Biofuels Bioproducts & Biorefining-Biofpr最新文献

The USA has significant potential to produce energy from anaerobic digesters (AD) due to the size of its agricultural sector. The use of ADs reduces greenhouse gas (GHG) emissions from manure management. The financial benefits to farmers come from the on-farm use, or off-farm sales, of biogas and its end products, namely renewable natural gas (RNG) or electricity. Current energy prices and policies in the USA are insufficient to trigger large-scale construction of ADs; however, payments to avoid GHG emissions and sequester carbon could become sufficiently high to prompt investment. This analysis quantifies the economic incentives necessary for the construction of ADs for swine producers and can easily be expanded to include other feedstocks. Various end-use pathways to produce RNG and electricity are considered to account for location, herd size, and other parameters to deliver a comprehensive analysis for the USA. The analysis and results are composed of a generic part to illustrate the effects of carbon payment on profitability in general as well as a specific analysis for states representing 83.6% of the US hog inventory. Our results indicate that carbon payments would be a stronger determinant than energy prices in farm-level decisions to install ADs, but that energy prices would be influential in determining the optimal biogas end use. The potential need for long-term contracts – both for energy and carbon payments – to reduce investment uncertainty and increase investment in ADs is also discussed.

Biodiesel, a promising alternative to traditional petroleum fuels, is a green energy solution. Photocatalysis is a facile, novel, economic, and efficient approach to biodiesel synthesis. Metal sulfides have been used extensively for various photocatalytic applications. The present study demonstrates, for the first time, the photocatalytic production of biodiesel using a novel metal sulfide-based heterogeneous photocatalyst under visible light irradiation.

A nano zero-valent silver doped hydroxyapatite (Ag/HAp) was synthesized using a green bio-reductant technique and decorated with tin sulfide nanoparticles (SnS₂/Ag/HAp or SAH) for photocatalytic biodiesel synthesis. The hydroxyapatite (HAp) was extracted from waste fish scales to minimize the use of chemicals and to utilize waste for useful applications. The prepared SAH photocatalyst was characterized through X-ray diffraction, UV-visible diffuse reflectance spectroscopy, photoluminescence spectroscopy, Fourier transform infrared analysis, energy dispersive X-ray analysis, scanning electron microscopy, high-resolution transmission electron microscopy and X-ray photoelectron spectroscopy analysis. The effect of reaction parameters was optimized, and under optimum conditions of 1 wt% photocatalyst loading, and 8:1 methanol-to-oleic-acid ratio, for 60 min, a high yield of 98.0 ± 0.61% could be achieved using a SAH photocatalyst.

Scavenger tests indicated the simultaneous generation of photoinduced electrons and holes necessary for photocatalytic biodiesel synthesis. A mechanism for the photocatalytic esterification reaction of oleic acid is proposed. The synthesized SnS₂-based photocatalyst could be easily recoverable and reusable for five consecutive runs, which can replace traditional industrial heterogeneous catalysts in the near future.

The economies of several countries have benefited significantly from the sugarcane industry, as a result of investment in the industry, foreign exchange earnings, the generation of substantial employment, and connections with significant suppliers. Sugarcane industry participants have been forced to find ways to offset high operating costs due to industry pressures. Proper management of wastes generated from sugar production is essential to reduce the environmental burden of pollution. This study reviews physical, chemical, and biological procedures for reusing or recycling wastewater and other sugar industry waste for various applications. Different countries are continuing to invest in industrial sugar waste, for example biomass and wastewater, to generate renewable energy, but limited investment in the sugar industry in African countries has been identified. Some by-products, including wastewater and filter cake, have been largely unused for the production of energy. The potential to generate bioenergy from sugarcane industry wastewater has been explored. Numerous technologies for obtaining energy from sugarcane wastewater are reviewed, including the reduction of energy needs through waste heat and process heat integration, generating biomass, combustion and gasification, anaerobic digestion for biogas, fermentation for bioethanol, and the direct production of electricity using microbial fuel cells. Reusing and recycling the sugar industry's waste would increase profits, create more job opportunities, and help to boost the global economy.

Population growth has generated an enormous increase in demand for energy and chemicals to supply goods and services and to maintain quality of life. Oil, coal, and natural gas are the primary sources of the chemicals and energy that directly impact the economy. However, the reserves of these resources are continuously reducing. New alternatives have emerged, including biotechnological tools such as microbial consortia (MC) to produce biofuels, chemicals such as organic acids, and processed foods. The diversity of MC as a biotechnological tool allows it to be used in complex substrates, opening the possibility of using other solid waste to implement consolidated bioprocesses (CPs). This review presents an overview of the uses of MC and CP for producing biofuels using different feedstocks.

