Optimization of the electrochemical exfoliation of graphene oxide synthesis was investigated in this report using varying potentials. Graphite from waste lithium-ion batteries was used as the electrodes for the DC (direct current) electrochemical set-up. Electric potentials of 7.5 V, 12 V, and 15 V were applied for 225 minutes using 0.2M H2SO4 as the electrolyte. The characterization of the produced graphene oxide was done using Raman spectroscopy, high-resolution scanning electron microscopy (HRSEM), and energy dispersive x-ray spectroscopy (EDS) attached to the scanning electron microscope (SEM). The results obtained showed that both the rate of graphene oxide yield and the C/O ratio increased correspondingly with the increase in electric potential. However, the structure of graphene oxide produced at 7.5 V was of superior quality compared to others produced at higher potentials with regards to the crystallite lattice characteristics such as defects, lateral dimensions, thickness, and the number of graphene layers. Consequently, tailor-made graphene oxide properties (and yield) for target applications may be achieved using the electrochemical exfoliation method via the choice of the electric potential.
{"title":"Effect of electric potential on the structure and yield of graphene oxide using electrochemical exfoliation method","authors":"O. D. Adigun, L. E. Umoru, T. N. Iwatan","doi":"10.4314/njtd.v20i3.1521","DOIUrl":"https://doi.org/10.4314/njtd.v20i3.1521","url":null,"abstract":"Optimization of the electrochemical exfoliation of graphene oxide synthesis was investigated in this report using varying potentials. Graphite from waste lithium-ion batteries was used as the electrodes for the DC (direct current) electrochemical set-up. Electric potentials of 7.5 V, 12 V, and 15 V were applied for 225 minutes using 0.2M H2SO4 as the electrolyte. The characterization of the produced graphene oxide was done using Raman spectroscopy, high-resolution scanning electron microscopy (HRSEM), and energy dispersive x-ray spectroscopy (EDS) attached to the scanning electron microscope (SEM). The results obtained showed that both the rate of graphene oxide yield and the C/O ratio increased correspondingly with the increase in electric potential. However, the structure of graphene oxide produced at 7.5 V was of superior quality compared to others produced at higher potentials with regards to the crystallite lattice characteristics such as defects, lateral dimensions, thickness, and the number of graphene layers. Consequently, tailor-made graphene oxide properties (and yield) for target applications may be achieved using the electrochemical exfoliation method via the choice of the electric potential.","PeriodicalId":31273,"journal":{"name":"Nigerian Journal of Technological Development","volume":"27 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-10-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135761122","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The purpose of this study is to provide an overview of sustainability evaluation techniques in textile and apparel sector. The review studies are divided into two namely product relate assessment methods and integrated assessment methods which summarizes the different dimension covered, weightage, number of indicators involved, and highlight the weakness and strength of the previous developed sustainability assessment methods in the textile industry. The analysis revealed that majority of the product-related assessment methods focused on environmental factors only, while all the studies reviewed in this category neglected triple bottom line (TBL) in their assessment approach. Nevertheless, there is still a need to focus more on integrated assessment tools to fulfil the TBL goals. This current study offers comprehensive details of product related assessment and integrated assessment methods that was published from 2010 to 2022. Furthermore, examined current sustainability evaluation methods and offered insights into how sustainability assessment techniques have evolved in the textile and apparel industry. The review showed the product related assessment tools are impact assessment techniques are frequently used as an independent tool for evaluating the specific impact of one sustainability measurement, also have no weights attached to them because most indicators assessed were more generic. While integrated assessment method revealed that results would be less reliable if weighting and data collection were non-standardized and inconsistent. However, from the uncertainty’s perspectives, only integrated assessment tools considered fuzziness, grey and stochastic ambiguities in some of their methods, whereas product related assessment tools studied, ignored fuzziness and grey uncertainties completely.
