International Journal of Chemistry

International Journal of Chemistry | Vol. 16, No. 11, November 2025 | pp. 81–88

DOI: 10.46882/2025/IJC/000205

Article Type: Original Research Paper

Title: Adsorptive Sequestration of Divalent Cadmium Ions Using Chemically Modified Wheat Straw Biomass

Names of Authors: E. N. Chidi¹, L. M. van der Westhuizen²*

Authors’ Affiliations:
¹Department of Pure and Industrial Chemistry, Nnamdi Azikiwe University, Awka, Nigeria.
²Department of Chemical Engineering, Stellenbosch University, Stellenbosch, South Africa.

Abstract: Heavy metal contamination of surface waters by industrial manufacturing operations requires the development of low-cost, chemically stable, and highly active biosorption matrices. This investigation reports the adsorptive efficiency of a modified agricultural adsorbent derived from wheat straw prepared via chemical modification with citric acid under alkaline conditions. The chemical transformations and surface porous architectures of the matrix were examined through scanning electron microscopy (SEM) and FT-IR spectroscopy. The analytical data confirmed that the modification process successfully integrated carboxyl-rich active ligand networks across the cellulosic biomass strands. Batch extraction experiments evaluated parameters of solution pH, equilibrium contact time, adsorbent dosage, and initial Cd(II) concentrations. Maximum cadmium adsorption occurred at an optimum solution pH of 5.5, using an equilibrium contact period of 90 minutes. Equilibrium data matched the Langmuir model closely, showing a maximum monolayer adsorption capacity of 58.45 mg/g at 298 K. Sorption kinetics followed a pseudo-second-order model with a high correlation coefficient (R² > 0.998), proving that chemical surface complexation reactions controlled the mass transfer rates. Thermodynamic parameters confirmed process spontaneity and endothermic characteristics, highlighting this modified biomass as an affordable choice for industrial water treatment.

Keywords: Wheat straw; Citric acid modification; Cadmium removal; Adsorption kinetics; Chemisorption; Wastewater treatment

Manuscript Timeline: Received: June 02, 2024; Revised: July 15, 2024; Accepted: August 10, 2024; Published: November 09, 2025.

Citation: Chidi, E. N., & van der Westhuizen, L. M. (2025). Adsorptive Sequestration of Divalent Cadmium Ions Using Chemically Modified Wheat Straw Biomass. International Journal of Chemistry, 16(11), 81–88.

International Journal of Chemistry | Vol. 16, No. 8, August 2025 | pp. 57–64

DOI: 10.46882/2025/IJC/000202

Article Type: Original Research Paper

Title: Ultrasonic Speeds, Excess Volumetric Parameters, and Intermolecular Interactions of Binary Liquid Systems of Heptanol with Aliphatic 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-heptanol 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-heptanol 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, 2024; Revised: March 12, 2024; Accepted: April 08, 2024; Published: August 03, 2025.

Citation: Chiemeka, E. C., & Al-Ghamdi, A. M. H. (2025). Ultrasonic Speeds, Excess Volumetric Parameters, and Intermolecular Interactions of Binary Liquid Systems of Heptanol with Aliphatic Amines. International Journal of Chemistry, 16(8), 57–64.

International Journal of Chemistry | Vol. 16, No. 6, June 2025 | pp. 41–48

DOI: 10.46882/2025/IJC/000200

Article Type: Original Research Paper

Title: Thermodynamic Modeling, Kinetic Runs, and Multilayer Adsorption of Acid Orange 7 Dye onto Modified Bentonite Clay

Names of Authors: A. D. Yusuf¹, M. A. Al-Ghamdi²*

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 anionic azo dyes like Acid Orange 7 from textile processing factories causes significant environmental and toxicity hazards in surface water channels. This study examines the adsorptive uptake performance of a surfactant-modified bentonite clay (SMB) prepared via chemical functionalization with hexadecyltrimethylammonium bromide (HDTMA-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° = 22.4 kJ/mol) and caused an increase in system randomness at the solid-solution interface (delta S° = 74.2 J/mol K). Negative values of Gibbs free energy (delta G°) spanning from -2.4 to -5.8 kJ/mol across the 298 to 328 K range confirmed process spontaneity, positioning SMB as an affordable material for industrial dye wastewater treatment.

Keywords: Bentonite clay; Surfactant modification; Acid orange 7; Adsorption isotherm; Chemisorption; Thermodynamic parameters

Manuscript Timeline: Received: September 10, 2023; Revised: October 22, 2023; Accepted: November 15, 2023; Published: June 03, 2025.

Citation: Yusuf, A. D., & Al-Ghamdi, M. A. (2025). Thermodynamic Modeling, Kinetic Runs, and Multilayer Adsorption of Acid Orange 7 Dye onto Modified Bentonite Clay. International Journal of Chemistry, 16(6), 41–48.

