Preparation of PEI/La2O3/Polypropylene fiber filter for household water purifiers and investigation of its phosphate reduction and bacterial control

Abstract

It has been accepted that limiting phosphate is a prerequisite for bacterial inactivation in tap water. La2O3 nanoparticles were loaded onto polypropylene (PP) fibers through the method of melt spinning. Hydrophilic modification of the adsorbent surface was performed using polyethyleneimine (PEI) to prepare PEI/La2O3/PP. The results indicated that the optimal loading amount of La2O3 was 1 %, and the optimal concentration of PEI was 1 %. The successful loading of La2O3 resulted in a roughened fiber surface and increased fiber diameters. After PEI modification the water contact angle was reduced from 98° to 50°. The pHzpc of PEI/La2O3/PP was determined to be 8.3. The co-existing ions have little effect on phosphate adsorption. Phosphate adsorption can be well described by Redlich-Peterson model with a maximum KR-P of 3.98 × 10−5 L/mg. Adsorption kinetics fit well with the pseudo-second-order reaction equation. The activation energy (Ea) is determined to be 57.9 kJ/mol, providing the evidence of chemical nature of the reaction involving phosphate ions on the surface of PEI/La2O3/PP. The PEI/La2O3/PP adsorbent can reduce the phosphate concentration in tap water to below 0.01 mg/L, leading to a reduction in Escherichia coli concentration from approximately 10,000 CFU/mL to around 10 CFU/mL. The survival rates of Escherichia coli in a multi-nutrient environment are higher than in a single phosphate source environment. Our research provides a new feasible approach for ensuring microbial water quality safety in household water purifiers.