Asian Journal of Chemical Sciences

Removal of Pollutants from Domestic Wastewater Using Macrophyte Filters Planted with Echinochloa pyramidalis (Lam.) Hutch

Mon, 08 Jun 2026 00:00:00 +0000

Domestic wastewater contains high concentrations of organic matter, nutrients, suspended solids, and trace metals that can cause significant environmental pollution if discharged without treatment. This study evaluated the efficiency of a macrophyte-based filtration system planted with Echinochloa pyramidalis (Lam.) Hutch for the treatment of domestic wastewater collected from student residences at Marien Ngouabi University, Republic of Congo. The experimental setup consisted of two pilot-scale filters: a vegetated filter planted with E. pyramidalis and an unvegetated filter used as a control. Wastewater was applied intermittently at seven-day intervals over six months, and physicochemical parameters were monitored to assess treatment performance. The planted filter demonstrated superior pollutant removal compared with the control filter. Average removal efficiencies achieved by the vegetated system were 76.97% for total suspended solids (TSS), 76.24% for turbidity, 78.49% for chemical oxygen demand (COD), 92.69% for nitrate (NO₃⁻), 78.28% for ammonium (NH₄⁺), 81.99% for orthophosphate (PO₄³⁻), 91.04% for nickel, 82.50% for chromium, and 94.55% for copper. In comparison, the control filter achieved removal efficiencies of 60.13%, 58.29%, 52.66%, 36.74%, 48.93%, 50.97%, 67.08%, 63.54%, and 63.38%, respectively. The results indicate that E. pyramidalis significantly enhances the removal of organic, nutrient, and metal pollutants through filtration, microbial activity, and plant uptake mechanisms. The study demonstrates the potential of E. pyramidalis-based constructed wetland systems as an efficient, low-cost, and environmentally sustainable technology for domestic wastewater treatment in developing regions.

Experimental Study and Comsol Multiphysics Simulation of Corrosion Inhibition for Mild Steel in Acidic Solutions Using Pteridium aquilinum Extract as Green Inhibitor

Tue, 09 Jun 2026 00:00:00 +0000

Corrosion of mild steel in aggressive environments remains a significant challenge in industrial processes. The corrosion behaviour of mild steel in 3 M HCl and its inhibition using an eco-friendly ethanolic extract of Pteridium aquilinum was investigated through combined experimental and numerical approaches. Mild steel specimens (30 × 30 mm, 1.5 mm thickness) were exposed to the acid medium in the presence of varying concentrations of Pteridium aquilinum extract as a green inhibitor for a period of six day. Phytochemical analysis revealed the presence of saponins, alkaloids, tannins, and flavonoids, while FT-IR results confirmed functional groups containing O, N, and S atoms, which act as adsorption centre on the metal surface. Weight loss measurements showed that inhibition efficiency increased with extract concentration but decreased with increase in immersion time. The efficiencies of 94.4%, 93.4%, 83.4%, 76.9%, and 52.5% were obtained at 500, 400, 300, 200, and 100 mg/L, respectively. COMSOL Multiphysics simulation supported the experimental findings, showing good agreement and confirming improved inhibition at higher concentrations, particularly during the initial exposure period. The corrosion protection is attributed to the formation of a protective adsorbed film by the plant extract constituents. Overall, Pteridium aquilinum extract demonstrated effective inhibition performance, especially at higher concentrations, highlighting its potential as an eco-friendly corrosion inhibitor for mild steel in acidic environments.

Distribution of Biogenic- Derived Polycyclic Aromatic Hydrocarbons in Sediment Cores from Gabu Lake, South East Nigeria: Diagenetic and Environmental Implications

Inyang O. Oyo-Ita, Ifiok E. Enyong, Orok E. Oyo-Ita — Thu, 11 Jun 2026 00:00:00 +0000

Polycyclic aromatic hydrocarbons (PAHs) in lake sediments can originate from both natural and human-related sources. In tropical environments, biogenic PAHs often predominate and provide valuable information on organic matter transformation, environmental conditions, and ecosystem history. However, data on the distribution and diagenesis of biogenic PAHs in tropical African lake sediments remain limited. A comparative study of 80‑cm sediment cores from Gabu Lake—GS near the shoreline and GC from open water—was conducted using gas chromatography–mass spectrometry to trace the diagenesis of natural precursors forming biogenic polycyclic aromatic hydrocarbons (PAHs). Prominent compounds identified included two isomers each of octahydrochrysene and tetrahydrochrysene, along with mono‑ and di‑aromatic lupeol derivatives. GS core contained higher levels of natural and diagenetically produced PAHs, likely due to proximity to diverse vascular plant stands along the catchment. Variable concentrations of lupeol and α‑/β‑amyrin derivatives across intervals suggest aromatization occurred within micro‑layers of the cores or in watershed under anoxic conditions and later transported by runoff. A greater conversion of triene (mono‑aromatic) to pentene (di‑aromatic) lupeol‑derived PAHs in GS indicates stronger microbial oxidation compared to GC. Initial selective aromatization of lupeol preceded transformations in α‑ or β‑amyrin. The dominance of biogenic PAHs over anthropogenic ones highlights the sediments’ good quality and the lake’s healthy ecosystem.

