Nutritional Evaluation of Seed and Characterization of Crude Jack Bean (Canavalia ensiformis) OIL

The Canavalia ensiformis used for this study was cultivated and harvested in Owo, Ondo state of Nigeria. The seed was prepared by sun drying for two weeks; it was later dehulled and milled to flour. The proximate and the mineral compositions of the seed were investigated using standard analytical techniques. The oil in the seed was extracted using solvent extraction method. The resulting crude oil was assessed for physicochemical parameters and fatty acid composition. Canavalia ensiformis contains high protein content, high carbohydrate content, high fibre content, low lipid and adequate minerals. The oil was bright in colour, transparent with low thermal stability when in contact with air. The free fatty acid and acid value was low, have high iodine and peroxide values, and low saponification value. Oleic acid has the highest fatty acid composition with 32.88%, followed by Linoleic acid with 25.93%. The total saturated fatty acid was 8.41%,while the total unsaturated fatty acid was 86.49%. Having considered the proximate and mineral compositions,the study revealed that the seed have high potential for animal and human consumption. In addition, it compared favourably with some conventional edible legumes. The oil, if refined and consumed will supply essential fatty acid to the body based on the fatty acid composition

Development of an Analytical Method for Nitric Oxide Radical Determination in Natural Waters

The measurement of photochemically generated nitric oxide radicals (NO) in natural waters has long been an arduous task because of a lack of simple analytical techniques, even though the environmental significance of this radical is paramount. We have developed a simple analytical method for the determination of photochemically generated NO in natural waters using 4,5-diaminofluorescein (DAF-2) as a probe compound. This method is based on the reaction of photoformed NO with DAF-2 in air-saturated solution to produce a highly fluorescent triazolofluorescein (DAF-2T) product. DAF-2T was determined by using reversed-phase HPLC with fluorescence detection, with excitation and emission wavelengths of 495 and 515 nm, respectively. Under optimum conditions, the calibration curve exhibited linearity in the range of 0.025−10 nM DAF-2T. The coefficients of variance for the measurements of the signal intensities of DAF-2T (from the photolysis of 0.5 μM and 5 μM NO2− with DAF-2) were less than 5% and 3%, respectively. For a total irradiation time of 30 min, the detection limit of the photoformation rate of NO was 1.65 × 10−13 M s−1, defined as 3σ of the lowest measured DAF-2T concentration (0.025 nM). The proposed method is relatively unaffected by potential interferents in seawater. The method was employed to determine the photoformation rate of NO in the Seto Inland Sea and the Kurose River in Hiroshima Prefecture, Japan. The measured NO photoformation rates in seawater and river water samples ranged from (5.3−32) × 10−12 M s−1 and (9.4−300) × 10−12 M s−1, respectively

Photochemical Production and Consumption Mechanisms of Nitric Oxide in Seawater

Nitric oxide (NO•) is an active odd-nitrogen species that plays a critical role in determining the levels of ozone (O3) and other nitrogen species in the troposphere. Here, we provide experimental evidence for photochemical formation of NO• in seawater. Photoproduction rates and overall scavenging rate constants were measured by irradiation of surface seawater samples collected from the Seto Inland Sea, Japan. Photoproduction rates of NO• ranged from 8.7 × 10−12 M s−1 to 38.8 × 10−12 M s−1 and scavenging rate constants were 0.05−0.33 s−1. The steady state concentrations of NO• in seawater, which were calculated from the photoproduction rates and scavenging rate constants were in the range 2.4−32 × 10−11 M. Estimation from the scavenging rate constant showed that the NO• lifetime in seawater was a few seconds. Our results indicate that nitrite photolysis plays a crucial role in the formation of NO•, even though we cannot exclude minor contributions from other sources. Analysis of filtered and unfiltered seawater samples showed no significant difference in NO• photoformation rates, which suggests a negligible contribution of NO• produced by photobiological processes. Using an estimated value of the Henry’s law constant (kH ≈ 0.0019 M atm−1), a supersaturation of surface seawater of 2 to 3 orders of magnitude was estimated. On the basis of the average values of the surface seawater concentration and the atmospheric NO• concentration, a sea-to-air NO• flux was estimated

Determination of Hydroxyl Radical in Seto Inland Sea and its Potential to Degrade Irgarol

