Ciprofloxacin adsorption onto Co/chitosan-derived carbon/smectite nanocomposite obtained by the hydrothermal synthesis

Abstract

Nowadays, environmental pollution caused by antibiotics attracts extensive attention. Adsorption has been successfully applied in the treatment of wastewater loaded by pharmaceutics, while diverse natural and eco-friendly materials have been recognized as promising adsorbents. In this work smectite clay from Bogovina (Serbia) and biopolymer chitosan (derived from waste of crustaceans) were used as eco-friendly starting materials for the adsorbent synthesis. The combination of transition metal, carbon materials, and clay minerals represents a useful way to develop functional nanocomposites with benefiting synergistic properties of all components. Simple, one-step hydrothermal procedure conducted at 180 ℃ for 24h was applied for synthesis of cobalt/smectite/chitosan-derived carbon (H_Co/C-S) nanocomposite. The sample was characterized using XRPD, FTIR, and low-temperature N2-physisorption analysis and tested as adsorbent of ciprofloxacin (CPX). The effects of temperature, initial pH, and CPX concentration on the adsorption process were investigated. The adsorption results were fitted by Langmuir, Freundlich, and Sips adsorption isotherms. Additionally, CPX adsorption was described by appropriate kinetics and thermodynamic parameters. It was found that temperature increase had the beneficial effect on CPX adsorption, while investigated adsorbent was efficient in a broad pH range (4-8). The H_Co/C-S adsorbent was found to be efficient in the removal of CPX antibiotic.