International Journal of Chemistry

International Journal of Chemistry | Vol. 2, No. 1, January 2011 | pp. 1–9

DOI: 10.46882/2011/IJC/000025

Article Type: Original Research Paper

Title: Comparative Study of Biogas Production from Co-Digestion of Cow Dung with Poultry Manure and Water Hyacinth

Names of Authors: M. A. Haruna¹, I. O. Abdullahi²*

Authors’ Affiliations:
¹Department of Industrial Chemistry, Bayero University, Kano, Nigeria.
²Department of Microbiology, Ahmadu Bello University, Zaria, Nigeria.

Abstract: Anaerobic co-digestion of diverse organic wastes enhances nutrient balances, optimizing methane yield while managing noxious municipal biomass. This study evaluates the cumulative biogas production profile achieved by co-digesting cow dung (CD) with poultry manure (PM) and water hyacinth (Eichhornia crassipes, WH) under mesophilic conditions (35 ± 2°C). Batch anaerobic digesters with a 10-liter volume were set up in variations containing pure CD (control), CD+PM (1:1), and CD+WH (1:1) at a uniform total solids loading of 8% over a 30-day retention period. Daily gas generation metrics were quantified via water displacement steps. The CD+PM system yielded the highest cumulative gas volume of 42.5 L, which was significantly greater than the CD+WH blend (31.4 L) and standalone CD matrices (24.8 L). Biogas composition tracking via gas chromatography showed that methane content peaked at 64.2% within the CD+PM digestate on Day 18. This enhanced yield is attributed to the low carbon-to-nitrogen (C/N) ratio of poultry waste balancing the high carbon levels of cow dung, which stabilizes pH profiles around 7.2. Kinetic parameters resolved via the modified Gompertz model offered strong predictive agreement (R² > 0.98), showing that waste co-digestion designs reduce lag phases and accelerate green energy yields.

Keywords: Anaerobic digestion; Biogas; Methane; Co-digestion; Water hyacinth; Gompertz model

Manuscript Timeline: Received: October 14, 2010; Revised: November 22, 2010; Accepted: December 08, 2010; Published: January 04, 2011.

Citation: Haruna, M. A., & Abdullahi, I. O. (2011). Comparative Study of Biogas Production from Co-Digestion of Cow Dung with Poultry Manure and Water Hyacinth. International Journal of Chemistry, 2(1), 1–9.

International Journal of Chemistry | Vol. 2, No. 4, April 2011 | pp. 52–59

DOI: 10.46882/2011/IJC/000031

Article Type: Original Research Paper

Title: Synthesis, Characterization, and Biological Screening of Novel Cobalt(II) Complexes Derived from Coumarin Derivatives

Names of Authors: A. O. Balogun¹, R. M. Shittu²*

Authors’ Affiliations:
¹Department of Chemistry, University of Ilorin, Ilorin, Nigeria.
²Department of Chemical Sciences, Fountain University, Osogbo, Nigeria.

Abstract: Coumarin derivatives represent an essential class of oxygen heterocycles with broad pharmacological frameworks, whose medicinal efficacy can be amplified via coordination to transition metal centers. This study details the synthesis and molecular characterization of novel cobalt(II) complexes derived from 3-acetylcoumarin Schiff bases. The synthesized coordination compounds were characterized using elemental analysis, molar conductance, magnetic susceptibility, and Fourier-transform infrared (FT-IR) spectroscopy. Analytical data established a 1:2 metal-to-ligand stoichiometry with an empirical formula of [Co(L)₂] where L represents the deprotonated Schiff base ligand. Molar conductivity metrics in dimethylformamide (DMF) indicated a non-electrolytic nature for the complexes. FT-IR spectra established that the ligand behaves in a bidentate manner, coordinating to the Co(II) center through the azomethine nitrogen and the deprotonated lactone carbonyl oxygen. Electronic absorption data and magnetic moment values suggested a stable octahedral geometry around the metal core. In vitro antibacterial and antifungal screenings were executed using the well diffusion technique against Staphylococcus aureus and Aspergillus flavus. The metal complexes demonstrated a two-fold increase in antimicrobial activity compared to the uncoordinated coumarin ligands, which is explained via Tweedy's chelation theory.

Keywords: Coumarin; Cobalt complexes; Coordination chemistry; FT-IR spectroscopy; Antimicrobial efficacy; Chelation theory

Manuscript Timeline: Received: January 10, 2011; Revised: February 18, 2011; Accepted: March 05, 2011; Published: April 02, 2011.

Citation: Balogun, A. O., & Shittu, R. M. (2011). Synthesis, Characterization, and Biological Screening of Novel Cobalt(II) Complexes Derived from Coumarin Derivatives. International Journal of Chemistry, 2(4), 52–59.

