International Journal of Chemistry

International Journal of Chemistry | Vol. 14, No. 5, May 2023 | pp. 33–40

DOI: 10.46882/2023/IJC/000175

Article Type: Original Research Paper

Title: Assessing the Hydrocarbon Tolerance and Phytoremediation Potential of Cajanus cajan L. in Aviation Turbine Fuel Spiked Soils

Names of Authors: O. F. Olawal¹, H. de Koning²*

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

Abstract: The accidental leakage of aviation turbine fuel from commercial storage facilities damages agricultural soil porosity and introduces toxic aromatic hydrocarbons into arable land, demanding green restoration strategies. This controlled study investigates the growth kinetics and remediation efficiency of Cajanus cajan L. (Pigeon pea) cultivated in soils artificially spiked with varying concentrations of aviation fuel (1.0% to 4.0% w/w). Plant structural indices, remaining soil total petroleum hydrocarbon (TPH) concentrations, and root zone microbial populations were quantified over a 90-day developmental period. Cajanus cajan demonstrated strong physiological tolerance, maintaining high root nodulation indices across all fuel loading levels below 3.0%. Gas Chromatography (GC-FID) profiling showed a 71.4% reduction in soil TPH content within the rhizosphere of cultivated systems, compared to minimal attenuation (24.5%) in unplanted controls. Soil microbiological testing revealed a five-fold expansion of heterotrophic degradation bacteria within the legume root matrix. This confirms that root exudates and symbiotic nitrogen-fixing bacteria actively interact to stimulate microbial proliferation, accelerating the degradation of complex petroleum structures in contaminated agricultural terrains.

Keywords: Aviation fuel; Cajanus cajan; Total petroleum hydrocarbons; Soil phytoremediation; Rhizosphere effect; Legume symbiosis

Manuscript Timeline: Received: December 08, 2022; Revised: January 20, 2023; Accepted: February 15, 2023; Published: May 05, 2023.

Citation: Olawal, O. F., & de Koning, J. (2023). Assessing the Hydrocarbon Tolerance and Phytoremediation Potential of Cajanus cajan L. in Aviation Turbine Fuel Spiked Soils. International Journal of Chemistry, 14(5), 33–40.

International Journal of Chemistry | Vol. 14, No. 9, September 2023 | pp. 65–72

DOI: 10.46882/2023/IJC/000179

Article Type: Original Research Paper

Title: Synthesis, Microcharacterization, and Antifungal Profiles of Novel Ethambutol-Based Transition Metal Complexes

Names of Authors: A. A. Yusuf¹, P. K. Ghosh²*

Authors’ Affiliations:
¹Department of Chemistry, Ahmadu Bello University, Zaria, Nigeria.
²Department of Pharmaceutical Technology, Jadavpur University, Kolkata, India.

Abstract: The emergence of drug resistance among opportunistic fungal strains requires the structural modification of classic drug structures via coordination to transition metal ions to boost clinical performance. This research outlines the synthesis, structural characterization, and in vitro antifungal testing of novel copper(II), nickel(II), and cobalt(II) complexes coordinated with ethambutol ligands. The synthesized coordination compounds were profiled utilizing elemental analysis, molar conductance measurements, magnetic susceptibility, and FT-IR spectroscopy. Analytical metrics established a 1:1 metal-to-ligand stoichiometric coordination pattern for all complexes, corresponding to a general structural configuration of [M(ETH)Cl₂], where ETH represents the neutral ethambutol molecule. Molar conductance tests in DMSO indicated a non-electrolytic nature. FT-IR spectra confirmed that ethambutol acts as a bidentate ligand, binding to the metal centers via the hydroxyl oxygen and the secondary amino nitrogen atoms. In vitro antifungal evaluation was conducted against Candida albicans and Aspergillus niger isolates via the disk diffusion test. The copper(II)-ethambutol complex demonstrated a two-fold increase in mycelial growth inhibition compared to standalone uncoordinated ethambutol, which is explained via cell permeability and chelation principles.

Keywords: Ethambutol; Metal complexes; Antifungal activity; FT-IR spectroscopy; Candida albicans; Chelation theory

Manuscript Timeline: Received: February 12, 2022; Revised: March 20, 2022; Accepted: April 15, 2022; Published: September 09, 2023.

Citation: Yusuf, A. A., & Ghosh, P. K. (2023). Synthesis, Microcharacterization, and Antifungal Profiles of Novel Ethambutol-Based Transition Metal Complexes. International Journal of Chemistry, 14(9), 65–72.

