Catalytic co-pyrolysis of oil palm trunk and polypropylene with Ni-Mo/TiO2 and Ni/Al2O3: Oil composition and mechanism

Revealing the Effects of Mo Doping to Ni on Catalyzing Hydrogenation of Fatty Acids to Fatty Alcohols

Fatty acid hydrogenation is an important method for the production of fatty alcohols. The combination of Ni and Mo has been reported to be an effective and low-cost catalyst. However, the effect of Mo doping has yet to be fully understood. Here Ni-MoOx/TiO2 catalysts were prepared via simple impregnation. and the enhancement effects of Mo doping were comprehensively revealed. First, MoOx can attract electrons from Ni, reduce the electron density of Ni to improve the intrinsic activity of Ni, and form a Niδ+-(MoOx)δ- heterojunction to induce H2 heterolytic cleavage to active hydrogen ions. Second, the reduction of MoOx generates oxygen vacancies, which can absorb C═O of the fatty acid and facilitate the reaction progression. Third, a Ni1-xMox solid solution can be formed, which can increase the hydrogen adsorption quantity and accelerate the reaction rate. Finally, the bond strength of Mo-O is found to be the most optimum that can absorb the fatty acids while releasing the alcohols so as to recover the oxygen vacancies and avoid overhydrogenation. Therefore, high activity and selectivity for the hydrogenation of carboxylic acid substrates to alcohols can be obtained. Under significantly milder conditions (155 °C, 3 MPa H2) the catalyst provided a 98% yield of lauryl alcohol from lauric acid hydrogenation with a low activation energy of 40.1 kJ/mol. This work could provide an insightful understanding about the effects of Mo doping to Ni on catalyzing hydrogenation reactions.

Municipal Solid and Plastic Waste Co-pyrolysis Towards Sustainable Renewable Fuel and Carbon Materials: A Comprehensive Review

The substantial rise in global energy demand, propelled by industrial expansion, population growth, and transportation needs, poses a formidable challenge. The concurrent urbanization places pressure on the disposal of solid municipal solid waste and the management of plastic waste. Addressing the global waste crisis requires innovative and sustainable garbage disposal solutions with an environmentally friendly approach. This review tackles the challenges of worldwide waste management, focusing on renewable and sustainable fuels and waste recycling through the exploration of co-pyrolysis as an innovative method. It explores the characteristics and environmental impact of municipal solid waste (MSW) and plastic waste (PW), delving into pyrolysis fundamentals, processes, and challenges. The primary emphasis is on co-pyrolysis, elucidating its integration of municipal and plastic waste, synergistic effects, and advantages. The manuscript thoroughly analyzes reaction kinetics, thermodynamics, and the feasibility of co-pyrolysis for energy recovery. It also delves into the synthesis of renewable fuels and valuable chemical intermediates, considering optimization of product distribution. Environmental and economic sustainability aspects, including impact assessment, greenhouse gas emissions, life cycle analysis, and cost analysis of co-pyrolysis processes, are comprehensively investigated. The review underscores the economic benefits of renewable fuel and chemical materials synthesis. The conclusion addresses challenges, proposes future directions, outlines limitations, technical challenges, environmental considerations, and recommends further exploration and integration with other waste management techniques. The manuscript emphasizes the ongoing importance of research in this critical field, aiming to contribute to the development of effective solutions for the escalating global waste management crisis.

Catalytic pyrolysis of liquor-industry waste: Product and mechanism analysis

The effects of three catalysts, namely Ni/γ-Al2O3, Fe/γ-Al2O3, and Mg/γ-Al2O3, on the three-phase products of liquor-industry waste pyrolysis were investigated in this study. Results indicated that the catalytic performance of Ni/γ-Al2O3 outperformed those of Fe/γ-Al2O3 and Mg/γ-Al2O3 significantly. The application of Ni/γ-Al2O3 facilitated the reformation of pyrolysis volatiles, leading to increased yields of H2 (174.1 mL/g), CH4 (80.7 mL/g), and CO (88.2 mL/g) by 980.00 %, 133.24 %, and 83.37 %, respectively. compared to catalyst-free conditions. The Ni/γ-Al2O3 also increased the low-level calorific value of biogas by 109.3 % compared to that under non-catalyst conditions. Moreover, Ni/γ-Al2O3 enhanced the relative concentrations of hydrocarbons in tar by 23.15 % while reducing the relative concentrations of O-species by 15.73 % compared to catalyst-free conditions through induced deoxygenation, decarboxylation, decarbonylation reactions as well as efficient steam reforming processes for tar and syngas upgrading purposes. Thus, incorporating Ni/γ-Al2O3 into the pyrolysis process represents a renewable approach for waste-to-energy conversion.