ABSTRACT
As a result of the 2019 coronavirus pandemic, disinfection byproducts generated by the extensive use of chlorine disinfectants have infiltrated the aquatic environment, severely threatening ecological safety and human health. Therefore, the accurate monitoring of the biotoxicity of aqueous environments has become an important issue. Biocathode sensors are excellent choices for toxicity monitoring because of their special electroautotrophic respiration functions. Herein, a novel electroautotrophic biosensor with rapid, sensitive, and stable response and quantifiable output was developed. Its toxicity response was tested with typical disinfection byproducts dichloromethane, trichloromethane, and combinations of both, and corresponding characterization models were developed. Repeated toxicity tests demonstrated that the sensor was reusable rather being than a disposable consumable, which is a prerequisite for its long-term and stable operation. Microbial viability confirmed a decrease in sensor sensitivity due to microbial stress feedback to the toxicants, which is expected to be calibrated in the future by the standardization of the biofilms. Community structure analysis indicated that Moheibacter and Nitrospiraceae played an important role in the toxic response to chlorine disinfection byproducts. Our research provides technical support for protecting the environment and safeguarding water safety for human consumption and contributes new concepts for the development of novel electrochemical sensors.
ABSTRACT
Till now, the unprecedented global spread of novel coronavirus disease (nCOVID-19) threatened human health, economy as well as ecosystem services gravely. An efficient disinfection technology is highly demanded. Ultraviolet (UV)/H2O2 process seems like a potential candidate, in which H2O2 is an indispensable oxidant for HO· species production. In this work, UV/H2O2, which coupled with in-situ generated H2O2, was demonstrated as an effective process for disinfection than UV, which would play a significant role in sterilization and disinfection for water treatment. In addition, we investigated the effects of catalyst layer (CL) calcination on the performance of two-electron oxygen reduction reaction (ORR) for H2O2 generation. It is found that the two-electron ORR activity can be intensified by avoiding calcination of CL, which can be mainly due to much oxygen functional groups (C − O and C = O) as well as higher conductivity and reaction kinetics.