International Journal of Chemistry

International Journal of Chemistry | Vol. 6, No. 12, December 2015 | pp. 89–96

DOI: 10.46882/2015/IJC/000087

Article Type: Original Research Paper

Title: Green Corrosion Inhibition of Carbon Steel in Hydrochloric Acid Using Fruit Peel Extract of Citrus aurantifolia

Names of Authors: M. A. Haruna¹, S. Swaminathan²*

Authors’ Affiliations:
¹Department of Chemistry, Federal University of Technology, Minna, Nigeria.
²Department of Chemistry, Indian Institute of Technology, Madras, India.

Abstract: The utilization of toxic synthetic chemical inhibitors in industrial acid descaling operations creates substantial environmental and safety hazards, driving research into sustainable green alternatives. The corrosion mitigation performance of the methanolic fruit peel extract of Citrus aurantifolia (CA-Extract) on carbon steel in 1.0 M HCl was investigated via gravimetric weight loss and electrochemical test protocols. Potentiodynamic polarization and electrochemical impedance spectroscopy (EIS) measurements were recorded across varying inhibitor dosages (0.2 to 2.0 g/L) and system temperatures (303 to 333 K). Weight loss metrics revealed that protection efficiency increased with extract concentration, peaking at 92.5% at a dose of 2.0 g/L. Polarization diagrams established that CA-Extract functions as a mixed-type inhibitor, suppressing both anodic iron dissolution and cathodic hydrogen gas evolution pathways. EIS scans confirmed that charge-transfer resistance (Rct) increased with higher extract amounts, indicating the formation of a robust organic protective film on the steel face. The adsorption behavior of the bioactive compounds conformed to the Langmuir isotherm model, yielding a negative standard free energy of adsorption (delta G°ads = -21.4 kJ/mol), denoting a spontaneous physical adsorption mechanism driven by the presence of rich plant flavonoids.

Keywords: Carbon steel; Corrosion inhibition; Citrus aurantifolia; Electrochemical impedance spectroscopy; Polarization; Adsorption isotherm

Manuscript Timeline: Received: April 18, 2015; Revised: June 05, 2015; Accepted: July 12, 2015; Published: December 04, 2015.

Citation: Haruna, M. A., & Swaminathan, S. (2015). Green Corrosion Inhibition of Carbon Steel in Hydrochloric Acid Using Fruit Peel Extract of Citrus aurantifolia. International Journal of Chemistry, 6(12), 89–96.

International Journal of Chemistry | Vol. 6, No. 5, May 2015 | pp. 33–40

DOI: 10.46882/2015/IJC/000080

Article Type: Original Research Paper

Title: Synthesis, Microcharacterization, and Antileishmanial Activity of Novel Artesunate Transition Metal Complexes

Names of Authors: A. A. Yusuf¹, S. K. Das²*

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

Abstract: The systemic spread of drug-resistant protozoal vectors requires the structural modification of classic sesquiterpene lactone frameworks via coordination to transition metal ions to enhance lethal cellular targeting. This study reports the synthesis, microcharacterization, and in vitro biological evaluation of novel copper(II), zinc(II), and iron(II) complexes coordinated with artesunate ligands. The newly synthesized structures were characterized using elemental analysis, molar conductance, magnetic susceptibility, and FT-IR spectroscopy. Analytical metrics established a 1:2 metal-to-ligand ratio, corresponding to the molecular formula [M(ART)₂Cl₂], where ART represents the deprotonated artesunate drug. Molar conductance values in DMF confirmed non-electrolytic properties. FT-IR spectra established that the drug coordinates in a bidentate manner, binding to the metal cores via the lactone carbonyl and the deprotonated carboxylate oxygen atoms. In vitro antileishmanial susceptibility testing was executed against Leishmania donovani promastigotes using the Alamar Blue assay. The iron(II)-artesunate complex demonstrated high lethal potency, yielding an IC50 value of 1.42 μM compared to standalone uncoordinated artesunate (6.84 μM). This enhanced performance is driven by metal-induced homolytic cleavage of the peroxide bridge, accelerating free radical generation inside the parasite cells.

Keywords: Artesunate; Metal complexes; Coordination chemistry; Antileishmanial activity; Leishmania donovani; Free radicals

Manuscript Timeline: Received: June 05, 2014; Revised: July 18, 2014; Accepted: August 20, 2014; Published: May 04, 2015.

Citation: Yusuf, A. A., & Das, S. K. (2015). Synthesis, Microcharacterization, and Antileishmanial Activity of Novel Artesunate Transition Metal Complexes. International Journal of Chemistry, 6(5), 33–40.

International Journal of Chemistry | Vol. 6, No. 7, July 2015 | pp. 49–56

DOI: 10.46882/2015/IJC/000082

Article Type: Original Research Paper

Title: Adsorptive Elimination of Cadmium(II) Ions from Industrial Effluents Using Xanthated Coconut Coir Matrices

Names of Authors: E. N. Chidi¹, M. H. van den Bosch²*

Authors’ Affiliations:
¹Department of Pure and Industrial Chemistry, Nnamdi Azikiwe University, Awka, Nigeria.
²Department of Chemical Engineering, Eindhoven University of Technology, Eindhoven, Netherlands.

Abstract: Heavy metal contamination of surface waters due to battery manufacturing operations presents severe ecological risks due to the toxicity and mobility of cadmium compounds. This study explores the adsorptive performance of modified coconut coir prepared via chemical modification with carbon disulfide in alkaline media (xanthation). The surface morphology and chemical modifications of the adsorbent were studied using scanning electron microscopy (SEM) and FT-IR spectroscopy. The analytical data confirmed that xanthation successfully integrated sulfur-rich dithiocarbonate groups onto the cellulosic biomass network. Batch extraction experiments evaluated parameters of solution pH, contact time, adsorbent dosage, and initial Cd(II) concentrations. Maximum Cd(II) adsorption occurred at an optimum pH of 6.0, using an equilibrium contact period of 90 minutes. Equilibrium data fit 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 > 0.997), proving that chemical surface complexation reactions controlled the mass transfer rates. Thermodynamic constants showed that the adsorption process was spontaneous (delta G° = -5.12 kJ/mol) and endothermic, establishing xanthated coir as an affordable material for wastewater treatment plant designs.

Keywords: Coconut coir; Chemical modification; Xanthation; Cadmium removal; Adsorption kinetics; Chemisorption

Manuscript Timeline: Received: January 20, 2015; Revised: March 02, 2015; Accepted: April 10, 2015; Published: July 05, 2015.

Citation: Chidi, E. N., & van den Bosch, M. H. (2015). Adsorptive Elimination of Cadmium(II) Ions from Industrial Effluents Using Xanthated Coconut Coir Matrices. International Journal of Chemistry, 6(7), 49–56.

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.