آب و فاضلاب (Nov 2020)
Separation of Reactive Red 120 Dye from Aqueous Solution by NiFe2O4-SiO2/PVDF Nanocomposite Membranes
Abstract
The discharge of dye-containing wastes by the dye-consuming industry causes irreparable damage to the environment and humans. Nowadays, the use of membrane separation technology is a new and applicable technology in dyes separation. However, membranes used in water and wastewater treatment suffer from problems such as permeability-selectivity trade-off as well as short life due to fouling. Therefore, in this study, we tried to improve the hydrophilicity and antifouling properties of polyvinylidene fluoride (PVDF) membranes by adding NiFe2O4-SiO2 nanocomposite and improve its performance in reactive dye separation from aqueous solution. For this purpose, first NiFe2O4-SiO2 nanoparticles were prepared by sol-gel method and then pure and NiFe2O4-SiO2/PVDF nanocomposite membranes were fabricated by wet phase inversion method and their performance was evaluated. The synthesized nanoparticles were characterized by X-ray diffraction (XRD) and Fourier transform infrared spectroscopy (FTIR) methods. Membranes morphology, surface roughness, hydrophilicity of the membrane surface, separation performance, pure water flux, porosity and pore radius were characterized by field emission scanning electron microscopy (FESEM), atomic force microscopy (AFM), contact angle tests (CA), pure water flux test (PWF) and gravimetric methods, respectively. Aqueous solution containing 10-30 ppm reactive red 120 was used as test wastewater. The results of the contact angle analysis showed that by addition of 0.3 wt.% NiFe2O4-SiO2 nanoparticles to the polymer matrix, the membrane contact angle decreased from from 77.5° in the pure membrane to 51.7° in the nanocomposite membrane. It showed an increase in membrane hydrophilicity. AFM results showed that the surface roughness decreased as NiFe2O4-SiO2 content increased in PVDF matrix. It was also found that nanocomposite membrane containing 0.3 wt.% NiFe2O4-SiO2 nanoparticles has the best separation performance among the other fabricated membranes and this membrane can reject reactive red 120 dye from aqueous solution completely (99.5%).
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