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Agro-industries produce over 2 billion tons of agricultural waste annually, including by-products like bagasse, molasses, seeds, stems, leaves, straw, and shells. The use of agro-industrial waste is a way to reduce the impact of industrial processes on the environment. The pea pod is a biomass with a high concentration of cellulose, hemicellulose and some lignin; therefore, it can be used to produce platform chemicals by means of a hydrothermal process. There is limited research on the hydrolysis of pea biomass, but it has been shown to obtain high yields. This study analyzed the effectiveness and selectivity of the hydrothermal process using pea pod biomass with a particle size of 0.5 mm at 180 °C for one hour. A 500 mL reactor was used, with a biomass-to-acid solution ratio of 1:20. The concentration of the acid solution was 0.02 M. The concentrations of sugar, formic acid, levulinic acid, HMF, and furfural produced were measured. Among the catalysts studied, adipic acid catalysis showed the highest yield of 65.16%, with 37.09% of sugar, 16.37% of formic acid, and 11.71% of levulinic acid. On the other hand, the catalysts with chloroacetic acid, butyric acid, anthranilic acid, and phthalic acid were less effective but demonstrated selectivity for sugar production, proving that the liquid phase obtained using the catalyst with those acids can be used as carbon sources for a fermentation process. In general, when comparing the process with or without the use of a catalyst, it is observed that with a catalyst in the reaction, the amount of HMF and furfural produced is reduced and the selectivity with respect to sugar production is increased. [ABSTRACT FROM AUTHOR]

The valorization of coffee cherry waste through hydrothermal carbonization (HTC) was investigated using various organic and inorganic acid catalysts to produce platform chemicals. This study aimed to evaluate the effectiveness of these catalysts for enhancing reaction rates, improving yields, and promoting selectivity. The results showed that sulfuric acid and adipic acid were the most effective, each resulting in a 20% increase in the total yield, demonstrating the potential of organic acids as efficient catalysts in HTC. Other catalysts, such as benzoic acid and phenylacetic acid, also showed promising results, while butyric acid significantly decreased the total yield. The most abundantly produced platform chemicals were sugars, followed by formic acid, levulinic acid, HMF, and furfural. These findings highlight the potential of coffee cherry waste as a valuable resource for producing key chemicals, and the feasibility of hydrothermal carbonization as a sustainable approach for biomass valorization. This study emphasizes the importance of selecting the appropriate catalysts to optimize the conversion process and maximize the extraction of valuable chemicals. The environmental and economic implications of these findings are significant, as they can contribute to the development of sustainable and efficient biomass utilization technologies that could transform agricultural waste into high-value products while reducing waste and promoting a circular economy. [ABSTRACT FROM AUTHOR]

Milling pretreatment is a crucial step in the bioconversion of lignocellulosic biomass such sugarcane bagasse because it facilitates access to cellulose for subsequent chemical treatments. However, most experiments have been conducted at the laboratory scale, where it has been identified that high energy is required for the processing of biomass. For this reason, it is proposed to implement the screw extruder technique for the processing of cellulose. This article focuses on the characteristics, types, and applications of milling pretreatment for sugarcane bagasse, with a particular emphasis on its role in lignin removal and the milling design. Milling pretreatment reduces the particle size of lignocellulose biomass through compression shear and tearing mechanisms, which enhances the accessibility of cellulose and hemicellulose to enzymes and chemicals, thereby improving the efficiency of bioconversion processes. Innovative mathematical modeling, a mechanical design in a CAD application, and an FEA analysis of the milling pretreatment equipment are presented, providing insights into the design and optimization of milling pretreatment processes. This article presents an innovative potential system for milling pretreatment in sugarcane bagasse for the production of bioethanol, heat and power, and other value-added products, contributing to a more sustainable and circular economy. [ABSTRACT FROM AUTHOR]

The management of coffee and peapod waste presents significant environmental challenges, with millions of tons generated annually, leading to disposal issues and resource inefficiencies. Hydrothermal processes offer a promising valorization method, though biomass characteristics significantly influence the resulting products. Biomass characterization revealed distinct profiles for coffee cherry waste (moisture: 10.94%, ashes: 7.79%, volatile matter: 79.91%, fixed carbon: 1.36%, cellulose: 27.6%, hemicellulose: 12.5%, and lignin: 13.7%) and peapods (moisture: 7.77%, ashes: 4.22%, volatile matter: 74.18%, fixed carbon: 13.0%, cellulose: 20.2%, hemicellulose: 17.4%, and lignin: 5.0%). Experiments were conducted in 100 mL and 500 mL hydrothermal reactors with varying conditions for temperature (120–260 °C), time (1–4 h), stirring (none and at 5000 and 8000 rpm), biomass/water ratio (1:5, 1:10, 1:20, and 1:40), particle size (0.5–5 mm), and catalysts (acids and bases). The results showed that peapods produced over 30 times more platform chemicals than coffee. High temperatures (over 180 °C) degraded peapods, whereas coffee yields increased. Both biomasses were influenced similarly by reaction conditions: lower biomass/water ratios, smaller particle sizes, acid catalysts, and no stirring increased yields. Peapods consistently had higher yields than coffee in all conditions. Biochar analysis revealed anthracite from coffee and coal from peapods. [ABSTRACT FROM AUTHOR]

