Microfibrillar Polysaccharide-Derived Biochars as Sodium Benzoate Adsorbents

Microfibrillar biochars of chitin (CTF), chitosan (CSF), and cellulose (CLF) were fabricated via green homogenization and a pyrolysis process, and were subsequently explored as adsorbents for removing over-released sodium benzoate (SB) in aqueous systems. The structure, composition, morphology, and adsorption behavior of the as-fabricated biochars were characterized. Results suggest that all biochars, with a microscaled fibrillar structure and foam-like network morphology, underwent severe chemical transition during the pyrolysis process, thereby causing an enhancement of the Brunauer-Emmett-Teller surface area, pore volume, and aromatic and carbonaceous composition. Consequently, N-doped porous CTF/CSF microfibrillar biochars displayed a distinguished capture capacity toward SB compared to that of their fibrillar precursors. Tailoring the chemical composition, porous structure, and sorption mechanism constitutes a possible strategy to achieve adequate structural effects of polysaccharide microfibrillar chars for potential application in environmental treatment or bioenergy.