Polyamine functionalized cotton fibers selectively capture negatively charged dye pollutants

Cotton fiber was functionalized with polyamine polymer PEI by a facile and eco-friendly method. The structural and chemical characteristics of the resulting PEI@cotton were investigated using various analysis techniques and the adsorption performance of the PEI@cotton was tested by removing organic dye pollutant from aqueous solutions. The incorporation of polyamine groups on the cotton fiber surface enabled PEI@cotton to selectively remove negatively charged organic dye pollutants from aqueous solution, and significantly outperformed, in terms of rate and capacity, untreated cotton fiber. The isotherm study indicated that the absorption of MO and XO by PEI@cotton obeyed the Langmuir model, and the maximum adsorption values were 755.7 mg/g and 303.4 mg/g, respectively. Kinetic experiments confirmed that the pseudo-second-order model was more suitable for describing the adsorption data. The possible adsorption mechanism of PEI@cotton to negatively charged dye contaminants has been provided. Furthermore, PEI@cotton can be regenerated multiple times through a simple operation with no significant loss of performance. Overall results of adsorption indicated that the PEI@cotton was a promising material for rapid and efficient adsorption of negatively charged dyes from aqueous solution. It is hoped that the facile and scalable methodology described in this work can provide ideas for the production of environmentally friendly water treatment materials.