Browsing by Author "Ramakokovhu, M. M."
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Item Extraction of silica from cassava periderm using modified sol-gel method(Faculty of Engineering and Technology, University of Ilorin, Nigeria, 2018) Adebisi, J. A.; Agunsoye, J. O.; Bello, S. A.; Haris, M.; Ramakokovhu, M. M.; Daramola, M. O.; Hassan, S. B.Cassava peridem wastes are generated and disposed indiscriminately or burnt due to zero economic value. In this study, modified sol-gel synthesis of amorphous silica nanoparticles from cassava periderm (CP) was investigated. The wastes were pretreated with HCl to remove soluble metallic impurities. Both treated and untreated CP flakes were calcined at 700 oC to obtain their respective ashes. The ashes were leached with HCl to remove soluble metallic oxides and thereafter sol-gelled to obtain silica gel modified with ethylene glycol. The gel was dried at 80 oC for 18 hours and then characterized using SEM, EDX, XRD, FT-IR, Raman, TEM and PSA. The SEM micrographs showed that silica modified with ethylene glycol is less agglomerated with higher silica yield and lower particle sizes. All the silica produced showed similar functional groups and non-crystallinity. The silica nanoparticles could be used as starting materials for synthesis of silicon nanoparticles.Item Extraction of Silica from Sugarcane Bagasse, Cassava Periderm and Maize Stalk: Proximate Analysis and Physico-Chemical Properties of Wastes(Springer, 2019) Adebisi, J. A.; Agunsoye, J. O.; Bello, S. A.; Kolawole, F. O.; Ramakokovhu, M. M.; Daramola, M. O.; Hassan, S. B.Indiscriminate disposal and burning of agricultural wastes constitute environmental pollution and increase in greenhouse gases emission. Renewable nature and availability of agricultural wastes has stimulated researchers to explore “wastes to wealth creation” policy. Three agricultural wastes were investigated for potential use for silica production. Proximate analysis, thermogravimetric analysis (TGA), compositional analysis, calcination and statistical analysis were carried out to quantify the ash and establish presence of silica. Response surface methodology was used for statistical analysis of CP calcination. The proximate analysis showed that sugarcane bagasse, cassava periderm and maize stalk ash contents are 1.73, 4.93 and 4.80%, respectively. The EDS results showed that their ashes contain 5.22,6.10 and 7.01% silicon, respectively. XRF results revealed presence of 38% SiO2 in CP ash. XRD revealed presence of silica and silicates phases. TGA shows that their calcination temperature must be above 500 °C. Numerical optimization of CP calcination gave optimum condition of 700 °C for 270 min to attain 82% weight loss. Calcination regression equation exhibited high coefficient of determination ( R2) of 0.8225. The three wastes contain silica and silicates from which silica could be extracted. Calcination temperature and time have been established to be significant in ash content enhancement.Item Green production of silica nanoparticles from maize stalk(Taylor & Francis, 2019) Adebisi, J. A.; Agunsoye, J. O.; Bello, S. A.; Haris, M.; Ramakokovhu, M. M.; Daramola, M. O.; Hassan, S. B.Amorphous silica has been produced from some agricultural wastes but with drawbacks on agglomeration challenges. In the present study, potential of maize stalk (MS) wastes as a source of nano silica was studied through modified sol-gel techniques, which involved acid pretreatment, calcination, leaching, sol-gel modification, and post-filtration treatments. Nano silica particles obtained were characterized by XRD, SEM, EDS, TEM, PSA, Raman, and FT-IR for morphology, elemental composition, particle size, and surface chemistry. Results obtained revealed that pre-calcination acid treatment of the MS did not improve the silica yield but reduced the Van der Waal’s interaction of the silica particles resulting in silica particles with a smaller degree of agglomeration. Sodium silicate modified with ethylene glycol sol-gel treatment prior to titration reduced silica agglomeration. Silica nanoparticles obtained according to XRD, TEM, and PSA are below 30 nm.Item Preparation and Characterization of Amorphous Silica Nanoparticles from Cassava Waste(International Journal of Engineering Research and Technology, 2017) Adebisi, J. A.; Agunsoye, J. O.; Ramakokovhu, M. M.; Daramola, M. O.; Haris, M.; Hassan, S. B.Agricultural wastes recycling has attracted researchers in order to reduce their undiscerning disposal to our environment which poses environmental challenges. Cassava is cultivated in large quantities by several developing countries, led by Nigeria, with lots of wastes generation. Cassava periderm (CP) is among the wastes generated in cassava processing industries. In this work, silica nanoparticles were produced from CP using a pyro-hydrometallurgical approach. Acid leaching followed CP sample preparation, calcination and lastly sol-gel. The silica nanoparticles obtained were characterised using SEM, EDS, XRD and PSA. The results showed an amorphous silica with Na, Al and P as impurities. The particle sizes were observed to be in nano-range but with agglomeration. Silica produced can be used in production of refined oil, detergents, adhesives as well as in pharmaceutical industry.Item Proximate Analysis and Physicochemical Properties of Sugarcane Bagasse, Cassava Periderm and Maize Stalk(Centre for Nanoscience and Technology, Anna Univeristy, Chennai, India, 2017) Adebisi, J. A.; Agunsoye, J. O.; Bello, S. A.; Ramakokovhu, M. M.; Daramola, M. O.; Haris, M.; Hassan, S. B.Recycling of agricultural wastes has attracted researchers to reduce their indiscriminate and unguided disposal that pose environmental challenges. The amount of several products from such recycling are proportional to the amount of volatile matter, carbon and ash contents. In order to investigate the potential of obtaining quantifiable amount of silica from three agricultural wastes (cassava periderm, maize stalk and sugarcane bagasse), their proximate and physicochemical characteristics were investigated. SEM, EDS, XRD and TGA analysis were carried out to comprehend their characteristics. Cassava periderm and maize stalk have higher ash content relative to sugarcane bagasse. The amount of free silica obtained from their XRD also revealed greater potential of yielding more silica than sugarcane. Sugarcane bagasse gave more volatile matter while cassava periderm has more carbon. It is therefore feasible to extract silica from all the wastes but with low yield from sugarcane.