Papers by Michael Olatunji
Polymer Bulletin, 2017
Cerium is an abundant rare earth element, with several stable and radioactive isotopes. Due to it... more Cerium is an abundant rare earth element, with several stable and radioactive isotopes. Due to its numerous industrial applications, cerium radioisotopes are common components of liquid radioactive wastes. We investigated the removal of 139 Ce radionuclide from wastewater by adsorption using composite of polypyrrole with wood sawdust, as a model for other cerium radioisotopes. The composite material was characterized by Brunauer-Emmett-Teller, field emission scanning electron microscopy and Fourier transform infrared spectroscopy techniques. Effects of pH, initial ion concentration and temperature on the uptake amount of 139 Ce were investigated by batch adsorption. The results indicated that the uptake amount of cerium ion increased with a rise in pH to optimum value of 8.0 and contact time of 120 min. The pseudo-second-order kinetics was found to best fit the kinetic data, while the isotherm data showed a good fit to both the Langmuir and Freundlich models. The maximum sorption capacity of 6.57 ± 0.54 mg/g was estimated by the Langmuir model. Thermodynamic studies indicated that the adsorption is feasible, spontaneous and endothermic in nature. The radiation hardness of polymer composite was also investigated by exposing it to 60 Co gamma source. Irradiation had practically no significant effect on the sorption performance of as-prepared polymer composite.
Development and Characterization of Polypyrrole-Based Nanocomposite Adsorbent and Its Applications in Removal of Radioactive Materials
IFMBE Proceedings, 2015
Development of environmental friendly materials is desirable in the fields of science and enginee... more Development of environmental friendly materials is desirable in the fields of science and engineering for various purposes. In environmental science, they find applications commonly in environmental remediation and the recovery of valuable metals. This aspect is of particular concern to health sciences due to the toxic effects and non-biodegradable nature of many substances that have found their way into the human body via environmental media. As for instance, though cobalt possesses some importance in diet it has been linked to health problems like cardiomyopathy, asthma etc. via overexposure. As a result, removal of this substance from the aqueous media of our environment is crucial. In this study, polypyrrole conducting polymer incorporated with biomass waste (sawdust) was prepared by simple chemical oxidative polymerization as a composite adsorbent for 57Co radionuclide removal from aqueous solution. The as-prepared composite material was characterized by FESEM, XRD and BET surface analysis. In the 57Co adsorption studies, the effects of several factors such as adsorbent dosage, contact time and competitive metal ions were investigated for real wastewater treatment applications. The results indicated that the removal process was rapid and reached saturation within 3 hours of contact of adsorbent and adsorbate at ambient temperature. Both Na+ and K+ coexisting ions were found to affect 57Co adsorption and the uptake percentage was reduced from 54.9 to ~ 20% at 0.1M of both Na+ and K+ ions. Langmuir isotherm model was used to fit the maximum sorption capacity.
Human exposure to ionizing radiation in the environment is mainly due to naturally occurring radi... more Human exposure to ionizing radiation in the environment is mainly due to naturally occurring radionuclides in the soils, building materials and rocks, but the level may vary depending on the anthropogenic activities prevalent in each location. Presently, in Nigeria, there are concerns due to environmental health implications of all sorts of mineral mining and processing spreading across the southwestern states of the country. As a result, a total of 200 composite soil samples were taken in five states in the southwest of Nigeria, close to active mining sites at the rooting (0.2 m) and at deep planting zones (0.5 m) for analysis by gamma-ray spectrometry using NaI(Tl) detector. The activity concentrations of natural radionuclides in the composite soil samples were determined to vary in the order of 40K > 232Th > 226Ra/238U for all locations. In contrast to the other locations, Olode and Igbokoda had average radium equivalent activities (Raeq) to be 1.6 and 1.8 times higher than...