{"title":"Sustainability assessment of textile and apparel sector: a review of current approaches and tools","authors":"T.G. Fadara, K. Y. Wong, M. I. Maulana","doi":"10.4314/njtd.v20i3.1255","DOIUrl":"https://doi.org/10.4314/njtd.v20i3.1255","url":null,"abstract":"The purpose of this study is to provide an overview of sustainability evaluation techniques in textile and apparel sector. The review studies are divided into two namely product relate assessment methods and integrated assessment methods which summarizes the different dimension covered, weightage, number of indicators involved, and highlight the weakness and strength of the previous developed sustainability assessment methods in the textile industry. The analysis revealed that majority of the product-related assessment methods focused on environmental factors only, while all the studies reviewed in this category neglected triple bottom line (TBL) in their assessment approach. Nevertheless, there is still a need to focus more on integrated assessment tools to fulfil the TBL goals. This current study offers comprehensive details of product related assessment and integrated assessment methods that was published from 2010 to 2022. Furthermore, examined current sustainability evaluation methods and offered insights into how sustainability assessment techniques have evolved in the textile and apparel industry. The review showed the product related assessment tools are impact assessment techniques are frequently used as an independent tool for evaluating the specific impact of one sustainability measurement, also have no weights attached to them because most indicators assessed were more generic. While integrated assessment method revealed that results would be less reliable if weighting and data collection were non-standardized and inconsistent. However, from the uncertainty’s perspectives, only integrated assessment tools considered fuzziness, grey and stochastic ambiguities in some of their methods, whereas product related assessment tools studied, ignored fuzziness and grey uncertainties completely.","PeriodicalId":31273,"journal":{"name":"Nigerian Journal of Technological Development","volume":"59 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-10-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135760611","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
E. Y. Salawu, K. A. Shittu, S. A. Afolalu, J. F. Kayode, S. L. Lawal, O. O. Ajayi, S. O. Ongbali
The study focused on the response of mild steel and HT250 grey cast iron in varying ethanol concentration. First, a robust review of both materials’ behaviour under different environment was established using microstructural evolutions. Secondly, 30 × 30 × 10 mm dimension of both materials were employed in the study by immersing them in varying ethanol concentrations of BG-43 %, ESG- 42 %, CG-43 %, SQD- 42 % using distilled water as control. The microstructural behaviour showed that every of the sample responded according to the medium of interaction (ethanol). The degree of surface damage also depends on the ethanol concentration and the heavy presence of Fe and oxygen especially in that of grey cast iron. Corrosion cracks and deposits can be attributed to the reaction between the surface and the ethanol. Thus, environment of application is important in material selection. Results suggests that the microstructural changes provide to the material scientist the qualitative corrosion information of these materials in different environment. Conclusively, the study has enlightened the design engineers and material specialist on the need for proper material selection during engineering design.
{"title":"Microstructural evaluations of mild steel and HT250 grey cast iron in ethanol environment","authors":"E. Y. Salawu, K. A. Shittu, S. A. Afolalu, J. F. Kayode, S. L. Lawal, O. O. Ajayi, S. O. Ongbali","doi":"10.4314/njtd.v20i3.150","DOIUrl":"https://doi.org/10.4314/njtd.v20i3.150","url":null,"abstract":"The study focused on the response of mild steel and HT250 grey cast iron in varying ethanol concentration. First, a robust review of both materials’ behaviour under different environment was established using microstructural evolutions. Secondly, 30 × 30 × 10 mm dimension of both materials were employed in the study by immersing them in varying ethanol concentrations of BG-43 %, ESG- 42 %, CG-43 %, SQD- 42 % using distilled water as control. The microstructural behaviour showed that every of the sample responded according to the medium of interaction (ethanol). The degree of surface damage also depends on the ethanol concentration and the heavy presence of Fe and oxygen especially in that of grey cast iron. Corrosion cracks and deposits can be attributed to the reaction between the surface and the ethanol. Thus, environment of application is important in material selection. Results suggests that the microstructural changes provide to the material scientist the qualitative corrosion information of these materials in different environment. Conclusively, the study has enlightened the design engineers and material specialist on the need for proper material selection during engineering design.","PeriodicalId":31273,"journal":{"name":"Nigerian Journal of Technological Development","volume":"16 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-10-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135803332","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
K. E. Aweto, O. Ohwohere-Asuma, G. Ovwamuedo, P. C. Atiti
Geoelectric, geochemical investigation, and groundwater modelling were integrated in areas surrounding the Ughelli West Engineered dumpsite in the Western Niger Delta. The study focused on assessing the environmental impact of the dumpsite on its surrounding groundwater. The geochemical analyses revealed that the leachates generated from the dumpsite have significant potential to contaminate the surrounding environment. The BOD5/COD ratio was less than 0.1, indicating that the dumpsite is old with stabilized leachate of low biodegradability and in the methanogenic phase of anaerobic degradation. The groundwater chemistry in monitoring wells outside the dumpsite and at other control sites showed no significant impact of the dumpsite on groundwater quality. Groundwater models showed groundwater flow in the north-western direction and significant vertical movement of contaminants up to depths of about 60 m beneath the dumpsite after a period of 3 years. The contaminant plume, however, had not moved considerably laterally away from the dumpsite. The location of the dumpsite within areas of low vulnerability due to the presence of clay/sandy clay between 1.3 and 6 m thick around the dumpsite limited the lateral migration of leachate in groundwater.
