Grantee Research Project Results
Final Report: A Biopolymer-based Simple Lead Check in Tap Water
EPA Grant Number: SV840021Title: A Biopolymer-based Simple Lead Check in Tap Water
Investigators: Lee, Woo Hyoung
Institution: University of Central Florida
EPA Project Officer: Aja, Hayley
Phase: II
Project Period: July 1, 2020 through June 30, 2022 (Extended to June 30, 2023)
Project Amount: $75,000
RFA: P3 Awards: A National Student Design Competition for Sustainability Focusing on People, Prosperity and the Planet - Phase 2 (2020) Recipients Lists
Research Category: P3 Awards
Objective:
This project aimed to detect the heavy metal ions (particularly lead) in water sources in situ and on-time, while utilizing one of the most abundant natural polymers, chitosan, as opposed to established fabrications using mercury (Mercury Export Ban Act of 2008). It is intended to be a sensitive and rapid design optimized to prevent consumption of lead in drinking water, noted as primarily contaminated through plumbing materials (CWA: Clean Water Act--Section 104). The proposed design allowed for an on-site, portable, convenient method of detection, and wireless connection. For rapid analysis, this eliminates the need for trained personnel and the time and costs associated with a laboratory analysis. The main strategy of this research is to develop and evaluate a highly sensitive sensor through regularly run research, tests, and laboratory meetings for maximum productivity. The sensor was tested using various water sources and contamination levels, from household water sources to spiked water. The objectives of the Phase II project was to 1) design a chitosan-modified electrode sensor and fabricate a carbon screen-printed sensor using chitosan-modified electrode; 2) identify and characterize sensor operating parameters for high sensitivity of lead detection; 3) evaluate sensor performance and reproducibility. Through this evaluation, it is expected that the chitosan-modified carbon screen-printed sensor will represent an easily operational, low-cost, non-toxic, and quick method for the determination of lead.
Summary/Accomplishments (Outputs/Outcomes):
During the project period, the lead detection microsensor was evaluated under different water environments such as tap water, mining wastewater, and soil leachate for future application evaluation.
Specific Objective 1: Fabricate chitosan modified screen-printed carbon electrode using electro-deposition method
The novel chitosan modified screen-printed carbon electrode, flexible copper-biopolymer nanocomposite sensors, was fabricated by electrodeposition of biopolymer metal composite material. The copper coating and chitosan layer was confirmed using surface characterization methods (e.g., SEM, XPS, and FT-IR).
Specific Objective 2: Characterize fabricated chitosan sensor using FTIR, scanning electron microscopy, optical microscopy and the electrochemical surface characterization tools
The morphological and chemical analysis of the composite films were investigated using the scanning electron microscope (SEM), Fourier Transform Infrared (FTIR), and X-ray photoelectron spectroscopy (XPS). Electrochemical impedance spectroscopy (EIS) was evaluated the electrode's electron transfer properties before and after surface modifications.
Specific Objective 3: Optimize the electro-deposition parameters for optimal stability and sensor performance
The developed microsensors were tested under different operational conditions of Square Wave Anodic Stripping Voltammetry (SWASV), which include; varying deposition time, amplitude, and frequency for the initial deposition of heavy metal ions on the electrode. The SWASV optimal parameters of the copper-biopolymer nanocomposite sensors were 300 s deposition time, -1.2 V deposition potential, 0.004 V potential step, 0.1 V amplitude, and 20 Hz frequency, respectively.
Specific Objective 4: Use developed sensor for multiple metal ion detection
Prioritizing a more relevant pollutant among others, the developed sensor has been investigated for lead detection under the different types of water such as tap water, mining wastewater, and soil leachate. The limit of detection (LOD) was 0.72 ppb for tap water, 1.4 ppb for mining wastewater, and 1.54 ppb for soil leachate. Similarly, reproducibility of the sensor for the mining wastewater and soil leachate samples exhibited consistent sensitivity for ten successive measurements with an RSD of 1.93% and 8.75% with a recovery of 96.5% and 94.8%, respectively.
Evaluation of the technical effectiveness and economic feasibility of the methods or techniques investigated or demonstrated.
The traditional methods such as electrothermal atomic absorption spectrometry (EAAS), flame atomic absorption spectrometry (FAAS), and inductively coupled plasma mass spectrometry (ICP-MS) and inductively coupled plasma (ICP)) have provided accuracy and reliability in detecting heavy metals. However, they often require large, expensive instruments, highly trained technicians, considerable time-consuming efforts, large volumes of reagents, an invasive collection of samples in the field, and transportation to centralized laboratories for analyses. The long-time delays associated with current procedures are considered inadequate for on-site applications and cannot be used for taking preventive measures in the early stage of the escalation of water crisis. It is of vital importance to develop a quick, simple, reliable method for heavy metal detection that can be used for real-world applications.
The electrochemical sensor developed in this project was developed using a chitosan electrodepositing technique for detecting lead (Pb2+) heavy metal ions. This in situ design extends to economic prosperity as use of electrochemical methods are low-cost, simple, and portable compared to conventional analytical methods. Overall, the development of a chitosan-modified carbon sensor has the great potential for a sustainable approach to lead control in drinking water.
Conclusions:
- Conclusion and Implications for Further Research, Development, or Demonstration
Results from this project successfully displayed a multiple heavy metal ions detection using different types of nanomaterial composite chitosan-modified carbon sensor and evaluated its lifetime, reproducibility, sensitivity, real sample application, and universal wireless electrochemical detector (UWED). The novel copper-chitosan (Cu-chitosan) nanocomposite-based flexible electrochemical sensor with an integrated Ag/AgCl reference electrode is fabricated using low-cost screen-printing technology on a flexible substrate, followed by the electrochlorination of silver to form an integrated Ag/AgCl reference electrode and electrochemical deposition of a Cu-chitosan nanocomposite film to produce a working electrode. The fabricated Cu-chitosan nanocomposite-based sensors are used to determine the trace level multiple heavy metal ions, such as lead (Pb2+) and zinc (Zn2+) ions in real-world water samples (i.e., tap water, mining wastewater, and soil leachate). The limit of detection (LOD) of the developed flexible electrochemical sensor in tap water is 0.72 ppb for Pb2+ and 1.2 ppb of Zn2+ with the relative standard deviations (n = 10) of 0.65 % for Pb2+ and 3.6 % for Zn2+, respectively. The developed Cu-chitosan sensor was successfully demonstrated for Pb2+ detection using the UWED, which was connected to the smart phone (~3m distance between sensor and smartphone) for the analysis of Pb2+ by SWASV. Through evaluation, it is expected that nano metal composite chitosan-modified carbon screen-printed sensor will represent an easily operational, low-cost, non-toxic, and quick method for the determination of heavy metal ions. For further development, we will continue to work on the optimization of the sensor fabrication processes and the development of sensor guidelines for the use of stakeholders. Going forward with this project, its progress in material fabrication and UWED will allow for field application providing research in fields such as for commercial use or private sector use.
Journal Articles:
No journal articles submitted with this report: View all 12 publications for this projectProgress and Final Reports:
Original AbstractP3 Phase I:
A Biopolymer-based Simple Lead Check in Tap Water | Final ReportThe perspectives, information and conclusions conveyed in research project abstracts, progress reports, final reports, journal abstracts and journal publications convey the viewpoints of the principal investigator and may not represent the views and policies of ORD and EPA. Conclusions drawn by the principal investigators have not been reviewed by the Agency.