Biodiesel Fuel from Differently Sourced Local Seed Oils: Characterization, Effects of Catalysts, Total Glycerol Content and Flow Rates

The recently observed depletion in the petroleum resources, which also mainly constituted carbon dioxide emission and global warming problems call for renewable and sustainable alternative fuels. Oils were extracted from various seeds: Jatropha curcas (Botuje), Pentaclethra macrophylla (Apara) and soybean, using petroleum ether (40-60℃). Alkali catalyzed transesterification of the oils (biodiesel pro-duction) in the presence of different kinds of alcohol (methanol, ethanol and propanol) were carried out using sodium hydroxide as catalyst. In the case of Jatropha oil, potassium hydroxide served as catalyst. Effect of catalysts to obtain optimum biofuel was established. In the case of soybean oil, fatty acid methyl ester, FAME, (96%), fatty acid ethyl ester, FAEE, (84%) and fatty acid propyl ester, FAPE, (37.50%) were pro-duced. In waste palm kernel oil, methyl ester (72.92%) and ethyl ester (46.25%) were obtained. In refined palm kernel oil, methyl ester (70.83%), ethyl ester (66.67%) and (14.17%) propyl ester were produced. However, only methyl ester conversion (20.83%) was possible in Pen-taclethra macrophylla oil. In Jatropha curcas using KOH catalyst, only methyl ester (80%) formation was possible. Moreover, yields were af-fected as the alcohol alkyl became bulkier giving relatively lower value of biodiesel. Sulphur content (0.01) obtained for each of the biofuel was satisfactory when compared with ASTM standard (0.05 maximum). The cetane value of soybean oil (45.5), refined palm kernel oil (46) and used oil (44.6) were quite reasonable compared with the special standard (47). The combustion energy of the fuels from refined palm kernel oil, waste palm kernel oil and soybean are 39, 36 and 45.5 respectively. The total glycerol content (Gc) of the methyl and ethyl esters emanat-ed from soybean are quite reasonable and fell within standard. Keywords: biodiesel, flow rates, local seed oils, total glycerol content, transesterificatio

GREEN SYNTHESIS OF CAPPED SILVER NANOPARTICLES AND THEIR HYBRIDS: ANTIMICROBIAL AND OPTICAL PROPERTIES

Unique properties of silver (Ag) and its allied nanoparticles are of great interest in the fields of chemistry and technology. However, the widespread applications of nanoparticles call for synthesis routes involving eco-friendly procedures. Silver nanoparticles (Ag NPs) and their hybrids nanoparticles (Ag-Ni and Ag-Co) were synthesized using locally available biodiversity plants as alternative method to the expensive and toxic chemicals previously used. Fresh plants were collected and extracted in water by cold extraction. Phytochemical screening was carried out on the plant extracts and green plant-mediated reduction method was employed. Nanoparticles formation and growth were monitored with UV-Vis spectrophotometer at time intervals. The nanoclusters were further characterized using photoluminescence (PL), scanning electron microscope (SEM), transmission electron microscope (TEM), fourier transmission infra-red (FTIR), x-ray diffraction (XRD) and selected electron area diffraction (SAED). Antimicrobial activity of the nanoparticles was investigated on clinically isolated pathogens. Formation of nanoparticles was indicated by colour change in the reaction medium when nucleation and growth commenced as early as 2 minutes in the reaction at 70°C, compared to the syntheses carried out at room temperature. Optical properties were displayed with surface plasmon resonance bands (SPR) above 400 nm in Ag NPs and their hybrids. The high intensities of absorption were characterized with red-shifted wavelengths, except the Ag NPs and the corresponding nanohybrids formed using the extract of S. occidentalis (327-350 nm). However, near uniform emission of fluorophores was exhibited by Ag NPs (438-466 nm) and Ag allied nanoparticles (581-778 nm) irrespective of the excitation wavelengths. The morphological characterization of Ag-Co nanohybrid using SEM and TEM revealed novel alloy structure in which Ag atoms were attached to the vertices of cobalt in a planar arrangement. Other morphologies obtained using C. indica leaf extract were cluster-in-cluster spherical arrangement, nanorod, nanocube with truncated edges, rectangle and quasi-spheres; all caged, thereby providing stability for the newly formed nanoparticles. Cubic structures with truncated/irregular edges and quasi-spherical morphologies were formed by monometallic Ag NPs using other plant extracts. However, the corresponding Ag-Ni and Ag-Co nanobimetallic derived from these plant extracts resulted in nanohybrid with Ag core and Ni shell arrangement, nanocubes with truncated edges and multiply-twinned nanoparticles. Evidence of capping of the newly formed nanoparticles by the biomolecules was demonstrated by the diagonal orientation of Agnanoparticles through mapping. Hexagonal shaped nanoparticles with truncated edges were observed in the Ag NPs obtained from L. inermis leaf extract. The formation of highly crystalline Ag dominated by face-centre cubic (FCC) was supported by p-XRD. SAED also supported formation of hybrid nanoparticles as crystallinity decreased when compared with the equivalent Ag monometallic nanoparticles. The antimicrobial activity of nanoparticles against clinical isolates was highly significant (6.25 mg/mL MIC, and 12.5 mg/mL MBC) in the hybrid nanoparticles which demonstrated higher growth inhibition of the test organisms as revealed in one-way analysis of variance (ANOVA) using SPSS statistical tool (p < 0.05). The outcome of these findings suggests the application of Canna indica-influenced Ag NPs as antibacterial against E. coli, S. pyogenes and antifungus against C. albicans. Ag-Co nanoparticles formed using the extract of C. indica is a potential material in optical devices. The use of Ag NPs with narrow size distribution can serve as conductive fillers in electronically conductive adhesives (ECA)

