Recovery of base and heavy metals from nitric and aqueous solutions using grapefruit resin
- Authors: Phali, Caleb Motlatsi
- Date: 2015
- Subjects: Grapefruit resin
- Language: English
- Type: Master’s Thesis
- Identifier: http://hdl.handle.net/10210/57316 , uj:16379
- Description: Abstract: In the mineral beneficiation the use of aqueous solution such as mineral acids (HCl, H2SO4 and HNO3) is important particularly for the recovery of base metals (Ni, Cu, Co etc.), and the recovery of heavy metals from water samples from coal, clay and other mineral processing. The environmental monitoring of heavy and base metals pollution due to small scale mineral beneficiation is critical and of equal importance in the identification of cost effective measures for the recovery this metals. Small scale mineral beneficiation is increasing in South Africa with severe consequences such as non- adherence to the documented mining protocols with regard to the mining process. In the same breath treatment of base and heavy metals contamination from the environment has become an expensive and complex process. The study investigate possible use of a synthetic grapefruit resin as an inexpensive alternative for bio sorption of heavy and base metals from small scale mineral beneficiation. Bio sorption process is observed as a cost-effective, high efficient and simple technique for water treatment as compared to conventional methods (Volesky, 1998). Due to high content of pectin grapefruit was cross-linked and used as a bio sorbent for the following selected metals: Pb, Co, Ni, Cu and Mn. The characterization of the modified grapefruit resin included: particle size distribution, FTIR, cationic exchange capacity and BET. Factors that affected bio sorption were investigated and optimized. The FTIR spectra of the grapefruit resin revealed that the active functional groups on the grapefruit resin are –COOH and OH. It was observed the uptake of Pb and Co were 0.01675 and 0.01782 mg/g respectively this values then drop to 0.01210 and 0.01317 mg/g when the -COOH and OH functional groups are chemically blocked. The best pH for metal... , M.Tech.
- Full Text:
- Authors: Phali, Caleb Motlatsi
- Date: 2015
- Subjects: Grapefruit resin
- Language: English
- Type: Master’s Thesis
- Identifier: http://hdl.handle.net/10210/57316 , uj:16379
- Description: Abstract: In the mineral beneficiation the use of aqueous solution such as mineral acids (HCl, H2SO4 and HNO3) is important particularly for the recovery of base metals (Ni, Cu, Co etc.), and the recovery of heavy metals from water samples from coal, clay and other mineral processing. The environmental monitoring of heavy and base metals pollution due to small scale mineral beneficiation is critical and of equal importance in the identification of cost effective measures for the recovery this metals. Small scale mineral beneficiation is increasing in South Africa with severe consequences such as non- adherence to the documented mining protocols with regard to the mining process. In the same breath treatment of base and heavy metals contamination from the environment has become an expensive and complex process. The study investigate possible use of a synthetic grapefruit resin as an inexpensive alternative for bio sorption of heavy and base metals from small scale mineral beneficiation. Bio sorption process is observed as a cost-effective, high efficient and simple technique for water treatment as compared to conventional methods (Volesky, 1998). Due to high content of pectin grapefruit was cross-linked and used as a bio sorbent for the following selected metals: Pb, Co, Ni, Cu and Mn. The characterization of the modified grapefruit resin included: particle size distribution, FTIR, cationic exchange capacity and BET. Factors that affected bio sorption were investigated and optimized. The FTIR spectra of the grapefruit resin revealed that the active functional groups on the grapefruit resin are –COOH and OH. It was observed the uptake of Pb and Co were 0.01675 and 0.01782 mg/g respectively this values then drop to 0.01210 and 0.01317 mg/g when the -COOH and OH functional groups are chemically blocked. The best pH for metal... , M.Tech.
