Poly Journal of Engineering and Technology (PJET)

Transforming Water Hyacinth Biomass to Phosphate Absorbent Biochar with Mg/Al Layered Double Hydroxides

2025-03-23T08:11:42+01:00

In Lake Tana, Ethiopia, influx of nutrients has resulted in excessive growth of water hyacinth (WH) in the last decades, which has also caused economic and environmental problems, and at the same time costing enormous labor and financial resources. Therefore, there is an urgent need for treatment and effective utilization process of WH. One of effective uses of waste biomass is biochar which is pyrolyzed biomass under oxygen-limited conditions. Biochar has attracted much attention for its use as an adsorbent because of abundant functional groups on surface and porous structure. Recent research has been conducted to improve adsorption performance of biochar for anionic contaminants by applying metal modification to biochar. Biochar-based layered double hydroxide (LDH) composite materials have been shown improved properties for removing phosphate (PO₄^3â€“). However, the performance of LDH-biochar as an adsorbent depends on the raw material. Therefore, it is necessary to investigate PO₄^3â€“ adsorption properties of biochar derived from WH. Thus, the objective of this study was to determine PO₄^3â€“ adsorption capacity of biochar derived from WH modified with Mg/Al-LDH and investigate the adsorption mechanism. The Langmuir maximum PO₄^3â€“ adsorption capacity was 45.7 mg g^â€“¹ for Mg/Al-LDH biochar. The adsorption mechanism was mainly chemical monolayer adsorption, replacement of surface hydroxyl groups with PO₄^3â€“, the electrostatic attraction between LDH and PO₄^3â€“, and the porous structure of the biochar. In this study, LDH treatment was shown to be effective to improve PO₄^3â€“ adsorption capacity of biochar, however as the adsorption capacity of Mg/Al-LDH biochar was lower than other studies, further research needs to be conducted.

Review on the state of art on renewable energy based green hydrogen energy carrier production processes for sustainable energy supply system

2025-03-23T08:11:28+01:00

The worldwide increase in energy consumption is primarily driven by anthropogenic activities, resulting in harmful effects on the environment and climate change due to the reliance on fossil fuels. However, renewable hydrogen has emerged as a potential alternative energy source that is both abundant and environmentally friendly. Despite its advantages, the efficiency of commercially available electrolysis for hydrogen production remains a limitation. This study focuses on exploring various methods of producing hydrogen using renewable energy, specifically water and biomass. The analysis reveals that all renewable energy-based hydrogen production methods are more environmentally friendly than fossil fuel-based methods. However, further improvements are necessary to enhance the economic viability and technical simplicity of utilizing renewable energy sources for hydrogen production. Among the examined technologies, biomass electrolysis stands out due to its convenience in using raw biomass directly. Another promising approach is the utilization of solar and wind power to split water into hydrogen and oxygen, resulting in green hydrogen. This sustainable and clean fuel can be used in various sectors such as industry, power generation, and transportation, with lower environmental impact compared to other methods.

Construction and Performance Test of Hand Operated Wooden Groundnut Sheller

2025-04-01T08:24:29+02:00

This study examines the construction and performance evaluation of a wooden groundnut sheller designed for small-scale rural farmers. Groundnut, a vital legume crop, is widely cultivated in tropical regions, offering significant nutritional and economic value. However, traditional hand-shelling methods in Ethiopia are inefficient, labor-intensive, and lead to health issues like "sore thumb syndrome." The objective of this research is to construct and test a low-cost, efficient sheller made from locally available materials to improve productivity and reduce labor.

The sheller was constructed using timber, a sieve, and a paddle mechanism that operates by manually shelling the groundnuts. Performance tests were conducted using various input amounts (1, 1.5, and 2 kg), and key parameters such as shelling percentage, damage percentage, unshelled nuts, and shelling efficiency were recorded. Results showed an average shelling percentage of 92%, a damage rate of 4%, and an efficiency of 15 kg/hr, significantly higher than traditional hand-shelling (3 kg/hr).

The findings indicate that moderate input quantities of groundnuts yield the best balance of shelling performance. The wooden sheller, constructed from affordable, local materials, presents a valuable tool for rural farmers, saving time, reducing labor, and enhancing productivity. Further modifications could explore motorization for larger-scale use.

Biodiseale SYNTHESIS AND CHARACTERIZATION OF K2O-CaO/Î³-Al2O3 CATALYST FOR BIODIESEL PRODUCTION FROM WASTE COOKING PALM OIL

2025-04-03T07:53:24+02:00

This study has focused on the preparation and characterization of K₂O-CaO/Î³-Al₂O₃ supported catalyst for transesterification of waste cooking palm oil with methanol to produce biodiesel. The catalyst was prepared by wet impregnation followed by activation at 700^oC for 4:30h in the furnace. The catalyst was characterized with X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), ICP-OES and Hammett indicator method. It was found that as prepared catalyst is highly active for the transfection reaction, up to 100% conversion was achieved. The leaching tendency of the catalyst was analyzed after using for four consecutive cycles by ICP-OES machine and it was determined that 18% K and 8.5% Ca leached into the reaction media at the end of the fourth cycle. Also, this study consists of the optimization of the biodiesel yield produced via transesterification of waste cooking palm oil using K₂O-CaO/Î³-Al₂O₃ solid base catalyst. Response surface methodology (RSM) in combination with central composite design (CCD) was used to optimize the operating parameters. Methanol to oil molar ratio, catalyst loading, and reaction temperature were chosen as the variables and the response selected was biodiesel yield. The optimum reaction conditions obtained were a methanol-to-oil molar ratio of 12:1, catalyst loading of 5.6wt%, and reaction temperature of 64Â°C. At these optimal operating conditions, biodiesel yield obtained was 96% for 3h reaction. Biodiesel was chemically characterized with ¹³C NMR and ¹H NMR machine.

WIRELESS SENSOR NETWORK NODE DEPLOYMENT STRATEGY IN THE CASE OF ETHIO-DJIBOUTI RAILWAY

2025-03-23T08:11:15+01:00

The EthioDjibouti route is a standard gauge international railway with a single track covering 639 kilometres of the total length. This paper introduced Wireless Sensor Networks for the Ethio -Djibouti route, for their advantage of low cost, ease of complexity in installation and maintenance, low energy consumption, increased line capacity, and real time monitoring data. But, depletion of nodes energy is a major concern since it creates a phenomenon called â€œEnergy Holeâ€, which decreases the lifetime of the network. Non-uniform node deployment strategy is used to mitigate the problem of network lifetime. It is a random node deployment technique which allows non-uniform distance between nodes. And the nodes create shortest paths between neighbouring nodes to ensure data transfer between source node and destination node with reduced power consumption, which in turn minimizes the effect of energy hole. In the MATLAB computation result the optimum communication range is twice of the sensing range of the sensor nodes.