Toxicity and Cytotoxicity Effects of Selected Nanoparticles: A Review

The appreciable development in nanotechnology has drawn the attention of several researchers cutting across different fields. However, some nanoparticles have been identified to possess harmful effects on humans and the environment. Hence, putting these cause and effect patternsinto context is highly required for future research and discussions about nanotechnology. This study reviewed existing literature on the toxicity and cytotoxicity effects of some nanoparticles to compare reaction patterns. Many kinds of research used different cell cultures, including cancer cell lines, human endothelial cells, hepatic cells, which were tested both in vitro and in vivo to check the mechanism of the possible toxicity effects. Adverse effects of nanoparticles identified involved damaged DNA leading to mutations and generation of reactive oxygen species (ROS). The prominent identified common toxicity responses in nanoparticle-cell interaction were lysosomes formation interference, necrosis and apoptosis, nanoparticles and protein interaction, and agglomerate formation in other body parts. Some reports showed that the causes of these responses might be due to the physicochemical properties of the interrogated particles, such as particle size, shape, surface functionalisation, surface charge. Furthermore, nanoparticles' toxicity effects are both concentration-dependent and time-dependent, highly pronounced in chemical or physical-based synthetic routes. Cytotoxic effects of nanoparticles were mainly linked to their synthetic method, nature of the reducing agent, and culture media

Exploration of the Chemistry and Biological Properties of Pyrimidine as a Privilege Pharmacophore in Therapeutics

The pyrimidine moiety is one of the most widespread heterocycles in biologically occurring compounds, such as nucleic acids components (uracil, thymine and cytosine) and vitamin B1. Due to its prebiotic nature to living cells in biodiversity, it is an highly privileged motif for the development of molecules of biological and pharmaceutical interest. This present work deals with the exploration of chemistry and medicinal diversity of pyrimidine which might pave way to long await discovery in therapeutic medicine for future drug design

Adsorption properties of Azadirachta indica extract on corrosion of Aluminium in 1.85 M Hydrochloric acid

The crude extract of Azadirachta indica was used in the corrosion inhibition study of aluminium metal coupons in 1.85 M hydrochloric acid environment by gasometric technique. The coupons were immersed in test solutions of uninhibited 1.85 M HCl and those containing extract concentrations of 10%, 20%, 30%, 40% and 50% (v/v) at room temperature. The rate of the reaction was captured by monitoring the volume of hydrogen gas evolved as a result of the interaction. The inhibition efficiency of the extracts and the adsorption isotherm of the process were calculated using Frumkin, Freundlich, Langmuir and Temkin adsorption theories and the surface morphology studied using Scanning Electron Microscopy (SEM). It was observed that the plant extract retarded the acid induced corrosion of aluminium and the volume of hydrogen gas evolved reduced with increasing extract concentration. The adsorption studies revealed that Langmuir isotherm is the best model for the adsorption of Azadirachta indica (R2 = 0.999) on aluminium surface. This implied that the Azadirachta indica extracts with aluminium metal undergoes chemisorption

Antibacterial and Morphological Studies of Electrospun Silver-Impregnated Polyacrylonitrile Nanofibre

Silver-impregnated polyacrylonitrile (PAN) nanofibre was prepared through electrospinning process. Infra-red spectroscopy (FT-IR), X-ray powder diffraction (XRD), scanning electron microscopy (SEM), Thermo gravimetric analyses (TGA/DTA) were used to characterize PAN and PAN/Ag composites. The XRD results reflects decrease in the crystallinity of PAN as it is been modified with Ag. Antibacterial activity of PAN/Ag was also investigated

Green Synthesis of Pseudo-Cubic Ag/Ni Bimetallic Nanoparticles using Senna occidentalis Leaf Extract

