Facile synthesis of agricultural waste-derived polymeric networks for effective uranium removal from real groundwater samples: A comparative study

Uranium levels in drinking water that exceed the WHO guideline of 30 μg/L can lead to chemical and radiological toxicity with serious health concerns on renal, neurological, hepatic and cardiovascular systems. Motivated by this concern, we developed sustainable biosorbents for uranium removal and routine monitoring applications. Cellulose extracted from agricultural waste was mixed with collagen to form a hybrid backbone, which was then interpenetrated with polyvinyl alcohol (PVA) using citric acid as a crosslinker and a ceric ammonium nitrate/nitric acid (CAN/HNO 3 ) redox system to generate a semi-interpenetrating network (semi-IPN). Subsequent impregnation with polyacrylamide chains yielded a full interpenetrating network (IPN). The materials were comprehensively characterized to determine their structural, elemental and surface features. Both the synthesized materials were examined as adsorbents for U(VI) from contaminated water. Under optimized conditions, removal efficiencies reached 98.5 % (semi-IPN) and 95.8 % (IPN). Adsorption behaviour was analysed with kinetic and isotherm models; the Langmuir model provided the best fit, having the maximum adsorption capacity (μg/g) of 49.41 for semi-IPN and 31.46 for IPN. The kinetic data for both materials align with a pseudo-second-order model, suggesting chemisorption. Biosorbents demonstrated robust regeneration and were successfully applied to uranium-contaminated groundwater samples, highlighting their promise as practical, eco-friendly materials for point of use water purification.