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Aromatic compounds and ester polymeric solvents interactions

  • Authors: Muzenda, Edison
  • Date: 2014
  • Subjects: Activity coefficients , Aromatic compounds , Esters , Solubility , Volatile organic compounds
  • Type: Article
  • Identifier: uj:4771 , ISSN 2320–4087 , http://hdl.handle.net/10210/11946
  • Description: This work focused on the interactions that occur between ester polymeric solvents and simple aromatic volatile organic compounds (VOCs). Solutes were selected from various functional groups in their simplest form and computations of infinite dilution activity coefficients were performed using the Modified UNIFAC Dortmund group contribution model using a Microsoft Excel spreadsheet designed for this purpose. For polar aromatic VOCs, solubility decreased with increase in size of the ester solvent molecule and the opposite behavior was observed for non-polar VOCs. For all aromatic - ester solvent interactions, solubility increased with the increase in the degree of ester unsaturation.
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Analysis of the biogas productivity from dry anaerobic digestion of organic fraction of municipal solid waste

Preparation, chemical composition, characterization, and properties of Napier grass paper sheets

  • Authors: Reddy, K. Obi , Maheswari, C. Uma , Shukla, M. , Muzenda, Edison
  • Date: 2014
  • Subjects: Pulp and papermaking , Napier Grass fibers
  • Type: Article
  • Identifier: uj:4767 , ISSN 1520-5754 , http://hdl.handle.net/10210/11942
  • Description: In this study, perennial fast growth Napier grass fibers were used for pulp and papermaking. Chlorination and alkaline processes were carried out using sodium chlorite and sodium hydroxide respectively, for pulp extraction from Napier grass. Detailed chemical composition analysis of the Napier grass fibers and the extracted pulp was carried out and a comparison with other perennial grasses was made. The extracted fibers and pulp obtained from Napier grass were characterized using scanning electron microscopy and Fourier transform infrared spectroscopy. The physical, optical, and mechanical properties of Napier grass pulp handmade paper sheets produced in the laboratory were investigated by finding the opacity, brightness, tensile index, breaking length, and burst index. Handmade paper sheets made from Napier grass pulp were compared to paper made from other perennial grasses. The superior properties of paper produced from Napier grass pulp indicate the suitability of Napier grass as an alternative non-wood source for papermaking.
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Atmospheric oxidative and non-oxidative leaching of Ni-Cu matte by acidified ferric chloride solution

Synthesis and characterization of new Schiff base ligands

The effect of leaching time and ammonia concentration on the atmospheric leaching of copper

Impact of agricultural waste additive on 1-dimensional clay consolidation behaviour

  • Authors: Agbenyeku, Emem-Obong Emmanuel , Muzenda, Edison , Msibi, Innocent Mandla
  • Date: 2014
  • Subjects: Rice husk ash , Kaolinitic clay , Soil treatment , Soil consolidation , Soil stabilization , Agricultural waste , Landfills , Fills (Earthwork)
  • Type: Article
  • Identifier: http://ujcontent.uj.ac.za8080/10210/386034 , uj:5050 , http://hdl.handle.net/10210/13589
  • Description: Soil treatment is of vital concern in geoenvironmental and construction engineering in present times as suitable naturally occurring materials are rapidly depleted. Efforts are continually invested towards the resourceful utilization of wastes as fillers, cement enhancers, stabilizers and blenders with little or no significant impacts on the environment. This paper explains the use of a locally available and abundant agricultural waste- Rice husk ash (RHA) in West Africa, Nigeria for the treatment and stabilization of kaolinitic clay (KC) sampled from an active landfill site in Johannesburg, South Africa. The impact of incorporating different percentages of RHA on the compressibility characteristics of a parent compressible landfill KC sample was investigated under a One-dimensional consolidation test. Compacted soil specimens were treated at optimum water content (OWC) and maximum dry unit weight (MDUW) by the addition of agricultural waste material to the parent KC. The compacted specimens were subjected incremental vertical loading in a fixed ring consolidometer device. This was done with a view to closely simulate the waste loading effects from a typical landfill on a treated and parent clay/clayey bottom barrier based on one-dimensional consolidation behaviours. The introduction of RHA waste material to the parent KC revealed an outcome with substantial improvements in compaction characteristics. Hence, the results presented herein showed the agricultural waste to positively increase one-dimensional rigidity while settlement was effectively decreased. From results and analysis, the KC stabilized with RHA can withstand loadings from waste heaps under conditions as were applied in this study. With due recommended examination by geoenvironmental specialists, the stabilized material may be considered as an environmental and cost saving beneficiation approach for use in landfill liners.
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Temperature effect on volatile organic compounds – polydimethylsiloxane Interactions

