Synthesis, Characterization and Size Evaluation of Biosynthesized Silver Nanoparticles by UV–Vis Spectroscopy

Mie-Gans (MG) fitting model theoretical model utilizing the phenomena of scattering light to determine the morphologies, shape, and size of metallic nanoparticles in solution. In the present work, the average radius of biosynthesized silver nanoparticles (AgNPs) was evaluated based on the fitting of their Ultraviolet-visible (UV-Vis) spectra by the MG fitting model for spherical and non-spherical particles. Biosynthesis of AgNPs using Lemon (Citrus Limon) leaves extract as a reducing agent and Gum Acacia as a capping and stabilizing agent was studied for various concentrations of Citrus Limon leaves extract. The investigation of structural and optical properties was carried out for the synthesized samples using X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), and UV-Vis spectroscopy. XRD confirmed the structure of AgNPs and revealed that the structure of these nanoparticles was face-centered cubic (fcc). FTIR measurements indicate the presence of citric acid in Citrus Limon leaf extract which is responsible for reducing bioreduced AgNPs. UV-Vis spectroscopy determined the surface plasmon resonance (SPR) for AgNPs; the peaks of resonances of samples appear at 436-461nm range. MG fitting evaluations show that most of AgNPs were spherical in shape with an average radius in the range of 39-47nm. Moreover, this model allows the estimation of the fraction of nonspherical and aggregated AgNPs. These unique characteristics of AgNPs have made them applicable in a large number of fields like water treatment, biomedical, energy science, catalysis, etc.

Energy and Exergy Analysis of a Steam Power Plant in Suda

In this study, the energy and exergy analysis of Garri 4 power plant in Sudan is presented. The primary objective of this paper is to identify the major source of irreversibilities in the cycle. The equipment of the power plant has been analyzed individually. Values regarding heat loss and exergy destruction have been presented for each equipment. The results confirmed that the condenser was the main source for energy loss (about 67%), while ex­ergy analysis revealed that the boiler contributed to the largest percentage of exergy destruction (about 84.36%) which can be reduced by preheating the inlet water to a sufficient temperature and controlling air to fuel ratio.

Assessment of Sludge Sample as a Feedstock for Power Generation

Treatment and disposal of sewage sludge has become an economically and environmentally sensitive problem. This necessitates cost-effective and innovative solutions whilst responding to environmental regulation and public pressures. This study examines the characteristics of a typical sludge samples as received following standard analytical procedures and its suitability for power generation. The results of the analysis revealed that the sample has good proxanal and ultanal attributes. The higher heating value of the sample on dry basis was found to be 21.21 MJ/kg. These characteristics are similar to qualities of standard coal used as fuel in power stations.

Recovery of Ionic Liquid from Aqueous Phase Pyrolytic Oil: A Simulation Using ASPEN HYSYS V10

Aqueous phase pyrolytic oil is generally considered less important and often discarded as a pyrolysis by-product due to lack of specific applications. Although, recent studies have proposed production of hydrogen via catalytic aqueous and steam reforming from this stream, however, these processes require complex system. Imidazole is one of the major components of aqueous phase pyrolytic oil which can be converted into different products. This study presents a new valorisation strategy of aqueous phase pyrolytic oil into renewable ionic liquid through simulation. A steady state process simulation for recovery of imidazole from aqueous phase pyrolytic oil and subsequent conversion into ionic liquid was developed using ASPEN HYSYS V10 ®. Effects of different operating variables such as feed flow rate, composition and temperature on the imidazole recovery, ionic liquid yield and composition were investigated. The simulation results revealed that high yield of renewable ionic liquid with physicochemical properties comparable to that of commercially available ionic liquids can be produced from aqueous phase pyrolytic oil. This product can be utilised for biomass refining since ionic liquid have been reported to selectively remove hemicellulose and lignin in many biomass related applications such as pre-treatment and characterization.

Sustainable development and the role of African scientific research centres

Scientific research in the engineering and technology domains plays a centric role in realizing sustainable development in Africa. In particular, a multidisciplinary research (and sometimes even cross-disciplinary) approach is required when tackling Africas complex challenges such as poverty, climate change, energy access, water resources management, energy-water-food nexus, sustainable urban environment, cybersecurity, and others. To advance this research, African researchers should be empowered to conduct high-quality research and communicate their findings and recommendations to all stakeholders in open-access platforms. Building on the above, the Sudanese Researchers Foundation (SRF) is proud to announce the launch of the African Journal of Engineering & Technology (AJET); our inaugural open-access peer-reviewed journal focusing on engineering, technology, and sustainable development.