International Journal of Chemistry | Vol. 2, No. 1, January 2011 | pp. 10–17

DOI: 10.46882/2011/IJC/000026

Article Type: Original Research Paper

Title: Synthesis, Characterization, and Catalytic Cracking Efficiency of Zeolite Y Modified with Lanthanum Ions

Names of Authors: O. D. Tarfa¹, S. M. Ibrahim¹*

Authors’ Affiliations:
¹Department of Industrial Chemistry, Federal University of Technology, Minna, Nigeria.

Abstract: Fluid catalytic cracking (FCC) catalysts require high hydrothermal stability and structural acidity to optimize the conversion of heavy gas oils into valuable light olefin fractions. This study reports the synthesis and structural modification of Zeolite Y through ion exchange with varying concentrations of lanthanum (La³⁺) ions (1.0% to 5.0% by weight). The parent sodium-Zeolite Y matrix was synthesized hydrothermally from local aluminosilicate precursors, followed by ammonium exchange and subsequent calcination to generate the protonated form (H-Y). Lanthanum modification was executed via wet impregnation using lanthanum nitrate solutions. Structural parameters were characterized using X-ray diffraction (XRD), Fourier-transform infrared spectroscopy, and temperature-programmed desorption of ammonia (NH₃-TPD). XRD metrics confirmed that the structural framework of the faujasite lattice remained intact post-lanthanum loading, with crystallinity values preserved above 92%. NH₃-TPD profiles revealed that La³⁺ integration increased the density of strong Brønsted acid sites by stabilizing the framework aluminum atoms against de-alumination. Catalytic cracking efficiency was evaluated in a micro-activity test reactor at 520°C using standard gas oil feedstocks. The 3% La-modified Zeolite Y catalyst achieved a 74.2% total conversion efficiency, with reduced coke formation profiles compared to unmodified H-Y matrices.

Keywords: Zeolite Y; Lanthanum; Fluid catalytic cracking; Brønsted acidity; Hydrothermal stability; Petrochemistry

Manuscript Timeline: Received: October 20, 2010; Revised: November 28, 2010; Accepted: December 12, 2010; Published: January 11, 2011.

Citation: Tarfa, O. D., & Ibrahim, S. M. (2011). Synthesis, Characterization, and Catalytic Cracking Efficiency of Zeolite Y Modified with Lanthanum Ions. International Journal of Chemistry, 2(1), 10–17.

International Journal of Chemistry | Vol. 2, No. 11, November 2011 | pp. 108–115

DOI: 10.46882/2011/IJC/000038

Article Type: Original Research Paper

Title: Validation of a Spectrophotometric Method for Quantitative Determination of Metronidazole in Tablet Dosage Forms

Names of Authors: E. O. Effiong¹, K. A. Udoh¹*

Authors’ Affiliations:
¹Department of Chemistry, University of Uyo, Uyo, Nigeria.

Abstract: Establishing simple, cost-effective analytical protocols is essential for routine quality monitoring of antimicrobial formulations in clinical testing labs. This paper describes the development and validation of a rapid UV-Vis spectrophotometric method for the quantification of metronidazole in tablet dosage forms. The analytical procedure relied on the reduction of the nitro group of metronidazole using zinc dust and hydrochloric acid, followed by diazotization and subsequent coupling with 1-naphthol in an alkaline medium. This reaction produced a stable, orange-red azo dye that was monitored spectrophotometrically at its wavelength maximum of 480 nm. Method validation was executed following the International Council for Harmonisation (ICH) guidelines. Excellent linearity was established over a concentration range of 2.0 to 20.0 mg/L with a correlation coefficient (R²) of 0.999. The limit of detection (LOD) and limit of quantification (LOQ) were determined to be 0.12 mg/L and 0.36 mg/L, respectively. Precision assessments yielded relative standard deviations (RSD) below 2.0%. The validated method was successfully applied to analyze five commercial brands of metronidazole tablets, producing recovery percentages between 98.6% and 101.4%, without any interference from common tablet excipients.

Keywords: UV-Vis spectrophotometry; Metronidazole; Diazotization; Method validation; Quantitative analysis; Quality control

Manuscript Timeline: Received: April 20, 2011; Revised: June 02, 2011; Accepted: June 28, 2011; Published: November 09, 2011.

Citation: Effiong, E. O., & Udoh, B. A. (2011). Validation of a Spectrophotometric Method for Quantitative Determination of Metronidazole in Tablet Dosage Forms. International Journal of Chemistry, 2(11), 108–115.

