ABSTRACT
In this research, a brick kiln integrated with pollutant emission control technology was designed and applied in order to produce charcoal from Eucalyptus Globules wood. The batch operation carbonization of wood biomass was undertaken in a 1.25 m3 volume brick kiln. A wet-packed scrubber was designed and constructed by filling gravels in a depth of 40 cm with aggregate sizes of 48-60 mm, 27-33 mm and 16-20 mm from the bottom to the top respectively aiming to treat emission from the charcoal-producing unit. The characteristics of the charcoal produced were determined to be composed of 9% moisture content, 1.5% ash content, 38% charcoal yield and a heating value of 27.53 MJ/kg. On the other hand, the wet scrubber integrated into a brick kiln was found to remove Hydrocarbons, CO2 and CO by 97.8%, 98.5% and 99% respectively, which makes it efficient and practical way of controlling the gasses released during producing of charcoal.
ABSTRACT
Industrial development in Ethiopia is rapidly increasing, leading to a growing gap between energy supply and demand. To address this, efficient energy utilization in existing industries is crucial. Energy audits identify energy losses and recommend saving measures. Therefore, this study evaluates energy efficiency through an audit and estimates greenhouse gas emissions for a Meta Abo brewery. The indirect method of energy audit and the greenhouse gas protocol of carbon footprint estimation were used to evaluate the energy efficiency and carbon emissions of Meta Abo brewery. The boiler efficiency for Bono Energia and Cochran boilers was found to be 79.2% and 80.9%, respectively. Poor insulation caused an estimated annual fuel loss of 35,350 l (638,768 Ethiopian birr) for steam pipes, while steam leakage resulted in a loss of 31,614 l (571,265 Ethiopian birr). The factory's high electricity expense was attributed to a diesel generator consuming 6000 l/d. Greenhouse gas emissions raised from 9156 to 22,697 tons of CO2 equivalent between 2014 and 2018. Implementing the proposed energy-saving measures could save 20.4 TJ of thermal and electrical energy annually, costing approximately 8.5 million Ethiopian birr, and reduce boiler emissions by 455 tons of CO2 equivalent. Therefore, implementation of these measures is recommended.
ABSTRACT
Methyl orange is abundantly present in wastewater generated from textile industries causing serious human health and environmental problems. Therefore, this study was aimed at preparing a low cost and effective biosorbent from the stem of Rumex abyssinicus plant for the removal of methyl orange from aqueous solution. Characterization of the prepared adsorbent material was carried out using a pH point of zero charge, Scanning Electron microscope (SEM), Fourier Transform Infrared (FTIR) spectroscopy and X-Ray Diffraction (XRD). The design and optimization of methyl orange batch adsorption was carried out using the Box Behnken approach to Response Surface methodology aiming to reduce the experimental runs and time with adequate results. The characterization of the adsorbent revealed 7.9 (pHpzc), porous and heterogonous surface (SEM), presence of multiple functional groups (FTIR) and amorphous structure (XRD). The maximum removal efficiency of 98.5 % was found at pH, contact time, Methyl orange concentration and adsorbent dosage of 6, 60 min, 20 mg/L and 0.2 g/100 mL respectively. The isotherm studies were carried out using Langmuir, Freundlich, Toth and Koble Corrigan models in which Freundlich isotherm with a maximum R2 of 0.95 was found to fit data best showing heterogeneous and multilayer surface interaction. On the other hand, a kinetics study revealed that pseudo-second-order fitted the data best. Moreover, the thermodynamics analysis showed the nature of the adsorption to be endothermic, spontaneous and feasible. Generally, this work proved that the low-cost, environmentally friendly and easily prepared Rumex abyssinicus-based material could be an alternative adsorbent for dye detoxification at an industrial scale.
ABSTRACT
The environmental pollution and human health impacts associated with the discharge of massive dye-containing effluents necessitate a search for cost-effective treatment technology. Therefore, this research work is conducted with the objective of investigating the potential of Rumex abyssinicus-derived activated carbon (RAAC) for the adsorption of Brilliant Blue Reactive (BBR) dye from aqueous solutions. Chemical activation with H3PO4 followed by pyrolysis was used to prepare the adsorbent. Characterization of the developed adsorbent was done using proximate analysis, pH point of zero charge (pHpzc), scanning electron microscope (SEM), Fourier transform infrared spectrometer (FTIR), Brunauer, Emmett, and Teller (BET), and X-ray diffraction (XRD). The experimental design and the effect of independent variables including pH (2, 6, and 10), initial dye concentration (50, 100, and 150 mg/L), adsorbent dosage (0.05, 0.1, and 0.15 g/100 mL), and contact time (20, 50, and 80 min) were optimized using the response surface methodology (RSM) coupled with Box Behnken design (BBD). The analysis results revealed the exitance of high specific surface area of 524 m2/g, morphological cracks, and the presence of multiple functional groups like -OH, C=C, alkene, and amorphous structure. Maximum removal efficiency of 99.98% was attained at optimum working conditions of pH 2, contact time of 50 min, dye concentration of 100 mg/L, and adsorbent dosage of 0.15 mg/100 mL, reducing the pollutant concentration from 100 to 0.02 mg/L. Evaluation of the experimental data was done using Langmuir, Freundlich, Temkin, and Sips isotherm models, in which the Langmuir model was found to be the best fit with the experimental data at R2 0.986. This shows that the adsorbent surface is homogeneous and mono-layered. Furthermore, the kinetic study confirmed that the pseudo second-order model best describes the experimental data with R2 = 0.999. In general, the research work showed that the low cost, environmental friendliness and high adsorption capabilities of the activated carbon derived from Rumex abyssinicus could be taken as an effective nt for the removal of BBR dye from aqueous solutions.
