Cationic polymer-immobilized polysulfone-based fibers as high performance sorbents for Pt(IV) recovery from acidic solutions

This work reports a novel concept for the development of a polysulfone (PS)-based fiber as a high-performance acid-tolerant adsorbent for the recovery of platinum group metals (PGMs), particularly Pt(IV), in acidic media. Polyethylenimine (PEI)-coated PS-Escherichia coli biomass composite fiber (PEI-PSBF) was prepared by spinning biomass-PS blends in water, coating with PEI and cross-linking with glutaraldehyde. The E. coli biomass on the fiber was executed as a functional group donor for binding PEI. PS fiber (PSF), PS-biomass composite fiber (PSBF), and PEI-modified PSF (PEI-PSF) were also prepared and compared with PEI-PSBF. The results of SEM and FTIR analyses revealed the presence of PEI on the surface of PEI-PSBF. Kinetic and isotherm experiments showed the negligible sorption capacity of PSF. In contrast, adsorption equilibrium on PSBF and PEI-PSBF was attained after 40. min and 6. h, respectively. The maximum Pt(IV) uptake of PEI-PSBF was 6.6 times higher than that of PSBF. Pt(IV) ions were completely recovered from loaded PEI-PSBF by 0.1. M thiourea in 1. M HCl solution. The PEI-PSBF was also stable in 0.1. M and 1. M HCl solutions. The PEI-PSBF exhibited promising properties as an adsorbent for PGMs-containing acidic wastewaters.