Photo-production rates and overall scavenging rate constants of the highly reactive hydroxyl radicals (•OH) were measured by irradiation of surface seawater samples collected from the Seto Inland Sea, Japan. Photo-production rates of •OH ranged from 7.2 × 10-12 M s-1 to 424 × 1012 M s-1 and scavenging rate constants were 1.3 – 4.1×106 s -1 . The steady state concentrations of •OH in seawater, which were calculated from the photo-production rates and scavenging rate constants were in the range 2.6 –189 × 10-18 M. Estimation from the scavenging rate constant showed that the lifetime of •OH in seawater ranged from 0.29 ×10-6 s to 0.55 ×10-6 s. Nitrates and hydrogen peroxide contributions to OH radical formation rates were negligible in the samples studied. However, direct photolysis of NO2 - accounted for up to 73% of the observed •OH formation rates. The rate constant for the reaction •OH with irgarol was found to be (9.7 ± 0.52) × 109 M - 1 s -1. Based on the steady state concentration of •OH, the calculated half-lives for Irgarol due to the reaction with hydroxyl radicals in the Seto Inland Sea were in the range 4.3-318 day

Biosorption of nickel from aqueous solution by Tithonia diversifolia

AbstractThis study investigated the feasibility of Mexican sunflower (Tithonia diversifolia), a common plant that inhabits the highway of the south western Nigeria, as a novel biosorbent for nickel from solutions. pH profile, time dependency and cation interference studies were conducted using stem biomass of this plant. Nickel uptake exhibited substantial enhancement both in terms of the kinetics of uptake as well as the loading capacity. Results of the investigation showed that the unmodified biomass was able to remove over 70% of the nickel content of a solution, whereas NaOH modification improved the adsorption efficiency to over 77% in the same contact time of 60 min. The optimum pH of adsorption was recorded as 5 for the metal using both types of biomass. However,modification improved the adsorption efficiency to a pH lower than 4. The kinetic study conducted showed that the adsorption process follows Lagergren’s pseudo-second order reaction with R2 values equal to 0.9988 and 0.9989 for both types of biomass. The presence of cations such as calcium and magnesium also interfered negatively with the adsorption process. Between 20–35% reductions in the metal adsorbed were recorded in the presence of a 1 M concentration of Mg, Ca or mixed Mg and Ca ions. Langmuir model of adsorption isotherm gave the best fit for this sorption process with R2 values of 0.994, 0.995 and 0.997 for Mg, Ca and mixed Mg and Ca studies, respectively

Assessment of anti-corrosion potentials of extract of Ficus asperifolia -Miq (Moraceae) on mild steel in acidic medium

FullThe inhibitory potentials of ethanolic extracts and four fractions of the stem bark of Ficus asperifolia Miq. for the corrosion of mild steel were assessed using weight loss method, Fourier atomi absorption spectroscopy,scanning electron microscopy (SEM). The effects of varying immersion period,concentration of the inhibitors and temperatures for mild steel corrosion in 5 M HCl acid solution were carried out. A detailed kinetic reaction, thermodynamic (Ea, ∆H, ∆S) and adsorption isotherm studies were obtained. The crude extract of F. asperifolia (EFA) has the highest inhibition efficiency of 55%. The inhibitory efficiency of the four fractions of F. asperifolia (EFA) compared with the crude extract was in the order ethyl acetate > n-hexane > butanol > EFA > Aqueous. The inhibition efficiency was found to increase with increase in the extracts concentration but decreased with temperature. Corrosion rate increases with time but decreases with extracts concentration. The kinetic studies of the data followed a first order reaction. Thermodynamic studies revealed that corrosion inhibition may be due to spontaneous mixed adsorption of the plant constituents on the metal surface. Experimental data were fitted to Langmuir, Freundlich and Temkin adsorption isotherms. The plant investigated showed a good potential for green corrosion inhibitors. Investigation of phytochemical constituents showed that the extracts contain alkaloids, flavonoids, saponins, tannins anthraquinones and reducing sugars

Application of Fenton reaction for nanomolar determination of hydrogen peroxide in seawater

A simple and sensitive method for the determination of nanomolar levels of hydrogen peroxide (H2O2) in seawater has been developed and validated. This method is based on the reduction of H2O2 by ferrous iron in acid solution to yield hydroxyl radical (•OH) which reacts with benzene to produce phenol. Phenol is separated from the reaction mixture by reversed phase high performance liquid chromatography and its fluorescence intensity signals were measured at excitation and emission of 270 and 298 nm, respectively. Under optimum conditions, the calibration curve exhibited linearity in the range of (0–50) × 103 nmol L−1 H2O2. The relative standard deviations for five replicate measurements of 500 and 50 nmol L−1 H2O2 are 1.9 and 2.4%, respectively. The detection limit for H2O2, defined as three times the standard deviation of the lowest standard solution (5 nmol L−1 H2O2) in seawater is 4 nmol L−1. Interference of nitrite ion (NO2−) on the fluorescence intensity of phenol was also investigated. The result indicated that the addition of 10mol L−1 NO2− to seawater samples showed no significant interference, although, the addition of 50mol L−1 NO2 − to the seawater samples decreases the fluorescence intensity signals of phenol by almost 40%. Intercomparison of this method with well-accepted (p-hydroxyphenyl) acetic acid (POHPAA)-FIA method shows excellent agreement. The proposed method has been applied on-board analysis of H2O2 in Seto Inland seawater samples