- Full Text:
Studies on the improvement of biogas production from anaerobic digestion of animal wastes
- Authors: Sebola, Mmabyalwa Rebecca
- Date: 2015
- Subjects: Biogas , Sewage - Purification - Anaerobic treatment , Renewable energy sources , Biomass energy
- Language: English
- Type: Master’s Thesis
- Identifier: http://hdl.handle.net/10210/57296 , uj:16377
- Description: Abstract: The unsustainability of intensive reliance on fossil fuels and none-renewable resources as the main sources of energy, frequent rises in energy prices, the need for climate change mitigation and environmental protection have intensified the need for green energy. In this respect, green energy, in the form of biogas, has gained increased attention as a cost effective and environmentally cautious approach. This dissertation presents various studies aimed at improving the biogas production from anaerobic digestion of animal wastes. The experiments were conducted using the batch scale mesophilic tests. Characterisation studies (ultimate and proximate analysis) were conducted to identify key characteristics of the selected feedstocks. In addition, an economic assessment on the feasibility of anaerobic technology was conducted. The waste had average moisture content (MC) ranging from 7 – 34% and 70 – 81% for the dry and wet samples, respectively. The average volatile matter (VM) varied between 44 – 58% with the C/N for CD, CM, PM and SW being 26.20, 8.13, 17.64 and 8.57, respectively. Decreasing the particle size of the feedstock increased the amount of biogas significantly by increasing the total surface area of the material exposed to the anaerobic microbes. At optimal particle size (25μm), methane production was 3 – 30 % higher as compared to that of 100μm and above. Highest methane yields were achieved from CD to CM, PM and SW at ratio of 1:1:1:1. At optimum temperature (40˚C), the highest methane yield (62% CH4/ d) was obtained on Day 6. Adding 50% VS resulted in more methane yields (64% CH4/d) than 30 and 40%. An introduction of 40% recycled liquid and 60% fresh water to the digester gave the best performance, with 73% CH4/d of biogas produced within 5 days. Soaking the feedstock prior digestion improved both the methane and biogas yields and stability of the process. An economic evaluation over a period of 5 years with 8 hours daily operation and a breakeven of 1.5 years was assessed. The proposed model has debt repayments of R 2,478,551 with the total revenue from years 2 – 5 being R 2,360,800, R 2,930,158, R... , M.Tech. (Chemical Engineering)
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- Authors: Sebola, Mmabyalwa Rebecca
- Date: 2015
- Subjects: Biogas , Sewage - Purification - Anaerobic treatment , Renewable energy sources , Biomass energy
- Language: English
- Type: Master’s Thesis
- Identifier: http://hdl.handle.net/10210/57296 , uj:16377
- Description: Abstract: The unsustainability of intensive reliance on fossil fuels and none-renewable resources as the main sources of energy, frequent rises in energy prices, the need for climate change mitigation and environmental protection have intensified the need for green energy. In this respect, green energy, in the form of biogas, has gained increased attention as a cost effective and environmentally cautious approach. This dissertation presents various studies aimed at improving the biogas production from anaerobic digestion of animal wastes. The experiments were conducted using the batch scale mesophilic tests. Characterisation studies (ultimate and proximate analysis) were conducted to identify key characteristics of the selected feedstocks. In addition, an economic assessment on the feasibility of anaerobic technology was conducted. The waste had average moisture content (MC) ranging from 7 – 34% and 70 – 81% for the dry and wet samples, respectively. The average volatile matter (VM) varied between 44 – 58% with the C/N for CD, CM, PM and SW being 26.20, 8.13, 17.64 and 8.57, respectively. Decreasing the particle size of the feedstock increased the amount of biogas significantly by increasing the total surface area of the material exposed to the anaerobic microbes. At optimal particle size (25μm), methane production was 3 – 30 % higher as compared to that of 100μm and above. Highest methane yields were achieved from CD to CM, PM and SW at ratio of 1:1:1:1. At optimum temperature (40˚C), the highest methane yield (62% CH4/ d) was obtained on Day 6. Adding 50% VS resulted in more methane yields (64% CH4/d) than 30 and 40%. An introduction of 40% recycled liquid and 60% fresh water to the digester gave the best performance, with 73% CH4/d of biogas produced within 5 days. Soaking the feedstock prior digestion improved both the methane and biogas yields and stability of the process. An economic evaluation over a period of 5 years with 8 hours daily operation and a breakeven of 1.5 years was assessed. The proposed model has debt repayments of R 2,478,551 with the total revenue from years 2 – 5 being R 2,360,800, R 2,930,158, R... , M.Tech. (Chemical Engineering)
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The plug-in plantation: A proposal for a resilient infrastructural system achieved via the participation-driven robotic reforestation of residual space along Johannesburg's Main Reef Road
- Authors: Jonker, Pieter Jacobus
- Date: 2015
- Subjects: resilient infrastructural system
- Language: English
- Type: Master’s Thesis
- Identifier: http://hdl.handle.net/10210/55909 , uj:16322
- Description: Abstract: Please refer to full text to view abstract , M.Tech. (Architecture)
- Full Text: false
- Authors: Jonker, Pieter Jacobus
- Date: 2015
