Enhanced adsorption of amido black (AB) dye using PAN/EPI-DMA-bentonite composite fibers as a novel electrospun solution for wastewater treatment

Abstract

This study investigates the use of PAN/EPI-DMA-bentonite composite fibers, synthesized through electrospinning, for the efficient adsorption of anionic azo dye, amido black (AB), in wastewater treatment. The composite fibers were developed by incorporating epichlorohydrin dimethylamine (EPI-DMA) modified bentonite into a polyacrylonitrile (PAN) matrix, enhancing the surface's positive charge and increasing adsorption sites. Characterization using SEM-EDX, FTIR, and BET analyses confirmed successful bentonite integration, increased fiber diameter, and enhanced surface area, contributing to improved dye affinity. Adsorption experiments revealed that a 3 wt% EPI-DMA-bentonite dosage achieved optimal AB dye removal, with the composite demonstrating a maximum adsorption capacity of 1829 mg/g at 200 ppm dye concentration. Acidic conditions (pH 2-4) significantly improved adsorption efficiency, reaching up to 92% dye removal due to increased electrostatic attraction between the anionic dye and cationic sites on the composite fibers. Isotherm and kinetic studies indicated that the adsorption process adheres to the Langmuir isotherm model and pseudo-second-order kinetic model, suggesting monolayer adsorption and chemisorption mechanisms. Compared to conventional adsorbents, the PAN/EPI-DMA-bentonite composite exhibited superior adsorption capacity, highlighting its potential as an effective and scalable solution for industrial dye-laden wastewater treatment.