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Herein, graphene oxide nanosheets (GO) were synthesized and employed as an additive at various proportions to fabricate a novel cation exchange membrane based on grafted cellulose acetate with sodium 4-styrenesulfonate (GCA) via a solution casting method for direct methanol fuel cell (DMFC) applications. The structure of composite membranes has been examined using FTIR, TGA, SEM, and DSC. The physicochemical properties of the GCA/GO membranes, such as ion exchange capacity, water uptake, mechanical and chemical stability, methanol permeability, and proton conductivity, were measured. The inclusion of GO significantly improved the ability to block methanol, contributing to the observed effects. Among the several composite membranes developed, GCA/GO (2 wt.%) had the highest selectivity with a water uptake of 45%, proton conductivity of 5.99 × 10−3 S/cm, methanol permeability of 1.12 × 10−7 cm2/s, and electrical selectivity of 26.39 × 103 Ss/cm3. Simultaneously, the composite membranes’ mechanical, oxidative, and thermal stabilities were also enhanced. Single-cell estimation using a 2 wt.% GO modified membrane demonstrated a maximum power density of 31.85 mW.cm−2 at 30 °C. Overall, these findings highlight the perspective of the application of these developed membranes in the DMFC.

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Greenhouses with efficient controlled environment offer a promising solution for food security against the impacts of increasing global temperatures and growing water scarcity. However, current technologies used to achieve this controlled environment consume a significant amount of energy, which impacts on operational costs and CO2 emissions. Using advanced metal organic framework materials (MOFs) with superior water adsorption characteristics, this work investigates the development of a new technology for a greenhouse-controlled environment. The system consists of MOF coated heat exchanger, air to air heat exchanger, and evaporative cooler. A three-dimensional computational fluid dynamics (CFD) model was developed using COMSOL software and experimentally validated for the MOF-801/Graphene coated heat exchanger (DCHE) to determine the best cycle time and power input. It was found that using desorption time of 16 min and power input of 1.26 W, the maximum water removal rate was obtained from MOF-801/Graphene of 274.4 g/kgMOF/W.hr. In addition, an overall mathematical model for the greenhouse climate control was developed and used to investigate the effects of air humidity and velocity on the input air conditions to the greenhouse. Results showed that with high relative humidity levels of 90% in the greenhouse can be conditioned to reach the required relative humidity of 50%.

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Waste management is a major challenge in Nigeria, where around 32 million tons of waste is generated annually including 13 million tonnes of agricultural waste and 2.5 million tons of plastic waste. Currently, the waste management system is very inefficient where almost 70% of the waste ends up in landfills, sewers, beaches and water bodies causing serious environmental and health problems. This work numerically investigates the conversion of mixed wastes (wood and plastics) to produce clean and affordable solid, liquid and gaseous fuels that can be used for cooking, heating and electricity generation. Pyrolysis process which involves heating the waste at different rates in the absence of Oxygen has received significant research interest since it can convert various types of waste to clean fuels thus reducing fossil fuel consumption and CO2 emission. For example, wood waste can be converted to high-quality syngas, oil, and char while plastic waste can be converted to high-quality syngas, oil, light and heavy waxes. Also, it generates lower emissions compared to other waste conversion processes such as combustion, gasification, and plasma treatment. In this study, a numerical model is developed to simulate the pyrolysis process of mixed wood and plastic waste materials to predict the outputs in terms of char, syngas, oil and wax production. The model is based on the kinetics of the reactions associated with wood and plastic when subjected to different heating rates from 320 to 923 Kelvin for 20 minutes. Results showed that for 1kg of mixed waste (30% plastic and 70% wood) and after 20 minutes of heating, the output consists of 50.13% syngas, 8.35% oil, 9.5% char, 10.8% light Wax and 8.33% heavy wax. This modelling allows for controlling the output composition based on varying the input waste constituents which can optimize the waste conversion process.