Synthesis,Characterization, and Some Utilization of Cellulose/Melamine Formaldehyde/Methylamine Anion Exchange Resin

Cellulose, melamine formaldehyde precondensate (MF), and methylamine hydrochloride (MA.HCl) were reacted in aqueous medium at different conditions, including time, temperature, MF/MA.HCl molar ratio, and liquor-to-cellulose ratio (LR). Reaction conditions were selected to prepare a cellulose/MF/MA anion exchanger having a total nitrogen and an amino nitrogen of 23.1% and 131 mEq/100 g, respectively. Potentiometric titration showed that the strength, pK_b , of this resin was 7.2. The resin lost about 3% and 9% of its total and amino nitrogen, respectively, during the first five cycles of the durability test, after which it suffered no losses up to 25 cycles. The resin was utilized in the removal of three anionic dyestuffs (direct, acid, and reactive) as well as permanganate and dichromate anions from aqueous solutions at different pH values ranging from 3 to 12. Maximum extents of removal were manifested at a pH value of 3, at which they followed the descending order: (permanganate ～ acid dye) > (reactive dye ～ dichromate) » direct dye.