Browsing by Author "Nyankson, E."

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Activated cashew carbon-manganese oxide based electrodes for supercapacitor applications
(Scientific African, 2023) Boamah, R.; Agyei-Tuffour, B.; Dodoo-Arhin, D.; Nyankson, E.; Brobbey, K.J.; et al.
The current global energy challenge which affects most developing countries in particular, is of major source of concern today. The availability of less expensive techniques of storing excess generated energy is critical to the success of the renewable energy roadmaps implementation. In this study, hydrothermal and chemical leaching methods have been used to synthesize MnO2 nanoparticles using KMnO4 and MnSO4 as precursors at 140 °C and from natural local manganese ore. Activated Carbon (ACF) have also been produced from agricultural Cashew biomass waste, through a physical carbonization and KOH activation process using temperatures of 700 °C – 900 °C for periods between 1 and 2 h. The as-prepared materials have been characterized via XRD, Raman, FTIR, SEM. Electrochemical performance measurements (CV, EIS and GCD) were carried out on the prepared electrodes. The specific capacitance values obtained were in the range of 2.8 F/g - 6.5 F/g at different scan rates of 20 mV -50 mV respectively in a potential range of -0.4 to +0.4 V and -0.4 to +0.6 V for the various types of electrodes
Advancements in Crude Oil Spill Remediation Research after the Deepwater Horizon Oil Spill
(Springer International Publishing, 2016) Nyankson, E.; Rodene, D.; Gupta, R.B.
An estimated 4.9 million barrels of crude oil and natural gases was released into the Gulf of Mexico during the Deepwater Horizon oil spill of 2010. The Deepwater Horizon oil spill affected the aquatic species in the Gulf of Mexico, vegetation, and the human population along the coast. To reduce the effect of the spilled oil on the environment, different remediation strategies such as chemical dispersant, and mechanical booms and skimmers were utilized. Over 2.1 million gallons of dispersants was applied to minimize the impact of the spilled oil. However, environmental and human toxicity issues arose due to the perceived toxicity of the dispersant formulations applied. After the Deepwater Horizon oil spill, various studies have been conducted to find alternative and environmentally benign oil spill response strategies. The focus of this manuscript is to demonstrate an objective and an overall picture of current research work on oil spill response methods with emphasis on dispersant and oil sorbent applications. Current trends in oil spill sorbent and dispersant formulation research are presented. Furthermore, strategies to formulate environmentally benign dispersants, as well as the possible use of photoremediation, are highlighted. © 2015 Springer International Publishing Switzerland.
Ag2CO3-halloysite nanotubes composite with enhanced removal efficiency for water soluble dyes
(Heliyon, 2019-06-13) Nyankson, E.; Agyei-Tuffour, B.; Annan, E.; Yaya, A.; Mensah, B.; Onwona-Agyeman, B.; Amedalor, R.; Kwaku-Frimpong, B.
The release of water soluble dyes into the environment is an utmost concern in many countries. This paper presents the effects of Ag2CO3-halloysite composites on the efficient removal of water soluble dyes. In this study, NaHCO3 solution was added dropwisely to halloysite nanotubes (HNTs) dispersed in aqueous AgNO3 to form Ag2CO3-HNTs composite. The synthesized Ag2CO3-HNTs composite was characterized with Diffused Reflectance Spectroscopy (DRS), X-ray Diffraction (XRD), Thermogravimetric analysis (TGA), Scanning Electron Microscopy- Energy Dispersive Spectroscopy (SEM-EDX) and Fourier Transform Infra-Red (FT-IR) spectroscopy. The photocatalytic activity and the adsorption capacity of Ag2CO3-HNTs on methylene blue and rhodamine b dyes were dependent on pH and the amount of HNTs used in the synthesis. The photodegradation efficiency of Ag2CO3 was lower when compared with that of the composite material. This observation is due to the reduction in the electron-hole recombination with the HNTs acting as electron trapping site and the enhanced aqueous dispersity of Ag2CO3-HNTs. The enhanced adsorption of water soluble dyes by the Ag2CO3-HNTs resulted from the electrostatic attraction of cationic dyes to the surface of the HNTs (negatively charged). The Ag2CO3-HNTs therefore removed dye pollutants through a combination of photocatalytic and adsorption processes. The results obtained during the study confirmed the potential application of Ag2CO3-HNTs composite in water treatment technologies.
