International Journal of Chemistry

International Journal of Chemistry | Vol. 6, No. 1, January 2015 | pp. 1–8

DOI: 10.46882/2015/IJC/000076

Article Type: Original Research Paper

Title: Assessing the Hydrocarbon Biodegradation and Phytoremediation Trait of Glycine max L. in Used Lubricating Oil Polluted Soil

Names of Authors: O. F. Olawal¹, H. de Vries²*

Authors’ Affiliations:
¹Department of Plant Biology, University of Ilorin, Ilorin, Nigeria.
²Department of Plant Physiology, Wageningen University, Wageningen, Netherlands.

Abstract: The accidental spill of used lubricating oil from automotive repair hubs destroys soil porosity and introduces complex aliphatic and aromatic hydrocarbons into agricultural systems, demanding remediation. This field investigation studies the growth tolerance and phytoremediation efficiency of Glycine max L. (Soybean) cultivated in agricultural soils contaminated with used lubricating oil at dosages spanning 1.5% to 4.5% w/w. Vegetative growth metrics, residual total petroleum hydrocarbons (TPH), and root zone microbial populations were monitored across a 12-week development cycle. G. max demonstrated moderate tolerance up to a 3.0% oil threshold, beyond which significant drops in root nodulation and total leaf chlorophyll occurred. Gas Chromatography (GC-FID) profiling demonstrated a 68.4% reduction in soil TPH levels within the rhizosphere of G. max rows, compared to a baseline 24.2% reduction observed in unplanted controls. Soil microbiological enumeration revealed a five-fold expansion of hydrocarbon-utilizing bacteria within the legume root zone. This confirms that root exudates and nitrogen-fixing bacteria interact to accelerate the structural degradation of oil hydrocarbons in contaminated terrains.

Keywords: Used lubricating oil; Glycine max; Total petroleum hydrocarbons; Phytoremediation; Rhizosphere effects; Hydrocarbon-utilizing bacteria

Manuscript Timeline: Received: April 02, 2014; Revised: May 15, 2014; Accepted: June 10, 2014; Published: January 03, 2015.

Citation: Olawal, O. F., & de Vries, H. (2015). Assessing the Hydrocarbon Biodegradation and Phytoremediation Trait of Glycine max L. in Used Lubricating Oil Polluted Soil. International Journal of Chemistry, 6(1), 1–8.

International Journal of Chemistry | Vol. 5, No. 3, March 2014 | pp. 17–24

DOI: 10.46882/2014/IJC/000066

Article Type: Original Research Paper

Title: Chemical Speciation, Contamination Assessment, and Ecological Risk Indices of Trace Metals in Estuarine Sediments

Names of Authors: C. I. Obi¹, K. H. Kim²*

Authors’ Affiliations:
¹Department of Pure and Industrial Chemistry, University of Port Harcourt, Port Harcourt, Nigeria.
²Department of Civil and Environmental Engineering, Hanyang University, Seoul, South Korea.

Abstract: Monitoring total heavy metal loads in coastal aquatic systems is inadequate for evaluating ecotoxicity because the mobility and environmental risks of contaminants depend heavily on their chemical fractions. This study assesses the total concentrations and geochemical binding forms of cadmium (Cd), chromium (Cr), lead (Pb), and copper (Cu) in estuarine surface sediments exposed to industrial effluents. Metal quantification was performed via Inductively Coupled Plasma Mass Spectrometry (ICP-MS) following the modified BCR three-step sequential extraction protocol. Total metal concentrations followed the sequence: Cr > Pb > Cu > Cd. Spatial mapping revealed heavy metal accumulation downstream from active petrochemical and manufacturing points. Speciation analysis showed that a substantial portion of cadmium (45.8%) and lead (32.4%) existed within the water-soluble and exchangeable fractions, suggesting high structural instability and bioavailable risk to benthic fauna. Conversely, chromium and copper were primarily locked within residual and organic crystal lattices, indicating low immediate mobility under baseline pH conditions. The Potential Ecological Risk Index (RI) calculated for cadmium showed a very high hazard rating, requiring urgent regional remediation actions.

Keywords: Estuarine sediments; Trace metals; BCR protocol; Geochemical speciation; Bioavailability; Ecological risk index

Manuscript Timeline: Received: April 02, 2013; Revised: May 20, 2013; Accepted: June 15, 2013; Published: March 11, 2014.

Citation: Obi, C. I., & Kim., K. H. (2014). Chemical Speciation, Contamination Assessment, and Ecological Risk Indices of Trace Metals in Estuarine Sediments. International Journal of Chemistry, 5(3), 17–24.

