skip to main content
US FlagAn official website of the United States government
dot gov icon
Official websites use .gov
A .gov website belongs to an official government organization in the United States.
https lock icon
Secure .gov websites use HTTPS
A lock ( lock ) or https:// means you've safely connected to the .gov website. Share sensitive information only on official, secure websites.


Title: Aqueous‐Phase Photocatalytic Degradation of Emerging Forever Chemical Contaminants
Abstract Heterogeneous photocatalysis is an emerging area of catalysis increasingly fraught with pains caused by the battle between hype and real‐ world application. Inspired by abundant yet diffuse solar energy and applications such as clean water and energy, ample motivation has provided the background for this situation. However, substantial fundamental (e. g., charge transfer, recombination), engineering (e. g., observed rates, photon management), and practical barriers (e. g., use of precious metals, competing technologies) have limited implementation. In this review, these are all outlined, in conjunction with typical strategies for improvements, with an emphasis on the use of semiconductor photocatalysts for the degradation of emerging forever chemical contaminants in water. The selected classes of forever chemical contaminants are (micro)‐plastics, per‐ and polyfluoroalkyl substances (PFAs), siloxanes, and dioxanes. Each has been identified as a key or emerging contaminant and often travel widely while accumulating in the atmosphere due to the lack of natural remediation processes. Recommendations to the field and opportunities for contributions are highlighted throughout and as part of the outlook to the future.  more » « less
Award ID(s):
2000980
PAR ID:
10233360
Author(s) / Creator(s):
 ;  
Publisher / Repository:
Wiley Blackwell (John Wiley & Sons)
Date Published:
Journal Name:
ChemistrySelect
Volume:
6
Issue:
21
ISSN:
2365-6549
Format(s):
Medium: X Size: p. 5225-5240
Size(s):
p. 5225-5240
Sponsoring Org:
National Science Foundation
More Like this
  1. null (Ed.)
    Monitoring water quality by detecting chemical and biological contaminants is critical to ensuring the provision and discharge of clean water, hence protecting human health and the ecosystem. Among the available analytical techniques, infrared (IR) spectroscopy provides sensitive and selective detection of multiple water contaminants. In this work, we present an application of IR spectroscopy for qualitative and quantitative assessment of chemical and biological water contaminants. We focus on in-line detection of nitrogen pollutants in the form of nitrate and ammonium for wastewater treatment process control and automation. We discuss the effects of water quality parameters such as salinity, pH, and temperature on the IR spectra of nitrogen pollutants. We then focus on application of the sensor for detection of contaminants of emerging concern, such as arsenic and Per- and polyfluoroalkyl substances (PFAS) in drinking water. We demonstrate the use of multivariate statistical analysis for automated data processing in complex fluids. Finally, we discuss application of IR spectroscopy for detecting biological water contaminants. We use the metabolomic signature of E. coli bacteria to determine its presence in water as well as distinguish between different strains of bacteria. Overall, this work shows that IR spectroscopy is a promising technique for monitoring both chemical and biological contaminants in water and has the potential for real-time, inline water quality monitoring. 
    more » « less
  2. Graphitic carbon nitride (g-C 3 N 4 ) is an emerging visible-light-responsive photocatalyst that has been explored since 2009. This photocatalyst has highly tailorable structures and properties that enable potential utilization of a large portion of solar energy. This material is also synthesized from earth-abundant precursors, is chemically and thermally stable, and is biocompatible with no reported toxicity to date. The merits and pioneering performance evaluation of g-C 3 N 4 indicate that this photocatalyst holds promise for the degradation of persistent and emerging contaminants, including chemicals and pathogens, for sustainable water purification with reduced energy and chemical footprint. In this perspective, we propose and answer five questions that are most relevant to the development and application of g-C 3 N 4 for photocatalytic water purification, including both benefits and current barriers, from molecular-scale mechanistic understanding of g-C 3 N 4 properties and photocatalytic performance to industrial-scale photoreactor design for g-C 3 N 4 implementation in practice. 
