The hydroxyl group of the chitosan polymer could adsorb
SRDW by covalent bonding, which is the same as the
adsorption mechanism of cellulose polymers with reactive
dyes in dyeing processes (Fig. 5). In dyeing processes, it is
known that the chloride group (–Cl) of reactive dyes can react
with fabric molecules at the hydroxyl group of cellulose
(HO–cellulose) by ionization after the higher pH is adjusted
with Na2CO3. The HO–cellulose was deprotonated under
caustic conditions and transformed to a cellulose ion