Solvothermal synthesis of microporous superhydrophobic carbon with tunable morphology from natural cotton for carbon dioxide and organic solvent removal applications

Abstract

Microporous carbonaceous materials were developed by the solvothermal carbonization of natural cotton for the first time. The morphology and surface area of solvothermal char (STC) depends on the concentration of p-toluene sulfonic acid (PTSA) catalyst. STC showed a transformation from a fibrous to spherical morphology with an increase in the PTSA concentration. STC showed a maximum surface area of 477 m² g⁻¹, pore volume of 0.60 cm³ g⁻¹ and CO₂ sorption capacity (at 0 °C and 1 bar pressure) of 2.28 mmol g⁻¹. The CO₂ adsorption showed excellent recyclability and selectivity over nitrogen. STC-0.04 obtained at PTSA to cotton weight ratio of 0.04 showed superhydrophobic character due to the nano projections on the fiber surface produced by the heterogeneous nucleation of STC particles. STC-0.04 is an excellent sorbent for organic solvents from water–solvent mixtures.