Open Access Short Research Article

Errors in Parameters Estimation Using Linearized Adsorption Isotherms: Sulfadimethoxine Adsorption onto Kaolinite Clay

Victor O. Shikuku, Chrispin O. Kowenje, Fredrick O. Kengara

Chemical Science International Journal, Page 1-6
DOI: 10.9734/CSJI/2018/44087

In this work, an isothermal investigation of the adsorption of sulfadimethoxine from aqueous solution onto clay mineral (kaolinite) using batch equilibration method is reported. The equilibrium data were modelled using five linear forms of Langmuir equation, linear Freundlich and Temkin isotherm models and their corresponding non-linear equations. It is demonstrated that the linear Langmuir equations underestimated the maximum adsorption capacity of the sorbent. Linearization of adsorption isotherms is shown to induce errors that may lead to unreliable conclusions. The equilibrium data was best modeled by the non-linear Langmuir equation with a maximum adsorption capacity of 4.59 mg/g.

Open Access Original Research Article

Tautomeric Equilibria of Substituted 2-Pyridone/2-Hydroxypyridine in the Gas and Aqueous Phases

Aamer A. Alhatem

Chemical Science International Journal, Page 1-11
DOI: 10.9734/CSJI/2018/42946

Heats of formation, entropies and Gibbs free energies for the twenty structures of substituted 2-pyridone and 2-hydroxypyridine were studied using semiempirical Austin Model (AM1) and Parametric Method 3 (PM3) calculations at the self-consistent field level, both in the gas and liquid phases, with full geometry optimization. It was revealed from the study that 2-hydroxypyridine is predominant in gas phase, while 2-pyridone in the liquid phase which agrees with the experimental and theoretical predictions. All substituents such as F, Cl, OH, CH3, NH2, NO2, CHO, CN, CF3 stabilize the 2-pyridone in the gas and liquid phases except F, Cl and NH2 in PM3 calculations in the gas phase. The substituents stabilization is more effective in liquid phase. This was also confirmed by thermodynamic calculations and isodesmic reactions.

Open Access Original Research Article

Comparative Phytochemical, Antinutrient and Trace Metal Composition of the Leaf, Flower and Seed of Moringa oleifera L. Grown in Southern Nigeria

Kokoette Raymond, Emmanuel Dan, Uwemedimo Udo

Chemical Science International Journal, Page 1-10
DOI: 10.9734/CSJI/2018/43004

Secondary metabolites, proximate, anti-nutrients, mineral and trace metals distribution in three parts (leaf, flower and seed) of Moringa oleifera L. grown locally in Akwa Ibom State, Southern Nigeria were investigated and compared using standard analytical procedures. The three plant parts indicated the presence of different secondary metabolites. Saponins, terpenoids, alkaloids and glycoside were common to the three plant parts at varying levels of abundance. Proximate results (% dry weight) of the plant parts indicated the following ranges: moisture (13.65 ± 0.54 – 35.23 ± 0.05); ash (3.13 ± 0.30 – 6.54 ± 0.01); crude fibre (8.59 ± 0.02 – 14.12 ± 0.01); crude lipids (3.10 ± 0.00 – 6.18 ± 0.02) and crude protein (5.15 ± 0.01 – 10.25 ± 0.03). Anti-nutrient profile (mg/100g DW) of the three plant parts recorded the following ranges: phytate (5.30 ± 0.03 – 9.60 ± 0.70); HCN (0.04 ± 0.00 – 1.01 ± 0.00) and oxalate (0.40 ± 0.01 – 0.82 ± 0.02). The mineral composition showed that among the mineral elements investigated, Moringa oleifera leaf was the richest in iron, zinc and sodium than the flower and seed, the flower was the richest in magnesium, while the seed was found to be the richest in calcium and potassium. The trace metal composition indicated mean ranges (mg/100 g DW) as follows: (0.005 – 0.008) Cd, (0.012 – 0.003) Pb, (1.210 – 2.202) Ni, (0.180 – 0.256) Cu, (1.401 – 1.684) Cr, and Mn (0.977 – 1.105). The results of the trace elements obtained were within acceptable limit stipulated by the World Health Organization for plants. Antinutrient analysis of the extracts indicated low levels of phytic acid, oxalates, and hydrocyanides below the lethal doses. These results, therefore, validate the various ethnomedicinal uses of the leaf, flower and seed of Moringa oleifera in the treatment of many diseases.

