Analysis of direct drinking water quality and its influencing factors in primary and secondary schools in Nanjing City / 中国学校卫生

Objective@#To investigate the quality and influencing factors of direct drinking water in schools in Nanjing City, so as to provide basis for management of school drinking water.@*Methods@#From April to July 2023, direct drinking water equipment from 146 primary and secondary schools were selected from Nanjing City using a stratified random sampling method and tested for colony forming units (CFU) and permanganate index. Mann-Whitney U test was used to compare the differences between groups, and multiple linear regression was used to analyze the influencing factors.@*Results@#The CFU and permanganate levels of school direct drinking water in Nanjing City were 1.00(0.00,15.50)CFU/mL and 0.47(0.26, 0.75)mg/L, respectively. The CFU level increased when the filter replacement time exceeded 3 months and when the water source was piped, while the permanganate index increased when the filter replacement time exceeded 3 months and using activated carbon technology ( Z =-2.21, -3.92, -2.31, -8.45 , P <0.05). The results of multiple linear regression analysis showed that the replacement time of filter element exceeding 3 months was positively correlated with the CFU level, and the process type involving activated carbon, a laid pipe network and a filter replacement time exceeding 3 months were positively correlated with the permanganate index( β =167.08, 0.32, 0.35, 0.11, P ＜0.05).@*Conclusions@#There are certain problems with the water quality of primary and secondary school direct drinking water in Nanjing City. Schools should promptly replace the filter and maintain the drinking water equipment to ensure the hygiene and safety of campus water quality.

In situ plasmonic Ag nanoparticle anchored TiO2 nanotube arrays as visible-light-driven photocatalysts for enhanced water splitting.

An ultrasonication-assisted in situ deposition strategy was utilised to uniformly decorate plasmonic Ag nanoparticles on vertically aligned TiO2 nanotube arrays (NTAs) to construct a Ag@TiO2 NTA composite. The Ag nanoparticles act as efficient surface plasmon resonance (SPR) photosensitizers to drive photocatalytic water splitting under visible light irradiation. The Ag nanoparticles were uniformly deposited on the surface and inside the highly oriented TiO2 nanotubes. The visible-light-driven hydrogen production activities of silver nanoparticle anchored TiO2 nanotube array photocatalysts were evaluated using methanol as a sacrificial reagent in water under a 500 W Xe lamp with a UV light cutoff filter (λ ≥ 420 nm). It was found that the hydrogen production rate of the Ag@TiO2 NTAs prepared with ultrasonication-assisted deposition for 5 min was approximately 15 times higher than that of its pristine TiO2 NTAs counterpart. The highly efficient photocatalytic hydrogen evolution is attributed to the SPR effect of Ag for enhanced visible light absorption and boosting the photogenerated electron-hole separation/transfer. This strategy is promising for the design and construction of high efficiency TiO2 based photocatalysts for solar energy conversion.