The aim of this study is to apply a new approach to the quantitative analysis of the formation of gaseous products generated during the thermochemical conversion of wood waste samples of different fineness by using thermogravimetric analysis with mass spectrometry (TGA-MS). Profiles of the release of gaseous components in the process of thermochemical conversion of wood samples were obtained based on data from the combined use of mass spectrometry and thermogravimetry. The resulting mass spectrometric data were processed according to the proposed methodology and the characteristics of the released gases were noted. The kinetic coefficients of the gases’ formation were calculated from the processed data.

This paper presents the results of the use of MFI zeolite as a catalyst modified with tin and iron. Sn-MFI and Fe-MFI catalysts were obtained by ion exchange under hydrothermal conditions with and without ammonium exchange. Catalytic materials were characterized with the use of analytical techniques such as X-ray diffraction (XRD), Brunauer–Emmett–Teller method (BET), diffuse reflectance spectroscopy in the ultraviolet-visible range (DRS UV–visible), hydrogen temperature programmed reduction (H₂-TPR), or Fourier transform infrared (FTIR) spectroscopy. The one-pot catalytic conversion of fructose was performed at 220 °C for 1–5 h. Based on the results, the influence of time and material selection on the products obtained can be seen. Lactic acid (LAC) was obtained with a yield of 68.7% (after 2 h) and levulinic acid (LA) with a yield of 70.9% (after 5 h) with the participation of MFI. In turn, formic acid with a yield of 28.5% (after 5 h) was obtained with the participation of Fe-MFI.

To maximize the reuse of citrus fruit processing waste, which is generated in large amounts due to juice production, this work shows the results of a new renewable approach for the extraction of high-added-value compounds present in orange biomass, specifically in orange peels (OP). The method is based on the use of diluted Ca²⁺, acid, and base solutions for the extraction of hesperidin (HSD), pectin, lignin, and cellulose sequentially, without generating any organic solid waste at the end, and without the need for air drying the starting biomass. Good yields of hesperidin were recovered (~1.56%), with excellent purity (up to 95%), as well as lignin (yield ~2.2%) and cellulose (yield ~12%). Pectin obtained by this process showed a high amount of galacturonic acid (~88%) and a low degree of methylation (~16%). All products were thoroughly characterized by applying Fourier transform infrared (FTIR) spectroscopy and solid-state cross-polarization/magic angle spinning carbon-13 nuclear magnetic resonance spectroscopy (CP/MAS ¹³C-NMR). The products recovered from OP can be applied in a wide array of fields, such as food, medicine, and pharmaceuticals, among others.

Increasing global waste generation is not only a threat but also an opportunity to address energy insecurity and pollution using green valorization techniques. However, this requires pretreatment of waste and byproducts and optimization of drying to obtain high-quality biofuels. Hence, this study aims to analyze the performance of currently used drying models, the influence of different drying temperatures, drying time, and seed pretreatment on the drying kinetics of two varieties of mango seed. Accordingly, whole seeds and crushed seeds were exposed to five drying temperatures (313–353 K) in a heating furnace. Weight loss was recorded systematically, converted into moisture ratio, and then fitted to four semitheoretical mathematical models, namely: (i) Lewis, (ii) Henderson and Pabis, (iii) Page, and (iv) Avhad and Marchetti models. The fitness of these models was compared using statistical parameters, such as R², X², root mean square error (RMSE), mean bias error (MBE), and mean absolute error (MAE). The results showed that seed pretreatment and increasing the drying temperature led to an increase in the rate of moisture evaporation and reduced the time required for drying. Among all models, the Avhad and Marchetti model provided higher R² values of 0.9994 and 0.9991 for local and hybrid mango at 313 K, and 0.9977, and 0.9970 for local and hybrid crushed mango seeds at 353 K and 313 K, respectively; hence, it showed the best performance. The activation energy (Ea) showed a slight differences for both varieties of mango seed and among pretreatments in all mathematical models. The mean Ea values for local and hybrid mango seeds were 41.18 kJ mol⁻¹ and 46.21 kJ mol⁻¹, respectively. For whole and crushed local and hybrid mango varieties, the mean Ea values were 31.37 kJ mol⁻¹, 40.80 kJ mol⁻¹, 50.99 kJ mol⁻¹, and 51.61 kJ mol⁻¹. The likely reason for this variation might be differences in variety, chemical composition, growing conditions, and cellular structure of the seed varieties.