Removal of triclosan and bisphenol A from water by selected natural adsorbents

Endocrine-disrupting compounds (EDCs) like triclosan (TCS) and bisphenol A (BPA) are persistent micropollutants in aquatic environments that threaten human health and ecosystems through bioaccumulation and disruption of hormonal pathways. Conventional water treatment processes often fail to achieve sufficient removal of these compounds, necessitating the development of efficient adsorptive methods. Rather than introducing new materials, this study compares the adsorption capabilities of four types of commercially relevant natural adsorbents—granular activated carbon (GAC), granular ferric hydroxide (GFH), natural clinoptilolite zeolite, and surfactant-modified bentonite organoclay—chosen for their structural diversity and environmental relevance. All experiments were conducted under identical batch conditions using single-solute systems to enable direct comparison of adsorption behaviour. Batch experiments and characterisation analysis assessed physical properties, sorption efficiency, kinetics, and equilibrium behaviour for TCS and BPA removal. Results revealed that GAC exhibited the most consistent and broad-spectrum removal (>95% for both TCS and BPA), suggesting that adsorption is governed by chemisorption, π–π interactions, and hydrogen bonding, best described by pseudo-second-order kinetics and suitable equilibrium models. Organoclays achieved near-complete TCS removal (up to 99.6%) via surfactant-mediated hydrophobic partitioning but were less effective for BPA (48–67%). GFH displayed remarkable selectivity, removing TCS with >90% efficiency but showing negligible affinity for BPA, reflecting compound-specific surface interactions such as surface complexation rather than non-specific adsorption. Zeolites demonstrated limited capacity, achieving ≤25% TCS removal and no detectable BPA adsorption, constrained by pore size and surface charge. These findings establish compound-specific adsorption mechanisms and selectivity patterns and highlight GAC as the most effective broad-spectrum option, while GFH and organoclays offer selective and potentially cost-effective alternatives. By decoupling surface area, pore structure, surface chemistry, and surface charge under controlled conditions, this study provides a mechanism-oriented comparative framework for adsorbent selection and optimisation in water treatment applications targeting EDCs.