Browsing by Author "Agyemang, Frank Ofori"

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    Anthropogenic Sources and Risk Assessment of Heavy Metals in Mine Soils: A Case Study of Bontesso in Amansie West District of Ghana
    (Journal of Chemistry, 2023-11-16) Baah, Douglas Siaw; Gikunoo, Emmanuel; Arthur, Emmanuel Kwesi; Agyemang, Frank Ofori; Foli, Gordon; Koomson, Bennetta; Opoku, Philipa
    Contamination of the environmental receptors with heavy metals due to mining is a major topical environmental issue in Ghana. *is research investigates the possible ecological and human health risks of heavy metal impacts due to mining in the Amansie West District in Ghana. A total of 18 soil samples were taken from the Bontesso illegal mining site in the district and analyzed for the levels of arsenic (As), cadmium (Cd), copper (Cu), nickel (Ni), and lead (Pb) using atomic absorption spectrometry (AAS). From principal component analysis, cluster analysis, and correlation coe8cient analysis, the metals are derived from multiple sources, with substantial levels of correlations. Using geo-accumulation index (Igeo), contamination factor (CF), degree of contamination (Cd), pollution load index (PLI), ecological risk index (Er), and noncarcinogenic and carcinogenic risks, respectively, the impacts of As (12.2 mg/kg) and Cd (1.3 mg/kg) are above the WHO stipulated limit. Findings for pollution indices indicate moderate contamination, while HQ< 1 for inhalation and dermal exposure route, except for ingestion which is HQ> 1. Based on the USEPA standard, the carcinogenic risk of the pollutants for humans is higher than the range of 1 × 10−6 to 1 × 10−4. Furthermore, the ingestion route represents the highest contributor to cancer risk with arsenic posing the greatest risk. *e results so far suggest that chemical components gradually accumulate and thus emphasize the importance of implementing the necessary mitigation methods to minimize the impacts of illegal mining activities in the study area.
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    Detoxification of lead and arsenic from galamsey polluted water using nano synthesized iron oxide from cupola furnace slag
    (Materials Chemistry and Physics, 2023-10-15) Koomson, John Ato; Koomson, Bennetta; Owusu, Clement; Agyemang, Frank Ofori
    Drinking of water polluted with heavy metals is a means by which heavy metals bio accumulate in the human body. The rise in galamsey (illegal mining) activities in Ghana has resulted in heavy metal pollution in most water bodies in the country. Above the permissible limits, these metals cause health issues such as cancer, brain damage, kidney damage and other respiratory diseases. Hence, a smart solution to this menace is urgently needed. In this study, iron oxides were recovered from cupola furnace slag by magnetic separation and froth flotation. The recovered iron oxide was modified using electrospinning with the aid of polyvinyl alcohol after which it was calcined and used as adsorbent to detoxify lead and arsenic from two galamsey polluted water bodies in Obuasi, Ghana. Samples of the adsorbent were characterized using X-ray Fluorescence (XRF), X-ray Diffractometry (XRD), Fourier Transform Infrared Spectrometry (FTIR), Scanning Electron Microscopy (SEM) and Brunauer-Emmer-Teller (BET) method. The highest recovery for iron oxide using magnetic separation was 99.42% and that of froth flotation was 90.64%. The recovered iron oxide used as adsorbent was composed 53.04% iron oxide, with major phases like magnetite, hematite, goethite and quartz. Moreover, the surface functional group were determined to be Fe–O and OH. Also, the calcined nano fibres which were spherical in shape with rough surfaces had a specific surface area of 1.1331 m2/g. The contaminated and detoxified water were also analyzed using Atomic absorption Spectroscopy (AAS). Both adsorbent (beneficiated iron oxide and calcined nano fibre) performed well in the adsorption process, with the recovered iron oxide having 97.33% maximum lead removal efficiency while an 81.00% maximum removal efficiency for arsenic. The calcined nano fibre had a maximum of 99.99% removal efficiency for lead and 88.40% maximum efficiency for arsenic. Additionally, the adsorption fits the Langmuirian isotherm model better than the Freundlich model, indicating mono layer coverage.
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    Heavy Metals Contamination and Distribution in Surface Water and Sediment of The Aboabo Stream, Ahafo Region, Ghana
    (Earth Sciences Malaysia (ESMY), 2021-05-11) Brobbey, Ebenezer Asante Boafo; Koomson, Bennetta; Agyemang, Frank Ofori
    Activities of illegal small-scale miners promote continual introduction of wide pollutants into the Aboabo stream. Their toxicity poses health threats to the inhabitants of Krapoo village in the Ahafo Region, Ghana. The study assesses the impacts of illegal small-scale mining activities on the water quality of the stream. Levels of physico-chemical and microbiological parameters were determined using standard methods. Samples of sediment, water and plant were acid-digested with aqua-regia. Total Arsenic and Total Cadmium were analysed using Flame Atomic Absorption Spectrophotometer (FLAAS) whiles Total Mercury was analysed using Cold Vapour Atomic Absorption Spectrophotometer (CV-AAS). Turbidity, faecal coliforms and E-coli readings exceeded permissible limit of 5NTU and 0MPN/100ml respectively by Ghana’s Environmental Protection Agency (GS 1212) and World Health Organisation (WHO). Temperature, Electrical Conductivity and pH values were within the limit of <30oC, 1500μs/cm and 6.5-85 respectively at both seasons. Total suspended solids readings at the midstream were higher than the permissible limit. However, levels of total dissolved solutes and dissolved oxygen recorded, were below the limit. The sediments were also heavily polluted with Mercury, Arsenic and Cadmium. Alchornea cordifolia, Chromolaena odorata and Spigella anthelmia growing within the stream were taken to assess their efficiency in removing the heavy metals from the stream. It was observed that the plants species had bioaccumulation factor (BF) greater than 1 for cadmium. Alchornea cordifolia was the only plant with BF greater than 1 for mercury. The plants species are potential hyper accumulators for mercury and cadmium hence are suitable for phytoremediation.
