Photocatalytic disinfection is a promising technology with low cost and high efficiency. However, most of the current studies on photocatalytic disinfection ignore the widespread presence of natural organic matter (NOM) in water bodies, so the incomplete conclusions obtained may not be applicable. Herein, this paper systematically studied the influence of humic acid (HA), one of the most important components of NOM, on the photocatalytic inactivation of bacteriophage f2 with electrospinning Cu-TiO 2 nanofibers. We found that with the addition of HA, the light transmittance of the solution at 550 nm decreased from 94 to 60%, and the band gap of the photocatalyst was increased from 2.96 to 3.05 eV. Compared with reacting without HA, the degradation amount of RNA of f2 decreased by 88.7% after HA was added, and the RNA concentration increased from 1.95 to 4.38 ng·μL −1 after the reaction. Hence, we propose mechanisms of the effect of HA on photocatalytic disinfection: photo-shielding, passivation of photocatalysts, quenching of free radicals, and virus protection. Photo-shielding and photocatalyst passivation lead to the decrease of photocatalyst activity, and the reactive oxygen species (ROSs) (·OH, ·O 2 − , 1 O 2 , H 2 O 2 ) are further trapped by HA. The HA in water also can protect the shape of phage f2 and reduce the leakage of protein and the destruction of ribonucleic acid (RNA). This work provides an insight into the mechanisms for the influence of HA in photocatalytic disinfection process and a theoretical basis for its practical application.
Rong Cheng,Mi Kang,Zhi-peng Shen,Lei Shi,Xiang Zheng
Pathogenic viruses in drinking water are great threats to public health. Visible-light-driven photocatalysis is a promising technology for virus inactivation. However, the existing photocatalytic antiviral research studies have mostly been carried out in single-component systems, neglecting the effect of natural organic matter, which exists widely in actual water bodies. In this paper, electrospun Cu-TiO 2 nanofibers were prepared as photocatalysts, and their photocatalytic antiviral performance in the presence of humic acid (HA) was comprehensively studied for the first time. The properties of the reaction mixture were measured during the reaction. In addition, the safety, reliability and stability of photocatalytic disinfection in the mixed system were evaluated. The results showed that the virus removal efficiency decreased with the increase of the HA concentration. The type of reaction solution, such as PBS buffer solution or water, did not affect the removal efficiency noticeably. Under acidic conditions, the electrostatic forces between photocatalysts and viruses were strengthened, leading to higher virus removal efficiency. As the reaction time went on, the pH value in the solution increased first and then tended to be stable, the conductivity remained stable, and the dissolved oxygen increased first and then decreased. The safety test showed that the concentration of Cu ions released into the solution was lower than specified by the international standards. No photoreactivation was observed, and the addition of HA significantly reduced the reutilization efficiency of the photocatalysts.
危险品化学品经营许可证（带存储）