- Subjects: resilient infrastructural system
- Language: English
- Type: Master’s Thesis
- Identifier: http://hdl.handle.net/10210/55909 , uj:16322
- Description: Abstract: Please refer to full text to view abstract , M.Tech. (Architecture)
- Full Text: false
Validation of concrete elastic modulus estimation methods
- Authors: Sun, Ryan Wok
- Date: 2015
- Subjects: Elastic analysis (Engineering) , Concrete - Testing , Reinforced concrete construction , Concrete products , Strength of materials
- Language: English
- Type: Master’s Thesis
- Identifier: http://hdl.handle.net/10210/56194 , uj:16341
- Description: Abstract: The modulus of elasticity (E) is an important property of concrete that needs to be quantified when designing complex structures. The methods to best quantify this property are empirical within the laboratory, but outside the laboratory, designers may depend on estimation models. There exists numerous estimation models at the designer’s disposal but the accuracy and reliability of those models have not been comprehensively and comparatively assessed. The actual E values of 108 specimens, whose properties differed in aggregate type, cement type, concrete strength and curing age, were measured. The actual E values were compared to the predictions made by 23 estimation models. The accuracy of each model was analysed statistically to conclusively determine which of the models was most accurate. The Noguchi et al (2009) model was found to be the most accurate and consistently so, rendering an overall coefficient of variation of 15.94%. The CEB-FIP (1970) model was found to be the least accurate, resulting with an overall coefficient of variation of 31.81%. In addition to the primary objective, this study included the analysis of the degree of influence of aggregate percentage content, compressive strength, curing age and concrete density on the actual elastic modulus of concrete. The concrete’s density was found to be a major factor in the resulting E of concrete as the statistics had shown that the correlation was highly significant (P = 2.39 x 10-7 %). Concrete strength on the other hand, a factor that most models use as a primary basis for their estimations, was not as influential as assumed. In fact, the statistical results showed the correlation to have a level of significance of 11.1 %. It was therefore highly recommended that E estimation models should, at least, include the density of concrete as a common parameter more than the inclusion of concrete strength. Separate to the topic of concrete E, this research also assessed the average strength relationship between concrete cylinders and concrete cubes. The average cylinder-cube strength relationship slightly increases with the increase in curing age indicated by a correlation coefficient of 0.998. The strength of the cylinders were found to be, on average, approximately 85 % of the cube strengths. , M.Tech. (Civil Engineering)
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- Authors: Sun, Ryan Wok
- Date: 2015
- Subjects: Elastic analysis (Engineering) , Concrete - Testing , Reinforced concrete construction , Concrete products , Strength of materials
- Language: English
- Type: Master’s Thesis
- Identifier: http://hdl.handle.net/10210/56194 , uj:16341
- Description: Abstract: The modulus of elasticity (E) is an important property of concrete that needs to be quantified when designing complex structures. The methods to best quantify this property are empirical within the laboratory, but outside the laboratory, designers may depend on estimation models. There exists numerous estimation models at the designer’s disposal but the accuracy and reliability of those models have not been comprehensively and comparatively assessed. The actual E values of 108 specimens, whose properties differed in aggregate type, cement type, concrete strength and curing age, were measured. The actual E values were compared to the predictions made by 23 estimation models. The accuracy of each model was analysed statistically to conclusively determine which of the models was most accurate. The Noguchi et al (2009) model was found to be the most accurate and consistently so, rendering an overall coefficient of variation of 15.94%. The CEB-FIP (1970) model was found to be the least accurate, resulting with an overall coefficient of variation of 31.81%. In addition to the primary objective, this study included the analysis of the degree of influence of aggregate percentage content, compressive strength, curing age and concrete density on the actual elastic modulus of concrete. The concrete’s density was found to be a major factor in the resulting E of concrete as the statistics had shown that the correlation was highly significant (P = 2.39 x 10-7 %). Concrete strength on the other hand, a factor that most models use as a primary basis for their estimations, was not as influential as assumed. In fact, the statistical results showed the correlation to have a level of significance of 11.1 %. It was therefore highly recommended that E estimation models should, at least, include the density of concrete as a common parameter more than the inclusion of concrete strength. Separate to the topic of concrete E, this research also assessed the average strength relationship between concrete cylinders and concrete cubes. The average cylinder-cube strength relationship slightly increases with the increase in curing age indicated by a correlation coefficient of 0.998. The strength of the cylinders were found to be, on average, approximately 85 % of the cube strengths. , M.Tech. (Civil Engineering)
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