Browsing by Author "Mensah, Michael Baah"
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- ItemAssessment of quantities and composition of corn stover in Ghana and their conversion into bioethanol(Elsevier, 2021) Mensah, Michael Baah; Jumpah, Henry; Boadi, Nathaniel O.; Awudza, Johannes A.M.; 0000-0002-8080-4812Corn stover (CS) has currently received great attention worldwide as a potential feedstock for the production of bioethanol as alternative renewable fuel or additive to gasoline. This work evaluates the quantities and chemical characteristics of the CS available in Ghana and their conversion into bioethanol. The average quantity of CS production in Ghana per year was estimated to be 1.77 × 106 t. The cellulose, hemicellulose, and lignin contents of CS obtained from Pioneer 30 W 40, a local maize variety, were found to be 37.72 %, 20.62 %, and 30.50 %, respectively. Alkali pretreatment and enzymatic hydrolysis of the CS yielded a reducing sugar concentration of 157.96 mg/ml within 24 h and an ethanol yield of 0.045 l/kg. It was estimated that 40 % of the average annual CS production has the potential of yielding 140.855 × 106 l of bioethanol.
- ItemGrowth Kinetics of Zinc Sulphide Nanocrystals Synthesized by Colloidal Thermolysis of Fatty Acid Carboxylates(Hindawi, 2022) Mensah, Michael Baah; Boadi, Nathaniel O.; Awudza, Johannes A. M.; 0000-0002-8080-4812Zinc sulphide (ZnS) is an important semiconductor with widespread electronic and catalytic applications. e growth kinetics of ZnS nanocrystals synthesized by the thermal decomposition of zinc ricinoleate carboxylates in an oleylamine:dodecanethiol (1 :1) solvent mixture isreported. Crystalline sphalerite ZnS nanocrystals with quantum dot sizes of 2.3–5.3 nm were obtained at temperatures higher than 240° C. e p-XRD patterns showed a clear relationship between the crystallite sizes and the peak broadness at a temperature range of 250–300°C. e optical bandgap energies of the ZnS nanocrystals reduced from 4.27 eV to 3.73 eV as the time of reaction increased from 20 to 60 min at 250°C. e activation energy for the growth kinetics of the ZnS nanocrystals was determined to be 36.24 kJ/mol which compares closely to those reported in the literature for aqueous systems.
- ItemHeavy metal pollution and the role of inorganic nanomaterials in environmental remediation(Royal Science Society, 2021) Mensah, Michael Baah; Lewis, David J.; Boadi, Nathaniel O.; Awudza, Johannes A. M.; 0000-0002-8080-4812Contamination of water and soil with toxic heavy metals is a major threat to human health. Although extensive work has been performed on reporting heavy metal pollutions globally, there are limited review articles on addressing this pernicious phenomenon. This paper reviews inorganic nanoparticles and provides a framework for their qualities required as good nanoadsorbents for efficient removal of heavy metals from water. Different inorganic nanoparticles including metals, metal oxides and metal sulfides nanoparticles have been applied as nanoadsorbents to successfully treat water with high contaminations of heavy metals at concentrations greater than 100 mg l−1 , achieving high adsorption capacities up to 3449 mg g−1 . It has been identified that the synthesis method, selectivity, stability, regeneration and reusability, and adsorbent separation from solution are critical parameters in deciding on the quality of inorganic nanoadsorbents. Surface functionalized nanoadsorbents were found to possess high selectivity and capacity for heavy metals removal from water even at a very low adsorbent dosage of less than 2 g l−1, which makes them better than conventional adsorbents in environmental remediation
- ItemNutritional composition and antioxidant properties of three varieties of carrot (Daucus carota)(Elsevier, 2021) Boadi, Nathaniel Owusu; Badu, Mercy; Kortei, Nii Korley; Saah, Selina Ama; Annor, Benjamin; Mensah, Michael Baah; Okyere, Harry; Fiebor, Alphonse; 0000-0002-8080-4812Carrots are a potentially rich source of antioxidants in addition to their nutritional proper ties. In this study, the nutritional composition and antioxidant properties of three varieties of carrots, namely Kuroda, Pamela and Amazonia cultivated in Ghana were determined. The peroxide scavenging method was used to determine the antioxidant properties of the ethanolic extracts of the carrot varieties at different concentrations. The protein, crude fi bre, fat and carbohydrate contents of the carrot varieties ranged 6.46 – 10.73 %, 7.18 – 8.87 %, 1.97 – 4.31 % and 6.25 – 8.39 % respectively. The three varieties had high moisture contents ranging from 69.06 to 75.30 %. The antioxidant properties were high even at low concentrations of extract, and their activity increased with time in the order Amazonia > kuroda > pamela. Amazonia had the highest fibre, protein and carbohydrate contents and the lowest moisture content, making it the most preferred variety.
