Preparation and characteristics of quaternary amino anion exchanger from wheat residue

Quaternary amino anion exchanger (QE) was prepared from wheat residue (WR) after reaction with epichlorohydrin and triethylamine in the presence of N,N-dimethylformamide and catalyst. The single influential factor experiments and orthogonal tests were carried out in order to obtain the optimal conditions for the preparation of wheat residue quaternary amino anion exchanger (WR-QE). The parameters of the influential factors, which included the types of catalysts, the amounts of WR and triethylamine, and experimental temperatures (activating temperature, catalytic temperature and reacting temperature) were also defined. The results indicated that pyridine was a suitable catalyst, and the catalytic temperature was a key factor of experimental temperatures. The optimal synthesis reaction parameters of dosages were WR:epichlorohydrin:pyridine:triethylamine = 2 g:20 ml:15 ml:30 ml. Optimal experimental temperature was 100 °C. Under these conditions, the nitrogen content of WR-QE was 6.0%, compared with WR of 0.4%. The yield was 556.3%. Nitrate removal was 89.1%; this was higher than the nitrate removal of wheat residue tertiary amino anion exchangers (WR-TE) of 6% −10%.