Flexible electronics for heavy metal ion detection in water: a comprehensive review.

Flexible electronics offer a versatile, rapid, cost-effective and portable solution to monitor water contamination, which poses serious threat to the environment and human health. This review paper presents a comprehensive exploration of the versatile platforms of flexible electronics in the context of heavy metal ion detection in water systems. The review overviews of the fundamental principles of heavy metal ion detection, surveys the state-of-the-art materials and fabrication techniques for flexible sensors, analyses key performance metrics and limitations, and discusses future opportunities and challenges. By highlighting recent advances in nanomaterials, polymers, wireless integration, and sustainability, this review aims to serve as an essential resource for researchers, engineers, and policy makers seeking to address the critical challenge of heavy metal contamination in water resources. The versatile promise of flexible electronics is thoroughly elucidated to inspire continued innovation in this emerging technology arena.

Stable and rapid partial nitrification achieved by boron stimulating autoinducer-2 mediated quorum sensing at room & low temperature.

The stable and rapid initiation of partial nitrification is a long-term interest of researchers. In this study, boron, an activator of autoinducer-2 (AI-2), was first proposed to promote partial nitrification and improve sludge properties. Two concentrations of boron were added to six laboratory-scale nitrification reactors to study the effects of boron stimulated AI-2-mediated quorum sensing on nitrification at room and low temperature. Boron could significantly increase the concentration of AI-2 in the reactor (p < 0.05), and the high concentration of boron showed better performance at two temperatures. The realization of partial nitrification was mainly due to the accumulation of NO2-- N promoted by the increase of AI-2 concentration. NO2-- N accumulation occurred in all the boron-treated reactors, while no NO2-- N accumulation occurred in the reactor without boron at room temperature or the accumulation efficiency was 14% lower at low temperature. Community analysis and qPCR further confirmed that exogenous boron had no significant effect on AOB, but inhibited NOB, especially at room temperature. The changes of EPS were slightly different at the two temperatures: at room temperature, boron increased the total EPS production, while at low temperature it mainly changed the PN/PS value of EPS. It was worth noting that the effect of boron on partial nitrification depended not only on its concentration, but also on NH4+-N concentration and temperature. This study provided a new strategy for the rapid and stable initiation of partial nitrification process.