Abstract

Fly ash (FA) was modified through alkaline fusion with NaOH (MFAAF) and applied as an adsorbent to remove methyl violet 10B (MV10B) in an aqueous medium. It was found that the alkaline fusion provided a significant reduction of the crystalline phase of FA. FA and MFAAF are mainly composed of aluminum, silicon, and iron oxides. The pore volume and surface area values of MFAAF were 0.154¹ and 65.4 m² g⁻¹, being 154 and 130 times higher than the precursor material. Alkaline fusion led to an alteration in the morphology, from spheres to an undefined shape. MFAAF presented an MV10B removal percentage eight times higher than the FA, employing an adsorbent amount of 1 g L⁻¹ at pH 7.5. The pseudo-second-order model well-described adsorption kinetics. For the equilibrium data, the Freundlich model was the proper one. At 298 K, the maximum adsorption capacity was 77.61 mg g⁻¹. The adsorptive process was exothermic and spontaneous. MFAAF adsorbent was effective in removing 62.3% of coloration from the simulated effluent. Last, the regeneration test shows that the adsorbent can maintain the adsorption capacity during 5 cycles. These results indicate that the MAAF revealed the potential to be used as an adsorbent in industrial adsorption processes.

摘要

粉煤灰 (FA) 通过与 NaOH (MFAAF) 进行碱熔改性并用作吸附剂以去除水介质中的甲基紫 10B (MV10B)。发现碱熔体显着减少了 FA 的结晶相。FA和MFAAF主要由铝、硅和铁的氧化物组成。MFAAF的孔容和表面积值分别为0.154 ¹和65.4 m ² g ^-1，分别是前驱体材料的154和130倍。碱性融合导致形态发生变化，从球体变为未定义的形状。MFAAF 的 MV10B 去除率比 FA 高 8 倍，吸附量为 1 g L ^-1在 pH 值 7.5 时。准二级模型很好地描述了吸附动力学。对于均衡数据，Freundlich 模型是合适的模型。在 298 K 时，最大吸附容量为 77.61 mg g ^-1。吸附过程是放热和自发的。MFAAF 吸附剂可有效去除模拟流出物中 62.3% 的着色。最后，再生试验表明，吸附剂在 5 个循环期间可以保持吸附容量。这些结果表明，MAAF 揭示了在工业吸附过程中用作吸附剂的潜力。