C HEMICAL modification of poly(vinyl chloride), PVC, was performed via its substitution reaction with 6-amino-2-thioxo-tetrahydropyrimidin-4-one (1) and three of its derivatives (1A-C). The chemical structures of the modified PVC samples have been confirmed via FTIR and 1 HNMR spectroscopic analyses. Photostability of the modified PVC were investigated by following the rates of dehydrochlorination of the 6-aminopyrimidine derivatives modified PVC samples conductometrically in comparison with both blank PVC and that stabilized with 2-hydroxy-4-(octyloxy)-phenyl-benzophenone as reference UV absorber. Moreover, thermal stability as well as physicomechanical properties of all investigated PVC samples have also been determined. Modified PVC samples exhibited enhanced photo and thermal stability as well as mechanical properties when compared to the blank unmodified sample. Antimicrobial properties of the tested PVC samples were explored against Gram +ve bacteria (Staphylococcus aureus), Gram-ve bacteria (Escherichia coli) as well as A. flavus and C. albicans as fungi. However, incorporation of 6-aminopyrimidine derivatives to the PVC backbone chains enhanced their inhibitory effect against the examined microorganisms.
m-Phenylenediamine was condensed with furfural in absence of catalyst at room temperature. The producedm-phenylenediamine-furfural resin was used for the removal of Cu(II) from aqueous solution. The pH for the optimum removal of Cu(II) was 6. The negative values of Gibbs free energy at low concentration of Cu(II) (20, 30 ppm) indicative of the spontaneous adsorption process, while, at higher Cu(II) concentration (40,50 ppm) the positive and weak values of ∆G° indicate that the process is feasible but non spontaneous. The values of ∆H° were positive indicating that the sorption process is endothermic. On the other hand, the values of activation energy (Ea) were inconsistent with the values of ∆H° both are positive and lie in the range of physisorption. The entropy ∆S° of the process was positive indicative of the randomness of the Cu(II) ions at the solid / liquid interface. The values of sticking probability S* were less than one which indicate a preferable adsorption process and the mechanism is physisorption.
In this work, an attempt was made to modify natural cellulose powder via three steps process; oxidation by potassium periodate followed by condensation with aminoguanidine and eventually reaction with phenyl isothiocyanate. The modified cellulose (PhGu-MC) was characterized by several techniques including Fourier transform infrared spectra (FTIR), scanning electron microscope (SEM), and elemental analysis (EA), Brunauer–Emmett–Teller analysis (BET) and thermogravimetric analysis (TGA). The modified cellulose (PhGu-MC) was used as an adsorbent for Cu2+, Hg2+ and Pb2+ from aqueous solution and environmental water samples. Effects of various factors on the adsorption efficiency were investigated including pH, initial metal concentration, contact time, adsorbent dose, temperature and interfering ions on adsorption was investigated to estimate the optimum adsorption conditions. At optimum adsorption conditions, the adsorption capacities of Cu2+, Hg2+ and Pb2+ were found to be 50, 94 and 55 mg.g−1, respectively. The adsorption process was, well described by the Langmuir model, and it was found to follow the pseudo-second-order kinetic model. The synthesized (PhGu-MC) has revealed significant potential towards heavy metal removal from environmental water samples.
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