Removal of bacteriophage f2 in water by nanoscale zero-valent iron and parameters optimization using response surface methodology

Abstract

The presence of pathogenic enteric viruses in water poses a significant risk to human health. Nanoscale zero-valent iron (NZVI) has recently been proposed for various environmental remediation due to its unique characteristics. Bacteriophage f2, which is similar to human enteric pathogenic virus, was used as the model virus to study the virus removal efficiency in the water by NZVI in this study. Response surface methodology (RSM), based on a three-level, four-variable Box–Behnken design, was applied to optimizing the experimental parameters. The results revealed that NZVI showed a brilliant ability in terms of removing bacteriophage f2 and was definitely more efficient than commercial iron particles. The removal rate was increased with the increase of NZVI dose and rotation rate, but decreased with the increase of pH value and virus concentration. The removal process involved reversible adsorption. The bacteriophage f2 with a lower concentration was more sensitive to acid condition. The determination coefficient (R2) for data fitting was 97.66%, which indicated that the model was adequate for prediction. The interaction between NZVI dose and rotation rate had a significant effect on the removal rate of virus, as well as the four independent variables. The optimum values of experimental parameters were as follows: pH value: 5.12, NZVI dose: 49.07 mg L−1, virus concentration: 3.5 × 106 PFU/mL, rotation rate: 148.75 rpm. Under this condition, 5.51 log removal was achieved, which was in close agreement with the value predicted from the proposed model.