Zeolite was successfully synthesized using a mixture of kaolinite clay (which served as the alumina source) and rice husk ash (silica source). The aim of this work was to synthesize highly efficient zelolite to remove methyle blue dye from aqueous solution. The synthesized adsorbent was characterised using Fourier Transform Infrared (FTIR) spectroscopy, powder x-ray diffraction (PXRD) analysis, differential scanning calorimetry (DSC), thermogravimetric analysis (TGA) and pH at the point of zero charge (pHpzc). The interaction of the zeolite with methylene blue was studied using equilibrium batch process. Factors investigated include; solution pH, adsorbent dose, ionic strength, adsorption temperature and initial dye concentration. Results show removal efficiencies between 80 and 90 %. Assessment of adsorption isotherms using the Freundlich and Langmuir models showed that the data from this work fitted the Freundich model with K_f = 7.388 mg^1-1/nL^1/ng⁻¹ and n = 0.89 signifying a physisorption model. The data also fitted the pseudo-second-order kinetic models with R² = 1.00. Assemment of the thermodynamic parameters gave an enthalpy change (ΔH°) of −1.871 kJ/mol and an entropy change (ΔS°) of +10.18 JK⁻¹mol⁻¹. Generally the Gibbs free energy (ΔG°) was negative and dereased with temperature. Results from this study shows that zeolite prepared from readily available raw materials is an efficient adsorbent for the removal of methylene blue from aqueous solution.

The interaction between nickel (Ni²⁺), copper (Cu²⁺), and zinc (Zn²⁺) ions and 1-methylimidazole has been studied by exploring the geometries of eleven crystal structures in the Cambridge Structural Database (CSD). The coordination behavior of the respective ions was further investigated by means of density functional theory (DFT) methods. The gas-phase complexes were fully optimized using B3LYP/GENECP functionals with 6-31G^∗ and LANL2DZ basis sets. The Ni²⁺ and Cu²⁺ complexes show distorted tetrahedral geometries around the central ions, with Zn²⁺ being a perfect tetrahedron. Natural bond orbital (NBO) analysis and natural population analysis (NPA) show substantial reduction in the formal charge on the respective ions. The interaction between metal d-orbitals (donor) and ligand orbitals (acceptor) was also explored using second-order perturbation of the Fock matrix. These interactions followed the order Ni²⁺ > Cu²⁺ > Zn²⁺ with Zn²⁺ having the least interaction with the ligand orbitals. Examination of the frontier orbitals shows the stability of the complexes in the order Ni²⁺ > Cu²⁺ < Zn²⁺ which is consistent with the Irving–Williams series.

The electronic spectra of phenol, 2-chlorophenol, 2-aminophenol, and 2-nitrophenol have been studied both experimentally and computationally. The effect of the substituents on the solvatochromic behavior of the phenols were investigated in polar protic (methanol) and aprotic (dimethyl sulfoxide (DMSO)) solvents. The spectra of 2-nitrophenol recorded the highest red shift in methanol. The observed spectral changes were investigated computationally by means of density functional theory (DFT) methods. The gas phase compounds were fully optimized using B3LYP functionals with 6-31++G(d,p) bases set. The effects of the substituents on the electron distribution in the σ-bonds as well as the natural charge on the constituent atoms were analyzed by natural bond orbital (NBO) and natural population analysis (NPA). Second-order perturbation analyses also revealed substantial delocalization of nonbonding electrons on the substituents onto the phenyl ring, thereby increasing its electron density. Full interaction map (FIM) also showed regions of varying propensities for hydrogen and halogen bonding interactions on the phenols.

Mixed-ligand palladium(II) chloride complexes bearing the nucleobases, adenine (Ad), cytosine (Cyt), and guanine (Gua), have been synthesized and characterized by UV-vis spectrophotometric methods, magnetic susceptibility, molar conductivity, elemental analysis, FTIR, and¹H-NMR. The complexes were found to have the composition cis-[PdCl₂(Gua)(Cyt)], cis-[PdCl₂(Ad)(Cyt)], and cis-[PdCl₂(Ad)(Gua)]. A four-coordinated square-planar geometry is proposed for these Pd(II) complexes based on magnetic evidence and electronic spectra. The complexes as well as the free nucleobase ligands were tested for theirin vitrocytotoxicity on human promyelocytic leukemia (HL60) and human histiocytic leukemia (U937) cell lines. cis-[PdCl₂(Ad)(Gua)] showed IC₅₀values of 11.29 ± 2.91 and 8.31 ± 1.44 μM against HL60 and U937, respectively, which was higher than that of the positive control (curcumin) against U937. The complexes also showed significant antioxidant activity when tested against 2,2-diphenyl-1-picrylhydrazylradical (DPPH).

Natural materials are widely used in the field of environmental remediation and are appreciated for their surface physical and chemical properties. Clay constitutes a typical example. In this work, we report the evaluation of sorbent and photocatalytic potentials of local clay of two irrigated rice field waters in the degradation of crystal violet. The structural, textural and compositional properties of the local clay were investigated by Fourier Transform Infrared Spectroscopy (FTIR), X-ray Diffraction (XRD) and X-ray Fluorescence (XRF) analysis. The analysis results showed that these materials were composed mainly of quartz and kaolinite. The efficiency of these adsorbents (Y. Clay and L. Clay) to eliminate crystal violet dye from aqueous medium was examined at different initial concentrations, pH, contact time, adsorbent dose and the possible interference of inorganic salts from fertilizers. Kinetic studies showed that the adsorption process was well described by the pseudo-second order model and the equilibrium modelling results fitted adequately to the Freundlich model. The maximum amount of uptake capacity achieved at pH 2.0 was 18.40 (mg·g⁻¹) and 20.40 (mg·g⁻¹), respectively, for Y. Clay and L. Clay. The evaluation of the photocatalytic potential showed that the raw clay samples do not show photocatalytic activities during the 30 min of exposure to UV light. On the other hand, their photocatalytic potential is manifested when loaded with titanium dioxide (TiO₂). Clays coupled with TiO₂ under UV light showed an improvement in the degradation of the crystal violet dye by 15%. The synergistic effects between the high photocatalytic activity of TiO₂ and the strong adsorption capacity of clays can be one promising technique for in situ remediation of contaminated soaked rice field.

Three clay samples (E1, E2, and C1) extracted from different parts of Ghana have been purified by sedimentation. The samples were further characterized by powder X-ray diffraction (PXRD), Fourier transform infrared spectroscopy (FT-IR), scanning electron microscopy (SEM), cation exchange capacity (CEC), and point of zero charge (pH_pzc). PXRD and FT-IR data revealed the samples to be predominantly muscovite clay with percentages ranging from 82.71 to 91.33%. The surfaces were mostly cationic with pH_pzc ranging from 5.58 to 6.40. Morphological studies by SEM confirmed the crystalline nature of the surfaces which is suitable for adsorption studies. Time-dependent adsorption studies show that C1 is a good candidate for the adsorption of chlorophenols, methyl orange, and Eriochrome Black T.