GOALI: INFEWS N/P/H2O: Real-Time and Low-Cost Monitoring of Orthophosphate Ions Using Novel Graphene-Based Transistor Sensors

University Of Wisconsin-Milwaukee, Milwaukee WI

Investigators

Abstract

1606057 Chen Phosphorus is one of the macro nutrients necessary for the growth of plants and animals. In instances where phosphorus is a growth-limiting nutrient, for example in some natural surface waters, the discharge of raw or treated wastewater, agricultural drainage, or certain industrial wastes may stimulate the growth of photosynthetic aquatic micro- and macro-organisms in large quantities. This project focuses on developing a low-cost, ultrasensitive, and real-time water sensor for continuous monitoring of phosphate in agriculture runoff, wastewater, and surface water. The ability to provide field-deployable, inexpensive, and environmentally- and energetically-sustainable sensors for real-time application and monitoring of phosphorus-containing species while reducing the amount of these species in waste or run-off streams would benefit food production, benefit water quality, and result in significantly less energy consumption. This project benefits from major innovations in a sensing platform in the PI's laboratory. The superior sensing performance could be directly used for low-concentration and real-time monitoring of phosphates in water and the new and reliable method to differentiate phosphates through coupling between target ions and chemical probes functionalized on the reduced graphene oxide surfaces. The proposed research is transformative since the new sensing platform combines the outstanding properties of reduced graphene oxide (e.g., low cost, large specific surface area, and high electronic sensitivity) with reliable probe immobilization on the reduced graphene oxide surface. Based on preliminary results, the novel phosphate ion sensor had a detection time on the order of seconds and a lower detection limit of 0.01 mg/L. Therefore, this high sensitivity platform offers a simpler and faster route to detecting phosphates, as well as significantly lower cost, as compared with existing methods. Experiments will be carried out to optimize the technical performance of the sensor in terms of sensitivity, while a long-term deployment in a water system will be conducted. Expected outcomes of the project include: (1) prototypes of real-time and ultrasensitive sensors to continuously monitor phosphate in various water systems; (2) field deployment and validation data of the sensors in agriculture runoff, wastewater, and surface water systems; and, (3) entrepreneurship training courses/activities for students and faculty and internship opportunities for students. A sensor innovation platform will be created in Milwaukee's Global Water Center to help students learn about the innovation and technology transfer process. The proposed education plan features proactive efforts to improve entrepreneurial engineering education; to attract underrepresented students into STEM fields; extensive integration of research and education; and, broad dissemination of water sensor research and educational findings.