Advanced separation strategies for up-gradation of bio-oil into value-added chemicals: A comprehensive review

Hydrothermal conversion of biomass to fuels, chemicals and materials: A review holistically connecting product properties and marketable applications

Biomass is a renewable and carbon-neutral resource with good features for producing biofuels, biochemicals, and biomaterials. Among the different technologies developed to date to convert biomass into such commodities, hydrothermal conversion (HC) is a very appealing and sustainable option, affording marketable gaseous (primarily containing H₂, CO, CH₄, and CO₂), liquid (biofuels, aqueous phase carbohydrates, and inorganics), and solid products (energy-dense biofuels (up to 30 MJ/kg) with excellent functionality and strength). Given these prospects, this publication first-time puts together essential information on the HC of lignocellulosic and algal biomasses covering all the steps involved. Particularly, this work reports and comments on the most important properties (e.g., physiochemical and fuel properties) of all these products from a holistic and practical perspective. It also gathers vital information addressing selecting and using different downstream/upgrading processes to convert HC reaction products into marketable biofuels (HHV up to 46 MJ/kg), biochemicals (yield >90 %), and biomaterials (great functionality and surface area up to 3600 m²/g). As a result of this practical vision, this work not only comments on and summarizes the most important properties of these products but also analyzes and discusses present and future applications, establishing an invaluable link between product properties and market needs to push HC technologies transition from the laboratory to the industry. Such a practical and pioneering approach paves the way for the future development, commercialization and industrialization of HC technologies to develop holistic and zero-waste biorefinery processes.

Spotlighting of the role of catalysis for biomass conversion to green fuels towards a sustainable environment: Latest innovation avenues, insights, challenges, and future perspectives

Recently, extensive resources were dedicated to studying how to use catalysis to convert biomass into environmentally friendly fuels. Problems with this technology include the processing of lignocellulosic sources and the development/optimization of novel porous materials as efficient monofunctional and bifunctional catalysts for biomass fuel production. This paper reviews recent advancements in catalysts procedures. Besides, it offers assessments of the methods used in catalytic biomass pyrolysis. Understanding the catalytic conversion process of lignocellulosic biomass into bio-oil remains a key research challenge in biomass catalytic pyrolysis.

Catalytic pyrolysis for upgrading silver grass (Miscanthus sinensis) and carbon dioxide into flammable gases

This study proposes a sustainable hydrogen production platform using a fast-growing and inedible biomass waste, silver grass (Miscanthus sinensis). Pyrolysis of silver grass waste (SGW) was investigated using CO₂ as a co-feedstock, focusing on the distribution of hydrogen in different products. When the catalyst was absent, hydrogen element distribution to H₂ gas during pyrolysis of SGW at 800 °C reached 10 wt%. During pyrolysis with the Ni/SiO₂ catalyst, 60.3 wt% of hydrogen was converted into H₂ gas, and 7.3 wt% of hydrogen was distributed in gaseous hydrocarbons at 600 °C. Owing to the addition of CO₂, CO production was promoted by the catalytic conversion of CO₂ and volatile matter. Notably, CO₂ has been proven to be a useful reactant for producing value-added CO. Thus, catalytic pyrolysis in the presence of CO₂ can be considered as a renewable approach to produce flammable gases with the mitigation of CO₂ emissions.

Valorization of Hazardous Materials along with Biomass for Green Energy Generation and Environmental Sustainability through Pyrolysis

Increased population growth, industrialization, and modern culture create a variety of consequences, including environmental pollution, heavy metal accumulation, and decreasing energy resources. This perilous position necessitates the development of long-term energy resources and strategies to address environmental threats and power shortages. In this study, an investigation into the use of castor seed oil cake and waste tyres as a feed material for the copyrolysis process for yielding maximum oil production was performed. The copyrolysis experiments were performed by changing the mass percentage of waste tyres with oil cake to make different ratios of 100 : 0, 75 : 25, 50 : 50, 25 : 75, and 0 : 100. At 50 : 50 ratio, the maximum positive synergy on oil production was obtained. At that condition, a maximum of 59.8 wt% oil was produced and characterized to analyze its physiochemical properties. The coprocessing of the selected two feed materials enables the stabilization of the oil, as the produced oil has a lower oxygen content with a maximum heating value of 38.72 MJ/kg. The Fourier transform infrared spectroscopy (FTIR) and gas chromatography-mass spectrometry (GC-MS) analysis of the oil showed the existence of aromatic hydrocarbons and phenolic elements. Adding waste tyres to the biomass improved the quality of the oil by increasing carbon content with reduced oxygen content.

Upcycling agro-industrial blueberry waste into platform chemicals and structured materials for application in marine environments

Blueberry pruning waste (BPw), sourced as residues from agroforestry operations in Chile, was used to produce added-value products, including platform chemicals and materials. BPw fractionation was implemented using biobased solvents (γ-valerolactone, GVL) and pyrolysis (500 °C), yielding solid fractions that are rich in phenols and antioxidants. The liquid fraction was found to be enriched in sugars, acids, and amides. Alongside, filaments and 3D-printed meshes were produced via wet spinning and Direct-Ink-Writing (DIW), respectively. For the latter purpose, BPw was dissolved in an ionic liquid, 1-ethyl-3-methylimidazolium acetate ([emim][OAc]), and regenerated into lignocellulose filaments with highly aligned nanofibrils (wide-angle X-ray scattering) that simultaneously showed extensibility (wet strain as high as 39%). BPw-derived lignocellulose filaments showed a tenacity (up to 2.3 cN dtex^-1) that is comparable to that of rayon fibers and showed low light reflectance (R _ES factor <3%). Meanwhile, DIW of the respective gels led to meshes with up to 60% wet stretchability. The LCF and meshes were demonstrated to have reliable performance in marine environments. As a demonstration, we show the prospects of replacing plastic cords and other materials used to restore coral reefs on the coast of Mexico.

Lipid Extracts Obtained by Supercritical Fluid Extraction and Their Application in Meat Products

Supercritical fluid extraction (SFE) has been recognized as the green and clean technique without any negative impact on the environment. Although this technique has shown high selectivity towards lipophilic bioactive compounds, very few case studies on the application of these extracts in final products and different food matrices were observed. Considering the recent developments in food science and the increasing application of supercritical extracts in meat products in the last decade (2012–2022), the aim of this manuscript was to provide a systematic review of the lipid extracts and bioactives successfully obtained by supercritical fluid extraction and their application in meat products as antioxidant and/or antimicrobial agents. Lipophilic bioactives from natural resources were explained in the first step, which was followed by the fundamentals of supercritical fluid extraction and application on recovery of these bioactives. Finally, the application of natural extracts and bioactives obtained by this technique as functional additives in meat and meat products were thoroughly discussed in order to review the state-of-the-art techniques and set the challenges for further studies.