{"title":"Hydro-geochemical characterization and groundwater modelling of the subsurface around Ughelli West Engineered Dumpsite in the Western Niger Delta, Nigeria","authors":"K. E. Aweto, O. Ohwohere-Asuma, G. Ovwamuedo, P. C. Atiti","doi":"10.4314/njtd.v20i2.1393","DOIUrl":"https://doi.org/10.4314/njtd.v20i2.1393","url":null,"abstract":"Geoelectric, geochemical investigation, and groundwater modelling were integrated in areas surrounding the Ughelli West Engineered dumpsite in the Western Niger Delta. The study focused on assessing the environmental impact of the dumpsite on its surrounding groundwater. The geochemical analyses revealed that the leachates generated from the dumpsite have significant potential to contaminate the surrounding environment. The BOD5/COD ratio was less than 0.1, indicating that the dumpsite is old with stabilized leachate of low biodegradability and in the methanogenic phase of anaerobic degradation. The groundwater chemistry in monitoring wells outside the dumpsite and at other control sites showed no significant impact of the dumpsite on groundwater quality. Groundwater models showed groundwater flow in the north-western direction and significant vertical movement of contaminants up to depths of about 60 m beneath the dumpsite after a period of 3 years. The contaminant plume, however, had not moved considerably laterally away from the dumpsite. The location of the dumpsite within areas of low vulnerability due to the presence of clay/sandy clay between 1.3 and 6 m thick around the dumpsite limited the lateral migration of leachate in groundwater.","PeriodicalId":31273,"journal":{"name":"Nigerian Journal of Technological Development","volume":"18 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-10-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"136359121","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Gearbox transmission system is a fundamental factor in the industrial applications. If gearbox stop working due to different faults, it may break normal machine operation and cause a production loss. This research paper focused on fault analysis of combination of worm wheel and bearing by using root mean square (RMS) and response surface method (RSM). Faults considered on outer race and inner race of worm wheel bearing, on worm wheel tooth. These faults and load were considered as an important independent factor to understand their effects on RMS response of worm gearbox. Worm gearbox experimental setup is for laboratory experimentation and RSM for analysis. Twenty-seven experimental trial conducted for three level of parameters based on design of experiment (DOE). Vibration based response measured in frequency domain and root mean square parameter extracted for the fault analysis. Box behnken design RSM is implemented to investigate independent parameters effect on output parameter i.e. RMS. The result shows that effect of faulty inner race bearing is more on worm wheel as compared to faulty outer race bearing and fault parameter influence RMS than load parameter.
