Determination of some total and bioavailable heavy metals in farmland soil around Rivers Niger and Benue in Lokoja, Nigeria

The work assessed the distribution of Cd, Cu, Mn, Ni, Pb and Zn in the farmland soils around Rivers Niger and Benue and beyond the confluence in Lokoja, Nigeria. The samples were collected in the dry and rainy seasons of 2013 and 2014, digested with aqua regia and analysed for heavy metals using atomic absorption  spectrophotometry. The soil pH ranged from 6.4 to 7.2 for the  farmland soils collected 50 m away from the bank of the rivers and each point 10 m apart (n=72). There was no significant  difference in the mean values of the organic matter, organic carbon and moisture contents of the soils across the seasons. Cd concentration (mg/kg)in the soil samples collected in March 2013, June 2013, January 2014 and May 2014 at 0 – 15 cm depth ranged from 3.95 - 8.4; Cu 11.6 - 20.2 ; Mn 150.3 - 211.5; Ni 177.0 - 281.0 ; Pb 20.3 - 34.2 and Zn 40.5 - 77.8. The levels of the metals in the soil follow the ranking: Ni > Mn > Zn > Pb > Cu > Cd; with Cd and Ni being above European Union permissible limits. The order of the percentage of extracted metal by EDTA to the total metal content was Pb>Zn>Cu>Ni>Mn>Cd. I-geo  pollution index showed that the farmland soils were moderately contaminated with Ni and Cd. Hence, there is the need to enforce environmental laws that borders on proper solid waste and effluent disposals.Key Words: Heavy Metals– Pollution index – River Niger and Benue – Soils – Seaso

Effect of Ulraviolet Light, pH and Temperature on the Thickening Property of Pectin Extracted from Banana, Orange and Lime Peels

Pectin is a polysaccharide used as rheology modifier in products such as food and beverages. This work assessed the effect of UV light, pH and temperature on the thickening property of pectin extracted from banana, orange and lime peels. Pectin was extracted using alcohol precipitation method and was analyzed using FT – IR spectrometer and GCMS. pH and UV light degradation/depolymerization of pectin solutions were carried out using viscometric and statistical methods. Increase in temperature negatively affects the viscosity of the samples. The viscosity of the banana, orange and lime pectin samples decreased on exposure to UV light for both 30 and 60 days. The observed decrease in the kinematic viscosity of the samples might be attributable to depolymerization which might have occurred with the samples on exposure to the UV light. The viscosity of the samples remained the same at the pH of 4, 7 and 10. Analysis of variance (one way) indicated significant difference in the kinematic viscosity measured to determine the effect of ultraviolet light and temperature (p < 0.05). No significant difference in viscosity was observed in the effect of pH (p > 0.05). Therefore, exposure to sunlight of pectin containing food drinks can cause decline in the quality of the product.Keywords: Pectin, viscosity, temperature, UV light, p

Influence of Vehicle Traffic Emissions on Spatial Variation of Ozone and its Precursors in Air of Port Harcourt City, Nigeria

This study aimed at assessing the influence of vehicle traffic on spatial variation of ozone (O3) and its vehicular emission precursors in the air of Port Harcourt city. Sampling was carried out in ten (10) sites, eight (8) located within the high traffic density area (study sites) and two (2) located within the very low traffic density area (reference sites). The precursor pollutants measured were nitrogen dioxide (NO2), carbon monoxide (CO) and volatile organic compounds (VOCSs). Ozone and the precursor pollutants were measured in situ using AeroQUAL 500 series portable ambient air analyzer while traffic flow survey was achieved by direct counting. Measurements were carried out at morning, evening and off-peak traffic periods respectively. The mean concentrations of ozone and the precursor pollutants were significantly higher (p = 0.05) in the study sites than in the reference sites. Mean concentrations were higher at peak traffic periods than at off-peak traffic periods except for ozone that was higher at off-peak than at morning peak. There was significant correlation between traffic density and each of the pollutants including ozone. The spatial variability in concentration of pollutants was influenced by vehicular traffic. VOCs and NO2 levels were higher than the National Ambient Air Quality Standard (NAAQS) limit of 0.05 ppm and 0.04 – 0.06 ppm respectively, O3 concentration was below the standard limit (0.06 ppm) but was at the verge of exceeding. Traffic emission within the city was significant and could be mitigated through regular monitoring and control

