Designing an electrochemical sensor for PFAS detection in water (New)
Currently the PFAS detection is completed by using centralized facilities, which needs long time and high cost. In this project, we target to design a carry-on electrochemical sensor that can rapidly detect PFAS in the field, which provides convenient way to detect PFAS in various water systems. The combination of large-cavity active polymer and high-surface-area, high electronic conductivity graphene displays large advantages in providing inclusion reaction with PFAS molecules and high electron transfer pathway, which results in a high-sensitivity and low-concentration-limit electrochemical sensor in detecting ppt-level PFAS molecules in various waters.
- University: UWM
- Research Area: Water Sensors & Devices / Novel Materials
- Investigators: Junjie Niu
Embedded Ultrasonic Inspection of Water Filled Equipment (Continuing)
Multiple forms of degradation can occur in water handling equipment including corrosion, erosion, cracking, and buildup of deposits and biofilms. Damage type degradations can eventually lead to breakage, flooding, and equipment down time. Deposits and biofilms can affect the efficiency of equipment and result in contamination of water.
This project will explore the ability to use a sparse array of permanently mounted piezoelectric transducers for ultrasonic inspection, to detect and locate degradation throughout a wetted structure. The project will leverage the existing knowledge of ultrasonic inspection of gas filled pressure vessels and structures using permanently mounted piezoelectric transducers. (note, in these studies a sticky patch was regularly used to simulate ‘damage,’ verifying the ability to detect surface contamination).
The continuing project will build on the previously gained knowledge which focused on a small, completely-filled, metal water-heater tank. This project seeks to expand capabilities to other relevant water handling equipment, including water tanks composed of different materials, and full pipes containing flowing water. Results are expected to be applicable to a much wider range of (consistently full, clear water handling) equipment.
The prior project investigated the fundamental ability to detect (simulated) damage in a metallic vessel with variable pressure. Challenges and novelty in the continuing project arise from:
- Variation in material properties, specifically mass-density, elastic-modulus, and damping are well known to have significant effects on elastic wave propagation in solids. This is compounded by the dispersive nature of waves in the ultrasonic range and surface interaction with water (on one side). Physics based analysis will support extrapolation of demonstrated capabilities to different water tanks composed of different materials.
- Pipes with flowing water are fundamental components to water handling equipment but have the potential to introduce noise and shifts into elastic wave propagation with potential to interfere with ultrasonic inspection. Analysis and understanding of these effects will support integration and compensation in algorithms for (automated) ultrasonic inspection.
This project will build on the knowledge gained in the initial project, toward a goal of automated inspection of water handling equipment, applicable to wetted structures, and advancing the movement towards the Internet of Things. Embedded systems that detect structural health eliminate many potential variations in sensor signals supporting automated signal analysis and state determination. Automation of the inspection process has the potential to reduce cost, downtime, and failures.
- University: UWM
- Research Area: Water Sensors & Devices
- Investigators: Nathan Salowitz
Remote sensing and machine learning to assess urban watershed best management practices: Phase II (Continuing)
The follow-up monitoring of water resources best management practices (BMPs) in urban areas is critical for achieving long-term water quality and ecological objectives. However, doing so can be a challenge due to the limitations of in-person monitoring that requires significant personal, equipment, and laboratory costs. The system-wide coverage of satellite systems has the potential to directly address this need, yet the application of satellite remote sensing to identify and track the maintenance needs of urban water resources BMPs is underexplored. Therefore, novel approaches are needed that can utilize satellite data to monitor and assess these practices in urban environments.
Phase I research demonstrated the feasibility of using drone and satellite remote sensing to assess urban water resources BMPs. This includes (1) using high-resolution (2 cm) multispectral imagery from drones to build machine learning models that can classify land cover type of urban BMPs; and (2) applying those models to lower-resolution (30 cm) multispectral imagery from satellites to identify urban BMPs that may need maintenance actions. While the previous Phase I work identified what the problem may be – urban BMPs in need of follow up actions – it was unable to identify the underlying causes. Furthermore, the previous work was restricted to only 3 satellite images during the summer months, which precludes its application in winter, spring, or fall months when BMPs have different reflectance characteristics.
This Phase II work will build upon those findings to improve the model performance across additional seasons (e.g., spring, winter, and fall) when land cover reflectance changes, as well as seek to identify why urban BMPs may have excessive plant stress through in-situ monitoring of soil moisture, temperature, and conductivity.
- University: MU
- Research Area: Water Policy / Water Sensors & Devices
- Investigators: Walter McDonald
Portable biosensor to rapidly detect bacteria in water (Continuing)
The commercially available sensors are based on PCR and SPR microscopy which require long time and high cost. In this proposed research, we develop a novel biosensor receptor with AMP and others such as Magainin I, PLL and enzymes grafted on graphene oxide sheet. The AMP grafted sensor has high sensitivity to detect bacteria including E. coli. The portable sensor can be carried easily onsite and detect the bacteria rapidly in drinking water, wastewater and other matrixes.