{"title":"Experimental investigation for fault diagnosis of a single stage worm gearbox using response surface methodology","authors":"R. R. Barshikar, P. R. Baviskar","doi":"10.4314/njtd.v20i2.1259","DOIUrl":"https://doi.org/10.4314/njtd.v20i2.1259","url":null,"abstract":"Gearbox transmission system is a fundamental factor in the industrial applications. If gearbox stop working due to different faults, it may break normal machine operation and cause a production loss. This research paper focused on fault analysis of combination of worm wheel and bearing by using root mean square (RMS) and response surface method (RSM). Faults considered on outer race and inner race of worm wheel bearing, on worm wheel tooth. These faults and load were considered as an important independent factor to understand their effects on RMS response of worm gearbox. Worm gearbox experimental setup is for laboratory experimentation and RSM for analysis. Twenty-seven experimental trial conducted for three level of parameters based on design of experiment (DOE). Vibration based response measured in frequency domain and root mean square parameter extracted for the fault analysis. Box behnken design RSM is implemented to investigate independent parameters effect on output parameter i.e. RMS. The result shows that effect of faulty inner race bearing is more on worm wheel as compared to faulty outer race bearing and fault parameter influence RMS than load parameter.","PeriodicalId":31273,"journal":{"name":"Nigerian Journal of Technological Development","volume":"10 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-10-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"136358489","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Conventionally employed zinc-rich paints and coatings for marine corrosion protection of steel still comprise environmentally unfriendly compounds such as zinc phosphate. This paper is focused on developing eco-friendly zinc ternary composite coatings of Zn-ZnO-CaCO3 utilizing CaCO3 additives derived from tympanotonus fuscatus (periwinkle) shell and calcareous eggshell respectively on low-carbon steel using electrodeposition technique. This is aimed at improving not only the surface corrosion resistance of steel structures in marine environment but also the sustainability of raw materials and minimal environmental pollution. Corrosion studies of uncoated and coated steel samples in simulated marine environment were done using linear polarization technique. Results obtained suggested that CaCO3 (i.e., calcareous eggshell) additive in the composite coating significantly improved the corrosion performance of the substrate. Steel coated with calcareous eggshell additive displayed superior corrosion performance having highest polarization resistance, Rp (156090 Ω), lowest corrosion rate, CR (0.01 mm/year) and highest coating efficiency, Ceff (97%) as against those of uncoated, zinc oxide, and tympanotonus fuscatus shell additives after 30 minutes deposition time. Scanning Electron Microscopy (SEM) and Energy Dispersive X-Ray Spectroscopy (EDS) results of selected developed coatings indicated presence of a homogeneous surface morphology and a significant amount of calcium in the calcareous eggshell coating.
{"title":"Electrolytic co-deposition of Zn-ZnO and Zn-ZnO-CaCO<sub>3</sub> composite substrates on low-carbon steel","authors":"R. N. Nnaji, M. A. Bodude, D. E. Esezobor","doi":"10.4314/njtd.v20i2.1314","DOIUrl":"https://doi.org/10.4314/njtd.v20i2.1314","url":null,"abstract":"Conventionally employed zinc-rich paints and coatings for marine corrosion protection of steel still comprise environmentally unfriendly compounds such as zinc phosphate. This paper is focused on developing eco-friendly zinc ternary composite coatings of Zn-ZnO-CaCO3 utilizing CaCO3 additives derived from tympanotonus fuscatus (periwinkle) shell and calcareous eggshell respectively on low-carbon steel using electrodeposition technique. This is aimed at improving not only the surface corrosion resistance of steel structures in marine environment but also the sustainability of raw materials and minimal environmental pollution. Corrosion studies of uncoated and coated steel samples in simulated marine environment were done using linear polarization technique. Results obtained suggested that CaCO3 (i.e., calcareous eggshell) additive in the composite coating significantly improved the corrosion performance of the substrate. Steel coated with calcareous eggshell additive displayed superior corrosion performance having highest polarization resistance, Rp (156090 Ω), lowest corrosion rate, CR (0.01 mm/year) and highest coating efficiency, Ceff (97%) as against those of uncoated, zinc oxide, and tympanotonus fuscatus shell additives after 30 minutes deposition time. Scanning Electron Microscopy (SEM) and Energy Dispersive X-Ray Spectroscopy (EDS) results of selected developed coatings indicated presence of a homogeneous surface morphology and a significant amount of calcium in the calcareous eggshell coating.","PeriodicalId":31273,"journal":{"name":"Nigerian Journal of Technological Development","volume":"32 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-10-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"136359115","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
This paper reports the results of three-dimensional numerical optimisation of microchannel heat exchanger with square and circular cooling channels. The objective of the optimisation is to maximise the global thermal conductance or minimise global thermal resistance. Response surface optimisation methodology (RSM) is used in the numerical optimisation. A high-density heat flux (2.5×106W/m2) is imposed at the bottom surface of the unit cell microchannel and numerical simulation carried out using ANSYS Fluent commercial software package.The elemental volume and axial length N=10mm of the microchannel were all fixed, while the width was free to morph. The cooling technique employs single-phase water which flows through the rectangular block microchannel heat sink to remove the heat at the bottom of the microchannels in a forced convection laminar flow regime. The velocity of the fluid pumped across the microchannel axial length is the range 400≤Rew≤500. Finite volume method (FVM) is used to descretised the computational domain and computational fluid dynamic (CFD) code employed to solve a series of governing equations. The effect of channel hydraulic diameter and Reynolds number of water-flow on peak wall temperature and minimised temperature are investigated and reported. The numerical results show that the microchannel with square cooling channel has the highest maximised global thermal conductance than the micro heat sink with circular configuration. The result of the numerical study agrees with what is in the open literature.
