Reusable macroporous polyethyleneimine sponges for sustainable removal of dual-arsenic species: mechanistic and life cycle assessment.

Groundwater arsenic contamination poses serious health risks, demanding sustainable and cost-effective remediation. This study reports the synthesis of macroporous polyethyleneimine (PEI) sponges prepared via ice-templating and glutaraldehyde crosslinking, designed for reusability and high adsorption performance in arsenic removal. The amine-rich PEI matrix provides abundant binding sites, while its interconnected macroporous structure enhances ion accessibility and mass transfer. The sponges achieved > 90% arsenic removal, decreasing concentrations from 83.75 µg/L to < 10 µg/L, meeting WHO/BIS standards. FTIR and FESEM-EDX analyses confirm electrostatic and chelation-based interactions between amine groups and arsenic species. Experimental adsorption capacities (qₑₓₚ) at 120 µg/L initial concentration were 187.0 ± 4.2 µg/g for As(V) and 182.5 ± 5.1 µg/g for As(III) at pH 6.7. The Langmuir model predicted theoretical maxima of 1251.7 µg/g (As(V)) and 1053.9 µg/g (As(III)). Techno-economic and life cycle assessments demonstrated a low treatment cost ($0.183/L), 70% reduced operational expenditure, and 40% lower carbon emissions compared to reverse osmosis and activated alumina. Field application in Murshidabad, India, verified real-world efficiency under co-contaminated groundwater conditions. The combination of scalable fabrication, reusability, and eco-efficiency positions PEI sponges as a sustainable alternative for decentralized arsenic remediation aligned with SDG 6.