A rational modification route to an amphiprotic cotton fiber as adsorbent for dyes
Fibers and Polymers, 16(7), pp 1512-1518, 2015-7
Two different modification routes (route 1 and route 2) were attempted to synthesize the amphiprotic cotton fiber (AP-cotton) as dyes adsorbent. Specifically, both the cationic monomer (3-chloro-2-hydroxypropyl trimethyl ammonium chloride, CTA) and anionic monomer (2-acrylamide-2-methyl propane sulfonic acid, AMPS) were introduced into the cotton fibers in a different order and the resulting AP-cottons (CTA/AMPS-cotton and AMPS/CTA-cotton) were characterized by Fourier transform infrared spectroscopy (FT-IR), X-ray photoelectron spectroscopy (XPS), and field emission scanning electron microscopy (SEM). The adsorption capacities of two kinds of AP-cottons for dyes were studied. The results indicate that the route 1 is a feasible way to introduce CTA and AMPS into cotton fiber by chemical binding, and the resulting CTA/ AMPS-cotton can adsorb both anionic dye (Congo red, CR) and cationic dye (Methele blue) effectively while the adsorption capacity is around 142.8 mg/g and 88.2 mg/g, respectively. However, the AMPS/CTA-cotton obtained by route 2 can only adsorb about 35.8 mg/g for CR and 43.9 mg/g for MB at most, because the surface of cotton fiber are mainly coated with the AMPS and CTA by physisorption. As a result, the route 1 is believed a better method for synthesis of AP-cotton compared with the route 2.
Modification; Amphiprotic cotton fiber; Adsorbent; Dyes