Carbon dots crosslinked chitosan/cellulose sponge capture of methyl blue by adsorption process.

For environmental protection, organic dyes and solvents of industrial wastewater must be eliminated. Here, a citric acid-based carbon dots (CA-CDs) crosslinked chitosan/microcrystalline cellulose (CS/MCC/CA-CDs) sponge was synthesized to study its adsorption performance for methyl blue (MB) dye. The morphology of sponge was a tangled fiber with a bundle formed by hydrogen bonds between CA-CDs and the CS/MCC composite matrix. The abundant amount of tangled fiber bundle units can offer plentiful active adsorption sites to collect the dye molecules. The adsorption capacity of CS/MCC/CA-CDs sponge toward MB was 306.8 mg/g at pH 10 and a temperature of 298 K. Meanwhile, the pseudo-second-order kinetic model was matched with the adsorption kinetic experimental data, and the adsorption isotherm data can be described by the Langmuir models. This study proposed that the CS/MCC/CA-CDs sponge adsorbent creates tremendous potential application value in wastewater treatment due to its fast kinetics, high adsorption capacity, simple preparation, and eco-friendly properties.