  • Authors: Muzenda, Edison , Ntuli, Freeman
  • Date: 2011
  • Subjects: Waste gas streams , Volatile organic compounds , Polydimethysiloxane , Gas liquid chromatography
  • Type: Article
  • Identifier: uj:2179 , ISSN 2010-0221 , http://hdl.handle.net/10210/4559
  • Description: Temperature dependence of specific retention volumes (og V) of 13 volatile organic compounds (VOCs) of environmental importance between the gas and liquid stationary phase (polydimethysiloxane) (PDMS) were studied using the gas liquid chromatographic technique (GLC). Temperature was varied from 303.15K to 423.15K to allow transport calculations for different seasons. Four PDMS polymers with average molecular weight ranging from 760 to 13 000 were used as solvents. The results of this work confirm that PDMS is well suited for VOCs scrubbing from waste gas streams. Linear plots of log g V against T1 were obtained in all cases permitting predictions and interpolations to temperatures not studied here. Also dependable enthalpies and entropies of solute transfer from the mobile phase to the stationary phase can be calculated. The specific retention volumes reported in this work are in agreement with literature for similar systems. Efforts were taken to ensure the best possible accuracy and trace the possible sources of error. A gas liquid chromatographic system which secured a simple retention mechanism and showed reproducible solute retention over a long period of time was devised.
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Interpretation of breakthrough curves and percolation factors from sub-tropical smectite, fe-chlorite and kaolinite clayey soil-AMD interactions

Industrial waste modified 1-dimensional compressibility of kaolinitic clay

  • Authors: Agbenyeku, Emmanuel Emem-Obong , Muzenda, Edison , Msibi, Innocent Mandla
  • Date: 2014
  • Subjects: Fly ash , Kaolinitic clay , Soil modification , Soil compressibility , Industrial wastes , Landfills , Fills (Earthwork)
  • Type: Article
  • Identifier: http://ujcontent.uj.ac.za8080/10210/365833 , uj:5053 , http://hdl.handle.net/10210/13592
  • Description: The modification of soil has become a major drive in construction and geoenvironmental engineering in recent years. Researches towards the effective incorporation of wastes as cement blenders and enhancers with environmental friendly impacts are increasing. This paper channeled the utilization of commercially available industrial waste- Fly ash (FA) in South Africa towards the modification and improvement of kaolinitic clay sampled from a disposal site. One-dimensional consolidation tests were conducted to investigate the effect of integrating varied proportions of FA on the compressibility behavioral patterns of a parent compressible landfill material. Compacted specimens were modified at optimum water content (OWC) and maximum dry unit weight (MDUW) by the incorporation of an industrial waste material to the parent soil. The generated specimens were subjected to incremental vertical loadings/pressures in a fixed ring odometer. This was done to simulate the impact of waste loads from a typical landfill on the consolidation characteristics of the modified specimens in a view for use as bottom liners in domestic waste containment facilities. The addition of different proportions of FA waste to the kaolinitic parent clay resulted in considerable improvements in compaction characteristics. Thus, the results of this study revealed that the incorporated industrial waste effectively increased one-dimensional stiffness and as such, successfully decreased settlement. Under adequate strength and operative conditions, the modified kaolinitic clay soil can withstand loadings from waste heaps and after recommended scrutiny by experts, may be initiated into landfill designs as an eco-friendly cost reducing agent.
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Prospective inclination of research and engineering education

