Biosafety of human environments can be supported by effective use of renewable biomass

Preventing pathogenic viral and bacterial transmission in the human environment is critical, especially in potential outbreaks that may be caused by the release of ancient bacteria currently trapped in the permafrost. Existing commercial disinfectants present issues such as a high carbon footprint. This study proposes a sustainable alternative, a bioliquid derived from biomass prepared by hydrothermal liquefaction. Results indicate a high inactivation rate of pathogenic virus and bacteria by the as-prepared bioliquid, such as up to 99.99% for H1N1, H5N1, H7N9 influenza A virus, and Bacillus subtilis var. niger spores and 99.49% for Bacillus anthracis. Inactivation of Escherichia coli and Staphylococcus epidermidis confirmed that low-molecular-weight and low-polarity compounds in bioliquid are potential antibacterial components. High temperatures promoted the production of antibacterial substances via depolymerization and dehydration reactions. Moreover, bioliquid was innoxious as confirmed by the rabbit skin test, and the cost per kilogram of the bioliquid was $0.04427, which is notably lower than that of commercial disinfectants. This study demonstrates the potential of biomass to support our biosafety with greater environmental sustainability.

Experimental Study On Pyrolysis of Rice Straw Catalyzed By CaO/Al2O3-Phosphate Mixture

This paper studied the synergistic effects of CaO or Al2O3 and three potassium phosphates (e.g., KH2PO4, K2HPO4·3H2O and K3PO4·3H2O) in the rice stalk pyrolysis through pyrolysis-gas chromatography-mass spectrometer (Py-GC/MS) experiments. The results show that after co-catalyzed by CaO/Al2O3 and potassium phosphates, the total contents of phenols, aldehydes, acids, LG from most samples decrease and those of ketones increase compared with those catalyzed by potassium phosphates alone. CaO/Al2O3 and potassium phosphates show synergistic effects in the regulation of the types or contents of phenols, ketones, aldehydes, etc. and are suitable for the production of ketone-rich bio-oil. Dehydration reactions, etc. are further promoted under the co-catalysis of the two catalysts, and some phenols can be converted to benzene products, etc. The contents of acetic acid can decrease to 0. For 50% K3PO4.3H2O impregnated sample, the yields of furans reduce sharply after CaO addition. For most impregnated samples except 50% K2HPO4·3H2O sample and 30%, 50% K3PO4.3H2O, the contents of total furans and furfural increase after Al2O3 addition.

Achieving Sustainable Energy Security in Indonesia Through Substitution of Liquefied Petroleum Gas with Dimethyl Ether as Household Fuel

Indonesia has been facing an energy security issue regarding Liquefied Petroleum Gas (LPG) consumption. The rapid increase of LPG consumption and huge import have driven the Indonesian government to develop the alternative for LPG in the household sector. Dimethyl ether (DME) is the well-fit candidate to substitute LPG because of its properties similarities. However, discrepancies in the properties, such as combustion enthalpy and corrosivity, lead to adjustments in the application. Coal is a potential raw material to produce DME, especially in Indonesia, known as the fourth-largest coal producer globally. However, the gasification of coal into DME brings a problem in its sustainability. To compensate for the emission, co-processing of DME with biomass, especially from agricultural residue, has been discovered. Recently, carbon dioxide (CO2) captured from the gasification process has also been developed as the raw material to produce DME. The utilization of CO2 recycling into DME consists of two approaches, methanol synthesis and dehydration reactions (indirect synthesis) and direct hydrogenation of CO2 to DME (direct synthesis). The reactions are supported by the catalytic activity that strongly depends on the metal dispersion, use of dopants and the support choice. Direct synthesis can increase the efficiency of catalysts used for both methanol synthesis and dehydration. This paper intended to summarize the recent advancements in sustainable DME processing. Moreover, an analysis of DME's impact and feasibility in Indonesia was conducted based on the resources, processes, environmental and economic aspects. Keywords: coal gasification, DME, energy security, LPG, sustainable