{"title":"Forced convection heat transfer in micro heat sinks with square and circular configuration","authors":"N. Y. Godi, L. B. Zhengwuvi, M. O. Petinrin","doi":"10.4314/njtd.v20i2.1272","DOIUrl":"https://doi.org/10.4314/njtd.v20i2.1272","url":null,"abstract":"This paper reports the results of three-dimensional numerical optimisation of microchannel heat exchanger with square and circular cooling channels. The objective of the optimisation is to maximise the global thermal conductance or minimise global thermal resistance. Response surface optimisation methodology (RSM) is used in the numerical optimisation. A high-density heat flux (2.5×106W/m2) is imposed at the bottom surface of the unit cell microchannel and numerical simulation carried out using ANSYS Fluent commercial software package.The elemental volume and axial length N=10mm of the microchannel were all fixed, while the width was free to morph. The cooling technique employs single-phase water which flows through the rectangular block microchannel heat sink to remove the heat at the bottom of the microchannels in a forced convection laminar flow regime. The velocity of the fluid pumped across the microchannel axial length is the range 400≤Rew≤500. Finite volume method (FVM) is used to descretised the computational domain and computational fluid dynamic (CFD) code employed to solve a series of governing equations. The effect of channel hydraulic diameter and Reynolds number of water-flow on peak wall temperature and minimised temperature are investigated and reported. The numerical results show that the microchannel with square cooling channel has the highest maximised global thermal conductance than the micro heat sink with circular configuration. The result of the numerical study agrees with what is in the open literature.","PeriodicalId":31273,"journal":{"name":"Nigerian Journal of Technological Development","volume":"52 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-10-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"136255106","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
C.O. Akinbile, E. M. Epebinu, O.O. Olanrewaju, A.T. Abolude
ABSTRACT: Activated carbon (AC) is one of the numerous cost-effective inputs for treating wastewater in an efficient and cost-effective manner, and several materials have been used to produce AC with diverse results. One such material with a large potential is African Bamboo (Bambusa vulgaris), especially due to its availability. In this study, bamboo was carbonized and then activated using trioxonitrate (V) acid (HNO3) and potassium hydroxide (KOH) as activating agents. The AC was characterized using Fourier Transform Infrared Spectroscopy (FTIR) and Scanning Electron Microscopy (SEM) technologies at 50 μm, 80 μm, 100 μm, and 200 μm magnification. The SEM imagery results at 50 μm and 1500x magnification showed that the AC produced using KOH had the largest and most well-developed pore spaces hence maximum capacity to absorb contaminants compared to HNO3's AC and inactivated carbonated charcoal. The FTIR spectra peak analysis results also confirmed that KOH's AC had the highest number of functional groups on its surface and, therefore, enhanced its adsorption capacity.
