Preparation and characteristics of quaternary amino anion exchanger from wheat residue

Preparation of agricultural by-product based anion exchanger and its utilization for nitrate and phosphate removal

“…In previous publications, agricultural by-products were first crosslinked with epichlorohydrin to form the epoxy ethers, and then the anion exchangers were produced after the graft of amine groups onto the epoxy ethers by amination reaction (Anirudhan and Unnithan, 2007;Xu et al, 2009;Gao et al, 2009). Results showed that these anion exchangers exhibited excellent sorption capacities for PO 4 -H, NO À 3 , AsO 2À 3 , AsO 2À 4 and other anions removal from aqueous solutions.…”

Preparation of Lignin-Based Quaternary Amine Anion Exchangers in NaOH Solutions and their Characteristics

“…As can be seen in Fig. 5(c), the intense vibration at 1320-1380 cm -1 indicates the existence of grafted amine groups in the structure of the LQAE (Gao et al 2009). As a result, the adsorption of nitrate anions onto LQAE can be ascribed to the significant increase of cationic quaternary amine groups, which are used as exchanger sites for sequestering nitrate anions.…”

“…In strong alkali solutions, the reaction between epichlorohydrin and lignin was induced after the hydroxyl groups in the lignin molecule were activated. The reaction occurs between the epoxy group of epichlorohydrin and the hydroxyl group of lignin, which grafts the halogen group onto the lignin structure (McCormick and Dawsey 1990;Gao et al 2009 Fig. 2.…”

“…During the amination reaction, the hydroxy lignin ether was cyclized by the catalyst existing in the alkaline condition to produce the epoxy lignin ether. Reaction with triethylamine is believed to occur after ring opening of the epoxide group and condensation through chloromethyl group in an excess of epichlorohydrin (Biçak and Şenkal, 1998;Orlando et al 2002b;Gao et al 2009). The free electrons of the N atom of triethylamine can attack the C atom in the epoxy group of the epoxidized lignin, triethylamine and epoxidized are then covalently together.…”

“…The free electrons of the N atom of triethylamine can attack the C atom in the epoxy group of the epoxidized lignin, triethylamine and epoxidized are then covalently together. LQAE was obtained after the graft reaction between epoxy lignin ether and triethylamine (Gao et al 2009). …”