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Matrix hybrid membranes, based on polyvinylidene fluoride (PVDF), poly (N-vinylpyrrolidone) (PVP), silica gel (SG) and zinc oxide (ZnO) were synthesized by phase inversion via immersion precipitation method. The characterization of membrane samples was performed using Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), optical microscopy, contact angle, porosity, mean pore size and water permeability measurements. The FTIR analysis showed the appearance of new bands attributed to the functional groups of SG and ZnO. The XRD analysis confirmed a modification in the structure of membranes. The prepared membranes were used for the removal of hexavalent chromium (Cr(VI)) from aqueous solution. Membrane filtration experiments show that the water permeability and Cr(VI) rejection ratios increase with increasing the weight ratio ZnO (%)/SG (%). The maximum values of the Cr(VI) rejection rate and water permeability were respectively 85% and 685 L/m2hbar for weight ratios (0.75% of ZnO/0.25% of SG). [ABSTRACT FROM AUTHOR]

The objective of this research is to manufacture new filter pellets based on polyacrylamide (PAM) activated carbon (GAC), iron oxide (Fe2O3), zinc oxide (ZnO) and kaolin and to evaluate their effectiveness in removing chromium and nickel from water. The synthesized filter pellets were characterized by FTIR, XRD and X-ray fluorescence. The XRF validation method would involve known amounts of chromium and nickel being retained by the filter pellets. the application of XRF gave precise measurements of the concentrations of Cr(VI) and Ni(II) fixed in the filter pellets. It was found that the values of the retention rates of Cr(VI) ions are higher in comparison with Ni(II) ions .The inclusion of inorganic additives influences the ability of filter pellets (FP) to retain Cr(VI) and Ni(II). FP2 (ZnO) showed reduced retention for both ions in comparison to FP1 (Fe2O3) and FP3 (Kaolin). FP3 (Kaolin) displayed better retention capacities for Cr(VI) and Ni(II) ions. The conductometric approach was also used to evaluate the retention of ions by the filter pellets. Comparing the conductivity of the feed solution with that of the filtered solution and the comparison between the different materials provided information on the most effective filter pellets for this purpose. [ABSTRACT FROM AUTHOR]