HIPE-templated cellulose-based porous IPN scaffold for efficient copper ion removal from wastewater

Industrial wastewater contaminated with heavy metals such as copper poses a significant threat to environmental and public health, necessitating the development of efficient and sustainable remediation strategies. In this study, a novel cellulose-based high internal phase emulsion interpenetrating polymer network (HIPE-IPN) was synthesized by polymerizing acrylic acid within a wood-pulp cellulose matrix to replicate the hierarchical porosity of natural adsorbents. This innovative approach integrates the structural robustness of cellulose with the functional tunability of synthetic polymers, resulting in a porous scaffold with enhanced sorption characteristics. Batch adsorption experiments were conducted to optimize key process variables, revealing that the maximum adsorption of Cu²⁺ occurred at an adsorbent dosage of 2 g/L, pH 5, initial Cu²⁺ concentration of 500 mg/L, and a contact time of 90 min. Under these conditions, the HIPE-IPN exhibited a significantly improved sorption capacity (q_max) of 139.8 ± 7.5 mg/g, surpassing both pre-treated wood-pulp cellulose (60.5 ± 3.3 mg/g) and bulk IPN (113.8 ± 6.1 mg/g). Kinetic modelling indicated that the adsorption process followed a pseudo-second-order model (R² > 0.99), while equilibrium data fitted the Langmuir isotherm model (R² > 0.98), with a maximum Langmuir adsorption capacity of 270.3 mg/g. The study highlights the novelty of utilizing a bio-derived HIPE-IPN framework for efficient copper ion removal, demonstrating a substantial improvement in adsorption performance over conventional methods. These findings suggest that the developed HIPE-IPN scaffold holds considerable promise for industrial wastewater treatment applications, offering an eco-friendly, scalable, and cost-effective solution for heavy metal remediation and resource recovery.