Preparation and Performance of Dimethyl-Acetoxy- (2-Carboxymethyl Ether)-Lignin Ammonium Chloride Amphoteric Surfactant

Abstract

To improve the added value of the lignin products, dimethyl-acetoxy-(2-carboxymethyl ether)-lignin ammonium chloride (DALAC) amphoteric surfactant was synthesized from wheat straw alkali lignin raw material. The structure was analyzed by Fourier transform infrared spectroscopy (FT-IR), and the solubility in different pH solutions was evaluated. The effect of DALAC on adsorption performance was investigated with a solution of copper ions as simulated wastewater, while its flocculation performance was investigated with acid black ATT and methylene blue (MB) wastewater as simulate dyes. The results showed that carboxyl and quaternary amine groups were successfully grafted, and nitrogen content of DALAC was 3.66%. The adsorption isotherm of copper ions with DALAC fit the Freundlich equation. Optimum adsorption conditions for Cu2+ were dosage 0.1 g/L, pH 5.5, and adsorption time 6 h, for which the maximum adsorption capacity was 399 mg/g. The maximum removal rate of Acid black ATT (anionic dye) was 97.8% when the optimum flocculation conditions were dosage 4 g/L, pH 2, and mass concentration of dye 0.1 g/L. The maximum removal rate of methylene blue (cationic dye) was 98.7 %, when the optimum flocculation conditions were dosage 2.5 g/L, pH 9, and mass concentration of dye 0.1 g/L. DALAC will be expected to a novel adsorbent of heavy metal ion and flocculants of dyes in the future.

Keywords

• Alkali lignin
• DALAC
• Amphoteric surfactant
• Adsorbent
• Flocculants