International Journal of Chemistry | Vol. 14, No. 4, April 2023 | pp. 25–32

DOI: 10.46882/2023/IJC/000174

Article Type: Original Research Paper

Title: Spatial Analysis, Speciation, and Carcinogenic Risk Profiling of Nickel Contamination in Well Water Networks near Metal Foundries

Names of Authors: T. H. Awotunde¹, R. M. Silva²*

Authors’ Affiliations:
¹Department of Chemistry, Federal University of Agriculture, Abeokuta, Nigeria.
²Department of Environmental Chemistry, University of São Paulo, São Paulo, Brazil.

Abstract: Metallurgical industrial foundry operations discharge significant amounts of nickel-rich waste into surrounding environments, causing heavy metal leaching into shallow drinking water aquifers. This study monitors the spatial variations, chemical speciation, and carcinogenic health risk profiles of nickel compounds across twenty household wells positioned around an active steel foundry. Water monitoring was carried out over consecutive wet and dry cycles. Total nickel levels and specific nickel fractions were quantified utilizing ion chromatography coupled with inductively coupled plasma mass spectrometry (IC-ICP-MS). Total nickel concentrations ranged from 10.5 to 138.4 μg/L, with 38% of monitored groundwater sites surpassing the strict WHO drinkable contaminant threshold of 70.0 μg/L. Speciation analysis showed that soluble nickel ions were the dominant species, accounting for up to 64.2% of the total metal burden profiles at down-gradient coordinates. Seasonal mapping confirmed elevated nickel mobilization during the rainy period, indicating rain-induced plume leaching. Chronic Daily Intake (CDI) projections and Lifetime Cancer Risk (LCR) indices for child consumption cohorts surpassed 1.8 in 10,000 near industrial boundaries, emphasizing an immediate public healthcare concern and a need for local membrane filtration arrays.

Keywords: Groundwater pollution; Nickel speciation; Ion chromatography; Foundry effluents; Cancer risk assessment; Heavy metals

Manuscript Timeline: Received: December 02, 2022; Revised: January 14, 2023; Accepted: February 10, 2023; Published: April 02, 2023.

Citation: Awotunde, T. H., & Silva, R. M. (2023). Spatial Analysis, Speciation, and Carcinogenic Risk Profiling of Nickel Contamination in Well Water Networks near Metal Foundries. International Journal of Chemistry, 14(4), 25–32.

International Journal of Chemistry | Vol. 14, No. 12, December 2023 | pp. 89–96

DOI: 10.46882/2023/IJC/000182

Article Type: Original Research Paper

Title: GC-MS Chemical Profiling, Quantitative Phytochemical Mapping, and Insecticidal Efficacy of Eucalyptus globulus Essential Oils

Names of Authors: S. A. Abdulrahman¹, G. E. D. M. Santos²*

Authors’ Affiliations:
¹Department of Chemistry, Federal University of Technology, Minna, Nigeria.
²Department of Chemistry, University of Campinas, Campinas, Brazil.

Abstract: The continuous emergence of chemical resistance among stored-grain insect pests requires the formulation of alternative botanical insecticides to minimize chemical pesticide hazards in agricultural facilities. This research reports the qualitative chemical characterization, volatile compound identification via Gas Chromatography-Mass Spectrometry (GC-MS), and in vitro insecticidal efficacy of Eucalyptus globulus leaf essential oil against Sitophilus zeamais (Maize weevil). Essential oils obtained via hydro-distillation in a Clevenger apparatus were separated into 22 distinct peaks through GC-MS profiling, with 1,8-cineole (45.8%), alpha-pinene (14.2%), and p-cymene (11.5%) emerging as the primary bioactive constituents. Insecticidal bioassays were conducted utilizing contact toxicity tests across a suite of oil concentrations (10 to 50 microliters/square meter) over 24-hour exposure periods. The essential oil demonstrated significant lethal potency, yielding an LC50 value of 18.4 microliters/square meter and an LC90 value of 34.2 microliters/square meter against the weevil populations. A linear correlation was observed between the concentration of oxygenated monoterpenes and insect mortality rates. This confirms that volatile monoterpenoids actively disrupt the respiratory and acetylcholinesterase enzymes of weevils, providing a sustainable botanical framework for grain storage protection.

Keywords: Eucalyptus globulus; Essential oils; GC-MS analysis; 1,8-Cineole; Contact toxicity; Sitophilus zeamais

Manuscript Timeline: Received: June 15, 2022; Revised: July 28, 2022; Accepted: August 22, 2022; Published: December 04, 2023.

Citation: Abdulrahman, S. A., & Santos, G. E. D. M. (2023). GC-MS Chemical Profiling, Quantitative Phytochemical Mapping, and Insecticidal Efficacy of Eucalyptus globulus Essential Oils. International Journal of Chemistry, 14(12), 89–96.