Abstract.This study reports plant-mediated co-reduction approach for the synthesis of Ag/Ni bimetallic nanoparticles (Ag/Ni BNPs). In view of sustainability development, aqueous leaf extract of an indigenous Senna occidentalis (coffee senna) acted as a reducing agent. Cold extraction was carried out on the biodiversity plant using water and methanol as solvent media by way of “green” synthesis. Qualitative analysis was done to identify possible secondary metabolites present in the extract. Synthesis of the nanohybrid was achieved using two different precursor concentrations at 70°C. Techniques including Uv-visible spectroscopy, scanning electron microscopy and energy dispersive X-ray spectroscopy were engaged for optical, morphological and compositional characterisation of the Ag/Ni BNPs, respectively. The reaction colour changed from green to dark brown due to the excitation of electron and change in the electronic energy levels of metal nanoparticles. Presence of nickel in the nanohybrid resulted in blue shift in the absorbance wavelengths when compared with the corresponding monometallic Ag NPs (341 to 327 nm). The optical property displayed by Ag/Ni BNPs is a pointer for potential application as optical materia

Green Synthesized Optically Active Organically Capped Silver Nanoparticles using Stem Extract of African Cucumber(Momordica charantia)

Silver nanoparticles (Ag NPs) were synthesized by a rapid facile plant-mediated green route. Sustainable and renewable stem extract of locally sourced African cucumber acted as reducing/capping agent, an alternative to toxic chemicals. The phytochemical screening indicated the existence of saponins and alkaloids in the stem extract of M. charantia. Unprecedented nucleation and growth of Ag NPs commenced within 5 minutes of the reaction. The mechanism of reaction was considered to be diffusion controlled Ostwald ripening process. Optical property of the as prepared Ag NPs was characterized by high intensity of absorption, revealed by narrow intense peaks, stipulating confinement of excitons.Surface Plasmon Band (SPB) of Ag NPs appeared at 400 - 460 nm. Photoluminescence (PL)excitation of the Ag NPs at 329 nm exhibited excitonic emission at 440 nm. The Ag NPs portrayed quasi-spherical shapes, with a mean size of 27.81 ± 1.64 nm from Transmission Electron Micrograph (TEM) measurement. XRD measurement showed peaks indexed to fcc Ag with a particle diameter of 25 nm, which corroborated TEM measurement. Elemental mapping of the nanoparticles showed an orientation of the Ag NPs, an evidence of capping by the biomolecules which stabilized the newly formed Ag NPs. Fourier Transformed Infra-red (FTIR) analysis showed the presence of hydroxyl groups (−OH) stretching, (−CH) stretching,C=C stretching and C−N group (in the phytochemicals) at 3237, 2913, 1620 and 1021 cm-1 respectively. It can be inferred that the as prepared Ag NPs is an optically active material

Dietary Fortification of Sorghum-Ogi using Crayfish (Paranephrops planifrons) as Supplements in Infancy

Malnutrition in neonates is a concern in developing countries where there is deficiency in nourishing foods for young ones. The utilization of fresh crayfish (Paranephrops planifrons) in enhancing the nutrient value of commonly used sorghum grain weaning food for infancy was investigated. The study was carried out using a 10 – 50 wt% mixture of sorghum grain and crayfish in three categories of soaked sorghum grains with unroasted crayfish (Case A); de-hulled roasted sorghum grains with roasted crayfish (Case B) and de-hulled, un-roasted sorghum grain with un-roasted crayfish (Case C). The proximate analysis, functional and pasting properties in addition to taste panel evaluation of the batch composition were determined. The result indicated beneficial fat and protein contents of the blend with increase addition of crayfish with Case B and Case C preferred. The overall acceptability at 5% confidence level of organoleptic evaluation identified Case B with over 70% acceptance value, while the amylograph pasting analysis indicated that crayfish blend improved the stability of sorghum-ogi, hence it is beneficial as weaning food for infancy

Nicotiana tabacum Mediated Green Synthesis of Silver Nanoparticles and Ag-Ni Nanohybrid: Optical and Antimicrobial Efficiency

A sustainable method was considered for the preparation of nanosilver and its allied nanoparticles. Nicotiana tabacum, an abused plant, has found an application as a bio-chemical instead of lethal chemical in the synthesis of nanoparticles. As part of green chemistry implementation, double distilled water was the solvent used for extraction. The phytochemicals present were analyzed using standard procedures. Nanoparticle synthesis was carried out at varying precursor concentrations, and the reaction was monitored with a UV-visible spectrophotometer. Another optical characterization was also achieved with photoluminescence. Other characterization involved: X-ray diffraction (XRD), transmission electron microscopy (TEM), energy dispersive X-ray (EDS), and Fourier transform infrared spectroscopy techniques (FTIR). A matched phase identification of nanosilver resembled a face-centered cubic of Ag with a mean size of 11.68 nm, and a lattice constant of 4.0862 Å. The Ag NPs displayed activity against clinical isolates of fungi, Gram-positive, and Gram-negative bacteria as the growth inhibition was significant at P < 0.05. Ag NPs obtained from the Nicotiana tabacum proved to be an antibacterial and antifungal candidate, unlike the Ag NPs derived using chemical and physical methods, which were harmful for this purpose. Both the Ag NPs and Ag-Ni NPs displayed optical activity, which qualifies them for application in visual materials