Adsorption of tetracycline antibiotic from aqueous solutions onto vitamin B6-upgraded biochar derived from date palm leaves

• Published in: Journal of molecular liquids 2020-11, Vol.318, p.114126, Article 114126
• Main Authors: Saremi, Faezeh, Miroliaei, Mohammad Reza, Shahabi Nejad, Mohaddeseh, Sheibani, Hassan
• Format: Article
• Language: English
• Subjects: Date palm-biochar; Tetracycline adsorption; Upgrade; Vitamin B6
• ISSN: 0167-7322; 1873-3166
• DOI: 10.1016/j.molliq.2020.114126

Tetracycline has been known as the most common group of antibiotics in production and consumption worldwide and entry of these into the sewage can pose risks to human health due to bacterial resistance. Hence, the present research exhibited the high adsorption capacity of date palm-based biochar which upgraded with vitamin B6 to use as a novel environmentally friendly and highly efficient adsorbent for the removal of tetracycline. This absorbent was prepared by chemical attaching of vitamin B6 (vitamin B6: pyridoxine hydrochloride with a pyridine ring) on biochar surface to change its acidic properties to alkaline). The structure of prepared absorbent was confirmed with different techniques such as FT-IR, XRD, SEM, and BET analyses. The kinetic, isotherm model, thermodynamic and effect of various adsorption conditions such as contact time, adsorbent dose, temperature and pH were investigated. The kinetic of this adsorption process was also described by the pseudo-second order equation and the adsorption isotherm followed the Langmuir model. The maximum monolayer coverage capacity (qm) from Langmuir model was found 76.92 mg/g achieved at that conditions (pH = 7, adsorbent dose = 1 mg/L, T = 25 °C) at 60 ppm initial concentration. Pseudo second order model best fit the kinetics with coefficient > 0.99 of determination and the intramolecular diffusion is not the dominant mechanism. On the basis obtained thermodynamic parameters the absorption process is spontaneous and endothermic. Furthermore, the mechanism of adsorption was investigated, and it was found that ionic and electrostatic interactions should serve as predominant contributions to the significantly enhanced adsorption capability. [Display omitted] •Chemical grafting of vitamin B6 onto biochar surface for biosorbent preparation.•Study and optimization of the equilibrium and removal factors.•Evaluations of the isotherm and kinetics models and thermodynamic parameters.•Successful removal of the tetracycline antibiotics from water matrices.