    more » « less
  3. Abstract Modeling evaporationEfrom inland water bodies is challenging largely due to the uncertainties of input data, particularly surface water temperature that plays a key role in the available energy, i.e., net radiationRnminus rate of water heat storage changeG. The equilibrium temperature approach (ETA) for estimating water surface temperature offers an alternative method to calculateRnandGusing standard meteorological data. This study evaluates the global lakeEestimates from the widely used Penman model (PM) coupled with the ETA (PM-ETA) against field observations and model simulations from the Lake, Ice, Snow, and Sediment Simulator (LISSS). Our analysis reveals that the PM-ETA tends to overestimateEby approximately 36% and 24% compared to observations and the LISSS simulations, respectively, despite being driven by the same input data. The biases of the PM-ETAEare more pronounced in the cold and polar regions with distinct seasonality ofRnandG. Furthermore, theEtrends from the PM-ETA deviate from the LISSS simulations over the period of 2001–16 due to the bias trends in the available energy. By incorporating the LISSS-simulatedRnandGinto the PM, the bias inEis reduced to less than ±5% compared to the LISSS results. This study highlights the need to improve the available energy input of the PM to improve the estimates of global lakeEfor better water resource management and planning. Significance StatementThis study addresses a crucial challenge in modeling evaporationEfrom inland water bodies—uncertainties in surface water temperature and available energy inputs, particularly net radiationRnand rate of heat storage changeG. By evaluating the widely used Penman model (PM) coupled with the equilibrium temperature approach (ETA), we reveal a tendency for the PM-ETA to overestimateEglobally, with the largest biases observed in cold and polar regions. Incorporating higher-qualityRnandGestimates from the Lake, Ice, Snow, and Sediment Simulator (LISSS) significantly reduces these biases. These findings highlight the importance of alternative higher-quality data products for available energy inputs for improvingEestimates by the PM. 
    more » « less
  4. Detection of micropollutants, such as pharmaceuticals and industrial chemicals with endocrine disrupting potency, in ground and surface waters is of emerging concern. Within the aquatic environment, these emerging contaminants (ECs) can interact with various surfaces and biological membranes. The implication is that, provided the ECs exhibit sufficient affinity, these surfaces can modulate their fate and transport properties. Knowledge of the types of interaction with biomembranes can also help decipher their impact on the aquatic organisms. Here, we show that selected pharmaceuticals and endocrine disrupting chemicals (EDCs) – amlodipine (AMP), carbamazepine (CBZ), β-estradiol (β-ED), and 4-propylphenol (4-PP) - exhibit proclivity for the air/aqueous interface. These compounds also interact differently with a zwitterionic phospholipid membrane. The adsorption free energy for the water surface, in the order of increasing affinity, is as follows: 4-PP < AMP < β-ED~CBZ. Of the four compounds studied, 4-PP has the greatest extent of disruption of the phospholipid membrane. Our results suggest that the extent of interaction with water surface and biological membrane is dependent upon the chemical nature of these micropollutants. This fundamental study highlights the importance of interfacial chemistry on the fate and transport of emerging contaminants in natural waters. 
    more » « less
  5. Abstract Advanced treated municipal wastewater is an important alternative water source for agricultural irrigation. However, the possible persistence of chemical and microbiological contaminants in these waters raise potential safety concerns with regard to reusing treated wastewater for food crop irrigation. Two low-cost and environmentally-friendly filter media, biochar (BC) and zero-valent iron (ZVI), have attracted great interest in terms of treating reused water. Here, we evaluated the efficacy of BC-, nanosilver-amended biochar- (Ag-BC) and ZVI-sand filters, in reducing contaminants of emerging concern (CECs),Escherichia coli (E. coli)and total bacterial diversity from wastewater effluent. Six experiments were conducted with control quartz sand and sand columns containing BC, Ag-BC, ZVI, BC with ZVI, or Ag-BC with ZVI. After filtration, Ag-BC, ZVI, BC with ZVI and Ag-BC with ZVI demonstrated more than 90% (> 1 log) removal ofE. colifrom wastewater samples, while BC, Ag-BC, BC with ZVI and Ag-BC with ZVI also demonstrated efficient removal of tested CECs. Lower bacterial diversity was also observed after filtration; however, differences were marginally significant. In addition, significantly (p < 0.05) higher bacterial diversity was observed in wastewater samples collected during warmer versus colder months. Leaching of silver ions occurred from Ag-BC columns; however, this was prevented through the addition of ZVI. In conclusion, our data suggest that the BC with ZVI and Ag-BC with ZVI sand filters, which demonstrated more than 99% removal of both CECs andE. coliwithout silver ion release, may be effective, low-cost options for decentralized treatment of reused wastewater. Graphical Abstract 
    more » « less