Air catalytic biomass (PKS) gasification in a fixed-bed downdraft gasifier using waste bottom ash as catalyst with NARX neural network modelling

Membrane-based carbon capture: Recent progress, challenges, and their role in achieving the sustainable development goals

The rapid growth in the consumption of fossil fuels resulted in climate change and severe health issues. Among the different proposed methods to control climate change, carbon capture technologies are the best choice in the current stage. In this study, the various membrane technologies used for carbon capture and their impact on achieving sustainable development goals (SDGs) are discussed. Membrane-based carbon capture processes in pre-combustion and post-combustion, which are known as membrane gas separation (MGS) and membrane contactor (MC), respectively, along with the process of fabrication and the different limitations that hinder their performances are discussed. Additionally, the 17 SDGs, where each representing a crucial topic in the current global task of a sustainable future, that are impacted by membrane-based carbon capture technologies are discussed. Membrane-based carbon capture technologies showed to have mixed impacts on different SDGs, varying in intensity and usefulness. It was found that the membrane-based carbon capture technologies had mostly influenced SDG 7 by enhancement in the zero-emission production, SDG 9 by providing 38-42% cost savings compared to liquid absorption, SDG 3 through reducing pollution and particulate matter emissions by 23%, and SDG 13, with SDG 13 being the most positively influenced by membrane-based carbon capture technologies, as they significantly reduce the CO₂ emissions and have high CO₂ capture yields (80-90%), thus supporting the objectives of SDG 13 in combatting climate change.

Thermocatalytic conversion of wood-plastic composite over HZSM-5 catalysts

Air gasification of the Wood-Plastic Composite (WPC) was performed over Ni-loaded HZSM-5 catalysts to generate H₂-rich gas. Increasing SiO₂/Al₂O₃ ratio (SAR) of HZSM-5 adversely affected catalytic activity, where the highest gas yield (51.38 wt%) and H₂ selectivity (27.01 vol%) were acquired using 20 %Ni/HZSM-5(30) than those produced over 20 %Ni/HZSM-5(80) and 20 %Ni/HZSM-5(280). Reducing SAR was also favorably conducive to increasing the acyclic at the expense of cyclic compounds in oil products. These phenomena are attributed to enhanced acid strength and Ni dispersion of 20 %Ni/HZSM-5(30) catalyst. Moreover, catalytic activity in the terms of gas yield and H₂ selectivity enhanced with growing Ni loading to 20 %. Also, the addition of promoters (Cu and Ca) to 20 %Ni/HZSM-5(30) boosted the catalytic efficiency for H₂-rich gas generation. Raising temperature indicated a positive relevance with the gas yield and H₂ selectivity. WPC valorization via gasification technology would be an outstanding outlook in the terms of a waste-to-energy platform.

Membrane-based water and wastewater treatment technologies: Issues, current trends, challenges, and role in achieving sustainable development goals, and circular economy

Membrane-based technologies are recently being considered as effective methods for conventional water and wastewater remediation processes to achieve the increasing demands for clean water and minimize the negative environmental effects. Although there are numerous merits of such technologies, some major challenges like high capital and operating costs . This study first focuses on reporting the current membrane-based technologies, i.e., nanofiltration, ultrafiltration, microfiltration, and forward- and reverse-osmosis membranes. The second part of this study deeply discusses the contributions of membrane-based technologies in achieving the sustainable development goals (SDGs) stated by the United Nations (UNs) in 2015 followed by their role in the circular economy. In brief, the membrane based processes directly impact 15 out of 17 SDGs which are SDG1, 2, 3, 5, 6, 7, 8, 9, 11, 12, 13, 14, 15, 16 and 17. However, the merits, challenges, efficiencies, operating conditions, and applications are considered as the basis for evaluating such technologies in sustainable development, circular economy, and future development.

Experimental microwave-assisted air gasification of biomass in fluidized bed reactor

Microwave-assisted heating is an effective heating method for thermochemical conversion of biomass. In this study, experimental syngas production from microwave-assisted air gasification of biomass in a fluidized bed reactor at different gasification temperatures, equivalence ratios and silicon carbide loads, was studied and reported. The results showed that the highest syngas yield (78.2 wt%), higher heating value (6.3 MJ/Nm³) and cold gas efficiency (81.8 %) were obtained at gasification temperature of 900 °C, equivalence ratio of 0.35 and silicon carbide load of 30 g, and the gasification temperature had significant influence on the syngas production. Microwave-assisted heating showed positive effect on tar reduction, i.e., the tar content at 900 °C (2.1 wt%) in this study was even lower than the tar content (3.2 wt%) from catalytic electrical air gasification of rice husk at 950 °C. Generally, the introduction of microwave-assisted heating showed positive effect on biomass gasification.