洗涤微环境中α-FeO(OH)在白色棉织物上的再沉积机理研究OA

Soil stains are the most common and complex inorganic particulate contaminants encountered during garment laundering,primarily composed of fine particles such as clay minerals and iron oxides.During washing,while mechanical forces and surfactants partially dislodge soil particles from fabrics,they readily redeposit onto fiber surfaces during wash solution circulation.This leads to reduced fabric whiteness and dulled color,severely compromising appearance quality and service life.Existing research has primarily focused on detergent formulations or the performance evaluation of anti-redeposition agents,lacking a systematic understanding of the deposition differences among various inorganic soil components in the washing microenvironment and their interfacial interaction mechanisms.Therefore,this study uses white cotton fabrics as the research subject to elucidate the redeposition behavior and microscopic adsorption mechanisms of typical iron-bearing minerals in soil under washing conditions.This provides scientific basis for theoretical analysis of soil stain redeposition and optimization of washing and care systems. This study selected four typical soil minerals—kaolinite,montmorillonite,hematite,and goethite(α-FeO(OH))—and conducted comparative analyses of their deposition behavior on cotton fabric surfaces and their effects on fabric optical properties through whiteness value and K/S value testing,supplemented by scanning electron microscopy(SEM)characterization.Results indicate that iron-bearing minerals significantly affect fabric whiteness and chromaticity,with α-FeO(OH)causing the most pronounced reduction in whiteness,thus selected as the primary study subject.Building on this,single-factor experiments and the Box-Behnken response surface method were employed to systematically investigate the effects of washing temperature,washing solution pH,and washing bath ratio on α-FeO(OH)deposition on white cotton fabrics.Concurrently,multiscale analysis of α-FeO(OH)redeposition in the washing microenvironment was conducted from macroscopic behavior to microscopic interfacial interactions through adsorption kinetics experiments,zeta potential measurements,and molecular dynamics simulations. Results indicate that washing temperature,pH,and bath ratio significantly influence α-FeO(OH)deposition on cotton fabrics.Higher temperatures,acidic or alkaline conditions,and moderate bath ratios promote enhanced deposition.Adsorption kinetics analysis reveals the deposition follows a pseudo-second-order kinetic model,suggesting adsorption behavior is governed by interfacial binding sites and intermolecular interactions.Zeta potential measurements indicate that α-FeO(OH)deposits significantly even when particles and fiber surfaces share negative charges,suggesting electrostatic interactions are not the dominant mechanism.Molecular dynamics simulations further confirm strong hydrogen bonding and van der Waals interactions between α-FeO(OH)and cellulose,with adsorption occurring as an exothermic process.The innovation of this work lies in integrating macroscopic experimental findings with molecular simulations from a washing microenvironment perspective,systematically revealing the redeposition mechanism of iron-containing minerals on cotton fabric surfaces.These results provide insights for refining soil stain redeposition theories and designing anti-redeposition washing systems,laying the foundation for subsequent studies on complex multi-component soil systems and functionalized laundry materials.