In this investigation, the mechanism of dye transfer during the mixed washing of natural cellulosic fabrics was elucidated through a comprehensive study of the hydrolysis of Reactive Red 195 (RR 195) and the subsequent adsorption of its hydrolysis products onto cellulose, approached both experimentally and theoretically. Initially, Reversed-phase high-performance liquid chromatography (RP-HPLC) was employed to identify the final products of Reactive Red 195 hydrolysis, collectively referred to as the unfixed dye substance ( UDS). This data provided theoretical insight into the hydrolysis mechanism of the dye. Following this identification, an adsorption kinetic model was established to delineate the interaction of the hydrolysis products with cellulose. Adsorption exhibited its maximal rate at a temperature of 60°C, under conditions of a wash bath ratio of 120:1 and a pH value of 7. Furthering the investigation, a molecular dynamics model was constructed to detail the adsorption process of these hydrolysis products on the hydrophobic surface Iβ(1 0 0) of cellulose within an aqueous environment. This model offered precise insights into the adsorption volume, kinetics, and mechanistic interaction at a molecular scale. Conclusive evidence from both theoretical analyses and experimental results suggested that the hydrolysis products, devoid of reactive groups, were incapable of chemically interacting with the hydroxyl groups inherent to cellulose. Instead, it was discerned that these products underwent a physical adsorption process onto the cellulose surface. Such adsorptive behavior is postulated to be a predominant factor influencing the dye transfer phenomenon in mixed washing conditions.

中文翻译：

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水解活性红 195 在纤维素上的吸附：实验和理论研究

在这项研究中，通过对活性红 195 (RR 195) 的水解及其随后水解产物在纤维素上的吸附的综合研究，从实验和理论上阐明了天然纤维素织物混合洗涤过程中的染料转移机制。 。最初，采用反相高效液相色谱（RP-HPLC）来鉴定活性红195水解的最终产物，统称为未固定染料物质（UDS）。这些数据为染料的水解机制提供了理论见解。经过这一鉴定，建立了吸附动力学模型来描述水解产物与纤维素的相互作用。在温度为 60°C、洗浴比为 120:1、pH 值为 7 的条件下，吸附表现出最大速率。为了进一步研究，构建了分子动力学模型来详细说明这些水解产物的吸附过程在水环境中纤维素的疏水表面 Iβ(1 0 0) 上。该模型提供了对分子尺度上的吸附体积、动力学和机械相互作用的精确见解。理论分析和实验结果得出的结论性证据表明，水解产物不含反应基团，无法与纤维素固有的羟基发生化学相互作用。相反，人们发现这些产品在纤维素表面上经历了物理吸附过程。这种吸附行为被认为是混合洗涤条件下影响染料转移现象的主要因素。