  • Authors: Agbenyeku, Emmanuel Emem-Obong , Muzenda, Edison , Msibi, Innocent Mandla
  • Date: 2016
  • Subjects: Sustainability , Engineering education , Sociotechnical systems
  • Language: English
  • Type: Conference proceedings
  • Identifier: http://hdl.handle.net/10210/123934 , uj:20853 , Citation: Agbenyeku, E.E., Muzenda, E & Msibi, I.M. 2016. Prospective inclination of research and engineering education.
  • Description: Abstract: The roles of Engineers are generally vital as their knowledge and expertise play a pivotal part in societal improvement, offer empowering ideas, innovations and initiatives that motivate financial and economic progress, enrich social and physical infrastructures, and also stimulate transformations that advance quality and standard of living. Concurrently, there are enormous challenges weighing on all facets of research and development (R&D), industry and manufacturing owing to globalization and circulated manufacturing. On this note, the corporate and commercial setting of manufacturing enterprises are categorized by incessant modification and growing intricacies. Most companies are in dire need of dynamic technical solutions as well as handling composite socio-technical systems geared towards substantially contributing to the sustainable growth and development of manufacturing and the environment. For this reason, in the ever changing industrial and business world of Engineering, Health delivery, Environment, Transportation, Logistics and Supply chain amongst others, researchers and graduates are profusely required once they display the ability to comprehend both composite technological processes and the resourceful arts and social skills. Thus, through the proficient technical and communication skills of engineering managers, various team-based activities are successfully supervised and executed. As such, aiming at the crucial role of engineering in solving simple to compound global problems make the career attractive to all gender of students.
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Optimization of biomethane production by anaerobic co-digestion of food waste with cow dung

The effect of zinc ion concentration and pH on the leaching kinetics of calcined zinc oxide ore

  • Authors: Muzenda, Edison , Simate, Geoffrey S.
  • Date: 2011
  • Subjects: Dissolution kinetics , Leaching , Zinc ions , Zinc oxide
  • Type: Article
  • Identifier: uj:4701 , http://hdl.handle.net/10210/10940
  • Description: Previous studies on the dissolution of zinc oxide have concentrated on the effects of temperature, reagent concentration, particle size and agitation rate, among other factors. However, there is dearth data on the effect of a combination of product concentration and pH on leaching rates. This work examines the effects of the concentration of pH and zinc ions on the dissolution kinetics of zinc oxide. The results showed that the rate of zinc dissolution was greatest at lower pHs. This is because at lower pH, the concentration of acid (H+ ions) is also expected to be high (pH = log10[H+]), thus increasing the reaction kinetics in accordance with the kinetic molecular theory. The rate of reaction was found to increase with an increase in the concentration of zinc ions (Zn2+), which is in contrast to established theories. This observation can be explained by the fact that since heat energy produced (via an exothermic reaction) was continuously being dissipated through a constant temperature water bath it favoured zinc oxide dissolution. Zinc oxide ore at 62.5% purity also comprised of other metal oxides (e.g., iron, copper, manganese, etc) which were simultaneously leached. Since the solution was recycled, the concentration of iron, for example, could have also increased. Since zinc is more reactive than iron, two reaction mechanisms could have possibly been occurring at the same time, i.e., the dissolution of zinc oxide ore by sulfuric acid and the displacement of iron in solution by zinc in zinc oxide forming iron hydroxide.
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Volatile organic compounds- biodiesel thermodynamic interactions: influence of temperature