Application of clay ceramics and nanotechnology in water treatment: A review
(Cogent Engineering, 2018-07) Annan, E.; Agyei-Tuffour, B.; Bensah, Y.D.; Konadu, D.S.; Yaya, A.; Onwona-Agyeman, B.; Nyankson, E.
The increasing demand to provide clean water for drinking has brought to the fore the importance of seeking other materials with the ability or combined effect with other materials to purify water. Clay ceramics are known to be natural and also easily engineered porous-structured materials. Review papers on water filtration over the last decade have been on specific mechanisms or technologies. This review paper presents a single platform which provides information encapsulating all these technologies. This paper highlights water contaminants, and their various treatment technologies. The effectiveness of these technologies are evaluated via scholarly documented peer-reviewed papers. Moreover, the discussions are interspersed with the World Health Organization’s (WHO) standard for various contaminants along with the exploration of the efficiency of clay minerals as potent water filtration material. Finally, current trends in application of nanotechnology in water purification systems are also highlighted. These technologies include adsorption, microbial disinfection, and photocatalysis.
Biomethane Production From Residual Algae Biomass (Ecklonia maxima): Efects of Inoculum Acclimatization on Yield
(Springer, 2021) Darko, C.N.S.; Agyei‑Tufour, B.; Faloye, D.F.; Goosen, N.J.; Nyankson, E.; Dodoo‑Arhin, D.
This paper presents the effects of inoculum acclimatization on biomethane production from extraction residues of the seaweed (Ecklonia maxima) via anaerobic digestion. Anaerobic digestion of Ecklonia maxima has been studied with and without acclimatized inoculum under mesophilic conditions (~37 °C) for a digestion period of twenty (20) days. The acclimatized inoculum-seaweed sample recorded the highest methane yield of~ 862 ml CH4/gVS (~ 55% of the total biogas produced) compared to the~580 ml CH4/gVS recorded for the non-acclimatized inoculum- seaweed sample, both within the first ten (10) days. Kinetic studies on acclimatized and non-acclimatized samples were carried out using the modifed Gompertz model. The model showed coefcients of determination (R2 ) of 0.99 and 0.98 with an estimated yield rate (µ) of~296 ml/ gVS/day (0.4 days phase lag, λ) and~60 ml/gVS/day (3.4 λ) for the acclimatized and non-acclimatized samples respectively. The Fourier transform infrared spectroscopy (FTIR) analyses revealed the presence of carboxylic, hydroxyl, ketone and ether groups which further corroborated the suitability of E. maxima for biogas production. The implications of the results are discussed to elucidate the potential of seaweed as a renewable energy source for macroalgae biorefnery.
Capturing Dioclea Reflexa Seed Bioactives on Halloysite Nanotubes and pH Dependent Release of Cargo against Breast (MCF-7) Cancers In Vitro
(Separations, 2021) Balapangu, S.; Nyankson, E.; Asimeng, B.O.; Asiamah, R.; Arthur, P.K.; Tiburu, E.K.
In this work, optimization parameters were developed to capture plant metabolites from Dioclea Reflexa (DR) seed ex-tracts onto halloysites nanotubes (HNTs). A one-step pool of the crude extracts at neutral pH from the HNT lumen failed to elicit a reduction in breast cancer, Michigan Cancer Foundation-7 (MCF-7) cell viability. However, the pH-dependent elution of metabolites revealed that the acidic pH samples exhibited profound antiproliferative effects on the cancer cells compared to the basic pH metabolites using both trypan blue dye exclusion assay and 3-(4,5- dimethylthiazol-2-yl)-2,5-diphenyl-2H-tetrazolium bromide (MTT) viability test. pH~5.2 samples demonstrated by half-maximal inhibitory concentration (IC50) of 0.8 mg and a cyclic voltammetry oxidation peak potential and current of 234 mV and 0.45 A, respectively. This indicates that the cancer cells death could be attributed to membrane polarization/depolarization effects of the sample. Fluorescence-activated cell sorting (FACS) studies confirmed that the plant metabolites affected breast cancer apoptotic signaling pathways of cell death. The studies proved that plant metabolites could be captured using simplified screening procedures for rapid drug discovery purposes. Such procedures, however, would require the integration of affordable analytical tools to test and isolate individual metabolites. Our approach could be an important strategy to create a library and database of bioactive plant metabolites based on pH values.