Ultrasonic pretreatment is a crucial step in the bioconversion of lignocellulosic biomass, such as peapods, into valuable products. Ultrasonic pretreatment is a highly effective physical method that utilizes ultrasonic waves to enhance various processes. Biomass pretreatment is achieved through physical effects such as acoustic cavitation, which disrupts the biomass structure, and chemical effects like radical formation, which breaks down complex molecules. This article focuses on the characteristics, types, and applications of ultrasonic pretreatment in peapods, with a particular emphasis on its role in lignin removal and ultrasound design. An innovative mechanical design in a CAD application of a continuous ultrasound treatment with a capacity of 5 L and an FEA analysis of the equipment are presented as results, providing insights for the design and optimization of ultrasonic pretreatment processes. [ABSTRACT FROM AUTHOR]

This study delves into the valorization of pea pod waste using hydrothermal processes, focusing on optimizing key parameters such as temperature, biomass-to-water ratio, particle size, and catalyst influence. Noteworthy findings include the significant impact of temperature variations on product yields, with 180 °C favoring sugars, HMF, and furfural, while 220 °C and 260 °C lead to distinct platform chemical productions. The utilization of a 1:20 biomass-to-water ratio consistently enhances yields by 10%, underscoring its importance in promoting efficient hydrolysis without excessive product degradation. Furthermore, the investigation into particle size reveals that smaller dimensions, particularly 1 mm particles, improved heat and mass transfer, reduced diffusion barriers, and enhanced digestibility, ultimately boosting overall efficiency in platform chemical production. Moreover, the study sheds light on the role of catalysts in the hydrothermal processes, showcasing the differential impact of acid and basic catalysts on product yields. Acid catalysts demonstrate a notable increase of up to 135.5% in the production of platform chemicals, emphasizing their crucial role in enhancing reaction efficiency. The complex relationship between agitation, temperature, and product formation is elucidated, with experiments revealing varying outcomes based on the presence or absence of agitation at different temperatures. These findings provide valuable insights into optimizing pea pod waste valorization, offering a pathway towards sustainable and efficient conversion of agricultural residues into valuable platform chemicals. [ABSTRACT FROM AUTHOR]

In Colombia alone, 12.6 million bags of green coffee are produced, but at the same time, 784,000 tons of waste biomass are dumped in open fields, of which only 5% is recovered or used, and 10 million tonnes of coffee emit 28.6 million tonnes of CO2 eq annually. This presents a worrying dilemma, and the need to develop a technology to transform the waste into usable products is increasing. As a response to this, the valorization of coffee waste was explored through the production of biochar and platform chemicals by implementing a set of hydrothermal experiments with different biomass/water ratios (1:5, 1:10, 1:20, 1:40), particle sizes (0.5, 1, 2, 5 mm), stirring rates (5000 and 8000 rpm), and catalysts (H2SO4, NaHCO3 and CH3COOH) at 180, 220, and 260 °C in a batch reactor with autogenous pressure. Notably, the smaller B:W ratios of 1:20 and 1:40, as well as smaller particle sizes of 0.5 and 1 mm, yielded higher amounts of platform chemicals, while stirring showed minimal influence. CH3COOH significantly enhanced the process compared to other catalysts. The biochar was characterized as anthracite, and this obtaining of coal-like materials from biomass itself represents a remarkable feat. Said anthracite presented little to no variation in physical parameters, while catalysts induced functionalization. By optimizing factors like B:W ratio, particle size, and catalyst application, valuable insights have been gained into enhancing the yield of platform chemicals and quality of biochar from coffee waste. The findings not only contribute to sustainable waste management practices but also highlight the importance of exploring innovative solutions for utilizing agricultural by-products effectively. [ABSTRACT FROM AUTHOR]