An investigation into the effect of temperature on the leaching of copper-matte

  • Authors: Muzenda, Edison , Ramatsa, I.M. , Ntuli, Freeman , Belaid, Mohamed , Tshwabi, P.M.
  • Date: 2011
  • Subjects: Coppermatte leaching - Effect of temperature , Leaching - Effect of temperature
  • Type: Article
  • Identifier: uj:4703 , http://hdl.handle.net/10210/10944
  • Description: A study was carried out to determine the influence of the temperature and the reaction involved on the leaching of coppermatte. Copper (Cu) bearing matte from Impala Refinery (Pty) Ltd was used in the investigation. The experiments were conducted in a leaching cell submerged in a water bath, with ammonia concentrations (leaching solution) of 3.0M, temperature of 50°C, 60°C and 70°C, pH of 11 and for a time period of 130 minutes. Leaching tests indicated that Cu recovery increased in the temperature range 50°C - 60°C, however at a temperature of 70°C Cu recovery decreases because of cementation process as nickel displace copper. The shrinking core model was used to determine if the leaching process was diffusion controlled, or chemical controlled, or even mixed controlled. It was found that the leaching process could not be determined using the shrinking core model due to the cementation process of Cu. It was concluded that an increase in temperature results in an increase in the Cu recovery however the temperature should not be too high as cementation process increase with increasing temperature.
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Thermodynamics of Cu (II) adsorption onto South African clinoptilolite from synthetic solution by ion exchange process.

Comparison of the structural configuration of cobalt nanoparticles on titania and titania nanotube supports

  • Authors: Afolabi, A. S. , Abdulkareem, A. S. , Muzenda, Edison
  • Date: 2012
  • Subjects: Cobaly catalysts , Titania , Titania nanotubes
  • Type: Article
  • Identifier: uj:4676 , ISSN 2306-4277 , http://hdl.handle.net/10210/10445
  • Description: In this study, two cobalt based catalyst samples were prepared on titania and titania nanotubes supports using the deposition precipitation method. Their structural configurations were characterized and compared using BET, and TRP analyses. The BET analysis showed that the surface area of TiO2 is much higher than that of TNT which was due to their structural differences. Analyses of the results obtained revealed that the surface area of the 10 % Co/TNT catalyst sample is higher than that of the 10 % Co/TiO2. The TPR analysis showed that it is much easier to reduce 10 % Co/TiO2, than 10 % Co/TNT. This is attributed to be due to the fact that the cobalt particles were adsorbed on the surface of the TiO2, and formed covalent bonds with TNT. Therefore reduction temperature was higher with TNT than TiO2. The investigation of structural changes of these catalysts when they were coated with carbon, using chemical vapour deposition method was also conducted. The catalyst prepared on TNT support showed better properties in terms of average pore diameter, pore volume and surface area than the catalyst sample prepared on TiO2 support when the two samples were exposed to carbon environment for the same period of time.
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Sizing of an anaerobic biodigester for the organic fraction of municipal solid waste

  • Authors: Kigozi, R. , Aboyade, A. O. , Muzenda, Edison
  • Date: 2014
  • Subjects: Anaerobic digestion , Biogas digesters , Clean energy , Municipal solid waste management
  • Type: Article
  • Identifier: uj:4982 , ISSN 2078-0966 , http://hdl.handle.net/10210/13114
  • Description: The anaerobic digestion (AD) of the organic fraction of municipal solid waste (OFMSW) for biogas production is a potential solution to the growing challenges associated with municipal solid waste (MSW) management while simultaneously providing an alternative clean energy source. Biogas is produced by the anaerobic digestion (AD) of biomass using microorganisms in specifically designed plants called biogas digesters under controlled conditions or naturally in marshes and landfills. It is a rather clean and versatile fuel as opposed to fossil fuels. To design an efficient AD system, a proper understanding of the quality and quantity of available feedstock must be made as well as prevailing operating conditions. This paper represents steps that were taken to come up with an optimal size of biodigester to treat OFMSW produced at the University of Johannesburg’s Doornfontein Campus in downtown Johannesburg. The campus generates 232.2kg of OFMSW per day which required 30m3 of biodigester capacity.
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Caco3 precipitation in selected bacteria mixture by activated microbial induction

