Removal of Amoxicillin Antibiotic from Polluted Water by a Magnetic Bionanocomposite Based on Carboxymethyl Tragacanth Gum-Grafted-Polyaniline

Abstract

Removal of antibiotics from contaminated water is very important because of their harmful effects on the environment and living organisms. This study describes the preparation of a bionanocomposite of carboxymethyl tragacanth gum-grafted-polyaniline and γFe2O3 using an in situ copolymerization method as an effective adsorbent for amoxicillin antibiotic remediation from polluted water. The prepared materials were characterized by several analyses. The vibrating sample magnetometer and thermal gravimetric analysis showed that the carboxymethyl tragacanth gum-grafted-polyaniline@ γFe2O3 bionanocomposite has a magnetization saturation of 25 emu g−1 and thermal stability with a char yield of 34 wt%, respectively. The specific surface area of bionanocomposite of about 8.0794 m2/g was obtained by a Brunauer–Emmett–Teller analysis. The maximum adsorption capacity (909.09 mg/g) of carboxymethyl tragacanth gum-grafted-polyaniline@ γFe2O3 was obtained at pH 7, an agitation time of 20 min, a bioadsorbent dose of 0.005 g, and amoxicillin initial concentration of 400 mg/L. The Freundlich isotherm and pseudo-second-order kinetic models were a better fit with the experimental data. The kinetic model showed that chemical adsorption is the main mechanism for the adsorption of amoxicillin on the bioadsorbent. In addition, the maximum adsorption capacity for amoxicillin compared to other reported adsorbents showed that the prepared bionanocomposite has a higher maximum adsorption capacity than other adsorbents. These results show that carboxymethyl tragacanth gum-grafted-polyaniline@ γFe2O3 would be a favorable bioadsorbent for the remediation of amoxicillin from contaminated water.