The use of 2-hydroxypropyl-3-trimethylammonium chitosan chloride (HTCC) to decrease the intense brown colour and COD of biomethanated wastewater was investigated. The effects of pH on the rheology of HTCC solutions and their ability to decolourise were examined. HTCC had a positive zeta potential that decreased as pH increased. Decolourisation and COD reduction were decreased slightly when the pH of the HTCC solution was increased from 4 to 9. Variation of pH of the wastewater from 6 to10 did not affect decolourisation. FT-IR spectra of HTCC and its flocs isolated after flocculation indicated that interaction of the major anionic colourant occurred at sites near the cationic quaternary nitrogen of HTCC. Acidic solutions of HTCC were very effective flocculants, producing >80% decolourisation and >50% COD reduction. Prevention of pollution caused by the discharge of the enormous volumes of biomethanated wastewater that are generated worldwide could be facilitated by its treatment with non-toxic HTCC.

中文翻译：

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季铵化壳聚糖处理生物甲烷化废水

研究了使用 2-羟丙基-3-三甲基氯化壳聚糖 (HTCC) 来降低生物甲烷化废水的深褐色和 COD。检查了 pH 值对 HTCC 溶液流变学的影响及其脱色能力。HTCC 具有正 zeta 电位，随着 pH 值的增加而降低。当 HTCC 溶液的 pH 值从 4 增加到 9 时，脱色和 COD 减少略有下降。废水的 pH 值从 6 到 10 的变化不影响脱色。HTCC 及其絮凝后分离的絮状物的 FT-IR 光谱表明主要阴离子着色剂的相互作用发生在 HTCC 阳离子季氮附近的位置。HTCC 的酸性溶液是非常有效的絮凝剂，产生 >80% 的脱色和 >50% 的 COD 减少。