Proof-of-concept for chemiresistive water quality sensors: free chlorine in drinking water; ammonia in wastewater

水对我们的生活是必不可少的。我们从环境中提取水，将其用于各种目的，然后将其排放回环境中。时刻保持水质是非常重要的。例如，我们的饮用水需要通过保持残留消毒剂水平来保持在整个分配系统中没有病原体。游离氯是用于这一目的的一种常见消毒剂，因为它在杀灭病原体方面很有效，尽管它不太稳定，在饮用水分配过程中很容易耗尽。这就是为什么需要在配电系统的多个点进行持续在线监测的原因。对排放到环境中的废水进行监测也同样重要。虽然它不会立即被人类消费，但它可能会严重影响排放点或其下游的生态系统。在大多数情况下，废水最终会通过其他饮用水系统的取水口。废水中的氮含量，特别是以氨水形式存在的氮，尤其令人关注。因此，氨传感器通常被部署在废水处理厂。作为Aztec和Navigator系列连续水分析仪的一部分，我们的工业合作伙伴ABB正在制造和分销游离氯和氨传感器。这些设备主要依靠比色传感器和电化学传感器。虽然ABB已经成功地减少了他们的比色传感器的试剂消耗，但它们仍然需要定期维护才能重新灌装。电化学传感器通常是无试剂的，但仍然受到其参比电极耐用性的限制。该提案旨在开发用于ABB在线分析仪的麦克马斯特化学抗性技术。

Water is essential to our life. We take water from the environment, consume it for various purposes, and discharge it back into the environment. Maintaining water quality at all times is very important. Our drinking water, for example, needs to be kept free from pathogens throughout the distribution system by maintaining residual disinfectant levels. Free chlorine is a common disinfectant used for that purpose because it is effective at killing pathogens, even though it is not very stable and can easily deplete during drinking water distribution. This is why continuous online monitoring is desirable at multiple points along the distribution system. Monitoring of wastewater during its discharge into the environment is similarly important. While it is not destined for immediate human consumption, it can severely impact the ecosystem at the discharge site, or downstream of it. In most cases, wastewater will eventually pass by the intake sites of other drinking water systems. The nitrogen content of wastewater, in especially in the form of aqueous ammonia, is of particular concern. Thus, ammonium sensors are commonly deployed at wastewater plants. Both free chlorine and ammonia sensors are being manufactured and distributed by our industrial partner ABB as part of the Aztec and Navigator series of continuous water analyzers. These devices mainly rely on colorimetric and electrochemical sensors. While ABB has succeeded in reducing the reagent consumption of their colorimetric sensors, they nevertheless require periodic maintenance for refills. Electrochemical sensors are typically reagentless, but nevertheless limited by the durability of their reference electrodes. This proposal aims to develop McMaster's chemiresistive technology for use in ABB's online analyzers.