Work

Feasibility of combining biological hydrogel reactive filter media with electrokinetic for sustainable site remediation

Year: 2025

Type: article

Abstract: The feasibility of electrokinetic (EK) for single and multiple heavy metals removal was investigated with and without a kappa carrageenan (kC) hydrogel reactive filter media (RFM) for a sustainable remediation process. Natural biodegradable polysaccharide kC hydrogel exhibits strong adsorption capacity, allowing the capture of heavy metal contaminants. Optimization tests confirmed that 4% kC RFM performs better than 5% and 6% kC RFMs, achieving 84% copper removal by the EK process. Then, the 4% kC was crosslinked with 2% glutaraldehyde (GD) to maximize the RFM adsorption capacity as well as impede the advancement of the alkaline front in the soil. Integrating the kC-GD hydrogel RFM in the EK system achieved, in two weeks, a 96.62% removal of copper, 93.98% removal of nickel, and 99.98% removal of zinc. SEM and EDX analysis confirmed the adsorption of heavy metals by the kC-GD RFM. In the multiple heavy metals decontamination test with RFM-EK, results showed preferential removal of zinc and nickel at 99.97% and 99.86%, while copper removal was about 93.38%. Density functional theory (DFT) simulation showed binding energies of 341.1, 545.7, and 106.0 kJ/mol for Cu²⁺, Zn²⁺, and Ni²⁺, revealing a notable discrepancy between theoretical and experimental results. This discrepancy is caused by copper-limited diffusion through the hydrogel and the dynamic variations in the soil pH during the EK process. Therefore, integrating computational and experimental approaches is recommended when designing responsive hydrogel-based sorbents for heavy metal remediation. • An optimized 4% KC crosslinked with 2%GD and integrated with EK for metals removal • The RFM-EK system achieved about 96%, 94%, and 99.98% removal of Cu, Ni, & Zn • For multiple metals, RFM-EK achieved ̴93%, and 99.97% removal of Cu, Zn, & Ni • DFT binding energies of 341.1, 545.7, &106.0 kJ/mol for Cu, Ni and Zn

Source: Journal of environmental chemical engineering

DOI: 10.1016/j.jece.2025.119514