Determination of the Band Gap and Intensity of Palladium/Silver Doped TiO2 Nano Particles Using Diffuse Reflectance and Photoluminescence Spectra

The photocatalysts Pd/TiO2, Ag/TiO2 and Ag/Pd-TiO2 were prepared using the sol immobilization method. The photocatalysts were characterized by the use of diffuse reflectance spectra (DRS) and photoluminescence spectra. Analysis of Ag/TiO2 and Ag/Pd -TiO2 using diffuse reflectance spectra (DRS) indicated reduction of band gap energy from 3.2 eV to 2.7 eV for Ag/Pd-TiO2 which makes it possible for the use of sunlight as excitation energy. Photo luminescence spectra analysis carried out on the dopants of Ag/TiO2, Pd/TiO2 and Ag/Pd-TiO2 measured the intensity which gives the rate of recombination of photo-generated electron-hole pairs in TiO2. The result indicated that reduction in intensity was highest for the co-doped Ag/Pd-TiO2. This accounts for its increase in photo catalytic property. Therefore, modification of TiO2 with Ag and Pd will provide the platform for its enhanced photocatalytic performance relevant in environmental science

Assessment of Wound Healing Activity of Green Synthesized Titanium Oxide Nanoparticles using Strychnos spinosa and Blighia sapida

The biosynthesis of nanoparticles has been proposed as a cost effective and environmentally friendly alternative to chemical and physical methods. The present work investigates the synthesis of titanium oxide nanoparticles (TiO2 NPs) by green approach using Strychnos spinosa and Blighia sapida leave extracts. The detailed characterization of the TiO2 NPs was carried out using UV-Visible Spectroscopy, Scanning Electron Microscopy (SEM), X- ray Diffraction (XRD), and Fourier-Transform Infrared (FTIR) Spectroscopy. The green synthesized TiO2 NPs excitation was confirmed using UV–Vis spectrophotometer at 270 and 290 nm for Strychnos spinosa and Blighia sapida respectively. SEM revealed that the synthesized TiO2 NPs were spherical and crystalline in nature. The overall sizes are 40 and 50 nm for Strychnos spinosa and Blighia sapida respectively. FTIR spectroscopic analysisshowed the presence of flavonoids, polyphenols and amide groups likely to be responsible for the green synthesis of titanium oxide nanoparticles using S. Spinosa and B .sapida aqueous leaf extracts. The XRD pattern showed the characteristic Bragg peaks of (111), (200), (220) and (311) facets of the anatase titanium oxide nanoparticles and confirmed that these nanoparticles were crystalline and spherical in nature. Furthermore, the green synthesized TiO2 NPs wound healing activity was examined in the excision wound model by measuring wound closure, histopathology and protein profiling. This revealed significant wound healing activity in Albino rats. In the present study, topical application ofnanoformulated extracts of B. sapidaa nd S. spinosa significantly accelerated wound healing with 20% nanoformulated ointment having the highest percentage wound contraction ability comparable with gentamicin (a commercially sold antimicrobial agent used in dressing wounds). In conclusion, this work proved the capability of using TiO2 NPs to deliver a novel therapeutic route for wound treatment in clinical practice. Keywords: Wound healing activity; SEM; TiO2; XRD; FTIR; UV–Vis spectroscopy

Assessment of the biodegradation of 1-methyl naphthalene using immobilized Pseudomonas macerans and Bacillus subtilis on periwinkle snail shell