The status of natural radioactivity in Nigerian environments
Radiation and Environmental Biophysics, Sep 29, 2022
Activity Conce Ntration and Radiological Impact Assessment of 226ra, 232th and 40k in Beach Sand and Sediment Samples Around Badagry Coastal Areas of Lagos
SSRN Electronic Journal
Polypyrrole-based nanocomposite adsorbents and its application in removal of radioactive materials
Polymer-based Nanocomposites for Energy and Environmental Applications, 2018
Abstract Conducting polymers form an important aspect of research in science and engineering due ... more Abstract Conducting polymers form an important aspect of research in science and engineering due to their various interesting properties, such as inherent high flexibility, structural diversity, light weight, and mechanical stability. Among them, polypyrrole due to its facile and easy synthesis at low cost, high electric conductivity, environmental friendliness, and ease of tailoring into nanocomposites has expanded its applications beyond the original scope of conventional polymers. Considering these properties, incorporation of nanofillers in polypyrrole for fabricating polypyrrole-based nanocomposites is currently receiving immense attention as beneficial resources for developing high-efficient adsorbents for addressing environmental issues. This chapter focuses on the synthesis of polypyrrole and its nanocomposites and the key issues for achieving high performance in the treatment of liquid radioactive wastes. Survey of literature on the recent studies on the uptake of radioactive materials and their nonradioactive homologues via applications of polypyrrole-based nanocomposite adsorbents was made. Finally, general outlook of the future prospects of polypyrrole-based nanocomposites in the removal of radioactive materials and possible problems they may encounter is presented.
Radiation Measurements, 2019
This is a PDF file of an article that has undergone enhancements after acceptance, such as the ad... more This is a PDF file of an article that has undergone enhancements after acceptance, such as the addition of a cover page and metadata, and formatting for readability, but it is not yet the definitive version of record. This version will undergo additional copyediting, typesetting and review before it is published in its final form, but we are providing this version to give early visibility of the article. Please note that, during the production process, errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain.
Journal of Radioanalytical and Nuclear Chemistry, 2018
Polypyrrole is incorporated with activated carbon in large size dopant solution and investigated ... more Polypyrrole is incorporated with activated carbon in large size dopant solution and investigated for 137 Cs removal studies. Adsorption experiments showed optimum conditions within 240 min contact time, pH 6, 0.2 g adsorbent and B 100 mg/l adsorbate dose, respectively, while the kinetic data followed pseudo-first-order model. Isotherm data were reproducible by the Langmuir isotherm yielding 23 mg/g maximum sorption capacity. Regeneration of adsorbent was attempted and indicated promising results within three cycles. The surface behavior has also been examined and revealed a well-ordered structure under gamma irradiation. This is a cheap adsorbent to consider and has also proven to possess higher sorption capacity than most highly-cost inorganic materials in use.
Results in Physics, 2018
Silica-based commercial glasses were studied for ionizing radiation effectiveness 59-1332 keV ene... more Silica-based commercial glasses were studied for ionizing radiation effectiveness 59-1332 keV energies of photon beams were used to obtain various interaction properties Glass sample 'Rider' from China shows aptness to be used as shielding material
Journal of Vinyl and Additive Technology, 2017
Electroactive polypyrrole has been synthesized by oxidative polymerization of pyrrole using ferri... more Electroactive polypyrrole has been synthesized by oxidative polymerization of pyrrole using ferric chloride hexahydrate as oxidant in the presence of sodium dodecylbenzene sulfonate (SDBS), and used to remove radioactive cesium from aqueous solution. The SDBS‐doped polypyrrole (PPy/SDBS) adsorbent was characterized by Field emission scanning electron microscopy, X‐ray diffraction and Fourier transform infrared techniques. A rapid and efficient adsorption of 137Cs radionuclide with a maximum sorption capacity of 26.2 mg/g has been achieved at 313 K. The kinetic data show the best fitting by the pseudo first‐order model while the Langmuir model properly reproduced the isotherm data. The thermodynamics parameters revealed an endothermic and spontaneous nature of the adsorption process. The adsorption efficiency shows only an insignificant variation with the gamma‐ray doses of 100 and 200 kGy. Considering the toxicity and nonbiodegradable nature of radioactive cesium, SDBS‐doped polypyr...
