Kapok/regenerated cellulose based carbon aerogel prepared at a low-temperature carbonization for oil/water separation

Abstract

With the requirement of sustainable development in modern society, selective filtration and separation of oils and organic solvents from polluted wastewater is a critical and very important goal. Herein, a novel hydrophobic and oleophilic cellulose-based carbon aerogel composed of kapok fiber/regenerated cellulose was prepared at a low-temperature carbonization technique (300 ℃) directly using kapok and hardwood pulp as raw material, the N-methyl N-oxide monohydrate (NMMO·H2O) as a green cellulose solvent, and NH4H2PO4 (ADP) as a carbonization promotor, which is denoted as AX-KRCA(AX: A indicates the ADP used, x is the concentration of ADP solution (g/L)) The regenerated cellulose (RC) was converted from hardwood pulp via NMMO·H2O treatment, and further combined with kapok fiber to form a 3D porous structure. By adding ADP, AX-KRCA can be rapidly dehydrated into carbon at 300 ℃, which not only saves energy consumption but also retains the basic form of kapok fiber and regenerated cellulose, making it have excellent compressibility, elasticity, and fatigue resistance. The ultra-light porous AX-KRCA samples can be an efficient oil/water adsorbent, with an adsorption capacity from 98.0 to 232.1 g g−1 for various oils, and can maintain 87.3 % adsorption capacity after 20 cycles and 99.6 % separation efficiency after 5 times of filtration.