Catalytic Stereoselective Conversion of Biomass-Derived 4′-Methoxypropiophenone to Trans-Anethole with a Bifunctional and Recyclable Hf-Based Polymeric Nanocatalyst

Anethole (AN) is widely used as an odor cleaner in daily necessities, and can also be applied in the fields of food additives, drug synthesis, natural preservatives, and polymeric materials’ preparation. Considering environmental and economic benefits, the use of biomass raw materials with non-precious metal catalysts to prepare high-value fine chemicals is a very promising route. Here, we developed an acid-base bifunctional polymeric material (PhP-Hf (1:1.5)) composed of hafnium and phenylphosphonate in a molar ratio of 1:1.5 for catalytic conversion of biomass-derived 4′-methoxypropiophenone (4-MOPP) to AN via cascade Meerwein–Pondorf–Verley (MPV) reduction and dehydration reactions in a single pot. Compared with the traditional catalytic systems that use high-pressure hydrogen as a hydrogen donor, alcohol can be used as a safer and more convenient hydrogen source and solvent. Among the tested alcohols, 2-pentanol was found to be the best candidate in terms of pronounced selectivity. A high AN yield of 98.1% at 99.8% 4-MOPP conversion (TOF: 8.5 h−1) could be achieved over PhP-Hf (1:1.5) at 220 °C for 2 h. Further exploration of the reaction mechanism revealed that the acid and base sites of PhP-Hf (1:1.5) catalyst synergistically promote the MPV reduction step, while the Brønsted acid species significantly contribute to the subsequent dehydration step. In addition, the PhP-Hf polymeric nanocatalyst can be recycled at least five times, showing great potential in the catalytic conversion of biomass.

Deep Dehydration as a Plausible Mechanism of the 2013 Mw 8.3 Sea of Okhotsk Deep-Focus Earthquake

The rupture mechanisms of deep-focus (>300 km) earthquakes in subducting slabs of oceanic lithosphere are not well understood and different from brittle failure associated with shallow (<70 km) earthquakes. Here, we argue that dehydration embrittlement, often invoked as a mechanism for intermediate-depth earthquakes, is a plausible alternative model for this deep earthquake. Our argument is based upon the orientation and size of the plane that ruptured during the deep, 2013 Mw 8.3 Sea of Okhotsk earthquake, its rupture velocity and radiation efficiency, as well as diverse evidence of water subducting as deep as the transition zone and below. The rupture process of this earthquake has been inferred from back-projecting dual-band seismograms recorded at hundreds of seismic stations in North America and Europe, as well as by fitting P-wave trains recorded at dozens of globally distributed stations. If our inferences are correct, the entirety of the subducting Pacific lithosphere cannot be completely dry at deep, transition-zone depths, and other deep-focus earthquakes may also be associated with deep dehydration reactions.

High-temperature decomposition of amorphous and crystalline cellulose: reactive molecular simulations

We study the thermal decomposition of cellulose using molecular simulations based on the ReaxFF reactive force field. Our analysis focuses on the mechanism and kinetics of chain scission, and their sensitivity on the condensed phase environment. For this purpose, we simulate the thermal decomposition of amorphous and partially crystalline cellulose at various heating rates. We find that thermal degradation begins with depolymerization via glycosidic bond cleavage, and that the order of events corresponds to a randomly initiated chain reaction. Depolymerization is followed by ring fragmentation reactions that lead to the formation of a number of light oxygenates. Water is formed mainly in intermolecular dehydration reactions at a later stage. The reaction rate of glycosidic bond cleavage follows a sigmoidal reaction model, with an apparent activation energy of 166 ± 4 kJ/mol. Neither the condensed phase environment nor the heating programme have appreciable effects on the reactions. We make several observations that are compatible with mechanisms proposed for cellulose fast pyrolysis. However, due to the absence of anhydrosugar forming reactions, the simulations offer limited insight for conditions of industrial interest. It remains unclear whether this is a natural consequence of the reaction conditions, or a shortcoming of the force field or its parameter set. Graphic abstract