Removal of a cationic dye from aqueous solution by a porous adsorbent templated from eco-friendly Pickering MIPEs using chitosan-modified semi-coke particles

Abstract

Porous materials prepared from high internal phase emulsions have been attracting much attention in recent years, but two major defects related to the high consumption of organic solvent and surfactants are always difficult to solve. In this work, an eco-friendly and novel porous material was fabricated by thermal-initiation polymerization of surfactant-free corn oil-in-water Pickering medium internal phase emulsions (MIPEs) stabilized using chitosan-modified semi-coke particles. The semi-coke particles modified by chitosan resist the drainage of the Pickering emulsion by generating a viscoelastic film at the oil-in-water interface, and improve the stability of the shearing Pickering emulsion. The pore structures of the porous materials are sufficient and regular, and have abundant –COO⁻ functional groups and rich pore structures, which resulted in high-efficiency adsorption capacity for cationic dye molecules. The saturation adsorption capacities of methylene blue, methyl violet and malachite green can be achieved as 797.91, 832.95 and 779.09 mg g⁻¹ within 30 min at 25 °C, respectively. Overall, this study supplied a viable and eco-friendly pathway for the fabrication of porous adsorbents for dye wastewater.