Abstract

Effective textile dye removal from aquatic wastewater is essential, as this effluent is harmful to human health, biodiversity, and natural environments. This study investigates the synthesis of zeolitic materials for dye removal from wastewater using metakaolin and fly ash as starting materials. In the first synthesis step, the starting materials are blended at various metakaolin-to-fly ash ratios and treated with a 3 M sodium hydroxide solution under stirring. The solid-to-liquid ratio of the precursor gel is 1:8 (w/v). The suspensions are then subjected to hydrothermal treatment at 120 °C for 6 h. In the second step, an impregnation method is used to obtain titanium dioxide (TiO₂)-containing zeolite, and the effect of the TiO₂ content on the zeolite adsorption performance is investigated. The synthesized products are characterized using X-ray diffraction, scanning electron microscopy, particle size analysis, surface area measurement, and ultraviolet-visible spectrophotometry. From the results, a metakaolin-to-fly ash weight ratio of 4:1 is optimal and yields sodalite and zeolite A. For 20-ppm methylene blue solution, the adsorption efficiencies of freshly synthesized zeolite and TiO₂-containing zeolite are found to be 87.63% and 99.87%, respectively. In addition, the adsorption performance of the reused product is similar to that of the freshly synthesized product. Thus, the synthesized modified zeolite is an efficient adsorbent for methylene blue removal.

摘要

从水生废水中有效去除纺织染料至关重要，因为这种废水对人类健康、生物多样性和自然环境有害。本研究以偏高岭土和飞灰为起始原料，研究了用于从废水中去除染料的沸石材料的合成。在第一个合成步骤中，起始材料以各种偏高岭土与飞灰的比例混合，并在搅拌下用 3 M 氢氧化钠溶液处理。前体凝胶的固液比为 1:8 (w/v)。然后将悬浮液在 120°C 下进行水热处理 6 小时。第二步，采用浸渍法得到含二氧化钛（TiO ₂）的沸石，TiO _2的作用含量对沸石吸附性能的影响进行了研究。使用 X 射线衍射、扫描电子显微镜、粒度分析、表面积测量和紫外-可见分光光度法对合成产品进行表征。从结果来看，偏高岭土与飞灰的重量比为 4:1 是最佳的，并且会产生方钠石和沸石 A。对于 20 ppm 亚甲蓝溶液，发现新合成的沸石和含 TiO 2 沸石的吸附效率_为分别为 87.63% 和 99.87%。此外，再利用产品的吸附性能与新合成产品相似。因此，合成的改性沸石是去除亚甲蓝的有效吸附剂。