Abundant availability and large silica content in rice husk black ash (RHBA) make the use of it very interesting to study. Many works only deal with lab-scale rice husk ash extraction while the studies on bench-scale RHBA extraction are still limited. This study, hence, presents the influence of pretreatment, extraction variables, and posttreatment on bench-scale RHBA processing to bio-silica. The pretreatment through acid leaching was carried out using HCl. The extraction was implemented under varying process variables such as alkaline-to-feed ratio (R_A/F), extraction duration, and acid precipitation agent. According to this study, the highest extraction yield up to 98% was gained under R_A/F 6 g/g and 1-h extraction. The amorphous bio-silica had an asymmetric siloxane bond and white appearance with a purity exceeding 95% and surface area up to 406.98 m²/g. Meanwhile, precipitation under HCl and H₂SO₄ had little impact on product purity and surface area. This study exhibits that acid leaching is executed to release mineral impurities but is still not sufficient to remove the remaining carbon content in bio-silica. However, the contribution of refining process is able to do so. Moreover, the produced bio-silica is suitable for adsorbent purposes which could adsorb up to 83.5% of 3-monochloropropanediol compound.

中文翻译：

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预处理、提取变量和后处理对小规模稻壳黑灰 (RHBA) 加工生物二氧化硅的影响

稻壳黑灰 (RHBA) 中丰富的可利用性和大量的二氧化硅使得使用它进行研究非常有趣。许多工作只涉及实验室规模的稻壳灰提取，而对实验室规模的 RHBA 提取的研究仍然有限。因此，本研究介绍了预处理、提取变量和后处理对实验室规模 RHBA 加工生物二氧化硅的影响。使用盐酸进行酸浸预处理。萃取是在不同的工艺变量下进行的，例如碱进料比 (R _A/F )、萃取持续时间和酸沉淀剂。根据这项研究，在 R _A/F下获得了高达 98% 的最高提取率6 g/g 和 1 小时萃取。无定形生物二氧化硅具有不对称硅氧烷键和白色外观，纯度超过95%，表面积高达406.98 m ² /g。同时，在 HCl 和 H ₂ SO ₄下的沉淀对产品纯度和表面积影响不大。该研究表明，酸浸可以释放矿物杂质，但仍不足以去除生物二氧化硅中剩余的碳含量。然而，炼化工艺的贡献却是能够做到这一点。此外，所生产的生物二氧化硅适用于吸附用途，可吸附高达83.5%的3-一氯丙二醇化合物。