Rice husk-based solid acid for efficient hydrolysis and saccharification of corncob

MS-Based Characterization of Biomass-Derived Materials: Activated Carbons and Solvent Liquefaction Products

Mass spectrometry (MS) is a powerful analytical technique that is widely used to characterize a variety of analytes across diverse fields. In the area of biomass conversion, which is essential for producing sustainable materials and energy, the role of MS is pivotal. Biomass conversion processes, such as solvent liquefaction and pyrolysis, generate a wide range of industrially valuable materials including bio-based polymers, fuels, and activated carbons. However, the inherent complexity and heterogeneity of biomass and its transformation products pose significant analytical challenges. Advanced MS techniques, such as GC-MS, LC-MS, ICP-MS and MALDI-MS, are essential for a comprehensive analysis, providing detailed insights into the compositions, impurities, and potential inhibitors that influence process optimization and product quality. This review systematically explores recent advancements in MS-based methods for the analysis of biomass-derived products. We discuss fundamental innovations in biomass conversion processes and highlight the applications of various MS techniques in assessing the chemical complexity of these materials. The insights provided by MS techniques not only facilitate process optimization but also support the sustainable production of high-value materials from biomass, aligning with ongoing efforts to enhance environmental sustainability and resource efficiency.

Insights into Preparation Methods and Functions of Carbon-Based Solid Acids

With the growing emphasis on green chemistry and the ecological environment, researchers are increasingly paying attention to greening materials through the use of carbon-based solid acids. The diverse characteristics of carbon-based solid acids can be produced through different preparation conditions and modification methods. This paper presents a comprehensive summary of the current research progress on carbon-based solid acids, encompassing common carbonization methods, such as one-step, two-step, hydrothermal, and template methods. The composition of carbon source material may be the main factor affecting its carbonization method and carbonization temperature. Additionally, acidification types including sulfonating agent, phosphoric acid, heteropoly acid, and nitric acid are explored. Furthermore, the functions of carbon-based solid acids in esterification, hydrolysis, condensation, and alkylation are thoroughly analyzed. This study concludes by addressing the existing drawbacks and outlining potential future development prospects for carbon-based solid acids in the context of their important role in sustainable chemistry and environmental preservation.

Biochar-based solid acid accelerated carbon conversion by increasing the abundance of thermophilic bacteria in the cow manure composting process

This study investigated the effects of biochar-based solid acids (SAs) on carbon conversion, alpha diversity and bacterial community succession during cow manure composting with the goal of providing a new strategy for rapid carbon conversion during composting. The addition of SA prolonged the thermophilic phase and accelerated the degradation of lignocellulose; in particular, the degradation time of cellulose was shortened by 50% and the humus content was increased by 22.56% compared with the control group (CK). In addition, high-throughput sequencing results showed that SA improved the alpha diversity and the relative abundance of thermophilic bacteria, mainly Actinobacteria, increased by 12.955% compared with CK. A redundancy analysis (RDA) showed that Actinobacteria was positively correlated with the transformation of carbon.

Effect of substrate load on anaerobic fermentation of rice straw with rumen liquid as inoculum: Hydrolysis and acidogenesis efficiency, enzymatic activities and rumen bacterial community structure

Rumen liquid is excellent to effectively degrade lignocellulose. In this study, the suitable rice straw load during anaerobic fermentation of rice straw with rumen liquid as inoculum was explored to improve volatile fatty acid (VFA) production. At 10.0% rice straw load, the highest VFA concentration reached 10821.4 mg/L, and acetic acid and propionic acid were the main components. In 10.0% rice straw load system, high concentration of soluble chemical oxygen demand (SCOD) was also observed, and the enzymatic activities at 48 h were higher than those at other rice straw loads. At 10.0% rice straw load, lower diversity and richness of rumen bacteria were found than those at other rice straw loads. Bacteroides, Prevotella, and Ruminococcus were the main rumen bacteria during rice straw degradation, and the rumen bacteria might secret effective lignocellulolytic enzymes to enhance the hydrolysis and acidogenesis of rice straw. The determination of suitable rice straw load will be beneficial to the application of rumen liquid as inoculum in actual production.

Sulfonated Sargassum horneri carbon as solid acid catalyst to produce biodiesel via esterification

A solid acid catalyst prepared by sulfonated Sargassum horneri carbon was utilized for the esterification reaction of oleic acid and methanol. The formed amorphous carbon layers during carbonization and the access of sulfonic acid groups during sulfonation can catalyze the esterification reaction for biodiesel preparation efficiently. The catalyst was characterized by various methods to investigate its physical and chemical properties. With carbonization at 300 °C for 2 h followed by sulfonation at 90 °C for 5 h, the catalyst reached acid density of 1.40 mmol/g. The catalyst dosage, methanol/oleic acid (molar ratio), reaction temperature, and reaction time were optimized to 10 wt%, 15:1, 70 °C, and 3 h, respectively. Under the optimal condition, the conversion of oleic acid reached 96.4%. Additionally, the catalyst was regenerated after four cycles, with the conversion of oleic acid still reaching 95.4%.

