Eco-friendly taro stem-sourced cellulose/polypyrrole hybrid aerogel: An efficient capture strategy for microplastics removal

The escalating issue of microplastic pollution poses significant threats to food safety and human health. A porous biomass aerogel synthesized by in-situ growth of polypyrrole on the surface of waste taro stem cellulose-based aerogel was prepared for the adsorption and enrichment of microplastics from aqueous solutions and liquid food. The optimized TS-MCC/PPy 4.0 aerogel demonstrated exceptional mechanical strength (137.55 kPa) and outstanding polystyrene (PS) microplastics adsorption capacity, with q m being 818.06 mg/g at 298 K. The aerogel maintained robust applicability across varying pH conditions and ionic strengths, exhibiting superior adsorption efficiency (>80 %) for microplastics of varying sizes (200 nm to 2000 nm) and types (polyethylene (PE), polyethylene glycol terephthalate (PET), polypropylene (PP) and PS). Scanning electron microscope, fourier transform infrared spectrometer and X-ray photoelectron spectroscopy analysis identified multiple adsorption mechanisms: physical entrapment (PE, PP, PS, PET), hydrogen bonding (PE, PP, PS, PET), electrostatic interactions (PP, PS, PET), and π-π interactions (PS, PET). The adsorption efficiency was kept 91.55 ± 0.53 % for PS after 5 reuse cycles, complemented by favorable biocompatibility and complete soil biodegradation within 12 weeks. The aerogel demonstrated exceptional adsorption performance and recovery rates in four liquid food matrices application. This study presented an efficient and green cellulose-based aerogel adsorbent for microplastics removal.