PLOS ONE, 2016
A radiotracer study was conducted to investigate the removal characteristics of cadmium (109 Cd) ... more A radiotracer study was conducted to investigate the removal characteristics of cadmium (109 Cd) from aqueous solution by polypyrrole/ sawdust composite. Several factors such as solution pH, sorbent dosage, initial concentration, contact time, temperature and interfering metal ions were found to have influence on the adsorption process. The kinetics of adsorption was relatively fast, reaching equilibrium within 3 hours. A lowering of the solution pH reduced the removal efficiency from 99.3 to~46.7% and an ambient temperature of 25˚C was found to be optimum for maximum adsorption. The presence of sodium and potassium ions inhibited 109 Cd removal from its aqueous solution. The experimental data for 109 Cd adsorption showed a very good agreement with the Langmuir isotherm and a pseudo-first order kinetic model. The surface condition of the adsorbent before and after cadmium loading was investigated using BET, FESEM and FTIR. Considering the low cost of the precursor's materials and the toxicity of 109 Cd radioactive metal, polypyrrole synthesized on the sawdust of Dryobalanops aromatic could be used as an efficient adsorbent for the removal of 109 Cd radioisotope from radionuclide-containing effluents.
Chemosphere, Jan 14, 2016
Malaysia, a rapidly growing industrial country, is susceptible to pollution via large-scale indus... more Malaysia, a rapidly growing industrial country, is susceptible to pollution via large-scale industrial engagements and associated human activities. One particular concern is the potential impact upon the quality of locally resourced vegetables, foodstuffs that contain important nutrients necessary for good health, forming an essential part of the Malaysian diet. As a part of this, it is of importance for there to be accurate knowledge of radioactive material uptake in these vegetables, not least in respect of any public health detriment. Herein, using HPGe γ-ray spectrometry, quantification has been performed of naturally occurring radionuclides in common edible vegetables and their associated soils. From samples analyses, the soil activity concentration ranges (in units of Bq/kg) for (226)Ra, (232)Th and (40)K were respectively 1.33-30.90, 0.48-26.80, 7.99-136.5 while in vegetable samples the ranges were 0.64-3.80, 0.21-6.91, 85.53-463.8. Using the corresponding activities, the tra...
RSC Adv., 2015
Due to rapid population growth, technological advancement and industrial revolution, the rate of ... more Due to rapid population growth, technological advancement and industrial revolution, the rate of generated waste effluents has become a grave concern.
AIP Conference Proceedings, 2015
Milk is the basic food stuff for the infants because they generally consume more milk on a daily ... more Milk is the basic food stuff for the infants because they generally consume more milk on a daily basis as its minerals and proteins are essential for their growth and development, therefore, it is very important to assess the natural radioactivity levels and the associated dose in the widely consumed powered infant's milk. As a result, 14 brands of infant's powdered milk were collected from different supermarkets around Selangor, Malaysia and analysed for 226 Ra, 232 Th and 40 K activities. The obtained mean activity of 226 Ra, 232 Th and 40 K are 3.05±1.84, 2.55±2.48 and 99.1±69.5 Bqkg-1 , respectively. Among the analysed milk samples, the brand from Philippines (Lactogen) showed low level of radioactivity while Singaporean brand (S26 SMA Gold) showed the highest. The estimated mean annual effective doses due to the ingestion of natural radionuclides in the sampled milk are 635 and 111 µSv for infant ≤ 1y and infant 1-2y, respectively. The obtained dose value does not yet pose any significant radiological hazards to the population under investigation comparing with the 1.0 mSvy-1 recommended by ICRP for all ages.
Physica Scripta, 2014
Owing to population growth, there has been high demand for food across the world, and hence, diff... more Owing to population growth, there has been high demand for food across the world, and hence, different agricultural activities such as use of phosphate fertilizers, recycling of organic matters, etc, have been deployed to increase crop yields. In Malaysia, a total of nine composite corn advance lines have been developed at the Institute of Biological Sciences, University of Malaya and are being grown under different conditions with a bid to meet the average daily human need for energy and fiber intake. To this end, the knowledge of radioactivity levels in these corn advance lines are of paramount importance for the estimation of possible radiological hazards due to its consumption. Hence, the radioactivity concentrations of 226 Ra, 228 Ra and 40 K in the corn have been determined using HPGe γ-ray spectrometry. The activity concentrations in the corn ranged from 0.05 to 19.18 Bq kg −1 for 226 Ra, from 0.10 to 3.22 Bq kg −1 for 228 Ra and from 26.4 to 129 Bq kg −1 for 40 K. In order to ascertain the radiological safety of the population regarding maize consumption, the daily intakes of these radionuclides as well as the annual effective dose were estimated. The total effective dose obtained due to the ingestion of radionuclides via maize consumption is 15.39 μSv y −1 , which is less than the international recommendations.