International Journal of Chemistry | Vol. 16, No. 9, September 2025 | pp. 65–72

DOI: 10.46882/2025/IJC/000203

Article Type: Original Research Paper

Title: Synthesis, Characterization, and Antifungal Activity of Novel Aminosalicylic Acid Transition Metal Complexes Sourced from Hydrazides

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 therapeutic agents 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 5-aminosalicylic acid ligands. The synthesized coordination compounds were profiled utilizing elemental analysis, molar conductance measurements, magnetic susceptibility, and FT-IR spectroscopy. Analytical metrics established a 1:2 metal-to-ligand stoichiometric coordination pattern for all complexes, corresponding to a general structural configuration of [M(ASA)₂Cl₂], where ASA represents the neutral aminosalicylic acid molecule. Molar conductance tests in DMSO indicated a non-electrolytic nature. FT-IR spectra confirmed that the ligand acts as a bidentate chelator, binding to the metal centers via the amino nitrogen and the carboxylate oxygen atoms. In vitro antifungal evaluation was conducted against Candida albicans and Aspergillus niger isolates via the disk diffusion test. The copper(II)-aminosalicylic acid complex demonstrated a two-fold increase in mycelial growth inhibition compared to standalone uncoordinated aminosalicylic acid, which is explained via cell permeability and chelation principles.

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

Manuscript Timeline: Received: February 12, 2024; Revised: March 20, 2024; Accepted: April 15, 2024; Published: September 09, 2025.

Citation: Yusuf, A. A., & Ghosh, P. K. (2025). Synthesis, Characterization, and Antifungal Activity of Novel Aminosalicylic Acid Transition Metal Complexes Sourced from Hydrazides. International Journal of Chemistry, 16(9), 65–72.

International Journal of Chemistry | Vol. 16, No. 12, December 2025 | pp. 89–96

DOI: 10.46882/2025/IJC/000206

Article Type: Original Research Paper

Title: GC-MS Volatile Characterization, Bioactive Compound Mapping, and Insecticidal Efficacy of Lavandula angustifolia 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 Lavandula angustifolia leaf essential oil against Rhyzopertha dominica (Lesser grain borer). Essential oils obtained via hydro-distillation in a Clevenger apparatus were separated into 20 distinct peaks through GC-MS profiling, with linalool (42.5%), linalyl acetate (18.2%), and camphor (12.4%) 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 borer 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 borers, providing a sustainable botanical framework for grain storage protection.

Keywords: Lavandula angustifolia; Essential oils; GC-MS analysis; Linalool; Contact toxicity; Rhyzopertha dominica

Manuscript Timeline: Received: June 15, 2024; Revised: July 28, 2024; Accepted: August 22, 2024; Published: December 04, 2025.

Citation: Abdulrahman, S. A., & Santos, G. E. D. M. (2025). GC-MS Volatile Characterization, Bioactive Compound Mapping, and Insecticidal Efficacy of Lavandula angustifolia Essential Oils. International Journal of Chemistry, 16(12), 89–96.

International Journal of Chemistry | Vol. 16, No. 4, April 2025 | pp. 25–32

DOI: 10.46882/2025/IJC/000198

Article Type: Original Research Paper

Title: Development and Validation of a Spectrophotometric Method for Quantitative Determination of Moxifloxacin in Dosage Forms

Names of Authors: E. O. Effiong¹, J. M. S. Cardoso²*

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

Abstract: Developing rapid, low-cost analytical protocols is essential for routine quality monitoring and the detection of substandard antibiotic formulations in clinical testing laboratories. This paper describes the development and validation of a simple UV-Vis spectrophotometric method for the quantification of moxifloxacin in commercial tablet dosage forms. The analytical procedure relied on the reaction of moxifloxacin with iron(III) chloride in an acidic medium, generating a highly stable yellow-colored complex monitored spectrophotometrically at its absorption maximum of 385 nm. Method validation parameters followed the International Council for Harmonisation (ICH) guidelines. Excellent linearity was established over a concentration range of 2.0 to 25.0 mg/L with a correlation coefficient (R²) of 0.999. The limit of detection (LOD) and limit of quantification (LOQ) were determined to be 0.08 mg/L and 0.24 mg/L, respectively. Precision assessments yielded relative standard deviations (RSD) below 1.8%. The validated method was successfully applied to screen five commercial brands of moxifloxacin tablets, producing recovery percentages between 98.6% and 101.4% with no interference from common tablet excipients, making it suitable for routine quality control setups.

Keywords: UV-Vis spectrophotometry; Moxifloxacin; Complexation; Method validation; Pharmaceuticals; Quality control

Manuscript Timeline: Received: August 14, 2023; Revised: September 25, 2023; Accepted: October 15, 2023; Published: April 02, 2025.

Citation: Effiong, E. O., & Cardoso, J. M. S. (2025). Development and Validation of a Spectrophotometric Method for Quantitative Determination of Moxifloxacin in Dosage Forms. International Journal of Chemistry, 16(4), 25–32.