International Journal of Chemistry | Vol. 14, No. 8, August 2023 | pp. 57–64

DOI: 10.46882/2023/IJC/000178

Article Type: Original Research Paper

Title: Ultrasonic Speeds, Excess Thermodynamic Parameters, and Intermolecular Transport Features of Binary Liquid Systems of Hexanol with Amines

Names of Authors: E. C. Chiemeka¹, A. M. H. Al-Ghamdi²*

Authors’ Affiliations:
¹Department of Chemistry, Federal University of Technology, Owerri, Nigeria.
²Department of Chemistry, University of Khartoum, Khartoum, Sudan.

Abstract: Experimental determination of ultrasonic velocities and fluid densities across varied temperature states yields critical baseline data needed to map hydrogen bond associations and molecular packing dynamics in multi-component chemical systems. This paper presents the measurement of ultrasonic velocity (u), density (rho), and dynamic viscosity (eta) for binary liquid mixtures of n-hexanol with diethylamine, triethylamine, and cyclohexylamine across the entire composition matrix at temperatures of 298.15 K, 308.15 K, and 318.15 K under atmospheric pressure. From these raw data metrics, excess molar volumes (V^E) and excess isentropic compressibilities (kappa_s^E) were calculated. The calculated excess datasets were successfully fitted to the Redlich-Kister polynomial expression to compute the binary interaction coefficients and standard deviations. All investigated binary mixtures exhibited significant negative excess molar volumes (V^E) and negative excess isentropic compressibilities (kappa_s^E) across all composition bounds. These strong negative deviations reveal dense interstitial molecular packing and strong intermolecular hydrogen bond formation between the hydroxyl protons of n-hexanol and the amine nitrogen centers, which decrease in intensity as thermal motion breaks the dipole networks.

Keywords: Ultrasonic velocity; Excess molar volume; Isentropic compressibility; Aliphatic amines; Redlich-Kister equation; Hydrogen bonding

Manuscript Timeline: Received: February 05, 2022; Revised: March 12, 2022; Accepted: April 08, 2022; Published: August 03, 2023.

Citation: Chiemeka, E. C., & Al-Ghamdi, A. M. H. (2023). Ultrasonic Speeds, Excess Thermodynamic Parameters, and Intermolecular Transport Features of Binary Liquid Systems of Hexanol with Amines. International Journal of Chemistry, 14(8), 57–64.

International Journal of Chemistry | Vol. 14, No. 10, October 2023 | pp. 73–80

DOI: 10.46882/2023/IJC/000180

Article Type: Original Research Paper

Title: Synthesis, Luminescent Kinetics, and Metal Sensing Performance of Novel Lutetium(III) β-Diketone Coordination Complexes

Names of Authors: A. O. Balogun¹, J. E. Kim²*

Authors’ Affiliations:
¹Department of Chemistry, University of Ilorin, Ilorin, Nigeria.
²Department of Chemistry, Seoul National University, Seoul, South Korea.

Abstract: Rare-earth coordination materials displaying highly sensitive photoluminescent behaviors are increasingly sought for chemical sensor fabrications due to their specific emission bands and high signal-to-noise ratios. This study reports the synthesis, material characterization, and analytical sensor optimization of a novel lutetium(III) complex using thenoyltrifluoroacetone and 1,10-phenanthroline ligands. Structural configurations were verified using elemental analysis, molar conductance, and Fourier-transform infrared (FT-IR) spectroscopy. Analytical calculations confirmed a 1:3:1 metal-to-ligand stoichiometric coordination pattern, conforming to the formula [Lu(TTA)₃(phen)]. Molar conductivity tests in acetonitrile confirmed a completely non-electrolytic layout. Photoluminescence scanning at room temperature showed narrow emission lines characteristic of the central Lu(III) complex framework. The analytical potential of the complex as a fluorimetric sensor for trace nitroaromatic explosives was evaluated in aqueous media. The introduction of picric acid caused immediate, highly selective luminescence quenching of the emission intensity. The fluorimetric quenching behavior followed the Stern-Volmer relationship with a high quenching constant (Ksv) of 4.2 x 10⁴ M⁻¹ and a low limit of detection (LOD) of 0.21 μM, pointing to a photoinduced electron transfer pathway.

Keywords: Lutetium complexes; Rare earth elements; Photoluminescence; Fluorimetric sensor; Nitroaromatic explosives; Stern-Volmer relation

Manuscript Timeline: Received: May 12, 2022; Revised: June 25, 2022; Accepted: July 18, 2022; Published: October 05, 2023.

Citation: Balogun, A. O., & Kim, J. E. (2023). Synthesis, Luminescent Kinetics, and Metal Sensing Performance of Novel Lutetium(III) β-Diketone Coordination Complexes. International Journal of Chemistry, 14(10), 73–80.