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    Molten salt synthesis of nitrogen-doped hierarchical porous carbon from plantain peels for high-performance supercapacitor
    (Journal of Electroanalytical Chemistry, 2022-09-01) Nanzumani, Nashiru Mahadeen; Agyemang, Frank Ofori; Mensah-Darkwa, Kwadwo; Appiah, Eugene Sefa; Arthur, Emmanuel Kwesi; Gikunoo, Emmanuel; Koomson, Bennetta; Jadhav, Amol R.; Raji, Akeem
    This work employs a non-corrosive and non-toxic molten salt combination of NaCl and KCl as an activation agent in an air environment to synthesize nitrogen-doped hierarchical porous carbon from plantain peels at 800 °C for supercapacitor application. Due to the synergistic effect of nitrogen doping, the synthesized nitrogen- doped activated unripe porous carbon (AUPN) has a hierarchical (micro-meso-macropores) porous structure and a high surface area of 959 m2/g, providing sufficient active sites for charge storage, rapid electrolyte and ionic mobility. X-ray diffraction and Raman spectroscopy analysis revealed the formation of a carbon product with a limited degree of graphitization and the crystallite size (La), which is valuable for evaluating the defects caused by nitrogen doping. In a three-electrode cell with a 6 M KOH electrolyte, AUPN recorded a specific capacitance of 550 F/g at 1 A/g. After 1000 cycles, capacitance retention was 99% at 4 A/g. Compared to other reported porous carbon materials, the overall electrochemical performance of AUPN is superior. This is due to the abundant nitrogen-doping, which introduces pseudocapacitance and increases the surface wettability of the porous carbon, resulting in a decrease in ionic-transport resistance. These findings indicate that this green and scalable technique is a potential synthesis method for producing porous carbon materials for energy storage applications.
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    MXene: fundamentals to applications in electrochemical energy storage
    (Discover Nano, 2023-02-03) Ampong, Daniel Nframah; Agyekum, Emmanuel; Agyemang, Frank Ofori; Mensah-Darkwa, Kwadwo; Andrews, Anthony; Kumar, Anuj; Gupta, Ram K.
    A new, sizable family of 2D transition metal carbonitrides, carbides, and nitrides known as MXenes has attracted a lot of attention in recent years. This is because MXenes exhibit a variety of intriguing physical, chemical, mechanical, and electrochemical characteristics that are closely linked to the wide variety of their surface terminations and elemental compositions. Particularly, MXenes are readily converted into composites with materials including oxides, polymers, and CNTs, which makes it possible to modify their characteristics for a variety of uses. MXenes and MXene-based composites have demonstrated tremendous promise in environmental applications due to their excellent reducibility, conductivity, and biocompatibility, in addition to their well-known rise to prominence as electrode materials in the energy storage sector. The remarkable characteristics of 2D MXene, including high conductivity, high specific surface area, and enhanced hydrophilicity, account for the increasing prominence of its use in storage devices. In this review, we highlight the most recent developments in the use of MXenes and MXene-based composites for electrochemical energy storage while summarizing their synthesis and characteristics. Key attention is paid to applications in supercapacitors, batteries, and their flexible components. Future research challenges and perspectives are also described.
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    MXene: fundamentals to applications in electrochemical energy storage
    (Discover Nano, 2023-01-31) Ampong, Daniel Nframah; Agyekum, Emmanuel; Agyemang, Frank Ofori; Mensah‑Darkwa, Kwadwo; Andrews, Anthony; Kumar, Anuj; Gupta, Ram K.
    A new, sizable family of 2D transition metal carbonitrides, carbides, and nitrides known as MXenes has attracted a lot of attention in recent years. This is because MXenes exhibit a variety of intriguing physical, chemical, mechanical, and electrochemical characteristics that are closely linked to the wide variety of their surface terminations and elemental compositions. Particularly, MXenes are readily converted into composites with materials including oxides, polymers, and CNTs, which makes it possible to modify their characteristics for a variety of uses. MXenes and MXene-based composites have demonstrated tremendous promise in environmental applications due to their excellent reducibility, conductivity, and biocompatibility, in addition to their well-known rise to prominence as electrode materials in the energy storage sector. The remarkable characteristics of 2D MXene, including high conductivity, high specific surface area, and enhanced hydrophilicity, account for the increasing prominence of its use in storage devices. In this review, we highlight the most recent developments in the use of MXenes and MXene-based composites for electrochemical energy storage while summarizing their synthesis and characteristics. Key attention is paid to applications in supercapacitors, batteries, and their flexible components. Future research challenges and perspectives are also described.