Gemifloxacin removal from aqueous solution by rice‐straw based activated carbon: Batch adsorption and thermal regeneration

Abstract

Due to the worldwide concern about emerging contaminants in aqueous systems, the main objective of the present study is the adsorption of gemifloxacin (GMF), a fluoroquinolone-type antibiotic, by rice straw-based activated carbon. The rice straw chemically activated with K 2 CO 3 (RSAC) had very high carbon content (>80%) and low silica content (due to the extraction step after activation), high specific surface area (1668 m 2 /g), and oxygenated functional groups. The GMF adsorption capacity of RSAC was relatively dependent on the initial pH of the solution and highly dependent on the adsorbent dose. The pseudo-second order model and the BET isotherm models were the best models for predicting adsorption's kinetic and equilibrium behaviors. The maximum monolayer adsorption capacities of RSAC at 25, 35, and 45 C were 565.6, 552.4, and 525.8 mg/g, respectively. The thermodynamic parameters indicated a spontaneous and exothermic character of the GMF adsorption process. n-π, π-π, electrostatic interactions, and hydrogen bonding were demonstrated as probable mechanisms involved. Thermal regeneration of GMF-saturated RSAC at 550 C resulted in perfect adsorbent regeneration in the second cycle and reasonable performance in the third cycle.

ZnCl2 activated mesoporous carbon from rice straw: optimization of its synthetic process and its application as a highly efficient adsorbent for amoxicillin

“…14 Examples of modification methods to improve the antibiotic adsorption of rice straw-derived biochar include tannic acid modification, 15 modification with TiO 2 , 16 magnetization method 9 and chemical activation. 17 Chemical activation of rice straw has been used to enhance the adsorption of various adsorbates such metals and dyes; however, limited studies have been reported on antibiotics. 18,19 According to our previous studies, it was found that carbon from rice straw with KOH and H 3 PO 4 activation exhibited high surface area with excellent remediation of methylene blue and Congo red.…”

“…14 Examples of modification methods to improve the antibiotic adsorption of rice straw-derived biochar include tannic acid modification, 15 modification with TiO 2 , 16 magnetization method 9 and chemical activation. 17 Chemical activation of rice straw has been used to enhance the adsorption of various adsorbates such metals and dyes; however, limited studies have been reported on antibiotics. 18,19…”