Adsorption isotherms, kinetics and thermodynamic studies of methylene blue dye removal using Raphia taedigera seed activated carbon

Staff PublicationThis present work revealed the isotherm, kinetic, and thermodynamic behaviour of methylene blue (MB) dye adsorbed onto acidic activated carbon (AAC) and base activated carbon (BAC) prepared from Raphia taedigera seed by carbonization and chemical activation. AAC and BAC were activated with sulphuric acid and sodium hydroxide respectively. Batch equilibrium studies were done under different experimental conditions such as MB dye concentration and temperature. The equilibrium data were modelled using Langmuir, Freundlich, Elovich, Temkin and Dubinin-Radushkevich isotherms. The Langmuir isotherm model best describes the uptake of MB dye onto AAC and BAC with R 2 > 0.998 in all cases. The pseudo-first-order, pseudo-second-order and intraparticle diffusion equations were used to evaluate the kinetic properties. It was observed that the adsorption of MB dye onto the two activated carbons could best be described by the pseudo-second order equation with 0.999 < R 2 ≤ 1. Thermodynamic parameters such as Gibbs free energy (ΔG0 ), standard enthalpy (ΔH0 ), standard entropy (ΔS0 ), and activation energy (Ea) were determined. The results of ΔG0 indicated a spontaneous and feasible for AAC and non-spontaneous but feasible for BAC. Results of ΔH0 confirmed that the adsorption of MB onto AAC and BAC are endothermic and physical in nature. It can be concluded that AAC and BAC prepared from Raphia taedigera seed could be used as low-cost adsorbent for the removal of MB dye from the wastewater

Microparticles and microplastics contamination in African table salts

Staff PublicationThe presence of micro/plastic particles has been reported in various seafood products. However, information on microplastics contamination in salts from African continent is very limited. This study analysed 23 brands of table salts from 8 African countries for microplastics using microscopic/spectroscopic techniques. South Africa showed the highest microplastics concentration (0–1.33 ± 0.32 particles/kg), Nigeria, Cameroun, and Ghana (0–0.33 ± 0.38 particles/kg each); characterized as polyvinyl acetate, polypropylene, and polyethylene. Other countries have no detectable microplastics at 0.3 μm filter pore size. To our best knowledge, this is the first study to characterize micro-fibres/plastics in table salts across African countries, confirming that it is an emission source of micro-fibres/plastics into the human food chain, highlighting the overarching need to understand their effects on human health

Inhibitory Action of Nicotiana tabacum Extracts on the Corrosion of Mild Steel in HCl: Adsorption and Thermodynamics Study

The toxic effects of synthetic corrosion inhibitors have led to the search for naturally occurring substances which are not only readily available but are also environmentally friendly. Therefore, this study investigates the inhibition efficacy of acid extract of Nicotiana tabacum leaves on mild steel in 1M HCl using weight loss method. Experiments are performed by varying immersion period, concentration of the inhibitor and temperature. The inhibition efficiency is markedly higher on the addition of Nicotiana tabacum leaves extract in acidic medium compared with those in the absence of inhibitor. The inhibition efficiency increased with an increase in inhibitor concentration but decreased with rise in temperature and exposure time. Thermodynamic studies revealed that corrosion inhibition may be due to the spontaneous physical adsorption of the plant constituents on the surface of mild steel. Experimental data fitted with the Langmuir and Temkin adsorption isotherms. Kinetic treatment of the data followed a first order reaction. Calculated half-lives increase as the concentration of the extracts increases suggesting that inhibition efficiency increases with increase in the concentration of the extracts.Preliminary investigation of the phytochemical constituents showed that Nicotiana tabacum contains tannin,flavonoid, terpenoid and some other compounds in trace constituents. [Olasehinde, EF, Olusegun, SJ, Adesina, AS, Omogbehin, SA, Momoh-Yahayah, H. Inhibitory Action of Nicotiana tabacum Extracts on the Corrosion of Mild Steel in HCl: Adsorption and Thermodynamics Stud