International Journal of Chemistry | Vol. 2, No. 2, February 2011 | pp. 18–26

DOI: 10.46882/2011/IJC/000027

Article Type: Original Research Paper

Title: Evaluation of Corrosion Inhibition of Aluminium in Hydrochloric Acid Solution by Methanolic Extract of Vernonia amygdalina

Names of Authors: C. E. Odo¹, J. C. Ifemeje²*

Authors’ Affiliations:
¹Department of Biochemistry, Michael Okpara University of Agriculture, Umudike, Nigeria.
²Department of Biochemistry, Chukwuemeka Odumegwu Ojukwu University, Uli, Nigeria.

Abstract: The corrosion of aluminum equipment during industrial pickling and acid cleaning processes leads to significant structural damage, demanding the development of non-toxic plant-derived inhibitors. This investigation evaluates the corrosion inhibition performance of the methanolic extract of Vernonia amygdalina (Bitter leaf) leaves on aluminum coupons in 1.0 M HCl solutions. Experimental monitoring was conducted using gravimetric (weight loss) and gasometric methods at temperatures ranging from 303 K to 323 K. The weight loss results proved that the extract acts as an efficient corrosion inhibitor, showing a maximum inhibition efficiency of 88.6% at an optimum concentration of 2.0 g/L. The corrosion rate decreased with increasing inhibitor dose but increased with rising system temperatures. Activation energy values (Ea) calculated using the Arrhenius expression increased from 34.5 kJ/mol in blank acid to 68.2 kJ/mol in the presence of 2.0 g/L extract, indicating a physical adsorption mechanism on the aluminum surface. The adsorption path fit the Freundlich adsorption isotherm model with a negative Gibbs free energy of adsorption (delta G°ads = -18.4 kJ/mol), confirming a spontaneous process. Phytochemical tracking revealed that the presence of saponins and flavonoids drives the formation of this protective organic barrier layer.

Keywords: Aluminum; Acid corrosion; Vernonia amygdalina; Green inhibitor; Activation energy; Adsorption isotherm

Manuscript Timeline: Received: November 05, 2010; Revised: December 14, 2010; Accepted: January 05, 2011; Published: February 02, 2011.

Citation: Odo, C. E., & Ifemeje, J. C. (2011). Evaluation of Corrosion Inhibition of Aluminium in Hydrochloric Acid Solution by Methanolic Extract of Vernonia amygdalina. International Journal of Chemistry, 2(2), 18–26.

International Journal of Chemistry | Vol. 2, No. 9, September 2011 | pp. 92–99

DOI: 10.46882/2011/IJC/000036

Article Type: Original Research Paper

Title: Geochemical Speciation, Partitioning, and Mobility Hazards of Trace Metals in Urban Roadside Dust Matrices

Names of Authors: C. I. Obi¹, S. O. Akpan², P. A. Nwachukwu¹*

Authors’ Affiliations:
¹Department of Pure and Industrial Chemistry, University of Port Harcourt, Port Harcourt, Nigeria.
²Department of Chemistry, Akwa Ibom State University, Ikot Akpaden, Nigeria.

Abstract: Heavy metals in urban street dust present significant health hazards to pedestrian populations through ingestion and inhalation pathways. This study determines the total concentration and geochemical speciation fractions of lead (Pb), cadmium (Cd), nickel (Ni), and copper (Cu) in street dust samples collected from five major intersections in Port Harcourt. Metals quantification was achieved via Atomic Absorption Spectrophotometry following the classic modified BCR three-step sequential extraction procedure. The total metal contents followed the decreasing sequence: Pb > Cu > Ni > Cd. Speciation profiling revealed that a substantial fraction of lead (41.5%) and cadmium (48.2%) was associated with the acid-soluble fraction, which is highly unstable and bioavailable. Conversely, nickel and copper were bound within the reducible and residual crystal lattices, suggesting lower mobility under neutral pH environments. The contamination factor (CF) and geoaccumulation index (Igeo) pointed to high pollution indices for Pb and Cd at high-traffic intersections. Strong positive Pearson correlations between Pb and Cu point toward automobile brake wear and exhaust emissions as the primary anthropogenic sources, highlighting a need for urban dust containment.

Keywords: Street dust; Trace metals; BCR sequential extraction; Bioavailability; Geoaccumulation index; Urban pollution

Manuscript Timeline: Received: March 20, 2011; Revised: April 30, 2011; Accepted: May 20, 2011; Published: September 11, 2011.

Citation: Obi, C. I., Akpan, S. O., & Nwachukwu, P. A. (2011). Geochemical Speciation, Partitioning, and Mobility Hazards of Trace Metals in Urban Roadside Dust Matrices. International Journal of Chemistry, 2(9), 92–99.