Volumen 5 (2021): Edición 1 (June 2021)

Polyphosphazenes was synthesized and their self assembly behavior was observed as reported in our previous work [1–5]. A number of experiments were carried out to study the polymerization behavior at various conditions of the polymerization time and temperature. The experimental data were analyzed by graphical and statistical methods and it was found that the polymerization phenomena was controlled by the synthesis time, i.e. M_w = M_o e^k_s^ts, where M_w is molecular weight of the polymer at time t_s, M₀(=203.24) is pre-exponential factor in the model and k_s is (=10686) is synthesis rate constant for the polymer.

This study examined potentially toxic elements (PTEs) from poultry feeds. The presence of PTEs in the environment raises health concern because these elements can be toxic, ubiquitous and cannot be degraded to non-toxic forms by any known method and as a result remain in the environment for decades. This is a potential pathway through which these PTEs could easily enter the food chain. Six PTEs (Cd, Cr, Cu, Pb, Mn, Ni and Zn) were determined from four feed types (starter, grower, finisher and layer) from four manufacturers coded A, B, C and D. The samples were prepared, digested and analysed for PTEs using atomic absorption spectrophotometer. The mean concentrations obtained were in the following ranges: 0.49 – 0.76 mg/kg (Cd); 11.9 – 7.90 mg/kg (Cr); 5.10 - 7.91 mg/kg (Cu); 7.17 - 9.47 mg/kg (Pb); 26.9 - 34.9 mg/kg (Mn); 3.80 - 6.50 mg/kg (Ni) and 27.8 - 38.4 mg/kg (Zn). These results were compared with the maximum acceptable concentration for PTEs in feeds as stipulated by the European Union standard and the concentrations of Pb and Ni exceeded maximum acceptable concentration. When concentrations exceed set standard, it implies risk to human health. Thus, the need for continuous monitoring of feed compositions.

The study depicts the production, optimization and characterization of bio-oil from pyrolyzed rice husk using a fabricated fixed bed reactor. The pyrolysis process was conducted with bio-oil response, bio-char response and non-condensable gases response as products. The effect of pyrolysis variables were observed by the production of the bio-oil as the response. Sixty runs of pyrolysis experiments were suggested by Box Benkhen design indicated optimum pyrolysis conditions at particle size of 2.03mm mesh, reaction time of 81.80 mins and temperature of 650oC for rice husk. The maximum bio-oil yield was obtained with 38.39% at optimum condition of the variables. The bio-oil sample obtained had better performance compared with ASTM standard. Such a determination would contribute so immensely to a significant comprehension of the chemical efficiency of the pyrolysis reaction.

Microplastic (MP) is currently a subject of discussion in all parts of the world because it has increasingly over the years become the dominant source of pollution in marine ecosystem. Huge number of these Mps emanate from waste management, decommissioning of ships and oil rigs, plastic products in aquaculture and fishery, sewage treatment, consumer products, agricultural production, transportation, offshore oil and gas production and city dust and wears. Microplastic are characteristically non- biodegradable or durable, exhibits buoyancy, travel long distances, complex with toxic chemicals and bioaccumulate being invisible to the human eye. Classification of MPs into primary and secondary based on source and established standard protocols visa-vis the sampling and identification in matrices were critically reviewed. Physicochemical processes for identification of MPs such as pyrolysis-Gas chromatography/Mass spectrometry, FTIR, Raman spectroscopy, SEM-GS and TGA/MS were reviewed. Deleterious chemicals such as polychlorinated biphenyls (PCBs), polybrominated diphenyl ethers (PBDEs), dioxins, phthalates, polycyclic aromatic hydrocarbons (PAHs) and persistent organic chemicals (POCs) associated with MPs and mechanisms of chelation were appraised. Several menace and health hazards such as hepatic inflammation, genetic mutation, increase in reactive oxygen species (ROS) /oxidative stress, tissue necrosis and proliferation of cells linked with MPs were also discussed. Furthermore, green approaches to arresting the menace such as replacing polymer products with biopolymer an eco-friendly alternative, recycling of plastic products, use of paper bags and glass materials and abrogation of consumer products laced with microbeads were advocated.

Metal Nanoparticles show specific physical and chemical properties attributed to its small size and high surface area to volume ratio. These chemical and physical properties using different strategies and conditions enhance its biological application especially in the field of medicine. Earth abundant and cheap cupper metal is the essential element in many processes and has been used as a focus element to synthesize nanoparticles by different methods using new technology, which are being broadly classified as biological methods that includes green synthesis, microorganism etc. and the non-biological synthesis which includes chemical and Physical methods. Thus, the imperative need to synthesize cupper nanomaterial that are economic and efficient is necessary. This review have briefly described the modern methods to synthesize nanoparticles particularly focusing on the non-biological methods of cupper nanoparticles. An overview of current methodologies that are used for cupper nanoparticle mainly chemical reduction using organic and inorganic solvents, Reverse micelle, microemulsion, polyol method and several physical methods such as vapor condensation, photo irradiation and plasma synthesis methods are discussed.

Nigeria demand for sustainable, affordable and accessible energy is on the rise. Hence, this led to rigorous research to determine affordable processes of using waste materials for production of sustainable energy. In this research pyrolysis was carried out in a fabricated fixed bed pilot-scale reactor using Gmelina arborea (sawdust) biomass for the production of bio-oil. The physical, chemical properties and the ultimate analysis of the bio oil produced were determined following standard methods. The physicochemical properties and ultimate analysis obtained were favourable. The highest moisture content of 21 % at 600 °C and least moisture content of 12 % at 900 °C were obtained from Gmelina arborea. The elemental results of the products show low sulphur quantity which is of good prospects that Gmelina arborea are good materials for bioenergy production without posing danger to the environment. Utilisation of Gmelina arborea for bio-oil production as an alternative fuel would shun unfavourable environmental abasement related to the use of conventional fuels.