Preparation and Characterization of Chitosan/TiO2 Composite Membranes as Adsorbent Materials for Water Purification

Abstract

As it is used in all aspects of human life, water has become more and more polluted. For the past few decades, researchers and scientists have focused on developing innovative composite adsorbent membranes for water purification. The purpose of this research was to synthesize a novel composite adsorbent membrane for the removal of toxic pollutants (namely heavy metals, antibiotics and microorganisms). The as-synthesized chitosan/TiO2 composite membranes were successfully prepared through a simple casting method. The TiO2 nanoparticle concentration from the composite membranes was kept low, at 1% and 5%, in order not to block the functional groups of chitosan, which are responsible for the adsorption of metal ions. Nevertheless, the concentration of TiO2 must be high enough to bestow good photocatalytic and antimicrobial activities. The synthesized composite membranes were characterized by Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), scanning electron microscopy (SEM), thermogravimetric analysis (TGA) and swelling capacity. The antibacterial activity was determined against four strains, Escherichia coli, Citrobacter spp., Enterococcus faecalis and Staphylococcus aureus. For the Gram-negative strains, a reduction of more than 5 units log CFU/mL was obtained. The adsorption capacity for heavy metal ions was maximum for the chitosan/TiO2 1% composite membrane, the retention values being 297 mg/g for Pb2+ and 315 mg/g for Cd2+ ions. These values were higher for the chitosan/TiO2 1% than for chitosan/TiO2 5%, indicating that a high content of TiO2 can be one of the reasons for modest results reported previously in the literature. The photocatalytic degradation of a five-antibiotic mixture led to removal efficiencies of over 98% for tetracycline and meropenem, while for vancomycin and erythromycin the efficiencies were 86% and 88%, respectively. These values indicate that the chitosan/TiO2 composite membranes exhibit excellent photocatalytic activity under visible light irradiation. The obtained composite membranes can be used for complex water purification processes (removal of heavy metal ions, antibiotics and microorganisms).

Facile synthesis and characterization of magnesium and manganese mixed oxides for the efficient removal of tartrazine dye from aqueous media

“…The concentration of the tartrazine dye was measured at 428 nm using a Shimadzu UV-1650 PC UV/Vis spectrophotometer. The effects of pH (2)(3)(4)(5)(6)(7)(8)(9)(10)(11)(12), contact time (5-90 min), concentration of the tartrazine (150-300 mg L −1 ), and temperature (298-328 K) were investigated.…”

“…The effect of temperature on the removal of tartrazine dye using the G500, G700, and G900 adsorbents can be represented by determining the thermodynamic parameters such as change in free energy (DG°, kJ mol −1 ), change in entropy (DS°, kJ mol −1 K −1 ), and change in enthalpy (DH°, kJ mol −1 ) using eqn (5)- (7). 28 Fig.…”

“…For wastewater treatment, different chemical and physical processes, like coagulation, sedimentation, ozonation, ultrasonication, photocatalysis, membrane separation, adsorbent polymer-based composites, strong photocatalysts, and adsorption, have been used alone or in combination. [7][8][9][10][11][12][13][14][15] However, adsorption is the most important method for removing non-degradable and persistent pollutants from wastewater because it is more economically and ecologically advantageous than other methods. [16][17][18][19][20][21][22] Nanomaterials had attracted considerable interest in the area of adsorption because of their unique characteristics of small size, enhanced porosity, and increased surface area.…”

Antibacterial Activity of Solvothermal Obtained ZnO Nanoparticles with Different Morphology and Photocatalytic Activity against a Dye Mixture: Methylene Blue, Rhodamine B and Methyl Orange

“…The use of nanomaterials for water purification is still in its infancy. The most promising nanomaterials are those that exhibit photocatalytic and antimicrobial activities [ 9 ]. Such nanomaterials could achieve two processes, removing the organic pollutants and killing pathogenic microorganisms, under visible light irradiation, in a single step.…”

Synthesis and Characterization of SPIONs Encapsulating Polydopamine Nanoparticles and Their Test for Aqueous Cu2+ Ion Removal

“…Many pollutants are not biodegradable and extremely toxic and can accumulate in living organisms, meaning, ultimately, that they are dangerous, not only for the environment but also for human health, as they may be responsible for several diseases, including cancer, neurological disorders, respiratory diseases and anemia [ 1 , 2 , 3 , 4 ]. Many physical-chemical methods have been developed and applied for removing water pollutants, including adsorption, photocatalytic degradation, ion exchange, biological treatment, membrane separation, solvent extraction and chemical precipitation [ 3 , 4 , 5 , 6 , 7 , 8 , 9 ]. Among the different approaches, adsorption is one of the most used methods due to its cost effectiveness, easy operation and high efficiency for the treatment of water contaminated by heavy metals and other emergent pollutants, including phenolic compounds, drugs and dyes [ 10 , 11 , 12 , 13 ].…”