{"title":"Comparative analysis of bamboo-based (<i>Bambusa vulgaris</i>) activated carbon produced through trioxonitrate (V) acid and potassium hydroxide","authors":"C.O. Akinbile, E. M. Epebinu, O.O. Olanrewaju, A.T. Abolude","doi":"10.4314/njtd.v20i2.1155","DOIUrl":"https://doi.org/10.4314/njtd.v20i2.1155","url":null,"abstract":"ABSTRACT: Activated carbon (AC) is one of the numerous cost-effective inputs for treating wastewater in an efficient and cost-effective manner, and several materials have been used to produce AC with diverse results. One such material with a large potential is African Bamboo (Bambusa vulgaris), especially due to its availability. In this study, bamboo was carbonized and then activated using trioxonitrate (V) acid (HNO3) and potassium hydroxide (KOH) as activating agents. The AC was characterized using Fourier Transform Infrared Spectroscopy (FTIR) and Scanning Electron Microscopy (SEM) technologies at 50 μm, 80 μm, 100 μm, and 200 μm magnification. The SEM imagery results at 50 μm and 1500x magnification showed that the AC produced using KOH had the largest and most well-developed pore spaces hence maximum capacity to absorb contaminants compared to HNO3's AC and inactivated carbonated charcoal. The FTIR spectra peak analysis results also confirmed that KOH's AC had the highest number of functional groups on its surface and, therefore, enhanced its adsorption capacity.","PeriodicalId":31273,"journal":{"name":"Nigerian Journal of Technological Development","volume":"54 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-10-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"136358486","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Exoskeleton of crab comprises a dominating mineral (calcium carbonate, CaCO3), protein and a natural polymer (chitin). Chemical treatments have been employed at different instances to isolate pure chitin from different sources. It is thus necessary to investigate how this treatment will influence the features of chitin isolated from the same source (crab). In this study, 0.4, 0.8 and 1.2 M hydrochloric acid (HCl) were separately used to demineralize crab shell particles and this was followed by deproteinization with 0.4 and 1.2 M sodium hydroxide (NaOH) at 100 °C. Results showed that chitin properties were influenced by concentrations of reagents. Fibrils of different forms and surface appearance were observed via Scanning Electron Microscopy (SEM). The highest crystallinity index of 71% was possessed by chitin extracted using 0.4 M HCl and NaOH while 65.5% remained the least displayed by chitin extracted with 1.2 M HCl and NaOH. This trend was similar for chitin’s thermal stability where Thermogravimetric analysis (TGA) results informed that using the highest concentrations of 1.2 M HCl and NaOH provided chitin with 80.12 kJ/mol activation energy. On the other hand, 112.54 kJ/mol was calculated for chitin isolated with the minimum demineralization and deproteinization reagents used in this study.
蟹的外骨骼由主要矿物(碳酸钙，CaCO3)、蛋白质和天然聚合物(几丁质)组成。化学处理已在不同的情况下，从不同的来源分离纯几丁质。因此，有必要研究这种处理如何影响从同一来源(螃蟹)分离的几丁质的特性。在本研究中，分别用0.4、0.8和1.2 M的盐酸(HCl)对蟹壳颗粒进行脱矿，然后用0.4和1.2 M的氢氧化钠(NaOH)在100℃下进行脱蛋白。结果表明，试剂浓度对甲壳素的性质有影响。扫描电镜观察到不同形态和表面形貌的原纤维。0.4 M HCl和NaOH浸提的几丁质结晶度最高，为71%，1.2 M HCl和NaOH浸提的几丁质结晶度最低，为65.5%。这种趋势与几丁质的热稳定性相似，热重分析(TGA)结果表明，使用最高浓度的1.2 M HCl和NaOH时，几丁质的活化能为80.12 kJ/mol。另一方面，本研究中使用的最小脱矿和脱蛋白试剂分离出的几丁质得到了112.54 kJ/mol。
{"title":"Crab (<i>Brachyura</i>) shell acid and alkali treatments: Influence on thermal and structural properties of isolated acetamide-rich natural polymer","authors":"O.P Gbenebor, C.C Odili, G.I. Lawal, S.O. Adeosun","doi":"10.4314/njtd.v20i2.1411","DOIUrl":"https://doi.org/10.4314/njtd.v20i2.1411","url":null,"abstract":"Exoskeleton of crab comprises a dominating mineral (calcium carbonate, CaCO3), protein and a natural polymer (chitin). Chemical treatments have been employed at different instances to isolate pure chitin from different sources. It is thus necessary to investigate how this treatment will influence the features of chitin isolated from the same source (crab). In this study, 0.4, 0.8 and 1.2 M hydrochloric acid (HCl) were separately used to demineralize crab shell particles and this was followed by deproteinization with 0.4 and 1.2 M sodium hydroxide (NaOH) at 100 °C. Results showed that chitin properties were influenced by concentrations of reagents. Fibrils of different forms and surface appearance were observed via Scanning Electron Microscopy (SEM). The highest crystallinity index of 71% was possessed by chitin extracted using 0.4 M HCl and NaOH while 65.5% remained the least displayed by chitin extracted with 1.2 M HCl and NaOH. This trend was similar for chitin’s thermal stability where Thermogravimetric analysis (TGA) results informed that using the highest concentrations of 1.2 M HCl and NaOH provided chitin with 80.12 kJ/mol activation energy. On the other hand, 112.54 kJ/mol was calculated for chitin isolated with the minimum demineralization and deproteinization reagents used in this study.","PeriodicalId":31273,"journal":{"name":"Nigerian Journal of Technological Development","volume":"90 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-10-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"136358997","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
