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This study investigated the solvent effect on the synthesis of Zinc Oxide (ZnO) nanoparticle using sol-gel method. Zinc acetate dihydrate and oxalic acid were used as a chemical precursor for the synthesis of the ZnO nanoparticle considering the effects of various solvents. The effect of using water, propanol, or ethanol as solvent during the synthesis were examined. The resultant gel in the aqueous and organic moderate solvent was thermally cracked into ZnO nanoparticles at 450 °C under atmospheric pressure. The results showed that the solvent type has a significant effect on the morphology and particles size of the ZnO nanoparticles synthesized. Atomic Force Microscopy (AFM) was used to investigate the microstructure of the nanoparticles. The crystalline and chemical structure of the prepared ZnO nanoparticle were studied by X-ray diffraction (XRD) and Fourier Transform Infrared spectroscopy (FTIR). The average diameter of nano-size particles obtained for ethanol, propanol and water are 79.55 nm, 83.86 nm and 85.59 nm, respectively. ZnO particles showed higher degree of crystalline in water compared to other solvents under current investigation. Copyright © 2021 by Authors, Published by BCREC Group. This is an open access article under the CC BY-SA License (https://creativecommons.org/licenses/by-sa/4.0).

Diglycidyl ether of bisphenol A (DGEBA) epoxy resin was cured with hardeners aliphatic amine triethylenetetramine (TETA). Differential scanning calorimetry (DSC) technique was utilized to study the kinetics of cure of (DGEBA)-(TETA) system, diverse hardener/resin ratios were studied, (5, 13and 20) phr. Isothermal as well as dynamic experiments were carried out of the above mentioned DGEBA/TETA system with three hardener/resin ratios, and cure kinetics were investigated at four temperatures (30, 45, 60 and 80) °C using (DSC) technique. The process of isothermal cure was simulated by the diffusion model (modified Kamal's model and four-parameter autocatalytic model. The obtained outcomes are in good agreement with the experimental results in the early and late cure stages. The events declare that complete cure at 80 °C attains at the stoichiometric ratio (13 phr).

This work integrates nanotechnology, adsorption, and magnetic separation to remove chromium (Cr) pollutant from industrial wastewater using magnetic nanoparticles. The magnetic nanocomposite consists of chitosan biopolymer and iron (Fe 3 O 4 ) magnetic nanoparticles. The Fe 3 O 4 magnetic nanoparticles were prepared by chemical co-precipitation technique and the chitosan magnetic nanocomposite (CMNC) was prepared by Ex situ process. Moreover, anoval amination of CMNC with hexamine to get functionalized CMNC was performed to remove Cr (VI) in wider range of pH. The prepared Fe 3 O 4 magnetic nanoparticles, CMNC and functionalized CMNC were characterized using different analytical techniques, XRD, FTIR, AFM, SEM, EDX and TGA.Batch adsorption was employed to determine the effects of pH. The adsorption results show that the functionalized CMNC possessed high activity for Cr (VI) removal in any condition of acidic, neutral and basic solutions with the percentage sorption of chromium reached to 91.7%.Sorption isotherms were fitted with the Langmuir, Freundlich and Temkin models, it was found that the Freundlich isotherm model have the best fit with R 2 =0.998 with functionalized CMNC. The kinetic data of Cr (VI) sorption with functionalized CMNC were fitted well with the pseudo-second order kinetic model. The reuse of the functionalized CMNC indicates that the adsorbent material is more than 80% adsorption capacity after five regeneration cycles. The results of this work shown that functionalized CMNC is a potential adsorbent to removal of Cr (VI) contaminated in a wider range of pH. Fig. 2(a) The infrared spectrum of Fe 3 O 4 magnetic nanoparticles. (b) The infrared spectrum of CMNC.(c) The infrared spectrum of functionalized CMNC.