Chemical Science International Journal

Use of botanical environmentally friendly and biodegradable insect repellants as opposed to chemical insecticides is increasingly becoming important as an alternative method of insect control. Housefly (Musca domestica L.) has potential of transmitting pathogen causing diseases such as typhoid, cholera, bacillary dysentery, tuberculosis, anthrax, ophthalmia, and parasitic worms. The aim of this study was to evaluate the repellency of oil extracted from the leaves of Pelargonium citrosum and Rosmarinus officinalis. Extraction of essential oils was by hydro-distillation. Condensed oil extracts were collected in n-hexane and insect behavioral response tested using adult houseflies (Musca domestica L.). N, N-diethyl-m-toluamide (DEET) was used as the positive control and acetone as the negative control. The bioactive oil was then analyzed using GC-MS. The characteristic volatiles obtained from the two plants showed different compositions. P. citrosum oil comprised mainly of Linalool, Geraniol, m-Camphorene, 2-naphthalenemethanol-1,2,3,4,4a,5,6,7-octahydroalpha, Geranylangelate while R. officinalis comprised mainly of α-Pinene, , Eucalyptol, α-Terpinenol. Dose-response evaluations of these oils showed that R. officinalis oil was more repellent (LD₅₀ = 0.299 mg) than that of P. citrosum (LD₅₀ = 0.445 mg). The results provide scientific rationale for traditional use of R. officinalis and Pelargonium citrosum essential oils in control of housefly and other common insects in the household.

Microcrystalline celluloses (MCC) were prepared from α-celluloses obtained from fluted pumpkin stalk and pod. The substrates were subjected to treatment with 2% (w/v) NaOH, 3.5% (w/v) NaOCl and 17.5% (w/v) NaOH solutions respectively to obtain alpha celluloses. Acid hydrolysis of the alpha-celluloses using 2.5 N hydrochloric acid were carried out. The study evaluates and compares the physicochemical properties of microcrystalline cellulose obtained from the pod and stalk of fluted pumpkin. Composition of cellulose, hemicellulose and lignin were also determined. Results showed cellulose; hemicellulose and lignin content of the pod husk and stalk were 49%, 26%, 9% and 41%, 24%, 26%, respectively. The morphology of the hydrolyzed MCCs’ were investigated using scanning electron microscopy (SEM) and the results revealed the stalk (FS-MCC) to have an individual rod-like shaped fiber when compared with flat-shaped large aggregated forms of the pod (FP-MCC). The particles sizes were also uneven with FP-MCC (6.689 µm) having larger particle sizes than FS-MCC (5.538 µm). The high cellulose content of the pod husk shows that the applications may be extended in the production of other cellulose derivatives while the high lignin content of the stalk reveals other alternative source of producing lignin in the making of textile dyes, coating and other agricultural chemical. Pod MCC (FP-MCC) had better physicochemical properties than the stalk MCC (FS-MCC).

This study was carried out to determine the levels of available nutrient parameters present in leachates from some selected dumpsites in Port Harcourt metropolis. Leachates from the 3-selected dumpsites were analyzed and compared with the seasons, controls and established standards using descriptive and analytical designs. Integrated samples were collected during both wet and dry seasons and analyzed for NO₃^- PO₄^3- , SO₄^2- and NH₄⁺. The use of 2-way ANOVA, t-test and mean variation were applied to explain trend and seasonal variations. The results showed that there was no significant difference in temporal dimension (seasonally) but there was a high level of spatial variation (stations) in most measured parameters. Though some of the parameters were relatively low compared to standard limits; the study revealed that these dumpsites remain major polluting and nutrient enriching sources to the ecosystem. In order to reclaim these dumpsites from acute contamination, government at all levels should ensure the introduction of active remediation processes alongside physico-chemical methods which can ameliorate the effects of pollution in the environment.

Heavy metal concentration in roadside soil and plants are increasingly becoming of health concern. This work determined the concentration of selected heavy metals (Cd, Pb, Zn, Cr, Fe, Mg, Mn, Co, Ni and Cu) in roadside soils and plants samples from selected sites (Plaifu, Shiwa, Fadama-rake and Damdrai) along major road in Hong. Soil samples were taken 10 m, 20 m and 30 m away from the edge of the road at the  depth of 0-10 cm, 10-20 cm and 20-30 cm. Plant samples were randomly collected within the vicinity where the soil samples were taken and were analysed using Atomic Absorption Spectrophotometer. The result revealed the trend in soil heavy metal concentration was Fe > Mn > Mg > Pb > Zn > Ni > Co > Cu > Cr > Cd and for plant the trend was Fe > Mn > Mg > Zn > Pb > Ni > Cu > Cd > Co > Cr. The concentrations decreased with increasing distance away from the edge of the road as well as with depth at which the soil sample were taken. The transfer factor showed that the concentration of Zn, Mn, Cu and Mg were greater than 1, which shows that plant were enriched by Zn, Mn, Cu and Mg from the soil. Mg and Cd equal to 1 at Plaifu and Damdrai. Most of the values of TF at the study area super pass 0.5, which implies that generally, the ability of bioaccumulation of these heavy metals in examined plants were relatively high.

Synthetic polyelectrolytes are currently the most used ones in the industry on account of the following advantages: structuration according to specific requirements, greater purity, higher quality, stability and greater efficiency compared to natural ones; they do not add insoluble substances to the sludge, nor do they modify the physico-chemical properties of water and thus liquids may be recycled. The main action of these products is to bring together and agglutinate the flocs formed by the coagulant, thus obtaining a considerable increase in the size of the same and a subsequent increase in the settling rate speed, as well as an improvement in the quality of the effluent. Polyacrylamide shows high solubility in water, while it is insoluble in most other common organic liquids such as methanol, ethanol, acetone, diethyl ether, and aliphatic and aromatic hydrocarbons. Paradoxically, however, despite this highly hydrophilic character, the main technical application of polyacrylamide is for flocculation of aqueous suspension and related purposes, where it is therefore required to have a relatively high affinity to the surface of the suspended solid if the necessary strong adsorption of the polymer is to take place. In practice, however, this adsorption is often enhanced by using modified (anionic or cationic) forms of polyacrylamide. Polyacrylamide can be classified to three categories: non-ionic, anionic and cationic polyacrylamide.