This study aims to find an alternative method to the landfill of spent bleaching earth (SBE), which is a solid waste generated by the refining of edible oil that causes enormous ecological and environmental problems. This solid waste is clay loaded with impurities, colourants, and a large amount of oil entrained during the various stages of refining. In this study, the SBE was initially regenerated (RSBE) by thermal processing in a muffle furnace (temperature: 400°C, time: 1 h) followed by washing with an HCl solution. Then, the regenerated materials were encapsulated with calcium alginate (Alg) to form adsorbent composite beads (Alg-RSBE). Different Alg/RSBE ratios were applied during materials elaboration, yielding beads denoted Alg-RSBE 1/1 (1/1, w/w), Alg-RSBE 1/2 (1/2, w/w), and Alg-RSBE 1/3 (1/3, w/w), respectively. The Alg–RSBE composite beads were characterized by several methods (FTIR, SEM, EDX, TGA, pH_PZC) and used as adsorbents of methylene blue (MB) in a fixed-bed adsorption system. The adsorption of MB was studied at different experimental conditions such as contact time and initial MB concentration. The results showed that the kinetics of MB adsorption fitted to pseudo-second-order kinetics and the adsorption isotherm fitted to Langmuir isotherm. Among the three types of Alg-RSBE composite beads, Alg-RSBE 1/1 presents the highest MB adsorption capacity at 833.33 mg/g. Intraparticle and film diffusion equations were used to evaluate the kinetic data. Finally, the regeneration study showed that MB dye was successfully desorbed from Alg-RSBE 1/1 with removal percentages from 93.32% to 88.15% after six cycles.

中文翻译：

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海藻酸钙再生废漂白土复合微珠高效去除亚甲蓝

本研究旨在寻找一种替代方法来替代废漂白土 (SBE) 的垃圾填埋场，SBE 是食用油精炼过程中产生的固体废物，会导致巨大的生态和环境问题。这种固体废物是含有杂质、着色剂和在精炼的各个阶段夹带的大量油的粘土。在这项研究中，SBE 最初通过在马弗炉中热处理（温度：400°C，时间：1 小时）进行再生 (RSBE)，然后用 HCl 溶液洗涤。然后，将再生材料用海藻酸钙（Alg）包封，形成吸附剂复合珠（Alg-RSBE）。在材料加工过程中应用了不同的 Alg/RSBE 比率，产生的珠子表示为 Alg-RSBE 1/1 (1/1, w/w )、Alg-RSBE 1/2 (1/2, w/w) 和 Alg-RSBE 1/3 (1/3, w/w )。Alg-RSBE 复合珠通过多种方法（FTIR、SEM、EDX、TGA、pH _PZC) 并在固定床吸附系统中用作亚甲基蓝 (MB) 的吸附剂。在不同的实验条件下研究了 MB 的吸附，例如接触时间和初始 MB 浓度。结果表明，MB吸附动力学符合准二级动力学，吸附等温线符合Langmuir等温线。在三种 Alg-RSBE 复合珠中，Alg-RSBE 1/1 的 MB 吸附容量最高，为 833.33 mg/g。颗粒内和膜扩散方程用于评估动力学数据。最后，再生研究表明，MB 染料成功地从 Alg-RSBE 1/1 上解吸出来，六次循环后去除率从 93.32% 提高到 88.15%。