Browsing by Author "Mbu, E.E."
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Item Photocatalytic Degradtion of Azo and Rhodamine Dyes Using Nanostructured Copper (Ii) Oxide.(University of Ghana, 2018-07) Mbu, E.E.Organic dye pollutants are sometimes released into the environment with wastewater from industries which make use of such dyes. In surface water, they contaminate the surrounding environment while their residue accumulates on land. These chemicals are noted for their toxicity to living organisms and they can cause cancers in human beings. In this study a relatively simple, long term and cost effective remedy for dye pollution reduction was developed; with a focus on the use of semiconductor photocatalysis for the breakdown of the dye in water. Due to their ease of synthesis, minimal toxicity and cost, copper (II) oxide (CuO) nanoparticles were used to degrade three commonly used dyes; Methyl Orange (MeO), Methylene Blue (MB) and Rhodamine B (RhB) which arise from two prominent dye families (Azo and Rhodamine dyes). CuO nanoparticles were synthesised following a simple solution method using two copper precursor salts; hydrated copper sulphate (CuSO4.5H2O) and hydrated copper nitrate (Cu(NO3)2.3H2O). The CuO was precipitated from a 0.02 M copper salt solution using 1.6 g/L NaOH pellets. The temperature at which these pellets were added to the copper salt solutions (25 °C and 60 °C) played a major role in determining the shape and size of the nanoparticles. The synthesised particles were then characterised using X-Ray Diffraction (XRD), Scanning Electron Microscopy (SEM), UV-Vis Spectrophotometry, Fourier Transform Infra-Red (FTIR) spectroscopy and Brunauer Emmett Teller (BET) surface area and porosity analysis. The synthesised nanoparticles were microporous with sizes ranging from 12 – 13.5 nm and BET surface areas of 26.8 m2/g, 28.4 m2/g and 49.3 m2/g. The photocatalytic character of the synthesised particles was assessed in the presence of visible light for 100 minutes at 25-minute intervals and the overall minimum and maximum degradation efficiency recorded amongst all the samples was 85 % and 99 %.Item Synthesis of nanostructured cupric oxide for visible light assisted degradation of organic wastewater pollutants(Taylor & Francis Group, 2021) Dodoo-Arhin, D.; Mbu, E.E.; Ntwampe, S.K.; Malenga, E.N.; Fosso-Kankeu, E.; Agyei-Tuffour, B.; Nyankson, E.; Yaya, A.; Agbe, H.When organic dye-containing wastewater from textile industries are sometimes released into the environment, the liquids tend to pollute the environment whilst their solid residue accrues on land after the evaporation of the water. Most of these synthetic compounds are known to be poisonous and carcinogenic to living organisms. For this study, a relatively simple, sustainable and cost-effective approach have been utilized to synthesize CuO nanoparticles using copper precursor salts: (CuSO4.5H2O) and (Cu(NO3)2.3H2O), as a remedy for dye pollution reduction in water. Due to their simplicity of synthesis, insignificant harmfulness and cost, copper (II) oxide (CuO) nanoparticles were used to breakdown three generally utilized dyes; Rhodamine B (RhB), Methylene Blue (MB)- [Methylthioninium chloride] and Methyl Orange (MeO). The as-prepared nanoparticles were characterized to determine the ordered arrangement of atoms, functional groups, weight loss, thermal properties, microstructure and surface characteristics. Most significantly, the predominant preferential crystal growth was along the {002}/{-111} plane for the sulphate-based precursor whiles for the nitrate based precursor, it was preferentially grown along the {111} direction. The mesoporous nanoparticles had aver age crystallite sizes of 12 nm and 15 nm; and BET surface areas of 42.9 m2 /g, and 69.6 m2 /g respectively. The as-prepared nanoparticles were assessed for their photocatalytic behaviour in response to visible light exposure for 100 minutes at 25- min’ intervals. The nitrate precursor-based CuO photocatalysts showed relatively higher photodegradation efficiency (MeO-94.3%; MB- 90.6%; RhB - 99.6%) as compared with the sulphate precursor-based CuO photocatalysts (MeO-85.2 %; MB-87.9%; RhB- 98.8%)