Research Article
Synthesis of 4-Anisidine/Cyclodextrin Covered Copper Nanomaterials and pH-Dependent of 4-Anisidine–Cyclodextrin Inclusion Complexes
Issue:
Volume 14, Issue 2, April 2026
Pages:
18-29
Received:
11 March 2026
Accepted:
23 March 2026
Published:
2 April 2026
Abstract: The spectral properties of the copper–4-anisidine–cyclodextrin (Cu: 4AS: CD) nanomaterial were examined using absorption, fluorescence, time-resolved fluorescence, SEM, DSC, FTIR, XRD, ¹H NMR, and molecular modeling techniques. The distinct spectral variations observed for 4AS upon adding α-CD and β-CD at different pH values indicate that the resulting inclusion complexes adopt different structural geometries. While 4AS exhibits a single emission maximum in all solvents and in α-CD solutions, dual emission bands are observed in β-CD. The confined geometry of the α-CD cavity likely restricts the free rotation of the amino or methoxy substituents of 4AS, suppressing the formation of the intramolecular charge-transfer (ICT) state and thereby enhancing the normal emission. The calculated HOMO–LUMO energy gap, total energy, free energy, enthalpy, entropy, dipole moment, and zero-point vibrational energy of the CD: 2AP complex differed significantly from those of the isolated 4AS, α-CD and β-CD molecules, and both the vertical and horizontal bond lengths between the amino and methoxy groups are smaller than the β-CD cavity size confirming the formation of an inclusion complex. SEM images and EDX analysis of the Cu: 4AS: β-CD nanomaterial reveal the presence of copper. In the FTIR spectra, several characteristic peaks disappear in the Cu: 4AS: CD nanoparticles, indicating strong interactions between 4AS and copper nanoparticles. The ¹H NMR spectra show both upfield and downfield shifts of 4AS proton signals support strong coordination of 4AS with copper in the CD-based nanomaterials.
Abstract: The spectral properties of the copper–4-anisidine–cyclodextrin (Cu: 4AS: CD) nanomaterial were examined using absorption, fluorescence, time-resolved fluorescence, SEM, DSC, FTIR, XRD, ¹H NMR, and molecular modeling techniques. The distinct spectral variations observed for 4AS upon adding α-CD and β-CD at different pH values indicate that the resul...
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Research Article
Chemical Removal of Toxic Heavy Metals in Acid Mine Drainage Using Hydrazine as Reductant
Issue:
Volume 14, Issue 2, April 2026
Pages:
30-41
Received:
10 April 2026
Accepted:
28 April 2026
Published:
12 May 2026
DOI:
10.11648/j.ajac.20261402.12
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Abstract: Acid mine drainage (AMD) wastewater generated from coal field mining activities going on in Mpumalanga Province in Republic South Africa contained toxic heavy metals which is harmful to human health and the environment, as it is required to be removed before discharged into the natural water body. The aim of this study is to remove toxic heavy metals (Hg, Th, Cr, Mn, Pb, As, Cd and Ba) from AMD using hydrazine (N2H2) as reductant. Chemical reduction method was used to remove the toxic heavy metals. Physicochemical analysis was carried out on the mine wastewater. Digestion method was also conducted on the acid mine wastewater. Quantification techniques used in this study are inductively coupled plasma optical emission spectroscopy (ICP-OES), ion chromatography (IC), X-ray diffraction (XRD), X-ray Fluorescence (XRF), transmission electron microscopy (TEM), FTIR and scanning electron microscopy energetic dispersion spectroscopy (SEM-EDS). The results of the maximum concentration and percent removal of heavy metals removed in the AMD using 1.0 M of N2H2 reductant solution are Hg (0.00019 mg/L, 82.49%), Th (3E-06 mg/L, 99.98%), Cr (0.0078 mg/L, 96.53%), Mn (22.31 mg/L, 82.54%), Pb (0.0004 mg/L, 89.04%), As (0.0009 mg/L, 98.32%), Cd (0.0028 mg/L, 99.09%), and Ba (0.0021 mg/L, 92.00%). The results of the maximum contact time of 120 minutes and percent removal of heavy metals removed in the AMD are Hg (0.00012 mg/L, 89.17%), Th (0.0014 mg/L, 92.49%), Cr (0.013 mg/L, 94.34%), Mn (10.53 mg/L, 91.68%), Pb (0.002 mg/L, 94.91%), As (0.005 mg/L, 90.93%), Cd (0.014 mg/L. 95.37%), and Ba (0.002 mg/L, 90.90%). The optimum concentration was 0.6 M NaBH4 reductant solution and contact time was 30 minutes. The concentration removal of the heavy metals in the treated AMD revealed that the maximum concentrations of some metals are within the WHO while the others are above WHO limits. In conclusion, N2H4 reductant removed most of the toxic heavy metals effectively in the AMD solution with brownish precipitate formed without generating sludge was identified to be Fe0 nanoparticles.
Abstract: Acid mine drainage (AMD) wastewater generated from coal field mining activities going on in Mpumalanga Province in Republic South Africa contained toxic heavy metals which is harmful to human health and the environment, as it is required to be removed before discharged into the natural water body. The aim of this study is to remove toxic heavy meta...
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,
Ayyadurai Mani