Capturing Dioclea Reflexa Seed Bioactives on Halloysite Nanotubes and pH Dependent Release of Cargo against Breast (MCF-7) Cancers In Vitro
(MDPI, 2021) Balapangu, S.; Nyankson, E.; Asimeng, B.O.; Asiamah, R.; Arthur, P.K.; Tiburu, E.K.
In this work, optimization parameters were developed to capture plant metabolites from Dioclea Reflexa (DR) seed ex-tracts onto halloysites nanotubes (HNTs). A one-step pool of the crude extracts at neutral pH from the HNT lumen failed to elicit a reduction in breast cancer, Michigan Cancer Foundation-7 (MCF-7) cell viability. However, the pH-dependent elution of metabolites revealed that the acidic pH samples exhibited profound antiproliferative effects on the cancer cells compared to the basic pH metabolites using both trypan blue dye exclusion assay and 3-(4,5- dimethylthiazol-2-yl)-2,5-diphenyl-2H-tetrazolium bromide (MTT) viability test. pH~5.2 samples demonstrated by half-maximal inhibitory concentration (IC50) of 0.8 mg and a cyclic voltammetry oxidation peak potential and current of 234 mV and 0.45 µA, respectively. This indicates that the cancer cells death could be attributed to membrane polarization/depolarization effects of the sample. Fluorescence-activated cell sorting (FACS) studies confirmed that the plant metabolites affected breast cancer apoptotic signaling pathways of cell death. The studies proved that plant metabolites could be captured using simplified screening procedures for rapid drug discovery purposes. Such procedures, however, would require the integration of affordable analytical tools to test and isolate individual metabolites. Our approach could be an important strategy to create a library and database of bioactive plant metabolites based on pH values.
Characteristics Of Stabilized Shrink-Swell Deposits Using Eggshell Powder
(2013) Nyankson, E.; Agyei-Tuffour, B.; Annan, E.; et al.
Shrink-swell soils expand and heave or contract and crack during periods of high and low moisture content. The expansion and contraction cause the lifting and or sinking of structures, crack development, and eventual collapse of engineering structures. The need to stabilize such plastic soils to improve their load-carrying capacities cannot be overemphasized. Therefore in this article, the effect of lime contained in eggshells and its application in the stabilization of shrink-swell soils have been explored. 4wt% and 8wt% of eggshell powder were mixed with equal masses of two different soil samples from Dodowa (DD) and Adalekope (AD) in Ghana. The samples were characterized with X-ray fluorescence (XRF), Plasticity Index analysis (PI), Free Swell Index (FSI), pH test, and a grading test. The x-ray fluorescence results showed that eggshell contains about 52wt% of CaO, which is largely responsible for soil stabilization. The sample mixed with 8wt% eggshell powder showed a decreased PI, FSI, and a high silt/clay fraction. The results obtained have been discussed and can influence the application of eggshell powders for large-scale stabilization of expansive soils.
Characterization and Evaluation of Zeolite A/Fe3O4 Nanocomposite as a Potential Adsorbent for Removal of Organic Molecules from Wastewater
(Journal of Chemistry, 2019-07-28) Nyankson, E.; Adjasoo, J.; Efavi, J.K.; Amedalor, R.; Yaya, A.; Manu, G.P.; Asare, K.; Amartey, N.A.
In this work, zeolite (Z) and Z-Fe3O4 nanocomposite (Z-Fe3O4 NC) have been synthesized. The Fe3O4 nanoparticles were synthesized using the extract from maize leaves and ferric and ferrous chloride salts and encapsulated into the zeolite framework. The nanocomposite (Z-Fe3O4 NC) was characterized using X-ray diffractometer (XRD), Fourier-transform infrared (FT-IR) spectroscopy, energy-dispersive X-ray (EDX) spectroscopy, and scanning electron microscopy (SEM). The potential of Z-Fe3O4 NC as an adsorbent for removing methylene blue molecules (MB) from solution was examined using UV-Vis and kinetic and equilibrium isotherm models. The adsorption data fitted best with the pseudo-second-order model and Weber and Morris model, indicating that the adsorption process was chemisorption, while the Weber and Morris described the rate-controlling steps. The intraparticle diffusion model suggests that the adsorption processes were pore and surface diffusion controlled. The Langmuir isotherm model best describes the adsorption process indicating homogeneous monolayer coverage of MB molecules onto the surface of the Z-Fe3O4 NC. The maximum Langmuir adsorption capacity was 2.57 mg/g at 25°C. The maximum adsorption efficiency was 97.5%. After regeneration, the maximum adsorption efficiency achieved at a pH of 7 was 82.6%.
