lead removal. CONCLUSION Both PEUF and NF methods effectively removed lead ions from wastewater, with PEUF showing higher removal efficiency. These findings demonstrate the potential of these filtration processes for heavy metals remediation in water treatment applications. © 2025 Society of Chemical Industry (SCI).