- ItemRisk of Exposure to Trace Elements through the Application of Facial Makeup Powders(Hindawi, 2022) Saah, Selina Ama; Boadi, Nathaniel Owusu; Sakyi, Patrick Opare; Darko, Godfred; Mensah, Michael Baah; 0000-0002-8080-4812e study aimed to ascertain the levels of trace elements present in the face powders marketed in Ghana. Fifteen di erent brands of facial makeup powders were purchased from a local market in Ghana. e samples were analyzed using an X-ray uorescence (XRF) analyzer to determine the concentrations of 16 elements (Pb, As, Hg, Zn, Fe, Mn, Cr, Ti, Cu, Ni, Co, Sb, Cd, Ag, Sn, and Au). e contents of the trace elements were ordered in the following descending order according to the maximum concentrations: Fe > Zn > Ti > Mn >Cr > Hg >As > Pb >Cu, Ni, Co, Sb, Cd, Ag, Sn, and Au. Pearson correlation statistics showed strong positive relationships between Pb and Zn (r 0.71), Pb and Cr (r 0.57), Hg and Zn (r 0.63), Hg and Fe (r 0.73), Hg and Cr (r 0.61), Zn and Fe (r 0.69), Zn and Cr (r 0.88), Fe and Cr (r 0.67), and Fe and Ti (r 0.62). Except for Pb and Cr, all the other elements had their margin of safety (MOS) values less than 100. e hazard indices (HIs) for Pb, Mn, Cr, and Ti were less than 1, indicating no risk. However, the HIs for As, Hg, Zn, and Fe were more than 1, indicating a potential risk of usage in adults. As a result, using face powders could put users at risk of exposure to trace elements. Dermal exposure to trace elements from cosmetics resulted in a lifetime cancer risk (LCR) that was higher than what was considered tolerable (LCR >10−6 ) due to the presence of Pb, As, and Cr. Mercury was identi ed as a potential skin sensitizer in the cosmetic samples examined by an exposure-based sensitization quantitative risk assessment (SQRA)
- ItemSynthesis of CdS and PbS nanoparticles by the thermal decomposition of ethyl xanthate complexes in castor oil using the heat-up technique(Elsevier, 2020) Mensah, Michael Baah; Awudza, Johannes A.M.; Revaprasadu, Neerish; O’Brien, Paul; 0000-0002-8080-4812Castor oil contains a range of fatty acids of which a high proportion is ricinoleic acid. We report the syntheses of CdS and PbS nanoparticles by the thermal decomposition of ethyl xanthate complexes of cadmium and lead in castor oil using the heat-up synthesis technique. The castor-oil capped CdS nanoparticles showed cubic zinc blende and wurtzite crystal structures and displayed band gap range of 2.63–2.84 eV. The CdS formed near spherical clusters of nanocrystals with average particle size of 6.78 (±1.89) nm. The castor-oil capped PbS nanoparticles showed a rocksalt crystal structure and displayed an average band gap of 0.85 eV. The PbS showed variety of morphologies of nanostructured particles ranging from rods to belts. The average width and length of the PbS nanobelts observed were 22.2 (±2.3) nm and 225.9 (±23.3) nm respectively.
- ItemSynthesis of Nickel Sulfide Thin Films and Nanocrystals from the Nickel Ethyl Xanthate Complex(Hindawi, 2022) Kotei, Patience Adei; Boadi, Nathaniel Owusu; Saah, Selina Ama; Mensah, Michael Baah; 0000-0002-8080-4812Nickel sul des have unique and diverse structural features, making them ideal for energy conversion and storage. is research focuses on the synthesis and characterization of nickel sul de thin lms and nanocrystals from nickel ethyl xanthate complex using spin-coating and solventless methods. e nickel ethyl xanthate complex (C6H10S4NiO2) was characterized using Fourier transformed infrared (FT-IR), ultraviolet-visible (UV-Vis), and nuclear magnetic resonance (NMR) spectroscopies as well as thermogravimetric analysis (TGA). e NiS thin lms and nanoparticles were analyzed with energy dispersive X-ray (EDX) spectroscopy and X-ray di raction (XRD). Nickel ethyl xanthate was synthesized in an 81.2% yield. e bandgaps of the nickel sul de obtained from the spin-coating method ranged from 4.35–4.88 eV. For the solventless method, the bandgap of the nickel sul de ranged from 3.93–3.96 eV. e crystal phase observed from the spin-coating and solventless methods was α-NiS (hexagonal). A direct correlation was observed between annealing temperature, bandgap, and particle size