# Glutaraldehyde-Crosslinked Bovine Serum Albumin Hydrogels for Efficient Cu2+, Ni2+, and Co2+ Removal from Water

## TL;DR

This paper introduces a new method using BSA hydrogels to efficiently remove heavy metals like Cu2+, Ni2+, and Co2+ from water.

## Contribution

The novel contribution is the development of glutaraldehyde-crosslinked bovine serum albumin hydrogels for heavy metal removal.

## Key findings

- BSA hydrogels crosslinked with glutaraldehyde showed high removal efficiency for Cu2+ (99.258%), Ni2+ (80.733%), and Co2+ (76.070%).
- Adsorption of Cu2+ and Co2+ followed the Langmuir model, while Ni2+ followed the Freundlich model.
- Hydrogels with higher BSA content performed better in metal removal.

## Abstract

Heavy metal contamination remains a critical threat to water quality, particularly in effluents associated with industrial activities such as electroplating. This study presents an exploratory proof of concept for a simplified and low-requirement method to fabricate bovine serum albumin (BSA) hydrogels crosslinked with glutaraldehyde (GA) as protein-based adsorbents for Cu2+, Ni2+, and Co2+ removal. Hydrogel slabs were prepared using BSA concentrations of 20% and 25% (w/v) and GA in the 0.6–1.0% (v/v) range, with formulation adjustments guided by handling and aqueous stability. Swelling behavior was monitored for 23 days, and 0.9% (v/v) GA was selected to balance network expansion with hydrogel consistency. FT-IR confirmed preservation of protein functional groups in the crosslinked network, and TGA/DTG demonstrated multi-step thermal behavior consistent with hydrated protein matrices and a stabilizing effect of increased GA content. Metal removal tests at 50–100 ppm (Cu2+, Ni2+) and 70–100 ppm (Co2+) showed rapid removal approaching equilibrium within the first hours and improved performance at higher BSA content, achieving maximum removal percentages of 99.258% for Cu2+, 80.733% for Ni2+, and 76.070% for Co2+. Adsorption behaviors for Cu2+ and Co2+ aligned with the Langmuir model, while Ni2+ was better described by the Freundlich model. Although the scope is intentionally preliminary and limited to controlled synthetic systems, these results support GA-crosslinked BSA hydrogels as promising, easily fabricated adsorbents and establish a foundation for future studies on broader ion selectivity, competitive adsorption, and adsorption–desorption performance.