# Adsorption of Ciprofloxacin onto CMCs/XG Hydrogel: Optimization, Kinetic, and Isotherm Studies

## TL;DR

A new eco-friendly hydrogel was developed to effectively remove ciprofloxacin from water, showing high adsorption capacity and reusability.

## Contribution

This study is the first to investigate the use of a CMCs/XG hydrogel for ciprofloxacin removal, demonstrating its high adsorption capacity and reusability.

## Key findings

- The hydrogel achieved a maximum adsorption capacity of 147.06 mg g−1 for ciprofloxacin.
- The hydrogel retained over 86% adsorption efficiency after five cycles, indicating good reusability.
- Adsorption was found to be spontaneous, favorable, and exothermic based on thermodynamic analysis.

## Abstract

The use of adsorbents based on naturally occurring materials to eliminate antibiotics from industrial effluents has attracted remarkable interest owing to the abundance of raw materials and the sustainability of this method. The ciprofloxacin (CIP) removal capacity of a previously synthesized antimicrobial hydrogel based on carboxymethyl chitosan (CMCs)/xanthan gum (XG) was investigated for the first time in this study. CMCs and XG were blended in an equivalent-weight ratio and crosslinked using trimellitic anhydride isothiocyanate (TAI) to synthesize an eco-friendly, low-cost hydrogel, which was characterized using FTIR, SEM, and XRD analyses. The pseudo-second-order model fitted the experimental data well: the experimental qe (49.59 mg g−1) was close to the theoretical value (51.81 mg g−1). The Langmuir isotherm best fitted the adsorption results (R2 = 0.999), with a maximum adsorption capacity of 147.06 mg g−1. The thermodynamic results indicate that adsorption is spontaneous, favorable, and exothermic in nature. The percentages of desorption obtained were 95.72, 94.34, 89.52, 88, and 86.28% after five consecutive cycles. Thus, this hydrogel possesses potential for further testing and application in wastewater remediation.