Development of microbial protein-based electrospun cellulose acetate nanofibers for the treatment of heavy metals-contaminated water

Heavy metals are hazardous water pollutants that require effective treatment strategies. Electrospun nanofibers, owing to their high surface area, are promising adsorbents for metal removal. This work developed electrospun cellulose acetate nanofibers incorporating microbial proteins derived from waste cheese whey (CAMP) for the removal of Pb2 + and Zn2+ from contaminated water. The incorporation of microbial proteins (∼20 wt% with respect to the polymer) introduced active adsorption sites involved in metal binding, enhancing both adsorption performance and selectivity. The morphological, physico-chemical, and thermal features of the prepared electrospun fibers were characterized by SEM, FTIR, TGA analyses. Batch adsorption experiments revealed that CAMP exhibited the highest selective adsorption toward Pb2+ (66.23 ± 3.10 mg/g) compared to Zn2+ (13.87 ± 1.20 mg/g) at pH 6.0. The adsorption data fitted well with the Langmuir isotherm model and followed pseudo-second-order kinetics. In binary metal systems (Pb2+/ Zn2+) CAMP showed preferential adsorption toward Pb2+, revealing the selectivity behavior of such system. EDTA (0.1 M) enabled effective metal recovery from CAMP for up to 4 consecutive adsorption-desorption cycles, maintaining ∼75% of the initial adsorption capacity. This waste-to-resource approach demonstrates the potential of transforming dairy industry waste (cheese whey) into high-value biosorbent for heavy metal wastewater treatment.