International Journal of Chemistry | Vol. 5, No. 7, July 2014 | pp. 49–56

DOI: 10.46882/2014/IJC/000070

Article Type: Original Research Paper

Title: Thermodynamic Modeling, Desorption Kinetics, and Multilayer Adsorption of Crystal Violet Dye onto Modified Illite Clay

Names of Authors: A. D. Yusuf¹, M. T. Al-Hajri²*

Authors’ Affiliations:
¹Department of Industrial Chemistry, Federal University of Technology, Yola, Nigeria.
²Department of Chemistry, Qatar University, Doha, Qatar.

Abstract: The release of highly stable cationic triphenylmethane dyes like Crystal Violet from textile finishing plants causes significant environmental and toxicity hazards in surface aquatic resources. This study examines the adsorptive uptake performance of a surfactant-modified illite clay (SMI) prepared via chemical functionalization with dodecyltrimethylammonium bromide (DTMA-Br). The structural parameters of raw and modified clays were characterized using X-ray diffraction (XRD) and FT-IR spectroscopy. Adsorption operations were conducted via batch runs, monitoring changes in contact time, solution pH, initial dye loading concentrations, and system temperatures. The equilibrium datasets fit closely with the Freundlich isotherm model, demonstrating successful multilayer dye attachment onto the hydrophobic surfactant bilayers. Kinetic parameters matched the intra-particle diffusion expressions alongside a pseudo-second-order mechanism, showing that chemisorption reactions controlled the mass transfer rates. Thermodynamic constants showed that the adsorption process was endothermic (delta H° = 24.5 kJ/mol) and caused an increase in system randomness at the solid-solution interface (delta S° = 78.4 J/mol K). Negative values of Gibbs free energy (delta G°) spanning from -2.1 to -5.4 kJ/mol across the 298 to 328 K range confirmed process spontaneity, positioning SMI as an affordable material for industrial dye wastewater treatment.

Keywords: Illite clay; Surfactant modification; Crystal violet; Adsorption isotherm; Chemisorption; Thermodynamic parameters

Manuscript Timeline: Received: July 20, 2013; Revised: August 28, 2013; Accepted: September 15, 2013; Published: July 08, 2014.

Citation: Yusuf, A. D., & Al-Hajri., M. T. (2014). Thermodynamic Modeling, Desorption Kinetics, and Multilayer Adsorption of Crystal Violet Dye onto Modified Illite Clay. International Journal of Chemistry, 5(7), 49–56.

International Journal of Chemistry | Vol. 5, No. 5, May 2014 | pp. 33–40

DOI: 10.46882/2014/IJC/000068

Article Type: Original Research Paper

Title: Development and Validation of an RP-HPLC Method for Quantitative Monitoring of Ciprofloxacin Formulations

Names of Authors: E. O. Effiong¹, A. G. Silva²*

Authors’ Affiliations:
¹Department of Chemistry, University of Uyo, Uyo, Nigeria.
²Department of Pharmacy, University of Porto, Porto, Portugal.

Abstract: Developing simple, automated, and accurate analytical methods is essential for routine quality monitoring and the detection of counterfeit antibiotics in commercial pharmacies. This paper describes the development and validation of a rapid Reversed-Phase High-Performance Liquid Chromatography (RP-HPLC) method for the quantitative determination of ciprofloxacin in tablet dosage forms. Separation was achieved using a C18 stationary phase column under an isocratic mobile phase composed of water-acetonitrile-triethylamine (75:25:0.1 v/v/v), adjusted to pH 3.0 using orthophosphoric acid, at a flow rate of 1.0 mL/min. Eluent monitoring was executed spectrophotometrically at a wavelength maximum of 278 nm. Method validation parameters followed the International Council for Harmonisation (ICH) guidelines. Excellent linearity was established over a concentration range of 1.0 to 50.0 mg/L with a correlation coefficient (R²) of 0.999. The limit of detection (LOD) and limit of quantification (LOQ) were determined to be 0.05 mg/L and 0.15 mg/L, respectively. Precision assessments yielded relative standard deviations (RSD) below 1.5%. The validated method was successfully applied to screen six commercial ciprofloxacin tablet brands, producing recovery percentages between 98.4% and 101.2% with no interference from common tablet excipients.

Keywords: RP-HPLC; Ciprofloxacin; Quantitative analysis; Method validation; Pharmaceuticals; Quality control

Manuscript Timeline: Received: May 02, 2013; Revised: June 15, 2013; Accepted: July 20, 2013; Published: May 09, 2014.

Citation: Effiong, E. O., & Silva., A. G. (2014). Development and Validation of an RP-HPLC Method for Quantitative Monitoring of Ciprofloxacin Formulations. International Journal of Chemistry, 5(5), 33–40.