Synthesis of a Stable Solid Acid Catalyst from Chloromethyl Polystyrene through a Simple Sulfonation for Pretreatment of Lignocellulose in Aqueous Solution

A stable solid acid catalyst, SCPR140-1, was synthesized from chloromethyl polystyrene resin (CPR) and used for catalytic pretreatment of corncob in aqueous solution. Under the optimized pretreatment condition, 73.07 % of xylose was directly obtained, and the enzymatic digestibility of treated residue reached up to 94.65 %, indicating that the SCPR140-1 had high selectivity for xylose production and effectively deconstructed the structure of corncob. The -CH₂ Cl group of CPR was substituted by -SO₃ H through the sulfonation, and the -SO₃ H was stably bound on the catalyst during the pretreatment process. Compared with other similar reports, the SCPR140-1 was not only synthesized through a simpler process but also had a more stable catalytic activity during multiple recycling runs.

Acid site-regulated solid acids for polysaccharide Se-functionalization: Structural explanations for high reactivity

In this work, the application of acid site-regulated solid acids in Se-functionalization of polysaccharide is evaluated for the first time, which aimed to further improve reaction efficiency and realize environmentally friendly chemistry. A series prepared M_xO_y/HZSM-5 catalysts possesses standard crystal structure, large specific surface area, pore volume, aperture as well as strong acidity. An efficient substitution of seleno-group on polysaccharide backbone is promoted by regulating the acid site of solid acids (Se content up to 15,170.49 μg/g) compared with the conventional Se-functionalization method (1703 μg/g). Strong Lewis and Brønsted acid sites lead to the driving forces toward low molecular mass polysaccharide fragments, but the deletion of main monosaccharide components is not observed. In summary, it is proved that solid acid can be employed in acid-dependent polysaccharide Se-functionalization which will promote useful in expanding our understanding of how to further develop polysaccharide resources.

Thermal effects

This review paper focuses on the researches published in 2019 in the field of thermal effects in wastewater and solid waste treatment. The content of this review paper includes five parts: wastewater and sludge treatment, nutrient removal and recovery, membrane technology, heavy metal removal and immobilization, and organic waste utilization. © 2020 Water Environment Federation PRACTITIONER POINTS: Thermal effect plays an important role in treatment of wastewater and sewage sludge. Recovery of nitrogen and phosphorus from wastewater and sewage sludge reduces environmental pollution and offers new products. Temperature improves removal and recovery of heavy metals and organic wastes.

Hydrolysis of Corncob Hemicellulose by Solid Acid Sulfated Zirconia and Its Evaluation in Xylitol Production

Corncob is an abundant agricultural residue containing high content of hemicellulose. In this paper, the hemicellulosic hydrolysate was prepared from the hydrolysis of corncob using the solid acid sulfated zirconia as a catalyst. According to response surface analysis experiments, the optimum conditions for preparing hemicellulosic hydrolysate catalyzed by sulfated zirconia were determined as follows: solid (sulfated zirconia)-solid (corncob) ratio was 0.33, solid (corncob)-liquid (water) ratio was 0.09, temperature was 153 °C, and time was 5.3 h. Under the optimized conditions, the soluble sugar concentration was 30.12 g/L with a yield of 033 g/g corncob. Subsequently, xylitol production from the resulting hemicellulosic hydrolysate was demonstrated by Candida tropicalis, and results showed that the yield of xylitol from the hemicellulosic hydrolysate could be significantly improved on a basis of decolorization and detoxification before fermentation. The maximum yield of xylitol from the hemicellulosic hydrolysate fermented by C. tropicalis was 0.76 g/g. This study provides a new attempt for xylitol production from the hemicellulosic hydrolysate.

Deciphering the mechanism of carbon sources inhibiting recolorization in the removal of refractory dye: Based on an untargeted LC-MS metabolomics approach

In this study, the biological decolorization of reactive black 5 (RB5) by Klebsiella sp. KL-1 in yeast extract (YE) medium was captured the recolorization after exposure to O₂, which induced a 15.82% reduction in decolorization efficiency. Similar result was also observed in YE + lactose medium, but not in YE + glucose/xylose media (groups YE + Glu/Xyl). Through biodegradation studies, several degradation intermediates without quinoid structure were produced in groups YE + Glu/Xyl and differential degradation pathways were deduced in diverse groups. Metabolomics analysis revealed significant variations in up-/down-regulated metabolites using RB5 and different carbon sources. Moreover, the underlying mechanism of recolorization inhibition was proposed. Elevated reducing power associated with variable metabolites (2-hydroxyhexadecanoic acid, 9(R)-HODE cholesteryl ester, linoleamide, oleamide) rendered additional reductive cleavage of C-N bond on naphthalene ring. This study provided a new orientation to inhibit recolorization and deepened the understanding of the molecular mechanism of carbon sources inhibiting recolorization in the removal of refractory dyes.

Integrated process for the production of fermentable sugar and methane from rubber wood

Pretreatment is required for the enhancement of the bioconversion of lignocellulosic biomass. This study aimed to develop an integrated process producing efficient biochemical conversion of rubber wood waste (RW) into co-biofuels, fermentable sugar and methane. The glucan conversion was enhanced to 93.8% with temperature (210 °C) and delignification by organosolv pretreatment (OS). Thereafter, anaerobic digestion of the residue left after enzymatic hydrolysis was conducted which further improved the methane yield (205.5 LCH₄/kg VS) by 33% over hydrothermal pretreatment (154.3 LCH₄/kg VS). Delignification during OS plays a key role in improving the degradability of RW resulting in efficient energy recovery (11.23 MJ/kg pretreated RW) which was clearly higher than an integrated process based on hydrothermal (HT) or HT plus process water. Scaled up to a biorefinery, the integrated process based on OS would economically produce fermentable sugar while other value-added chemicals might be produced from the process water.