Sustainable Pt(IV) removal using polyethyleneimine-functionalized jute powder: Adsorption mechanism and performance optimization

• Optimized PEI/GA ratio and pH for higher adsorption capacity. • PEI-JT demonstrates 5.5-fold improvement in Pt(IV) adsorption compared to UM-JT. • Achieved 662.71 mg . g - 1 adsorption with excellent reusability over 10 cycles. • PEI functionalization shifts the isoelectric point from 2.39 to 8.81. • PEI-JT provides selective, sustainable, and cost-effective Pt(IV) recovery method. Recent advancements in bio-based materials for the adsorption of platinum group metals (PGMs) have shown their potential for sustainable environmental remediation. Surface functionalization of these biological materials plays a pivotal role in enhancing adsorption capacity and elucidating the adsorption mechanism. This study crosslinked jute powder with polyethyleneimine (PEI) and glutaraldehyde (GA) via solution polymerization, resulting in a material (PEI-JT) with enhanced platinum adsorption capacity. The PEI-JT powder exhibited a theoretical sorption capacity of 662.7 ± 1.7 mg . g - 1 at pH 3 and 30 °C, representing a 5.5-fold improvement over unmodified jute (UM-JT). The adsorption kinetics followed a pseudo-second-order model and the isotherm data fitted the Langmuir model. Reusability tests revealed that PEI-JT maintained 88 % of the initial capacity after ten adsorption–desorption cycles and demonstrated excellent selectivity for Pt(IV) in a multi-metal solution. Several characterization methods confirmed a uniform distribution of PEI on the jute powder and successful introduction of key functional groups, raising the isoelectric point from 2.39 to 8.81. As a result, PEI-JT became positively charged at the working pH, enabling efficient electrostatic adsorption of negatively charged Pt(IV) complexes. The high adsorption capacity, acid resistance, and reusability of PEI-JT make it a sustainable and cost-effective material for Pt(VI) adsorption, with potential applications for the recovery of platinum from industrial effluents.