Penicillium chrysogenum-loaded hybrid cryogel discs for heavy metal removal

Rapid urbanization and industrialization have brought heavy metal pollution together. Removal of heavy metals from wastewater has gained the most attraction today because of their hazardous effect on living organisms. Biosorption is a cost-effective and eco-friendly process that uses biological materials as an adsorbent for heavy metal ions removal. In the present study, filamentous fungus Penicillium chrysogenum was used as a biosorbent and P. chrysogenum-loaded hybrid poly(2-hydroxyethyl methacrylate) [Pc-PHEMA] cryogel discs were prepared for removal of cadmium (Cd2+), lead (Pb2+) and zinc (Zn2+) heavy metal ions from aqueous solutions. Thanks to their large interconnected pores, cryogels are excellent polymeric materials that can be used as an adsorbent. Characterization of Pc-PHEMA cryogel discs was performed by swelling experiments, scanning electron microscopy (SEM) and microcomputed tomography. Heavy metal binding efficiency of these hybrid cryogels was evaluated with different parameters such as binding time, fungal biomass amount, heavy metal ions concentration, pH, temperature, flow rate and effect of competitive environment. Inductively coupled plasma mass spectrometry was used for detecting metal ion concentrations in aqueous solutions. Also, the presence of metal ions on the surface of Pc-PHEMA cryogels was also proven with EDS (energy-dispersive x-ray spectroscopy) analysis. Heavy metal biosorption efficiency of Pc-PHEMA cryogel discs was increased with the increase in the fungal biomass amount, contact time and pH. Biosorption efficiency of the hybrid Pc-PHEMA200 cryogel was found to be over 82.8% for Cd2+, Pb2+ and Zn2+ between 0.1 and 2.5 mg/L heavy metal concentration. The highest metal ions biosorption efficiency was found to be 99.7% for Cd2+, 99.9% for Pb2+ and 85% for Zn(2+)at pH 6.5 at 24 degrees C. Hybrid Pc-PHEMA cryogel discs provided reusability for biomass, and after three binding-elution cycles, the biosorbent exhibited no significant decrease in metal ions biosorption efficiency.