Synthesis and Characterizations of PEG-nZVI-Montmorillonite Nanocomposite for Adsorption and Photocatalytic Degradation of Tetracycline

For years the design and synthesis of a systems for absorbing and degrading the antibiotic that have the maximum absorption capability in low to high concentrations of pollutants with photodegradability has been raised as a challenge of many researches. In this study, a novel photocatalyst known as polyethylene glycol modified zero-valent iron nanoparticles-montmorillonite (PEG-nZVI-Mt) was synthesized for the adsorption and photocatalytic degradation of tetracycline (TC) in ranges of concentrations. nZVI particles was formed well dispersed on montmorillonite carriers covered by polyethylene glycol polymer. The results demonstrated that the maximum adsorption capacity of TC on the EG-nZVI-Mt (153.8 mg/g) were considerably higher than that of on montmorillonite (78.4 mg/g) at the same condition (after 48 hr with 400 ppm TC). In addition, as the concentration of TC increased, the maximum quantity of adsorption also increased from approximately 20 mg/g to over 300 mg/g. Compared to other adsorbents, the PEG-nZVI-Mt showed the lowest desorption value at 10.1 mg/g, which is less than 6.5% of total TC absorbed. Moreover, the utilization of nZVI as a photocatalyst, results in an enhancement of photocatalytic degradation process of TC, leading to a degradation of over 95% of adsorbed TC in nZVI-Mt and PEG-nZVI-Mt samples after 180 min. The photocatalytic-degradation capacity of tetracycline (TC) on PEG-nZVI-Mt (96.7%) and nZVI-Mt (93.6%) was more than 3-fold beyond that on Mt, Na-Mt and PEG-Mt.