# Evaluation and Optimization of Azithromycin Removal by Raw and Alkali‐Modified Peanut Shells Using Taguchi‐Based Experimental Design Approach

## TL;DR

This study shows that modified peanut shells can efficiently remove azithromycin from water, offering a sustainable and cost-effective solution.

## Contribution

The novel use of alkali-modified peanut shells for azithromycin removal, optimized via the Taguchi method, is presented.

## Key findings

- Modified peanut shells achieved 85% azithromycin removal under optimized conditions.
- pH and initial concentration were the most influential factors in the adsorption process.
- Surface analysis confirmed enhanced adsorption due to increased functional groups and electrostatic interactions.

## Abstract

Advanced treatment methods for removing antibiotics are cost‐intensive. Subsequently, the goal of environmental and economic sustainability has switched attention towards bio‐adsorbents. This study evaluated the effectiveness of raw and alkali‐modified peanut shell powder as a cost‐effective, novel adsorbent for removing azithromycin, one of the most widely used drugs worldwide. Prepared adsorbents were characterized by FTIR and SEM equipped with EDX. Experiments designed using a Taguchi‐based approach were performed with a synthetic azithromycin solution to optimize initial concentrations, adsorbent dose, pH, and time. The results showed 63% removal with raw adsorbent at pH 11, an initial concentration of 20 mg/L, a time of 45 min, and an adsorbent dose of 0.4 g/L. With the modified adsorbent, an attractive 85% (maximum) removal was achieved at pH 11, an initial concentration of 30 mg/L, a time of 60 min, and an adsorbent dose of 0.4 g/L. Based on analysis of variance (ANOVA), pH and initial concentration are identified as the most influential factors for azithromycin removal. The improved adsorption performance of modified peanut shells (qmax = 192.1 mg/g compared to 159.2 mg/g for raw PS) was due to increased surface heterogeneity, enhanced electrostatic interactions, and greater accessibility of oxygen‐containing functional groups, as confirmed by kinetic, isotherm, and surface analysis.

The Taguchi approach optimizes adsorption parameters for enhanced removal.Modified peanut shell adsorbent removes up to 85% of azithromycin.π–π interaction and hydrogen bonding drive the adsorption mechanism.Chemical adsorption mechanisms are revealed through SEM and FTIR analysis.Bioadsorbents offer a sustainable solution to antibiotic removal.

The Taguchi approach optimizes adsorption parameters for enhanced removal.

Modified peanut shell adsorbent removes up to 85% of azithromycin.

π–π interaction and hydrogen bonding drive the adsorption mechanism.

Chemical adsorption mechanisms are revealed through SEM and FTIR analysis.

Bioadsorbents offer a sustainable solution to antibiotic removal.

This study demonstrates the optimization of azithromycin removal using raw and alkali‐modified peanut shell adsorbents via the Taguchi method, achieving up to 85% efficiency. The adsorption is governed by π–π interactions and hydrogen bonding, highlighting bio‐adsorbents as sustainable solutions for antibiotic removal from wastewater.