The biosensing system with graphene/ antimicrobial or other peptides/nanomaterial displays promising applications. However, detection of bacteria in industrial/municipal or groundwater using such sensing system without magnetic field or fluorescence has not been studied. We apply electrochemical reaction to receive signal which is more reliable by measuring the voltage/resistance difference via CV/EIS when any specific bacteria contact with the receptor and undergo redox reaction. The designed sensor can detect whole bacteria at low levels in various water systems. The sensor is portable and has a short detection time which will reduce the overall cost and waiting time. The technology transfer to the interested companies can be executed by UWM Research Foundation through patent licensing.
- University: UWM
- Research Area: Water Sensors & Devices
- Investigators: Junjie Niu
Development of positively charged nanofiltration membranes for water softening: Phase II (Continuing)
Problem Statement: Water softening is an essential water treatment process for many domestic and industrial water users. Most commercial products use the ion exchange unit to replace magnesium and calcium with sodium or potassium ions, with the regeneration process producing a considerable amount of salt brine. With concerns about the salty wastewater produced, many communities in the US have restricted or even banned the use of salt-based water softeners. Therefore, there is a need to develop an energy-efficient, salt and chemical-free technology to remove hardness from the water supply. Results from our Phase 1 project have demonstrated the high potential of employing positively charged nanofiltration membranes for water softening. To enhance and refine this technology, it is imperative to investigate and tailor membrane performance for high-water recovery softening applications.
How to Address: We aim to address the aforementioned challenges in this Phase 2 project. Specifically, our objectives are to (1) improve the membrane selectivity, i.e., enhance the passage rate of salts unrelated to hardness, such as NaCl, while maintaining high rejection of hardness-causing calcium and magnesium minerals; (2) increase the water permeance; and (3) evaluate the membrane performance under high-water recovery conditions.
- University: UWM
- Research Area: Treatment Systems
- Investigators: Xiaoli Ma, Ying Wang and Shangping Xu
Low-cost surface alloying of brass to improve corrosion resistance in chlorine and chloramine-rich environments: Phase II (Continuing)
This proposal aims to develop the technology of low-cost surface alloying of copper alloy plumbing fixtures during sand casting, to extend the life of components and reduce corrosion and surface damage in water containing chlorine and chloramine. In 2023, our team has been able to demonstrate the initial feasibility of surface alloying of two copper alloys, including yellow brass and Bi-alloy, at the lab scale; slurries containing metal powders were coated on the selected surfaces of molds and cores to achieve surface alloying on inner and outer surfaces of castings. Limited castings have also been made on the industry floor with slurry-coated molds and cores. An invention disclosure on this process has been submitted to UWMRF in July 2023. However, the surface alloyed layers observed in lab-cast samples in 2023 were thin (<200µm) and often had defects and nonuniformities. In 2024, the research will be directed to increase the thickness, uniformity, soundness, and reproducibility of surface alloyed copper alloy castings. Alloying elements, including Cu, Sn, Ni, and Al and their combinations will be used to enrich surfaces of castings during the casting process to improve corrosion resistance. A techno-economic analysis will be conducted in 2024 after optimizing the process to estimate the savings by using surface alloyed castings developed in the project in relation to base alloy castings as well as through alloyed castings and to predict the life of surface alloyed castings in chloramine environments. Our approach is much cheaper and does not require line of sight as in laser surface alloying and other surface alloying processes; it is also especially suited for surface alloying interior surfaces of castings by coating the slurry on cores that form the internal surfaces. In fact, our process can enable varying degrees of surface alloying on different surfaces of the same casting depending on different exposures to corrosive environments. In addition, our process will enable the use of lower-cost copper alloys in the interior with surface alloyed layers instead of using highly alloyed castings where costly and scarce alloying elements are incorporated throughout the cross sections. Our process can be readily implemented by either captive foundries of IAB members or at foundries that manufacture plumbing castings of copper alloys for our IAB members by coating the surfaces of molds and cores with slurries containing metal powders before pouring the melts in the molds. The UWM team will provide the know-how on the selection of metal or alloy powders to be mixed in slurries and the application of slurries on selected surfaces of molds and cores. IAB member companies can make the surface alloyed castings themselves or get them made at their suppliers and test them to demonstrate their increased life, followed by their mass manufacture for use in their products and systems. In addition, the use of surface alloyed components will reduce the amounts of metal ions leaching into the water, reducing dezincification and pit formation on the casting surface. For example, enriching the surface of yellow brass in Cu will bring the surface composition closer to red brass, which has higher corrosion resistance. Enriching the surface of red brass with Ni and other elements will further increase their corrosion resistance, similar to Monel, which shows much higher life in chloramine environments, at much lower costs.
- University: UWM
- Research Area: Novel Materials
- Investigators: Pradeep Rohatgi and Benjamin Church