ABSTRACT

In this work, coal bottom ash was modified by alkaline fusion route in order to improve its pore properties and make it a potential adsorbent to remove crystal violet dye from aqueous medium. The solids were characterized and posteriorly subjected to kinetic, isotherm, and thermodynamic studies, as well as regenerated and reused for five adsorption tests. The alkaline fusion step resulted in the amorphization of material and generation of high surface area (102 m ² g ⁻¹) and pore volume (0.180 cm ³ g⁻¹), resulting in superior performance compared to the raw material. Kinetic and equilibrium studies showed that the adsorption process was better adjusted by the pseudo-second order and Langmuir models, respectively. The maximum adsorption capacity at equilibrium was 177. 37 mg g⁻¹, with the adsorptive step occurring spontaneously and endothermically. The adsorbent maintained notable levels of dye removal after five consecutive cycles of thermal regeneration and reuse. Besides, the adsorbent was able to remove 64% of the colour of simulated industrial wastewater. Therefore, the alkaline fusion step proved to be a route capable of transforming the coal bottom ash into an adsorbent with improved textural and adsorptive properties.

摘要

在这项工作中，通过碱熔法对煤底灰进行改性，以改善其孔隙性能，使其成为从水介质中去除结晶紫染料的潜在吸附剂。对固体进行表征，然后对其进行动力学、等温线和热力学研究，并对其进行再生和再利用以进行五次吸附测试。碱熔步骤导致材料非晶化并产生高表面积（102 m ² g ^-1）和孔体积（0.180 cm ³ g ^-1)，与原材料相比，性能更优越。动力学和平衡研究表明，吸附过程分别可以通过伪二级模型和 Langmuir 模型更好地调整。平衡时的最大吸附容量为177. 37 mg g ^-1，吸附步骤自发地和吸热地发生。在连续五个热再生和再利用循环后，吸附剂保持显着水平的染料去除。此外，吸附剂能够去除模拟工业废水中64%的颜色。因此，碱熔步骤被证明是一种能够将煤底灰转化为具有改善的质地和吸附性能的吸附剂的途径。