The generation of platform chemicals and hydrochar is of great interest because they reduce dependence on fossil resources and contribute to climate change mitigation by reducing carbon emissions. The main objective of this study was to evaluate the effect of biomass particle size and biomass-to-water ratio in a hydrothermal conversion system for the generation of value-added products obtained from sugarcane bagasse. Biomass characterization was performed using proximal, elemental, and structural analysis; hydrothermal carbonization was carried out at 220 and 260 °C for one hour; and conversion was monitored using pH, conductivity, and IR spectroscopy. Platform chemicals were quantified using HPLC-IR. Hydrochars were characterized by using scanning electron microscopy and energy dispersive spectroscopy. Optimizing biomass particle size and water ratio is crucial for maximizing the yield of platform chemicals and hydrochar. The study's outcomes revealed that specific combinations, such as a biomass-to-water ratio of 1:50 and a particle size of 212 μm at 220 °C, resulted in a substantial 31.07% yield of platform chemicals on a dry basis. This highlights the critical role these parameters play in influencing the production efficiency of valuable chemicals. Furthermore, variations in biomass particle size and water ratio also affect the characteristics of hydrochar. For instance, utilizing a biomass-to-water ratio of 1:50 and a larger particle size of 600 μm at 260 °C led to the production of hydrochar with higher carbon content and increased porosity. These findings underscore how adjustments in these factors can impact not only chemical yields, but also the properties and quality of the resulting hydrochar. [ABSTRACT FROM AUTHOR]

Colombia is the world's leading producer of mildly washed arabica coffee and produces 12.6 million bags of green coffee, but at the same time, 784,000 tons of waste biomass are dumped in open fields, of which only 5% is recovered or used. The objective of this project was to evaluate the production of platform chemicals from these coffee wastes for sustainable resource management. To achieve this, biomass characterization was carried out using proximate analysis, ultimate analysis, and structural analysis. Hydrothermal valorization was carried out at a temperature range of 120–180 °C (LHW) and 180–260 °C (HTC) for one hour. The platform chemicals obtained were quantified by HPLC-RI and monitored by pH and conductivity, and the solid fraction was characterized by monitoring the functional groups in IR spectroscopy and elemental analysis. Hydrolysis processes were obtained at 150 °C, production of platform chemicals at 180 °C, and maximum concentration at 180 °C-4 h; over 200 °C, degradation of the products in the liquid fraction starts to take place. Homogeneous basic and acid catalysts were used to improve the yields of the reaction. The kinetics of the hydrolysis of lignocellulosic structures to sugars were also analyzed and described, and reaction orders of 1 (LHW), 3 (HTC), and their respective reaction rate equations were reported. [ABSTRACT FROM AUTHOR]

Featured Application: obtention of biofuels and platform molecules from agricultural waste. Pea pod cultivation spans various regions and climates, with a global production of around 20 million tons. The pea peel wastes, which make up 30–40% of the total weight of the peas, are freely available in large quantities. The biomass used was characterized via ultimate, proximate, and structural analysis, obtaining 20.2%w of cellulose and 17.4%w of hemicellulose, which, via valorization processes, can be transformed into platform chemicals. Hydrothermal valorization presents itself as a clean form of treatment for these wastes, ranging from 120 to 180 °C (LHW) and from 180 to 260 °C (HTC). The use of LHW can lead to the production of sugars (up to 70%w yield) and levulinic acid (4%w yield), while the use of HTC leads to formic acid (40%w yield) and levulinic acid (4%w yield). The use of LHW for longer periods favors the production of HMF and furfural. The use of homogeneous catalysts (H2SO4, CH3COOH, KOH, and NaHCO3) was implemented, and their selectivity was described. Solid fractions of LHW and HTC were characterized via FTIR and elemental analysis, and the change in their structure was described as they shifted from biomass to biochar. Optimal conditions for each platform chemical were reported to best utilize the pea pod waste. [ABSTRACT FROM AUTHOR]

Transition metal oxides (TMO) have been successfully used as electrocatalytically active materials for CO2 reduction in some studies. Because of the lack of understanding of the catalytic behavior of TMOs, electrochemical methods are used to investigate the CO2 reduction in thin-film nanostructured electrodes. In this context, nanostructured thin films of Fe2O3 and MoO3 in an aprotic medium of acetonitrile have been used to study the CO2 reduction reaction. In addition, a synergistic effect between CO2 and the TMO surface is observed. Faradic cathodic processes not only start at lower potentials than those reported with metal electrodes, but also an increase in capacitive currents is observed, which is directly related to an increase in oxygen vacancies. Finally, the results obtained show CO as a product of the reduction. [ABSTRACT FROM AUTHOR]

This document presents a brief history of catalysis, as well as of the selective oxidation processes of hydrocarbons. On the other hand, the basic concepts involved in heterogeneous catalysis are addressed, emphasizing the role of catalytic materials in chemical oxidation processes and posing a series of guiding questions that must be followed when addressing a process catalyzed by solid materials. In the same way, the preparation methods known in the literature as sol-gel and impregnation are shown, identifying the influence of each preparation step with the physical and chemical properties of the materials. Finally, a case study applied to the selective catalytic oxidation of methane and methanol using iron, molybdenum, and vanadium catalytic materials synthesized by the sol-gel method is presented. [ABSTRACT FROM AUTHOR]