Sorptive riddance of enrofloxacin from wastewater: linear and non-linear isotherm and kinetics, safe disposal, and cost analysis

• Published in: Biomass conversion and biorefinery 2023-09, Vol.13 (14), p.12795-12807
• Main Authors: Das Sharma, Debasish, Show, Sumona, Samanta, Sucharita, Kondi, Vanitha, Khan, Anoar Ali, Halder, Gopinath
• Format: Article
• Language: English
• Subjects: Activated carbon; Adsorptivity; Aqueous solutions; Biotechnology; Cost analysis; Energy; Isotherms; Original Article; Phosphoric acid; Renewable and Green Energy; Sorbents; Sorption; Wastewater
• ISSN: 2190-6815; 2190-6823
• DOI: 10.1007/s13399-021-02172-8

The current study focuses at the adsorptive evacuation of enrofloxacin (ENF) using acid-activated carbon generated from green Cocos nucifera shells by penetrating the bio-char with 85% (w/w) ortho-phosphoric acid using the appropriate procedures. The effects of initial ENF concentration (5–30 mg/L) (conc.), temperature (15–40 °C) (temp), pH (3–10), sorbent dose (1–10 g/L), interaction period (6–30 h), and agitation speed (100–200 rpm) on ENF sorption were examined using sequential batch experiments. With concentration of 10 mg/L, pH 7, temp of 25 °C, sorbent dose of 6 g/L, speed of 160 rpm, and interaction period of 18 h, the maximum removal% of ENF achieved was 93.98%. The reusability capability of modified carbon was found to be 80.06% after the fifth cycle. The maximum adsorption capacity was noted as 0.015 mg/g. BET, SEM analysis was used to characterize the biosorbent. For both linear and non-linear approaches, the kinetic data from the sorption investigation has been best suited into a pseudo-second-order kinetic model. The Langmuir, Freundlich, and Temkin isotherm models have been examined, and the Freundlich and Temkin isotherm models have been observed to be the best-fitted models from the experimental evidence for both linear and non-linear techniques. For negative values of ∆ G ° and ∆ H °, the thermodynamic evaluation of the recent sorptive separation process indicates the spontaneity as well as exothermic nature of the system. The cost analysis of developed adsorbent proved to be appropriate for large-scale use. Biochar generated from green coconut shells may therefore be used to induce adsorptive elimination of ENF from aqueous solutions. Graphical abstract