Chicken Feather Protein Dispersant for Effective Crude Oil Dispersion in the Marine Environment
(American Chemical Society, 2023) Adofo, Y.K.; Nyankson, E.; Agyei-Tuffour, B.; et al.
Various studies report that aside from the adverse impact of crude oil on the marine environment, there is the likelihood that chemical dispersants used on the surface of water as oil-treating agents themselves possess a degree of toxicity, which have additional effects on the environment. To eliminate the subject of toxicity, there are several materials in nature that have the ability to form good emulsions, and such products include protein molecules. In In this study, chicken feathers, which are known to contain ≥90% protein, were used to formulate a novel dispersant to disperse crude oil in seawater (35 ppt). Protein from chicken feathers was extracted and synthesized into the chicken feather protein (CFP) dispersant using deionized water as a solvent. Emulsions formed from CFP-synthesized dispersants were stable over a considerably long period of time, whereas the droplet sizes of the emulsion formed were on the average very small in diameter, making droplet coalescence very slow. The CFP dispersants exhibited moderate surface and interfacial activity at normal seawater salinity. Using the US EPA’s baffled flask test, at 800 and 1000 mg/ml CFP surfactant-to-oil ratios, dispersion effectiveness values of 56.92 and 68.64 vol % were obtained, respectively, which show that CFP has a great potential in crude oil dispersion. Moreover, the acute toxicity test performed on Nile tilapia showed that CFP was practically nontoxic with an LC50 value of more than 100 mg/L after 96 hours of exposure. The results obtained showed that the CFP dispersant is environmentally friendly.
Chitosan-Coated Halloysite Nanotubes As Vehicle for Controlled Drug Delivery to MCF-7 Cancer Cells In Vitro
(MDPI, 2021) Nyankson, E.; Aboagye, S.O.; Efavi, J.K.; Agyei-Tuffour, B.; Paemka, L.; Asimeng, B.O.; Balapangu, S.; Arthur, P.K.; Tiburu, E.K.
The aim of the work is to improve the release properties of curcumin onto human breast cancer cell lines using coated halloysite nanotubes (HNTs) with chitosan as a polycation. A loading efficiency of 70.2% (w/w) was attained for loading 4.9 mg of the drug into 0.204 g bed volume of HNTs using the vacuum suction method. Results acquired from Brunauer-Emmett-Teller (BET), Fourier-transform infrared (FTIR) spectroscopy, transmission electron microscopy (TEM), scanning electron spectroscopy (SEM), zeta potential, and thermogravimetric analysis (TGA) indicated the presence of the drug and the biopolymer in and around the nanotubes. The release properties of drug-loaded HNTs (DLHNTs) and chitosan-coated drug-loaded HNTs (DLHNTs-CH) were evaluated. The release percentages of DLHNTs and DLHNTs-CH after 6 h were 50.7 and 37%, respectively. Based on the correlation coefficients obtained by fitting the release nature of curcumin from the two samples, the Korsmeyer-Peppas model was found to be the best-fitted model. In vitro cell viability studies were carried out on the human breast cancer cell line MCF-7, using the MTT and trypan blue exclusion assays. Prior to the Trypan blue assay, the IC50 of curcumin was determined to be ∼30 µM. After 24 h of incubation, the recorded cell viability values were 94, 68, 57, and 51% for HNTs, DLHNTs-CH, DLHNTs, and curcumin, respectively. In comparison to the release studies, it could be deducted that sustained lethal doses of curcumin were released from the DLHNTs-CH within the same time. It is concluded from this work that the “burst release” of naked drugs could be slowly administered using chitosan-coated HNTs as potential drug carriers.
