Abstract

Excessive use of fossil fuels has accelerated climate change and global warming necessitates the need for renewable energy sources that have a lower environmental impact. In the recent decade, lignocellulosic biomass has become a prominent alternative to renewable energy resources for the production of bioenergy. The pretreatment procedure is considered a pivotal step for transforming biomass into value-added products such as sugars, biofuels, etc. Therefore, the present work aims to study the effect of different pretreatment approaches on rice husk with acids (H₂SO₄ and HCl), alkalis (NaOH and KOH), and organic solvents (ethanol and methanol) utilizing different concentrations like (2, 4 and 6% in case of acids), (2,4 and 6% for alkalis) and (50% and 70% for organic solvents) with different residence time (1, 3, 6, and 24 h). The most effective results obtained from the aforementioned steps were further adopted for enzymatic hydrolysis. Further, the changes in structural properties of biomass were assessed in relation to the pretreatment process employing scanning electron microscopy (SEM), X-ray diffraction (XRD), and Fourier Transform Infrared (FTIR) analyses. This paper also highlights the techno-economic analysis of alkali pretreatment. Additionally, the operational targets for the process were identified by using a modeling software-SuperPro Designer. Results obtained from the study showed a maximum yield of reducing sugar i.e., 1.906 ± 0.2 mg/ml (4% NaOH with 6 h of incubation). This study demonstrates that 4% NaOH pretreatment effectively disintegrates the biomass and yields high sugar recovery which can be used further for the production of biofuels and value-added products

摘要

化石燃料的过度使用加速了气候变化，全球变暖需要对环境影响较小的可再生能源。近十年来，木质纤维素生物质已成为可再生能源生产生物能源的重要替代品。预处理程序被认为是将生物质转化为糖、生物燃料等增值产品的关键步骤。因此，本工作旨在研究不同预处理方法对稻壳酸（H ₂ SO ₄和 HCl）、碱（NaOH 和 KOH）以及使用不同浓度的有机溶剂（乙醇和甲醇），例如（酸的情况下为 2%、4% 和 6%）、（碱的情况下为 2%、4% 和 6%）和（50%和 70% 的有机溶剂）具有不同的停留时间（1、3、6 和 24 小时）。从上述步骤中获得的最有效结果进一步用于酶水解。此外，还使用扫描电子显微镜 (SEM)、X 射线衍射 (XRD) 和傅立叶变换红外 (FTIR) 分析评估了与预处理过程相关的生物质结构特性的变化。本文还强调了技术经济分析碱预处理。此外，该过程的操作目标是通过使用建模软件 SuperPro Designer 确定的。从研究中获得的结果显示还原糖的最大产量，即 1.906 ± 0.2 mg/ml（4% NaOH，孵育 6 小时）。该研究表明，4% NaOH 预处理可有效分解生物质并产生高糖回收率，可进一步用于生产生物燃料和增值产品