Open Access Original Research Article

Chemical Evaluation of Petroleum Sludge Impacted Soils from Itsekiri Communities around Warri Refinery, Delta State, Nigeria

Useh Mercy Uwem, Dauda Mary Sunday

Chemical Science International Journal, Page 1-15
DOI: 10.9734/CSJI/2018/42965

Effluents from petrochemical operations are generally considered to be harmful to the environment particularly due to their accumulated levels of petroleum hydrocarbons which distort the properties of the habitat immediate to such facilities. This study was undertaken to compare and appraise the petroleum hydrocarbon constituents from oily sludge discharge as well as changes in the physicochemical composition of soils within an 8.5 km radius from Warri refinery in Delta State, Nigeria. Data obtained revealed an almost identical acidic soil environment (5.31 – 5.54) to that of the contaminating sludge (5.25) unlike that of the control (7.81). The overall levels of sulphate (412.73 – 465.13 mg/l), electrical conductivity (0.44 – 0.57 µs/cm), organic carbon (10.02 – 18.22%), oil and grease (96077 – 587642 mg/kg) were observed to be higher across all tested soil samples in comparison to that of the control sample; 56.73 mg/l, 0.26 µs/cm, 4.25%, 1032 mg/kg in that order while that of the total nitrogen (0.08 – 0.44%) and phosphorus (8.72 – 12.40% ) were low compared to the control (0.87, 15.62)% respectively. The total petroleum hydrocarbon (TPH) content ranged from 48063 – 293846 (mg/kg) across the 5 tested sampling sites with the sludge sample having 686615.6 mg/kg whilst that of the control was found to be averaging 651 mg/kg as detected via GC-FID. The Polycyclic aromatic hydrocarbon (PAH) values ranged from 189.93 – 4255.87 (mg/kg) across the 5 tested sites with that of the sludge being 13648.33 mg/kg while the control site exhibited a 68.06 mg/kg PAH concentration as detected via GC-MS. Dibenzothiophene was also detected with values ranging from 3167.31 – 19001.84 mg/kg which was very high compared to other hydrocarbons. The risk assessment of the soil quality conducted indicated that all the studied sites were seriously contaminated but the level of contamination was a function of proximity of each site to the refinery. The presence of oily sludge due to the operational activities at the refinery resulted in change of known physicochemical properties of the soil which undoubtedly distorted the natural fauna and flora in the affected sites.

Open Access Original Research Article

Preparation and Characterization of Activated Carbons from Bitter Kola (Garcinia kola) Nut Shells by Chemical Activation Method Using H3PO4; KOH and ZnCl2

Kuete Tiotsop Idris-Hermann, Tchuifon Tchuifon Donald Raoul, Doungmo Giscard, Anagho Solomon Gabche

Chemical Science International Journal, Page 1-15
DOI: 10.9734/CSJI/2018/43411

Aims: Investigate the changes occurring in the composition of Garcinia kola nut shell after an activation process, especially the characteristics of the chemically activated carbons (ACs) obtained.

Study Design: Determine of the physicochemical properties of the prepared ACs using optimized experimental data.

Place and Duration of Study: Research Unit of Noxious Chemistry and Environmental Engineering, Department of Chemistry, Faculty of Science, University of Dschang, between February 2016 and March 2018.

Methodology: Garcinia kola nut shell (bitter kola nut shell) were used to prepare ACs by chemical activation using H3PO4, KOH and ZnCl2 using the carbonization temperatures 400, 450 and 500°C and the different impregnation ratios 1/1 and 2/1. The effects of the composition of the components on the iodine number and iodine methylene blue number of the ACs were investigated. The best ACs were selected after optimization of the experimental data obtained in the laboratory.

Results: Increase in carbonization temperature from 400°C to 500°C led to a decrease in the iodine number and an increase of in burn-off. For the production of ACs, the optimum temperature was found to be 400°C for 1 hour heating, with impregnation ratio of 1/1 by KOH, ZnCl2 ACs and 2/1 for the H3PO4 AC. Thermo-gravimetric analysis of the raw material was carried out to confirm the thermal stability of the ACs obtained at the optimum temperature of 400°C. The functional surfaces of the ACs and raw materials were studied by Bohem titration, pH, pzc, and FT-IR techniques. SEM analysis illustrates an irregular and heterogeneous surface morphology with a developed and fragmented porous structure of various sizes. Powder X-ray diffraction analysis showed that the raw material and ACs prepared are essentially amorphous.

Conclusion: Chemical activation is one of the appropriate methods that can be used to obtain new ACs. The maximum iodine number of the ACs was obtained at carbonization temperature of 400°C for a period of 1 hr, with impregnation ratios 2/1 and 1/1.