Comparative analyses of rice husk cellulose fiber and kaolin particulate reinforced thermoplastic cassava starch biocomposites using the solution casting technique
(Wiley, 2021) Agyei-Tuffour, B.; Asante, J.T.; Nyankson, E.; Dodoo-Arhin, D.; Oteng-Peprah, M.; Azeko, S.T.; Azeko, A.S.; Oyewole, O.K.; Yaya, A.
he potential of biodegradable packaging materials from thermoplastic cassava starch (TPS) reinforced with rice husk cellulose fibers (RHCF) and kaolin particulates (KP) using the solution casting method has been presented. This involved the blending of TPS and RHCF/KP in a plasticizer of ~4 ml of glycerol and ~45 ml of distilled water at 125°C and stirred at 60 rpm until a gel was formed. The gel was cast into sheets and bone-shaped tensile specimens and allowed to dry for 5 days and characterized. The results show a semicrystalline structure for TPS with an ~36% increase in crystallinity after reinforcement. The O-H bond stretching and the C-H bending bonds due to starch–glycerol reactions were the common functional groups in TPS–RHCF biocomposites, and Si-O-C bonds were characteristics of the silica phase in the kaolin. The water vapor transmission rate (WVTR) reduced to ~34% with KP reinforcements from ~238 g/m.day to 177 g/m.day and to ~74 g/m.day and ~164% for TPS–RHCF. The strength increased with up to 50 wt% kaolin content; ~0.96 MPa yield strength and ~2.60 MPa ultimate tensile strength (UTS) were recorded. For the RHCF reinforced composites, TPS-50 wt% also showed high strengths of ~0.96 MPa yield strength and ~3.50 MPa UTS. The WVTR reduced as content of kaolin was increased. Typically, from 0 to 30 wt% volume fraction of kaolin, the WVTR was reduced by ~34% to 177 g/m.day for TPS–kaolin and by ~164% to ~74 g/m.day in TPS–RHCF. The as-prepared biocomposites have potential as good packaging materials.
A comparative study of the interaction of nickel, titanium, palladium, and gold metals with single-walled carbon nanotubes: A DFT approach
(Results in Physics, 2019-03) Kayang, K.W.; Nyankson, E.; Efavi, J.K.; Apalangya, V.A.; Adetunji, B.I.; Gebreyesus, G.; Tia, R.; Abavare, E.K.K.; Onwona-Agyeman, B.; Yaya, A.
Interactions between transition metal atoms, nickel, titanium, palladium and gold and (3,3), (4,2), (6,0) and (5,1) carbon nanotubes were studied using first principles calculations. The Fermi energy levels of the carbon nanotubes studied were found to increase during interactions with the transition metal atoms. Amongst the four metals, gold atom was found to have an enhanced interaction with the nanotubes transforming from semiconducting to a conducting tube. Titanium was also found to show similar characteristics to gold only when the atom was placed in the middle of the carbon nanotubes. Nickel and palladium atoms interactions did not affect much the electronic properties of the carbon nanotubes, with some slight changes in the electronic properties at some specific sites of the nanotubes. It is proposed from this study that, the carbon nanotube-metal interactions could be used as a guide to shed light on the electronic properties of such materials which could become promising engineering materials and revolutionize the electronic industry.
Curcumin loaded Ag–TiO2-halloysite nanotubes platform for combined chemo-photodynamic therapy treatment of cancer cells†
(Royal Society of Chemistry, 2022) Nyankson, E.; Awuzah, D.; Tiburu, E.K.; Efavi, J.K.; Agyei-Tuffour, B.; Paemka, L.
