Published online by Cambridge University Press: 08 February 2019
Three sizes of beads 1, 2 and 3 mm of chitosan and poly (vinyl alcohol) were generated and crosslinked with ethylene glycol diglycidyl ether. The modification was carried out using a glass reactor, in which the beads were exposed to the glow discharge plasma (GDP). The adsorption experiments were carried out in triplicate at 30 °C, 200 rpm, 72 h at different pH values in the range between 2 and 7. The concentrations of the dye in the supernatants were determined by UV-vis spectrophotometry. The 1 mm beads with and without modification, as well as those adsorbed and without adsorbing were characterized by FTIR and SEM. A higher and constant adsorption capacity was observed using modified beads (814, 857 and 1509 mg/g for the 3, 2 and 1 mm beads, respectively). For unmodified beads the adsorption capacity decreased when the initial pH value was increased. This makes the beads modified by GDP a robust material with respect to pH variation and a good candidate to be used in the removal of synthetic dyes.