  • Authors: Agbenyeku, Emmanuel Emem-Obong , Muzenda, Edison , Msibi, Innocent Mandla
  • Date: 2016
  • Subjects: Natural soils , Bacillus subtilis , Sporosarcina pasteurii , Bacteria , Microbial attack
  • Language: English
  • Type: Conference proceedings
  • Identifier: http://hdl.handle.net/10210/93685 , uj:20379 , Citation: Agbenyeku, E.E., Muzenda, E. & Msibi, I.M. 2016. Caco3 precipitation in selected bacteria mixture by activated microbial induction.
  • Description: Abstract: Activated microbial induction of CaCO3 precipitation (AMICP) is a niche with innovative approaches that involves the exploration of bacterial attacks towards the alteration/transformation of the physical properties of soils. A handful have been documented on this technology in developed countries however, much is yet to be understood in developing African countries like South Africa, just as vermicomposting and waste water treatment technologies are gaining grounds. It is widely known that AMICP by urea hydrolysis in natural soils is possibly affected by contacts between ureolytic and non-ureolytic bacteria, the study explored a designed and experimental assessment of the relations between ureolytic and nonureolytic bacteria and their interactive effects on AMICP. Through existing studies an artificial leveled groundwater medium was injected with model species of bacteria i.e., ureolytic species Sporosarcina pasteurii and the non-ureolytic species Bacillus subtilis. The control treatment was inoculated with a pure culture of S. pasteurii under measurements of pH, optical density (OD), development of NH4-N, dissolved calcium (DC) and dissolved inorganic carbon (DIC). Outcomes revealed DC precipitated as CaCO3 slower in the control mixture than in the mixed culture irrespective of unfavorable conditions in the mixed culture, i.e., lower concentrations of pH and CO32−. Higher density of bacterial cells in the mixed culture resulted from B. subtilis showing significant higher growth rate than S. pasteurii. Previous authors indicate that the presence of the non-ureolytic bacterial species, B. subtilis, stimulate AMICP process through supply of nucleation sites in the form of non-ureolytic bacterial cells.
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Technology in Africa for sustainable alternative energy growth : an innovative bird eye view

  • Authors: Agbenyeku, Emmanuel Emem-Obong , Muzenda, Edison , Msibi, Innocent Mandla
  • Date: 2015
  • Subjects: Renewable energy , Electricity , Innovative learning
  • Language: English
  • Type: Conference proceedings
  • Identifier: http://hdl.handle.net/10210/73433 , uj:18410 , Citation: Agbenyeku, E.E., Muzenda, E. & Msibi, I.M. 2015. Technology in Africa for sustainable alternative energy growth : an innovative bird eye view.
  • Description: Abstract: Over the last decade, numerous ideas have insistently emerged and triggered several social, economic and environmental discuss emanating from energy insufficiencies in Africa. A lot around energy poverty are currently argued particularly, on how chiefly Africa’s industrialization is prime to its potential sustainability across all facets of growth and development. Sadly, only few member countries since post-colonialism have earnestly attempted innovative approaches towards new alternative energy schemes. Nonetheless, wasteful sums have drowned in projects of less critical nature. For this reason; an innovative bird eye view (IBEV) portrayed how member countries might augment rates of dispensable energy to increase access to electricity. Hence, versatile industrialization via renewable and greener alternative energy sources can be reached. The employed measures herein, extend past industries and research institutes to involve cultural, institutional, economic and political players of key positions in innovative process. Firstly, a conceptual idea of “learning” was conveyed as vital to IBEV, seeing innovation and production as pertinent and dynamic. On a second note, the work featured instances of trials to create renewable energy industries around the continent. Lastly, the possible transformation of research outlets such as the African Network for Solar Energy (ANSOLE) into inventions was highlighted, emphasizing how innovations might be born from inventions. A vital policy suggestion was that divisions of African “innovative force” such as a technological head like South Africa can for example; engage more with member countries involved in production or assembly while creating beneficial agreements with them. Thus, with mixed innovation schemes, more effective knowledge transfer can be groomed across the continent.
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