Toxicological Evaluation of Herbal Formulation Containing Moringa olifera and Zingiber officinale in Wistar Rat

P. A. Oyewusi, D. A. Apata — Fri, 12 Jun 2026 00:00:00 +0000

The use of herbal formulation has become part of traditional medicine especially in Africa region. The presence and activity of different bioactive compounds in the herb may triggered the toxicity and efficacy. Herbs have now become important and widely used globally. The formulation and utilization of this herbs need proper scrutiny and analysis as regard the interaction with physiological and biochemical component of body system. In this present study, a toxicological evaluation was conducted for safety and efficacy of a herbal product formulated from Moringa olifera and Zingiber officinale at 99: 1. In the toxicity test, Wistar rat grouped into four ( Group I, II, III and IV) were administered with the herbal formulation at 50mg/g , 100mg/g and 200mg/g body weight to the animals in Group II, III and IV respectively, while Group I was designated as control and only administered with ordinary pure water for twenty-eight days. The effect of the herbal formulation on body weight, food and water consumption, hematology as well as clinical biochemistry were studied. There were no significant differences in the body weight and feeding habit between control and treated animals. Analysis of Hematological parameters such as Red Blood Cell (RBC) count, Hemoglobin (Hb) concentration, Hematocrit (HCT), White Blood Cell (WBC) count showed no obvious differences (P> 0.05) as compared to control group. Also, the biochemical parameters such as AST, ALP, ALT, cholesterol, triglycerides, creatinine were also examined.

The Degree Based Topological Indices of Ceria Oxide

S. Nagarajan, A. Vijaya — Mon, 15 Jun 2026 00:00:00 +0000

Quantitative Structure-Property Relationship (QSPR) analysis represents a pivotal approach in computational chemistry and chemo-informatics, enabling the prediction of various molecular properties based on structural descriptors. Among the diverse methodologies employed in QSPR studies, topological indices have emerged as fundamental tools for characterizing molecular structure and properties. These indices encapsulate critical topological features of molecules, providing a quantitative framework for understanding and predicting their physicochemical behaviors. In this article, a degree based approach is done for the Ceria oxide that can be used for the QSPR analysis of the Ceria oxide.

Colorimetric and Spectrophotometric Sensing of Heavy Metal Ions using 5,10,15,20-Tetrakis(4-sulfonatophenyl) porphyrin (TPPS₄) in Aqueous Media: Selectivity, Paper-based Detection, and Field Assessment in Nigerian River Water

Emmanuel Efan Anuwe, Gabriel K. Obiyenwa, Jude E. Emurotu, Samson Mopah Benu — Thu, 02 Jul 2026 00:00:00 +0000

This study provides a preliminary evaluation of 5,10,15,20-tetrakis(4-sulfonatophenyl) porphyrin (TPPS₄) as a colourimetric and UV–Visible spectrophotometric sensing material for selected heavy metal ions in aqueous media. The response of TPPS₄ was examined towards Fe³⁺, Hg²⁺, Pb²⁺, Cd²⁺, Zn²⁺, Ni²⁺, and Cr⁶⁺ over a concentration range equivalent to 0.05–100 equivalents relative to TPPS₄. Free TPPS₄ in water displayed a characteristic Soret band at 413 nm and Q-bands in the visible region. Among the tested cations, Fe³⁺ produced the most prominent spectral change, including new absorption features at approximately 489–493 nm and near 700 nm. Hg²⁺ induced a bathochromic shift of the Soret band from 413 nm to 445 nm at higher equivalents, with Q-band changes around 586 and 641 nm. Pb²⁺ produced a dual Soret-band pattern at approximately 413 and 466 nm, whereas Cd²⁺ and Zn²⁺ caused smaller spectral shifts. Ni²⁺ and Cr⁶⁺ produced limited spectral changes under the conditions studied. Anions and selected organic compounds produced no notable colourimetric response, indicating preferential interaction of TPPS₄ with coordinating metal cations. TPPS₄-impregnated filter-paper strips also showed visible colour changes after exposure to selected metal ions, particularly Hg²⁺, Fe³⁺, Pb²⁺, and Cd²⁺. Application to water samples from the Niger–Benue confluence, Ganaja River, and borehole water showed no visible false-positive response on the paper strips, while UV–Visible spectra indicated minor matrix-dependent changes. The findings support the potential use of TPPS₄ as a simple preliminary screening material for selected heavy metal ions in aqueous environments.

Effect of Selected Alcohols on Surface Properties of Cationic Gemini Surfactant Hexanediyl-1,6 Bis (dimethyldodecylammonium bromide) (12-6-12)

Riyaj Mohammad — Sat, 11 Jul 2026 00:00:00 +0000

The effect of selected alcohols on the surface characteristics of the cationic gemini surfactant hexanediyl-1,6-bis (dimethyldodecylammonium bromide) (12-6-12) was investigated using surface tension measurements at 303.15 K. The evaluated surface parameters included the critical micelle concentration (CMC), C₂₀ (the concentration required to decrease the surface tension of water by 20 mN m^-1), maximum surface excess (Γ_max), minimum molecular area (A_min), the CMC/C₂₀ ratio and surface pressure at the CMC (Π_CMC). These parameters were used to assess the influence of selected alcohols on mixed micelle formation and adsorption behaviour. The results showed that alcohol addition appreciably affected the interfacial and micellization properties of the gemini surfactant. In all systems studied, increasing the alcohol concentration caused a progressive decrease in the CMC, indicating facilitated micelle formation. The extent of this effect depended on the molecular structure and chain length of the alcohol, suggesting favourable hydrophobic interactions between the alcohol molecules and the surfactant aggregates. The calculated thermodynamic parameters, including the standard Gibbs free energy of adsorption (ΔG°_ads) and the minimum free energy at the air-water interface (G^(s)_min)), indicated that alcohol addition promoted spontaneous adsorption and improved interfacial stability. The increase in surface excess, together with the reduction in molecular area, further indicated closer packing of surfactant molecules at the interface.