Surface and internal modification of composite ion exchange membranes for removal of molybdate, phosphate, and nitrate from polluted groundwater

Abstract

Al2O3/chitosan-multiwall carbon nanotubes (MWCNTs) were created to increase the exchange capacity of polyvinylidene fluoride (PVDF) ion-exchange membranes. The composite membranes were made by mixing Al2O3 nanoparticles into the PVDF cast solution, then applying a thin coating of chitosan functionalized carbon nano tubes (Cs-MWCNTs) to the PVDF membrane surface. The structure and characteristics of the hybrid membranes were described using XRD, SEM, IR, and TG-DTA. The Al2O3-PVDF/Cs-MWCNTs membrane beat the other Al2O3-PVDF/Cs, Al2O3-PVDF, and PVDF membranes in terms of molybdate, phosphate, and nitrate adsorption. The removal efficiency, pH solution, adsorption capacity, and desorption process of molybdate, phosphate, and nitrate anions by Al2O3-PVDF and PVDF membranes were investigated. The removal effectiveness of molybdate, phosphate, and nitrate, according to the testing findings, was 94.3, 65.6, and 85.78 %, respectively. The adsorption of MoO42−, PO43−, and NO3− increased as the pH increased initially until the best adsorption was achieved, and then decreased significantly as the pH increased further. The total adsorption capabilities of MoO42−, PO43−, and NO3−for the Al2O3-PVDF/Cs-MWCNTs membrane were 65.50, 61.22, and 59.77 mg/g, respectively. Using regeneration and reuse experiments for the simultaneous adsorption of molybdate, phosphate, and nitrate during three consecutive cycles, the adsorption/desorption of Al2O3-PVDF/Cs-MWCNTs was assessed. Al2O3-PVDF/Cs-MWCNTs offer a lot of promise when it comes to eliminating MoO42−, PO43−, and NO3−from actual wastewater samples.

Keywords

• Nanocomposite
• Ion-exchange membranes
• Adsorption
• Polluted groundwater