Search

Sub‐micro organosolv lignin (OBs) isolated from beechwood biomass, comprising of sub‐micro sized particles (570 nm) with low molecular weight and dispersity and relatively high total phenolic −OH content, is utilized for the production of bio‐based epoxy polymer composites. OBs lignin is incorporated into the glassy epoxy system based on diglycidyl ether of bisphenol A (DGEBA) and aliphatic polyoxypropylene α,ω‐diamine (Jeffamine D‐230), being utilized both as a curing agent, partially replacing D‐230, and as an additive, substituting part of both petroleum‐derived components. Up to 12 wt % replacement of D‐230 by OBs lignin is achieved, whereas approximately 17 wt % of OBs effectively replaces the conventional epoxy polymer. The incorporation of OBs lignin in the polymeric matrix is achieved without the use of any solvent or previous functionalization. Enhanced properties are obtained, with substantial increases in tensile strength, strain, stiffness, glass transition temperature, antioxidant activity, and resistance to solvents. [ABSTRACT FROM AUTHOR]

Textile effluents pose a massive threat to the aquatic environment, so, sustainable approaches for environmentally friendly multifunctional remediation methods degradation are still a challenge. In this study, composites consisting of bismuth oxyhalide nanoparticles, specifically bismuth oxychloride (BiOCl) nanoplatelets, and lignin-based biochar were synthesized following a one-step hydrolysis synthesis. The simultaneous photocatalytic and adsorptive remediation efficiency of the Biochar–BiOCl composites were studied for the removal of a benchmark azo anionic dye, methyl orange dye (MO). The influence of various parameters (such as catalyst dosage, initial dye concentration, and pH) on the photo-assisted removal was carried out and optimized using the Box–Behnken Design of RSM. The physicochemical properties of the nanomaterials were characterized by scanning electron microscopy, energy-dispersive X-ray spectroscopy, X-ray diffraction, thermogravimetric analysis, nitrogen sorption, and UV–Vis diffuse reflectance spectroscopy (DRS). The maximum dye removal was observed at a catalyst dosage of 1.39 g/L, an initial dye concentration of 41.8 mg/L, and a pH of 3.15. The experiment performed under optimized conditions resulted in 100% degradation of the MO after 60 min of light exposure. The incorporation of activated biochar had a positive impact on the photocatalytic performance of the BiOCl photocatalyst for removing the MO due to favorable changes in the surface morphology, optical absorption, and specific surface area and hence the dispersion of the photo-active nanoparticles leading to more photocatalytic active sites. This study is within the frames of the design and development of green-oriented nanomaterials of low cost for advanced (waste)water treatment applications. [ABSTRACT FROM AUTHOR]

Fluid Catalytic Cracking (FCC) has traditionally been a key refining process in generating transportation fuels. Recently, the focus on FCC has been further intensified as it plays an increasingly important role in the generation of key building blocks for the petrochemical industry. Nickel is considered as one of the most challenging contaminants in FCC and originates from Ni-containing compounds in petroleum fractions, not only during unit operation but also in handling of the equilibrium and spent catalysts. Despite this critical role it plays throughout the complete lifecycle of an FCC catalyst, the nature of Ni is not yet well understood at various stages of its journey after depositing on the catalyst surface. The main objective of this contribution is the qualitative and quantitative identification of the various possible phases of Ni that are usually present in an equilibrium FCC catalyst (Ecat). A series of conventional and advanced analytical techniques have been employed, including XRF, ICP-AES, PXRD, FT-IR, UV-Vis-NIR, SEM-EDS, TEM/HRTEM and STEM/EXDS, XPS, RAMAN and TPR-H2, on prototype Ni-impregnated SiO2, Al2O3 and USY zeolite samples, Ni-impregnated and lab-deactivated FCC samples, and equilibrium FCC catalysts obtained from different refineries. Detailed analysis of the obtained results on the basis of background information, showed the strengths and weaknesses of the various methods. It was shown that powder x-ray diffraction (pxrd) can be effectively used for the quantitative determination of the NiO (bunsenite) phase at levels representative of equilibrium FCC catalysts. A comparison of conventional versus boron-based Ni-passivation is presented. It was shown that catalysts from boron-based technology (BBT) can keep Ni at a less-reducible state, effectively hindering its deleterious role in FCC operations. [ABSTRACT FROM AUTHOR]

This review sheds light on urgent questions that arise from the need to replace a polymer resin,–poly(ethylene terephthalate), which represents 7.7% market-share in the global plastic demand (Plastics–the Facts 2019), by renewable alternatives. The main question that this review will address is: what are the most promising PET replacements made from biomass? Currently, under debate is naturally its biobased counterpart bio-PET (or even recycle rPET), as well as other aromatic key-players with comparable thermo-mechanical performance and enhanced barrier properties, such as poly(ethylene 2,5-furandicarboxylate) (PEF) and poly(trimethylene 2,5-furandicarboxylate) (PTF). They are most adequate for packaging, but not restricted to. Additional alternatives are the miscellaneous of lignin-based thermoplastic polymers, although the technology involved in this latter case is still premature. (Bio)degradable aliphatic polyesters, despite their typical inferior thermo-mechanical properties, can also play a role e.g., among PET fiber industry applications. Poly(lactic acid) (PLA) is the most developed renewable polyester, already a commercial reality. All biobased polymers reviewed face a major hindrance for their wider deployment their cost-competitiveness. A pertinent question arises then: Are these alternatives, or will they be, economically feasible? Social, political and legal frameworks together with supportive financial schemes are boosting rapid changes. In the future, most probably more than one polymer will come to the market and will be used in some of the panoply of PET applications. This evaluation overviews sustainability issues, including perspectives on their green synthesis. Moreover, this review does also not neglect the accumulation of plastics waste in the environment and the inherent challenges of polymers' end-of-life. Approximately 8 M tons of polymers waste leaks into the environment each year, a fact not disconnected to PET's non-biodegradability and still insufficient collection and recycling rates. [ABSTRACT FROM AUTHOR]

Sustainable production of bio-based materials and chemicals requires integrated approaches which utilize all fractions of lignocellulosic biomass. In this work, highly crystalline cellulose was isolated via combined pretreatment/fractionation and extraction processes from beechwood sawdust. The proposed approach was based on the selective recovery of hemicellulose components in the first step, followed by enhanced delignification in the second step, permitting the efficient recovery of the remaining cellulose via bleaching in the final step. Hydrothermal pretreatment under tailored conditions in neat water or dilute acid resulted in almost complete hemicellulose removal (80-96 wt %) in the liquid fraction. In the second step, the formed surface lignin was isolated via mild extraction while enhanced removal of both native/structural and surface lignin (71 wt %) was achieved by applying the organosolv treatment using dilute sulfuric acid as catalyst. Dilute sulfuric acid pretreatment followed by acid catalyzed organosolv pretreatment proved to be the most efficient combined approach, leading to 80 wt % hemicellulose removal as xylose monomer, and 71 wt % delignification. High crystallinity cellulose (<88%), with an overall cellulose recovery of 68-91 wt % based on native cellulose in parent biomass was isolated in the last step via bleaching of all pretreated biomass solids. The proposed integrated biorefinery procedures that aim to whole "waste" biomass valorization, replacing fossil resources, with the use of green solvents (water, ethanol) at relatively mild temperature/pressure conditions, are in line with the scope of several United Nations Sustainable Development Goals, such as UN SDG 8, 11, 12, and 13., Competing Interests: The authors declare no competing financial interest., (© 2024 The Authors. Published by American Chemical Society.)