This paper reports the application of an advanced multilayer model to study the adsorption of food dyes FD&C blue No. 2, acid red 18, FD&C red No. 2, and FD&C yellow 5 from aqueous solutions with a chitosan film. These dyes' adsorption mechanisms were discussed and analyzed at 298-328 K and pH 4-7 via statistical physics calculations. Physicochemical parameters were utilized to explain the dye adsorption at the molecular scale. Modeling results showed dye aggregation phenomena where each functional group of chitosan film adsorbed several dye molecules simultaneously at different tested temperatures. Aqueous solution temperature reduced the dye adsorption capacities, attributed to the exothermic nature of dye removal. The chitosan film was more effective for the adsorption of dye FD&C yellow 5. The estimated adsorption energies for dye-chitosan film and dye-dye interactions confirmed an exothermic physisorption associated with van der Waals forces and hydrogen bonding. This study's results contributed to expanding the knowledge on the adsorption mechanisms of dye molecules using biopolymers like chitosan.

本文报道了一种先进的多层模型在研究食用染料FD＆C蓝色2号，酸性红18号，FD＆C红色2号和FD＆C黄色5从具有壳聚糖膜的水溶液中的吸附性能的应用。在298-328讨论并分析了这些染料的吸附机理。 通过统计物理计算得出K和pH 4-7。利用理化参数来解释染料在分子尺度上的吸附。建模结果显示了染料聚集现象，其中壳聚糖膜的每个官能团在不同的测试温度下同时吸附了多个染料分子。水溶液温度降低了染料的吸附能力，这归因于染料去除的放热性质。壳聚糖膜对染料FD＆C黄5的吸附更有效。染料-壳聚糖膜和染料-染料相互作用的估计吸附能证实了与范德华力和氢键相关的放热物理吸附。这项研究的结果有助于扩大使用壳聚糖等生物聚合物对染料分子的吸附机理的认识。