O. O. Ayeni, S. O. Oyegoke, O. I. Ndububa, A. E. Adetoro
There is need to study the impact of seasonal variations on well water quality especially in Ado – Ekiti metropolis as this will assist in creating awareness on groundwater quality for domestic consumption. The quality of groundwater obtained during dry and rainy seasons from 60 privately utilized hand-dug closed wells in Ado Ekiti metropolis were assessed. Physicochemical and bacteriological investigations were carried out according to required standards. The temperature, colour, turbidity, pH, total solids, chlorides, sulphate, calcium, magnesium, nitrate, and iron, which are physico-chemical parameters of the well water samples ranged from 24.7 to 25.6 °C, 4.1 to 7.3 HU, 3.7 to 6.9 NTU, 7.3 to 7.5, 95.7 to 211.1 mg/L, 38.6 to 74.6 mg/L, 34.3 to 64.9 mg/L, 24.3 to 49.4 mg/L, 48.1 to 89.0 mg/L, 0.4 to 0.8 mg/L and 0.05 to 1.0 mg/L respectively. Despite the fact that the parameters were within the acceptable ranges, bacteriological studies showed the presence of E. coli (ranged from 19.5 to 81.6 CFU) throughout the seasons, thus, individuals who rely on groundwater for their health are exposed to disease-causing organisms. Deductions from the correlation matrix equally, demonstrated the relative dependence of the parameters on one another as they variate according to the change in weather. Mostly during the rainy seasons, higher concentrations of the physicochemical and bacteriological parameters were observed than during the dry seasons, proving that the rainy seasons aid anthropogenic activities from the surface to transmit dissolved harmful waste materials to the subsurface which eventually finds its paths into the groundwater. Improper disposal of faeces, faulty soak-pits, latrines, dumpsites and burial grounds are part of the factors that contribute to bacteriological pollutants in the groundwater source.
{"title":"Physico-chemical and bacteriological assessments of shallow well water samples during the dry and rainy seasons","authors":"O. O. Ayeni, S. O. Oyegoke, O. I. Ndububa, A. E. Adetoro","doi":"10.4314/njtd.v20i2.1291","DOIUrl":"https://doi.org/10.4314/njtd.v20i2.1291","url":null,"abstract":"There is need to study the impact of seasonal variations on well water quality especially in Ado – Ekiti metropolis as this will assist in creating awareness on groundwater quality for domestic consumption. The quality of groundwater obtained during dry and rainy seasons from 60 privately utilized hand-dug closed wells in Ado Ekiti metropolis were assessed. Physicochemical and bacteriological investigations were carried out according to required standards. The temperature, colour, turbidity, pH, total solids, chlorides, sulphate, calcium, magnesium, nitrate, and iron, which are physico-chemical parameters of the well water samples ranged from 24.7 to 25.6 °C, 4.1 to 7.3 HU, 3.7 to 6.9 NTU, 7.3 to 7.5, 95.7 to 211.1 mg/L, 38.6 to 74.6 mg/L, 34.3 to 64.9 mg/L, 24.3 to 49.4 mg/L, 48.1 to 89.0 mg/L, 0.4 to 0.8 mg/L and 0.05 to 1.0 mg/L respectively. Despite the fact that the parameters were within the acceptable ranges, bacteriological studies showed the presence of E. coli (ranged from 19.5 to 81.6 CFU) throughout the seasons, thus, individuals who rely on groundwater for their health are exposed to disease-causing organisms. Deductions from the correlation matrix equally, demonstrated the relative dependence of the parameters on one another as they variate according to the change in weather. Mostly during the rainy seasons, higher concentrations of the physicochemical and bacteriological parameters were observed than during the dry seasons, proving that the rainy seasons aid anthropogenic activities from the surface to transmit dissolved harmful waste materials to the subsurface which eventually finds its paths into the groundwater. Improper disposal of faeces, faulty soak-pits, latrines, dumpsites and burial grounds are part of the factors that contribute to bacteriological pollutants in the groundwater source.","PeriodicalId":31273,"journal":{"name":"Nigerian Journal of Technological Development","volume":"52 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-10-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"136358637","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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