World Journal of Nuclear Science and Technology, 2013
The activity concentrations of natural radionuclides 226 Ra, 232 Th and 40 K in bauxite ore, alum... more The activity concentrations of natural radionuclides 226 Ra, 232 Th and 40 K in bauxite ore, alumina, dross tailing, aluminium scraps and soil samples collected from an aluminium industry in Nigeria were determined by gamma ray spectroscopy method. The mean values of 226 Ra, 232 Th and 40 K content of the samples ranged from 16 ± 6 (alumina) to 31 ± 10 (scrap), 41 ± 0.12 (scrap) to 134 ± 21 (bauxite) and 47 ± 14 (bauxite) to 354 ± 8 (scrap) Bq•kg −1 , respectively. The mean activity concentrations of 226 Ra and 40 K in all the samples are lower than the world average for soil while 232 Th is higher with the exception of alumina and scrap. As a measure of radiation hazard to the occupational workers and the members of the public, the radium equivalent activities and external gamma dose rates due to the radionuclides at 1 m above ground surface were calculated. The radium equivalent activities which varied between 88 ± 10 (alumina) and 222 ± 34 (bauxite) Bq•kg −1 are within the safety recommended limit of 370 Bq•kg −1. The mean annual effective doses calculated from the absorbed dose rates in air were between 54 ± 6 (alumina) and 134 ± 20 (bauxite) µSv•y −1 , which is lower than the 1 mSv•y −1 recommended for the general public. The annual gonadal dose equivalent of all the samples with the exception of alumina was higher than the world average for soil.
Radiation Protection Dosimetry, 2015
Malaysia is among the countries with the highest fish consumption in the world and relies on seaf... more Malaysia is among the countries with the highest fish consumption in the world and relies on seafood as a main source of animal protein. Thus, the radioactivity in the mostly consumed marine animals such as fishes, crustaceans and molluscs collected from the coastal waters around Peninsular Malaysia has been determined to monitor the level of human exposure by natural radiation via seafood consumption. The mean activity concentrations of naturally occurring radionuclides 226 Ra (238 U), 228 Ra (232 Th) and 40 K ranged from 0.67 + + + + + 0.19 Bq kg 21 (Perna viridis) to 1.20 + + + + + 0.70 Bq kg 21 (Rastrelliger), from 0.19 + + + + + 0.17 Bq kg 21 (Teuthida) to 0.82 + + + + + 0.67 Bq kg 21 (Caridea) and from 34 + + + + + 13 Bq kg 21 (Caridea) to 48 + + + + + 24 Bq kg 21 (Teuthida), respectively. The mean annual committed effective dose due to the individual radionuclides shows an order of 228 Ra > 226 Ra > 40 K in all marine samples. The obtained doses are less than the global internal dose of 290 mSv y 21 set by the United Nations Scientific Committee on the Effects of Atomic Radiation, discarding any significant radiological risks to the populace of Peninsular Malaysia.
Radio aeronomy in Nigeria: First results from very low frequency (VLF) radio waves receiving station at Anchor University, Lagos
2020 International Conference in Mathematics, Computer Engineering and Computer Science (ICMCECS), 2020
The study of the Earth’s atmosphere and the space environment is important because of the role pl... more The study of the Earth’s atmosphere and the space environment is important because of the role played by the medium in the activities that affect the Earth and its inhabitants directly or indirectly. A robust capability to monitor, model and predict the happenings in the atmospheric space through deployment of both space- and ground-based observational systems for data acquisition, is key to result-oriented scientific research in atmospheric and space sciences. In this paper, we highlight the importance of regional deployment of observational facilities for data acquisition to complement current observational tools. We briefly review the capabilities of very low frequency (VLF) radio waves (in monitoring and studying changes in the atmosphere and ionosphere), and also present data obtained from our newly deployed VLF radio waves receiver at Anchor University, Lagos (AUL). We show that the diurnal signature characterised by VLF radio signal reflected in the data of three of four prop...
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Papers by Michael Olatunji