The use of naturally occurring anticancer materials in combination with doped metal oxide has emerged as one of the most promising ways for improving anticancer treatment efficacy. In this study, the anticancer potential of curcumin-loaded Ag–TiO2-halloysite nanotubes (curcumin-loaded Ag–TiO2-HNTs) was examined. Ag–TiO2-HNTs with different wt% of Ag–TiO2 were synthesized and characterized using XRD, TGA, FT-IR, UV-Vis spectroscopy, and SEM-EDX. The XRD results revealed the presence of crystalline TiO2. However, the presence of Ag was detected through the SEM-EDX analysis. Cyclic voltammetry measurements suggested the enhancement of the release of ROS from TiO2 upon deposition with Ag. FT-IR and TGA analysis confirmed the successful loading of curcumin inside the nanotubes of the halloysite. In vitro drug released studies revealed the release of approximately 80–99% curcumin within 48 hours. Kinetic model studies revealed that the release of curcumin from HNT and Ag–TiO2-HNT followed the first-order and Higuchi models, respectively. The light irradiated curcumin-loaded Ag– TiO2-HNTs samples exhibited considerable anticancer potential as compared to the free curcumin, irradiated Ag–TiO2 NPs samples, and unirradiated curcumin loaded Ag–TiO2-HNTs samples. The obtained results revealed that combined chemo- and photodynamic therapy using curcumin-loaded Ag–TiO2-HNTs nanomaterial has the potential as an effective anticancer treatment method
Dispersants as an oil spill clean-up technique in the marine environment: A review
(Heliyon, 2022) Adofo, Y.K.; Nyankson, E.; Agyei-Tuffour, B.
Oil is a major source of energy in the industrial world. Exploitation of oil and rigging activities, transportation via sea, and many other mechanical failures lead to oil spills into the marine environment. In view of these, the suitability and effectiveness of oil spill response methods have always been a topical discussion worldwide. It has become necessary, now than ever, for existing spill response methods used to remove oil from the environment to be improved upon and more importantly, develop new response materials that are sustainable and environmentally friendly. There exist surfactants in nature that are non-toxic and biodegradable, which can be explored to produce potential dispersants to help remove oil safely from the surface of marine water. This review comprises of the works and resourceful materials produced by various researchers and agencies in the field of oil spill response, placing emphasis on the use of dispersants in the marine environment.
The effect of NaOH catalyst concentration and extraction time on the yield and properties of Citrullus vulgaris seed oil as a potential biodiesel feed stock
(South African Journal of Chemical Engineering, 2018-03) Efavi, J.K.; Kanbogtah, D.; Apalangya, V.; Nyankson, E.; Tiburu, E.K.; Dodoo-Arhin, D.; Onwona-Agyeman, B.; Yaya, A.
In this work, oil was extracted from Citrullus vulgaris (watermelon) seeds for potential feedstock in biodiesel production. The results showed that, the oil content from Citrullus vulgaris seeds oil during extraction reached an average yield of 50%. Biodiesel was produced via transesterification using NaOH as catalyst. The effect of NaOH on the yield of the biodiesel was investigated at three different concentrations; 0.13, 0.15 and 0.18 g and oil to methanol ratio of 5:1 under different reaction times; 90, 120 and 150 min at 60 °C. The yield of biodiesel from NaOH concentration of 0.13 g was found to be 70% as compared to those of concentrations, 0.15 g and 0.18 g which were 53% and 49% respectively. Gas chromatography was used to identify the methyl ester groups present in the biodiesel and the results revealed both concentration and time-dependent increase in oil yield. The physicochemical properties of the watermelon seed oil such as flash point (141.3 ± 0.4–143.4 ± 0.2), density (0.86 ± 0.04–0.91 ± 0.01 g/cm3), kinematic viscosity (30.50 ± 0.1–31.20 ± 0.04 mm2/s) and acid value (mg KOH/g) are similar to conventional vegetable oils. This work therefore, highlights the potential utility of water melon seeds for biodiesel production. © 2018 The Authors
The effect of titanium dioxide synthesis technique and its photocatalytic degradation of organic dye pollutants
(Heliyon, 2018-07) Dodoo-Arhin, D.; Buabeng, F.P.; Mwabora, J.M.; Amaniampong, P.N.; Agbe, H.; Nyankson, E.; Obada, D.O.; Asiedu, N.Y.
