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Abstract
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Microplastic (MP) contamination in aquatic ecosystems is a global concern, highlighting the urgent need for
innovative remediation solutions. This study introduces a biodegradable chitin-based adsorbent with exceptional
compressive resilience under both dry and wet conditions for the removal of MPs from aqueous environments.
Comprehensive characterization techniques, including Fourier-transform infrared (FT-IR) spectroscopy, field
emission scanning electron microscopy (FESEM), adsorption capacity, kinetic, isotherm, thermodynamic, and
reusability tests, were employed to evaluate the properties of this environmentally friendly adsorbent. The adsorbents exhibited superior mechanical properties, with compressive strengths ranging from 0.61 to 1.3 MPa in
dry conditions, and elasticity retention up to 97 % after multiple compression cycles. Characterized by high
water absorption capacity (up to 600 %) and remarkable pore interconnectivity, the sponges efficiently adsorbed
functionalized MPs (~1 µm) in a pH range of 6–8, achieving maximum adsorption efficiencies of 93.07 % for
polystyrene (PS), 75.54 % for carboxylate-modified polystyrene (PS-COOH), and 90.17 % for polyaminemodified polystyrene (PS-NH2). Thermodynamic studies confirmed the endothermic and spontaneous nature
of the adsorption process, with ΔG◦ values reaching − 13.48 kJ mol− 1. The sponges maintained 79–88 % efficiency after four regeneration cycles, ensuring cost-effectiveness. Toxicity assessments using Chromochloris
zofingiensis demonstrated biocompatibility, while biodegradation experiments indicated up to 92 % mass loss
within 28 days, underscoring their environmental sustainability. This research presents a reusable, biocompatible adsorbent for the efficient removal of harmful MPs from water, addressing aquatic pollution and providing a
foundation for future investigations.
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