International Journal of Chemistry | Vol. 5, No. 10, October 2014 | pp. 73–80

DOI: 10.46882/2014/IJC/000073

Article Type: Original Research Paper

Title: Isolation, Kinetic Optimization, and Characterization of Thermophilic Alkaline Lipases from Spent Bleaching Earth Soil

Names of Authors: C. N. Nwosu¹, Y. S. Takahashi²*

Authors’ Affiliations:
¹Department of Biochemistry, Nnamdi Azikiwe University, Awka, Nigeria.
²Department of Biomolecular Engineering, Tokyo Institute of Technology, Tokyo, Japan.

Abstract: Industrial biocatalysis in detergent formulations and biodiesel production requires robust lipolytic enzymes that maintain activity under high temperatures and alkaline pH conditions. This study focuses on the isolation, kinetic optimization, and biochemical characterization of thermophilic alkaline lipases produced by a novel fungal strain sourced from oil refinery spent bleaching earth dumpsites. Soil suspensions underwent enrichment cultures in olive oil-infused media at 45°C. The highest-yielding isolate was identified via 18S rRNA gene sequencing as Aspergillus flavus strain SBE-L1. Solid-state fermentation parameters were optimized using response surface methodology. Maximum lipase activity (42.5 U/mL) was achieved at an incubation temperature of 45°C, an initial substrate pH of 8.5, and a fermentation period of 96 hours using palm kernel cake as a solid matrix. Characterization profiles showed that the crude enzyme complex retained over 85% of its initial catalytic activity across a temperature range of 40 to 60°C and a pH stability window of 7.5 to 9.5 for 12 hours. The enzyme exhibited high tolerance toward commercial anionic surfactants, proving its industrial viability for bio-detergent product lines.

Keywords: Alkaline lipase; Aspergillus flavus; Response surface methodology; Thermal stability; Surfactant tolerance; Biocatalysis

Manuscript Timeline: Received: February 18, 2014; Revised: March 25, 2014; Accepted: May 02, 2014; Published: October 05, 2014.

Citation: Nwosu, C. N., & Takahashi, Y. S. (2014). Isolation, Kinetic Optimization, and Characterization of Thermophilic Alkaline Lipases from Spent Bleaching Earth Soil. International Journal of Chemistry, 5(10), 73–80.

International Journal of Chemistry | Vol. 5, No. 9, September 2014 | pp. 65–72

DOI: 10.46882/2014/IJC/000072

Article Type: Original Research Paper

Title: Biochemical Composition, Functional Properties, and Antinutritional Profiles of Non-Conventional Legume Seeds from West Africa

Names of Authors: A. E. Ogunkoya¹, M. G. R. S. Dias²*

Authors’ Affiliations:
¹Department of Chemistry, Ekiti State University, Ado-Ekiti, Nigeria.
²Department of Food and Nutrition, National Institute of Health Dr. Ricardo Jorge, Lisbon, Portugal.

Abstract: Non-conventional underutilized legumes are promising nutritional resources for mitigating protein-energy malnutrition in developing countries, though their baseline chemical characteristics require detailed mapping. This research examines the proximate composition, mineral fingerprinting, and antinutritional profiles of three wild legume seeds (Mucuna pruriens, Sphenostylis stenocarpa, and Canavalia ensiformis) harvested in West Africa. Proximate analysis established high crude protein contents ranging from 26.4% to 32.5% on a dry weight basis, low fat contents (2.1% to 4.5%), and total carbohydrate profiles spanning 48.5% to 54.2%. Mineral profiling using Inductively Coupled Plasma Optical Emission Spectrometry (ICP-OES) revealed high concentrations of potassium (840 to 1120 mg/100g) and phosphorus, while toxic heavy metals like lead remained below hazardous legal thresholds. Quantified antinutritional matrices showed high initial levels of phytic acid (4.2 to 6.8 mg/g) and total oxalates (3.1 to 5.2 mg/g). Processing simulations proved that combined soaking and autoclaving treatments effectively reduced antinutrient levels by over 78% without significant loss of core structural proteins, establishing these seeds as safe, functional dietary additives.

Keywords: Underutilized legumes; Proximate composition; Mineral fingerprinting; Antinutrients; Food chemistry; Protein-energy malnutrition

Manuscript Timeline: Received: February 10, 2014; Revised: March 18, 2014; Accepted: April 20, 2014; Published: September 09, 2014.

Citation: Ogunkoya, A. E., & Dias, M. G. R. S. (2014). Biochemical Composition, Functional Properties, and Antinutritional Profiles of Non-Conventional Legume Seeds from West Africa. International Journal of Chemistry, 5(9), 65–72.