Nanostructured mesoporous titanium dioxide (TiO2) particles with high specific surface area and average crystallite domain sizes within 2 nm and 30 nm have been prepared via the sol-gel and hydrothermal procedures. The characteristics of produced nanoparticles have been tested using X-Ray Diffraction (XRD), Brunauer–Emmett–Teller (BET) surface area analysis, Scanning Electron Microscopy (SEM), Fourier Transform Infra-Red (FTIR), and Raman Spectroscopy as a function of temperature for their microstructural, porosity, morphological, structural and absorption properties. The as-synthesized TiO2 nanostructures were attempted as catalysts in Rhodamine B and Sudan III dyes' photocatalytic decomposition in a batch reactor with the assistance of Ultra Violet (UV) light. The results show that for catalysts calcined at 300 °C, ∼100 % decomposition of Sudan III dye was observed when Hydrothermal based catalyst was used whiles ∼94 % decomposition of Rhodamine B dye was observed using the sol-gel based catalysts. These synthesized TiO2 nanoparticles have promising potential applications in the light aided decomposition of a wide range of dye pollutants.
Effects of substrates on the performance of optoelectronic devices: A review
(Cogent Engineering, 2020) Asare, J.; Agyei-Tuffour, B.; Amonoo, E.A.; Dodoo-Arhin, D.; Nyankson, E.; Mensah, B.; Oyewole, O.O.; Yaya, A.; Onwona-Agyeman, B.
This review discusses the effects of substrates on devices fabricated for optoelectronic applications. It includes the types and characteristics of substrates, synthesis and fabrication of substrates, and the influence of substrates on the optical properties, surface morphology and current-voltage behaviour of optoelectronic devices. The study showed that two main types of substrates: planar and textured are commonly used in the industry. Flexibility, semi-rigidity and rigidity are characteristics of the substrates and they vary in modulus, transparency and texture. Whereas glass and metal substrates can be produced via melt casting, polydimethylsiloxane (PDMS), polyethylene terephthalate (PET), etc are produced by crosslinking polymer base materials with curing agents. The mechanical and current-voltage characteristics are also shown for planar and textured substrate-based devices. The textured substrates showed ridges, wrinkles, buckled surface morphology whereas the planar showed uniform and largely flat morphology. Textured substrates also recorded higher optical absorbance and improved device efficiencies compared with planar substrates. The molecular configuration of the polymer chains are edged-on for planar substrates and both edge-on and face-on for textured substrates. The findings and their implications have been discussed to highlight the importance of substrates in the fabrication and performance of optoelectronic devices.
Flow Improvers and Pipeline Internal Coating Benefits and Limitations with Respect to Pipeline Capacity Enhancement
(Journal of Advanced Research in Fluid Mechanics and Thermal Sciences, 2023) Okyere, M.S.; Damoah, L.N.W.; Nyankson, E.; Konadu, D.B.
This article illustrates the outcome of a theoretical examination of applying internal coating and flow improver to gas and liquid pipeline systems. A test case of a 12-inches, 18-inches, 24-inches, 30-inches, 36-inches, and 42-inches diameter gas and liquid transmission pipelines evaluates hypothetically, synergistic use of pipeline internal coating with flow improver to enhance flow rate of a pipeline and minimize internal friction. The improvements in pipeline hydraulics are recognized and the enhancement of pipeline capacity calculated over a broad range of parameters. The hydraulic benefits are presented as percentage increase in pipeline capacity using flow equations. Analysis shows that internal coating of pipelines plus injection of flow improver is hydraulically and economically viable for both gas and liquid pipelines with a typical capacity increase greater than 116%. Corrosion protection and safety is improved with low operating cost.
Industrial Applications of Clay Materials from Ghana - A Review
(Oriental Journal of Chemistry, 2018-08) Asamoah, R.B.; Nyankson, E.; Annan, E.; Agyei-Tuffour, B.; Efavi, J.K.; Kan-Dapaah, K.; Apalangya, V.A.; Damoah, L.N.W.; Dodoo-Arhin, D.; Tiburu, E.K.; Kwofie, S.K.; Onwona-Agyeman, B.; Yaya, A.
Clay minerals are phyllosilicate groups naturally found in soils in all parts of the world. They have proven to be among the most essential industrial minerals because of their unique physicochemical properties and versatile applications within a wide range of fields including ceramics, construction, and environmental remediation, biomedical as well as cosmetics. Clay minerals are also primary to the production of other materials such as composite for secondary applications. In Ghana, clay mineral deposits are commonly found in several areas including soil horizons as well as geothermal fields and volcanic deposits, and are formed under certain geological conditions. This review seeks to explore the geographical occurrence and discusses the current uses of various local clay materials in Ghana in order to highlight opportunities for the utilization of these materials for other applications.