Nanocomposite TiO2/ASS (TiO2 nanoparticle coated sewage sludge-based activated carbon) was synthesized by the sol-gel method. The changes in surface properties of the TiO2/ASS nanocomposite were characterized by X-ray diffraction (XRD), scanning electron microscope (SEM) and X-ray fluorescence. The prepared TiO2/ASS nanocomposite was applied for simultaneous removal of methyl orange dye (MO) and Cd2+ from bi-pollutant solution. The factors influencing photocatalysis (TiO2 : ASS ratios, initial pollutant concentrations, solution pH, nanocomposite dosage and UV irradiation time) were investigated. The results revealed that high removal efficiency of methyl orange dye (MO) and Cd2+ from bi-pollutant solution was achieved with TiO2/ASS at a ratio (1 : 2). The obtained results revealed that degradation of MO dye on the TiO2/ASS nanocomposite was facilitated by surface adsorption and photocatalytic processes. The coupled photocatalysis and adsorption shown by TiO2/ASS nanocomposite resulted in faster and higher degradation of MO as compared to MO removal by ASS adsorbent. The removal efficiency of MO by ASS adsorbent and TiO2/ASS (1 : 2) nanocomposite at optimum pH value 7 were 74.14 and 94.28%, respectively, while for Cd2+ it was more than 90%. The experimental results fitted well with the second-order kinetic reaction.
We report the one‐pot synthesis of ball‐like nanosphere structures composed of an α‐Fe core and an organic shell of ethylenediaminetetraacetic acid that connected together to form a nanochain necklace‐like morphology. The hierarchical zigzag nanochain sphere structures have branches growing in clumps, a large surface area, and spherical pore‐like cages and entrances for capture/trapping Cd2+ ions from water sources. The pH solution (i.e., at pH 5) plays a key role in the generation of actively negative surfaces along the entire nanochain sphere adsorbent, thereby creating surfaces with strong binding affinity to Cd2+ ions. The thermodynamic and kinetic characteristics indicated that the nanochain sphere adsorbent with macro‐ and meso‐cage caves and organically decorated surfaces show promise for the spontaneous and endothermic capturing of Cd2+ ion containments from water solutions. The zigzag nanochain mesoporous necklace‐like structure trapper (MNT) exhibited long‐term stability, indicating that it can be used several times (reduced waste volume). The adsorption efficiency and uptake of the deleterious Cd2+ ions retained even after multi‐particulate processing of reuse cycles. The pH‐dependent Cd2+ ion selectivity indicated high adsorption capacity (526.3 mg⋅g−1) and Cd2+ ion‐to‐MNT binding affinity, despite the addition of interfering cations or anions. The zigzag nanochain sphere necklace allows the development of a simple and effective adsorbent model for water purification and management of toxins.
Abstract. The UV-visibie spectra of some azo compounds derived from 3-amino-l,2,4-triazole and various active-methylene or active-hydrogen compounds have been investigated in organic solvents of different polarities. The spectral bands obtained are assigned to the possible electronic transitions. It was found that the azo compounds containing the acetylacetone moiety exist mainly in the hydrazone form, while those containing ethylcyanoacetate, c~ or [3-naphthol substituents exist in an azo ~ hydrazone tautomeric equilibrium in solution. The extra visible band exhibited in the spectra of o-hydroxyazo compound is assigned to an intermolecular electronic transition. The spectral shifts observed in the various organic solvents are discussed on the basis of the solute-solvent interaction through the formation of hydrogen bonds with different species. The variation of the absorbance with pH is employed to determine the acid dissociation constants.
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