即时合成层状双氢氧化物处理酸性大红GR染料实验研究

EXPERIMENTAL STUDY ON TREATMENT OF ACID SCARLET GR BY Mg/Al-LDH SYNTHESIZED IN-SITU

印染废水是重要的工业污染源之一，研究新的印染废水脱色技术是水污染控制技术领域重要课题之一。以酸性大红GR为典型代表。初步研究了镁-铝盐水解共沉淀法即时合成层状双氢氧化物（LDH）处理阴离子型染料溶液的效果、影响因素和染料去除机理。结果表明，镁-铝盐水解共沉淀法即时合成LDH对酸性大红CR染料溶液有非常好的脱色效果，影响处理效果的主要因素是MS／Al比和pH值。在pH值8．5．10．0，MS／Al比2：1～4：1，都可以获得较好的净化效果，酸性大红CR染料浓度0．65mmol／L时，染料去除率达99％。其净化机理是，当在染料溶液中投加Mg^2＋、Al^2＋溶解盐和NaOH时，Mg^2＋、Al^3＋水解共沉淀形成LDH的同时，染料阴离子以平衡LDH结构电荷的形式进入LDH结构层间，含有染料的LDH通过沉淀分离从溶液中去除。

Dying and printing wastewater is the main resource of industrial pollution. Developing novel technologies for treatment of dying and printing wastewater is one of the tasks controlling water pollution. Efficiency, effect factors, mechanism of removal anionic dyestuff were discussed in this paper with Mg^2＋ and Al^3＋ co-precipitation to synthesize LDH in-situ to treat acid scarlet GR. The results indicate that factors affecting the impact efficiency of removing dyestuff include Mg/Al ratio and pH. The great removal efficiency of dyestuff can be reached when pH values are between 9 - 9.5 and Mg/ Al ratios 2：1. Meanwhile, Mg and Al added can be made good use of. For the concentration of acid scarlet GR 360 rag/ L, removal efficiency of dyestuff is more than 99 %. The removal mechanism of dyestuff is that by adding Mg^2＋, Al^3＋ and NaOH in dyestuff solution, dyestuff anions are selectively intercalated into the interlayer of LDH to balance positive structural charge while Mg^2 ＋ and Al^3＋ is co-precipitated to form LDH, the dyestuff in solution is ＂removed by the settlement of LDH synthesized in-situ, which is confirmed by X-ray diffraction and FT-IR data.