The treatment of pollution using eco-friendly and sustainable methods is one of the bases of biotechnology. The work reports the use of periwinkle snail shell (PS) as carrier to immobilize Pseudomonas macerans and Bacillus subtilis for the biodegradation of 1-methyl naphthalene in aqueous medium. The biodegradation of 1-methyl naphthalene (500 mg L-1) were monitored after 36 h and 72 h by determining the concentration of carbonic acid (by titrimetric method) following the release of carbon (IV) oxide. The pH as well as the Fourier Transform-infrared (FT-IR) of the metabolites from the bioreactors/reactors were also studied. The pH of all the supernatants in the bioreactors/reactors decreased with time. There was increase in the concentration of H2CO3 due to the biodegradation of 1-methyl naphthalene by immobilized Pseudomonas macerans and Bacillus subtilis on 1.0 g and 2.0 g of PS. However, the use of immobilized Pseudomonas macerans on PS resulted to significant biodegradation of 1-methylnaphthalene (range of 0.61 - 0.81 mg/L H2CO3) compared to degradation alone with PS after 72 h. FTIR of the metabolite at end products show new peaks within 3372- 3268 cm-1 and within 1643-1640cm-1, these bands are attributed to overlapping of hydroxyl (OH) and carbonyl (C=O) stretching in carboxylic acid respectively, this implies that 1-methyl naphthalene got converted to carboxylic acid. Therefore, the use of carbonaceous wastes for localization in order to enhance biodegradation of hydrocarbons can be harnessed for mop-up of oil spills.Keywords: Biodegradation, Immobilized, Periwinkle snail shell, Pseudomonas macerans, Bacillus subtili

Evaluation of Antibacterial Potential of Biosynthesized Plant Leave Extract Mediated Titanium Oxide Nanoparticles using Hypheae Thiebeace and Anannos Seneglensis

The need for new antimicrobial agent has drawn attention on developing new and emerging materials based on nanoparticles with antimicrobial activity. The aim of this research was to evaluate the antibacterial activity of nanoparticles of titanium dioxide. A green synthesis of TiO2 nanoparticles was done using a plant extract of H. thelbiecea and Ananos seneglensisa The presence of various photochemical like flavonoids, steroids, polyphenols, and terpenoids was investigated by following standard biochemical methods. The titanium oxide nanoparticles (TiO2 NPs) synthesized was confirmed by their change of colour to brown and reddish brown due to the phenomenon of surface Plasmon resonance. The characterization studied was done by UV-vis spectroscopy, scanning electron microscopy (SEM), X-Ray diffraction (XRD) and Fourier Transmission infrared spectroscopy (FTIR). The green synthesized TiO2 NPs excitation was confirmed using UV–Vis spectrophotometer at 270 and 290 nm. SEM revealed that the synthesized TiO2 NPs are spherical and crystalline in nature. The overall sizes are 40 and 50 nm for H. thelbiecea and Ananos respectively. FTIR spectroscopy analysis showed the presence of flavonoid, polyphenols and amide groups likely to be responsible for the green synthesis of titanium oxide nanoparticles using H. thelbiecea and Ananos seneglensis aqueous leaf extracts .The XRD pattern showed the characteristic Bragg peaks of (111), (200), (220) and (311) facets of the anatase titanium oxide nanoparticles and confirmed that these nanoparticles are crystalline and spherical in nature. The two plants used to synthesized titanium oxide nanoparticle (H. thelbiecea and ananos seneglensisa) showed good antimicrobial activity against clinically important pathogens.. The antimicrobial study of TiO2 NPs shows that 20 μg/ml TiO2 NPs is effective for complete inactivation of Gram positive, Gram negative as well as fungal cultures. This effective microbial inactivation is mainly attributed to its ability to cause damage to the cell membrane.Keywords: Titanium oxide, phytochemicals, antimicrobial activity, H. thelbiecea, Ananos seneglensis

Adsorption performance of zinc semiconductor nanoparticles in tetracycline removal

Zinc semiconductor nanoparticles have been employed as potential adsorbents for the remediation of organic pollutants. However, the influence of its non-metallic components on the adsorption performance of zinc semiconductor nanoparticles is yet to be understood. Herein, using zinc oxide (ZnO) and zinc chalcogenide (ZnS) as adsorbents, we demonstrated the effect of O and S constituents on the adsorption performance of zinc semiconductor nanoparticles. The morphology, crystallinity, surface area, thermal stability, and the functionals group of both samples were investigated using scanning electron microscopy (SEM), X-ray diffraction spectroscopy (XRD), Brunauer–Emmett–Teller (BET), thermogravimetric analysis (TGA), Fourier Transform Resonance Spectroscopy (FT-IR), respectively. Although the surface area of ZnS was observed to be 26 times that of ZnO, the Langmuir adsorption capacity for (TC) of the latter (78.70 mg/g) was significantly higher than the former (47.79 mg/g). The enhanced adsorption performance by ZnO is ascribed to its high porosity and broader point of zero charges (PZC). The present study establishes the impact of S and O on the adsorption performance of zinc nanoparticle adsorbents