The picric acid removal from aqueous solutions by multi‐walled carbon nanotubes/<scp>EDTA</scp>/carboxymethylcellulose nanocomposite: Central composite design optimization, kinetic, and isotherm studies
Mina Azadfar, Hasan Tahermansouri, Mahnaz Qomi
Abstract
Abstract The removal of hazardous picric acid is of great importance to making healthy and drinkable water. In this research, a nanocomposite (MWCNT‐EDTA‐CMC) based on carboxylated multiwall carbon nanotubes (MWCNT‐COOH) modified by carboxymethylcellulose (CMC) and ethylenediamintetraacetic acid (EDTA) was prepared for adsorption and removal of picric acid from aqueous solutions. MWCNT‐EDTA‐CMC was characterized by Fourier transform infrared (FT‐IR), field‐emission scanning electron microscopy (FESEM), thermal gravimetric analysis (TGA). Central composite design (CCD) was used to study the influence of pH, adsorbent dosage, and initial picric acid concentrations on the removal percentage of picric acid. At optimum conditions (pH 3.0, MWCNT‐EDTA‐CMC dosage 0.050 g, picric acid concentration 30 mg L −1 ), high removal efficiency (97.67%) was obtained for picric acid which was reasonably well predicted by the model. The adsorption process was demonstrated by the pseudo‐second‐order kinetic and Freundlich isotherm models for both adsorbents. In addition, the consumed MWCNT‐EDTA‐CMC could be reused up to 3th cycle of regeneration.