Grantee Research Project Results
Final Report: Development of Reactive Nanobubble Systems for Efficient and Scalable Harmful Algae and Cyanotoxin Removal
EPA Grant Number: SV840019Title: Development of Reactive Nanobubble Systems for Efficient and Scalable Harmful Algae and Cyanotoxin Removal
Investigators: Zhang, Wen
Institution: New Jersey Institute of Technology
EPA Project Officer: Aja, Hayley
Phase: II
Project Period: July 1, 2020 through June 30, 2022
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:
In this Phase II research project, we aim to develop and implement an innovative green process to produce reactive ozone nanobubbles (NBs) in water for diverse potential environmental applications such as rapid oxidation and decomposition of organic water pollutants and microbial contaminants (e.g., bacteria and algae). The research aims to assess and quantify ozone yield, quantum efficiency of the photochemical conversion of oxygen NBs into ozone (molecules and/or NBs) under VUV irradiation and evaluate the radical formation in water containing oxygen/ozone NBs. Furthermore, we will further investigate the cyanotoxin degradation in the O3/O2 NB water and compare the results with those waters with only oxygen NBs or saturated ozone molecules. This new process holds potential to be implemented for water disinfection and pollutant removal, and water remediation.
Summary/Accomplishments (Outputs/Outcomes):
In the pursuit of generating high-quality and consistent ozone nanobubbles (NBs) in water, we evaluated the three common ozone detection methods to measure the aqueous phase ozone concentration, namely, the Indigo method, the KI method, and the electrochemical sensor method using a DO3 Meter (KWJ Engineering Inc, USA). First, the ozone saturated water was prepared by injecting ozone gas generated by a MP-5000 ozone generator (A2Z Ozone, USA) with the ultrapure oxygen as the feed gas (5 psi, 1.15 LPM, and 20 0C). The generator could generate approximately 5 g·h-1 according to the manufacturer’s manual under this condition. The 1-L DI water was purged by the produced ozone gas for 1 h. Thus, the ozone concentration may reach up to 5000 mg·L-1 if no ozone lost due to evaporation or decay, which in fact will occur quite rapidly. Thus, the actual dissolved ozone concentration could be much less than 5000 mg·L-1. The measured concentrations by the three detection methods were found to quite deviate from each other due to the different detection principles. Three ozone concentrations were obtained at 178.2±4.8, 89.6±4.5, and 29.7±1.3 mg·L-1 respectively from the Indigo method, the KI method, and the electrochemical sensor method. We adopted the result from the Indigo method in all future tests, because this method is more reportedly used in literature and yielded the relatively high ozone concentration that may be close to the real level of the dissolved ozone.
Furthermore, extended DLVO theory was used to calculate the surface interaction energies, considering surface interfacial forces were mainly responsible for the attachment behavior of NBs/bacteria on pipe surface. The results show that biofilm formation in 1X PBS solution could be suppressed by the fast surface adsorption of NBs at the fluid/pipe interface and the resulted interaction energy (barrier) predicted by the soft EDLVO theory.
Finally, to assess the potency of NBs against bacterial deposition as the initial step for biofilm formation, we established the platform to study the bacterial interactions with aqueous NBs using a customized microfluidic cell, where bacteria were spiked in the buffer solution to flow into the cell via the light blue tubular port. Biofilm growth on the substrate surfaces induces a change in the electrical characteristics in both the surround medium and the interface of the solid substrate surface. To characterize these changes, the electrochemical impedance (EIS) measurements was conducted with a gold coated electrode and a stainless-steel plate as the counter electrode (CE) and the work electrode (WE) respectively. The impedance of the fluidic environment between WE and CE in the microfluidic channel was monitored versus time to indicate the surface deposition of bacteria or biofilm formation with or without the presence of NBs. Our preliminary data indicates the nanobubbles in water had negligible effects on bacteria deposition on the working electrode, probably due to the repulsion of NBs against the electrode surface or the limited sensitivity of EIS signals for indicating bacterial deposition. To better understand the potential influences of nanobubbles on bacterial deposition, our team is employing quartz crystal microbalance (QCM) to assess the interfacial bacterial deposition rates on gold substrate sensor electrode surfaces that are functionalized to achieve specific surface chemistry or charges. The results will be reported by our future journal articles and conference presentations.
Journal Articles on this Report : 5 Displayed | Download in RIS Format
Other project views: | All 24 publications | 9 publications in selected types | All 7 journal articles |
---|
Type | Citation | ||
---|---|---|---|
|
Zhang W, Xue S, Shi X, Marhaba T. In Emerging Nanotechnologies for Water Treatment. Royal Society of Chemistry, 2022. Chapter 16, Nanobubble Technology: Generation, Properties and Applications; p. 447-506. |
SV840019 (2021) SV840019 (Final) |
Exit Exit |
|
Shi X, Marhaba T, Zhang W. Advanced Ozonation Processes for Water and Wastewater Treatment. Royal Society of Chemistry, 2022. Chapter 12, Ozonation Nanobubble Technology; p. 353-370. |
SV840019 (Final) |
Exit Exit |
|
Shi X, Xue S, Marhaba T, Zhang W. Probing Internal Pressures and Long-Term Stability of Nanobubbles in Water. Langmuir 2021 ;37(7):2514-22. |
SV840019 (2021) SV840019 (Final) |
Exit |
|
Xue S, Zhang Y, Marhaba T, Zhang W. Aeration and dissolution behavior of oxygen nanobubbles in water. Journal of Colloid and Interface Science. 2022; 609:584-91. |
SV840019 (Final) |
Exit |
|
Shi X, Ma Q, Marhaba T, Zhang W. Probing Surface Electrochemical Activity of Nanomaterials using a Hybrid Atomic Force Microscope-Scanning Electrochemical Microscope (AFM-SECM). Journal of Visualized Experiments. 2021; (168):e61111. |
SV840019 (Final) |
Exit |
Supplemental Keywords:
Ozone nanobubble, generator evaluation, colloidal stability, reactivity characterization, biofilm preventionRelevant Websites:
Progress and Final Reports:
Original AbstractP3 Phase I:
Reactive Nanobubble for Algae and Cyanotoxin Removal | 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.