Browsing by Author "Kyei, Sampson Kofi"

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    Chemistry and application of emerging ecofriendly antifouling paints: a review
    (J. Coat. Technol. Res., 2020) Kyei, Sampson Kofi; Darko, Godfred; Akaranta, Onyewuchi; 0000-0001-7157-646X
    There has been a global concern about the use of tributyltin-based coatings in combating biofouling in the marine industry. Although there have been alternatives to tributyltin in preventing biofouling, the emphasis is now on the use of non-toxic and/or eco-friendly natural materials which do not negatively affect the environment upon application. Natural materials are eco-friendly, biodegradable, cost-effective, and can be employed as precursors in the synthesis and formulation of biodegradable antifouling coatings. Consequently, many researchers are investing time into the synthesis and formulation of natural, eco-friendly antifouling coatings, comprised of higher biofiber, which would perform analogous antifouling like other conventional coatings, thus minimizing the more toxic base polymer proportion. A safe environment is surely the signal of a bright future; hence, cost-effective, biodegradable raw materials result in a long-term attainment of sustainability of these products to replace the expensive conventional ones. This review presents an overview of ecologically friendly, cost-effective, and legally acceptable ways of preventing and mitigating the growth of algae and other marine organisms from settling on the hull of a ship and other static constructions in oilfields.
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    Drying and adhesive properties of novel surface coatings derived from peanut skin extract and cashew nutshell liquid
    (Pigment & Resin Technology, 2022-04-23) Kyei, Sampson Kofi; Eke, William Iheanyi; Darko, Godfred; Akaranta, Onyewuchi; 0000-0001-7157-646X
    Purpose – This study aims to synthesize pigment and resin from agro-wastes and use them in the formulation of eco-friendly surface coatings. Design/methodology/approach – The pigments and resin were synthesized through a chemical modification of agro-wastes. The pigments were characterized by infrared spectroscopy (FTIR) and were screened for their antimicrobial activities. The physicochemical characteristics of the cashew nutshell liquid (CNSL)-modified resin were evaluated. These precursors and other natural additives were used to formulate surface coatings, and their drying and adhesive properties were evaluated using international testing methods. Findings – It was observed that the curing of the CNSL-modified resin depended on time and temperature. The pigments exhibited antimicrobial activity against E. coli and S. aureus and had high melting points, affirming their stability. The chemically modified precursors successfully yielded surface coatings with acceptable drying times and adhesion to the base substrate. Practical implications – The use of agro-wastes as the main components of the surface coatings implies waste valorization, a reduction in production costs and the creation of job opportunities for sustainable development. To increase the chemical, physical, corrosion resistance and antimicrobial qualities of paint compositions, chemically modified peanut skin extracts and CNSL can be used as pigments and resins, respectively. This could be a green approach to achieving the targets of Sustainable development goals 11 and 12. Originality/value – The paper outlines a prospective approach to use unwanted waste (peanut skin, cashew nutshells) and other natural additives as industrial raw materials. These novel surface coating precursors are cost-effective, readily available, eco-friendly and could replace conventional precursors
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    The Reactivity of Soil Organic Fractions towards Cadmium, Copper, Calcium and Zinc
    (2006-08-25) Kyei, Sampson Kofi
    Humic substances are extremely important soil components because they constitute a stable fraction of carbon and improve their water holding capacity. They also play an important role in the behaviour of trace metals in natural environments, due to the formation of complexes which modify can mobility of these ions. In this project, the physico-chemical characteristics and metal binding for six (6) different soil types from Bibiani mines have been investigated. The physical properties viz: pH, conductivity,particle size distribution, moisture content, exchangeable acidity were determined on the raw Samples and potassium, phosphorus, iron, calcium, cadmium, lead and zinc were determined from the digest. The total nitrogen and organic matter were also determined. Although the characterization could not reveal details of chemical processes taking place in the sample, some characteristics that revealed differences between the samples were identified. The mine tailings ^exhibited some characteristics similar to samples Bibiani forest (cocoa plantation) eg: Organic ter (New Tailings - 0.53%; Old Tailings - 0.64%; Cocoa Plantation - 0.58%); and Carbon- Nitrogen ratio (New Tailings -12; Old Tailings -10.30; Cocoa Plantation -11,20) were similar. Humnic substances were extracted from the soil samples using various standard procedures. The amount of humic acids extracted ranged from 0.493g to 0.092g, whilst the volumes of orange fulvic acid were 215mL for Russel Pit and 212mL for the Old Tailings. A study of complexation of humic acids by trace metals (Cd, Zn, Ca, and Cu) revealed that metal-humic substances association depends on the metal, the nature of the humic substance and concentration. Ca was complexed to a higher extent than Cu, followed by Cd and Zn. The Complexation strength was in the order FA < HA. A comparison of the calculated stability constants suggests that the strength of metal complexation by humic substances from Old Tailings was higher than that of humic substances from Russel Pit. For the Old Tailings, the order of decreasing complexation stability constants of the humic and fulvic acids is Ca ^ > Cu+ Cd 2+ > Zn 2+ and Ca 2+ > Cu 2+ > Zn 2+ > Cd 2+ respectively. For Russel Pit the order is ric Acid: Ca 2+ > Cu 2+ > Cd 2+ > Zn 2+ Humics Acid: Ca 2+ > Cd 2+ > Cu 2+ > Zn 2+