Browsing by Author "Gikunoo, Emmanuel"

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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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    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.