Department of Environmental Science and Forestry
The Connecticut Agricultural Experiment Station
123 Huntington Street
New Haven, CT 06511
Voice: (203) 974-8518 Fax:(203) 974-8502
E-mail: Joseph.Pignatello@ct.gov

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Expertise:
Dr. Pignatello has expertise in physical organic chemistry; soil chemistry; environmental chemistry and engineering; fate of organic compounds in the environment; and water and soil treatment processes.

Education:
B.A., Chemistry, University of Minnesota, Minneapolis
Ph.D., Chemistry, University of California, Berkeley

Station Career: 

Assistant Scientist II, 1984-1988

Associate Scientist, 1988-1993

Scientist, 1993-2004

Senior Scientist, 2004-2013

Chief Scientist, 2013-2022

Chief Distinguished Scientist, 2022

Emeritus Scientist, 2022-present

 

Dr. Pignatello leads the Environmental Chemistry group, which conducts research in several areas in the environmental chemistry of pollutants and the chemistry of natural processes, including:

• physical-chemical interactions of organic compounds with soils and soil components;
• bioavailability of organic contaminants in natural particles;
• physical-chemical processes for removing or degrading pollutants in soil, water and air; and
• chemistry of natural processes in the environment.

 

Their research covers both fundamental and applied aspects, and deals with a diversity of agrochemicals, legacy and emerging organic contaminants, and excess nutrients. The group uses a variety of physical and chemical techniques, such as gas and liquid chromatography, solid and liquid state NMR spectroscopy, high resolution gas adsorption, diffuse-reflectance FTIR and UV/visible spectroscopies, XRD, HRTEM, SEM, AFM, radioisotope techniques, and computational molecular modeling. Many of the projects are collaborative with individuals at Federal laboratories, US and foreign universities, and others within The CAES. Outside funding has been provided over the years by USDA, NSF, EPA, SERDP, and industry sources.

Past Research:
Biodegradation of fumigants in soil and groundwater. Solvent extraction techniques for determining volatile organic compound and pesticide concentrations in soil. Field and laboratory studies to determine the causes of sequestration of pesticides and other chemicals in soil. Mechanistic modeling of sorption by soil organic matter. Rates of sorption and desorption in soil. Advanced oxidation process (especially the Fenton reaction) for degrading pesticides and many other types of compounds in soil and water.

• Driving forces controlling sorption of organic compounds to natural organic matter and pyrogenic carbons, including special interactions, application of a glassy polymer model to soil organic matter, and the causes of sorption hysteresis and irreversibility.
• Spectroscopic characterization of natural organic matter and chars.
• The chemistry of peroxide-based advanced oxidation processes (AOPs) for treating wastewaters.
• Sunlight-driven photolysis of organic pollutants and dissolved organic matter in marine and estuarine waters with emphasis on the influence of water chemistry.
• Bioavailability of pollutants sorbed to environmental black carbon particles.
• Electron-transfer and nucleophilic reactions mediated by pyrogenic carbons.
• Interactions between engineered nanoparticles and biochar particles.
• Trapping and degradation of fumigant emissions.

 

Present Research:
In general terms, the group’s research interests include interactions of organic compounds with soils and sediments, remediation of contaminated water and soil, and sunlight-driven reactions in the environment. Its research covers both fundamental and applied aspects of these areas and deals with a diversity of compounds within the categories of legacy pollutants, emerging pollutants such as endocrine disrupting compounds and pharmaceuticals, and nanomaterials. The group uses a variety of physical and chemical techniques, such as gas and liquid chromatography, solid and liquid state NMR spectroscopy, high resolution gas adsorption, diffuse-reflectance FTIR and UV/visible spectroscopies, XRD, HRTEM, SEM, AFM, thermomechanical and thermogravimetric analyses, radioisotope techniques, and computational molecular modeling.

Many of the projects are collaborative with individuals at CAES, Federal research laboratories, American and foreign universities, and private industry. In addition to my position at CAES, I also hold the position of Professor Adjunct of Chemical and Environmental Engineering at Yale University http://seas.yale.edu/departments/chemical-and-environmental-engineering.

Current Projects in the Group:

• Adsorption of contaminants to pyrogenic carbons. Pyrogenic carbons include natural chars, biochars, activated carbons, and related models such as graphite, graphene, and carbon nanotubes. The group is investigating novel interactions of organic compounds on their surfaces, including, i) formation of exceptionally strong hydrogen bonds with ionizable contaminants (e.g., carboxylic acids, phenols, sulfonamides); ii) p-p electron donor-acceptor interactions with compounds containing electron-poor aromatic rings; and iii) impacts on adsorption of physical-chemical changes in carbons induced by air oxidation during pyrolysis and after aging in the environment.

• Potential roles for biochar in environmental management. Biochar is the carbonaceous byproduct of anoxic pyrolysis of biomass waste that has potential beneficial applications as a soil amendment in agriculture and environmental remediation, partially as a consequence of its strong adsorptive properties. We are tailoring biochars with superior ability to capture nutrient ions in animal wastes into less leachable forms. We are studying the use of biochar to remediate marine and land spills of crude oil, relying on its efficient absorption of crude and its ability to stimulate microbial activity. And we are investigating the interaction of nitrous oxide with biochar following reports that biochar inhibits emissions of the potent greenhouse and ozone-depleting gas, nitrous oxide, in soil.

• Advanced oxidation processes for treating contaminated water. We are conducting fundamental chemical studies on advanced oxidation processes for ‘deep’ oxidation of organic pollutants that use hydrogen peroxide, peracetic acid, peroxymonosulfate, and peroxydisulfate as the bulk oxidant.  We are designing carbonaceous or inorganic nano-scale catalysts and photocatalyst for peroxides activation. Our emphasis is on the kinetics and mechanisms of these reactions, with special concern for the effects of water chemistry, since many treatable waters contain high levels of dissolved substances.
  
  
• Involvement of Low-Barrier Hydrogen Bonds in Natural Environmental Processes. Hydrogen bonds between weak acid groups with similar pK_a values can be much stronger and shorter than ordinary hydrogen bonds. We are examining whether such bonds play a role in bonding between soil organic matter molecules or strands, between SOM and pyrogenic carbons, and between SOM and natural and anthropogenic inorganic weak acids.

Recent publications available from the author, Joseph.Pignatello@ct.gov, (see http://www.ISIHighlyCited.com for a full list)

• Charge-assisted hydrogen bonding as a cohesive force in soil organic matter: water solubility enhancement by addition of simple carboxylic acids, Ni, Jinzhi and Pignatello, J.J., Environ. Sci.: Processes and Impacts, 2018; DOI: 10.1039/c8em00255j.
• Oxidation of Organic Contaminants by Unactivated Peroxymonosulfate, Yi Yang, Gourab Banerjee, Gary W. Brudvig, Jae-Hong Kim, Joseph J. Pignatello*, Environ. Sci. Technol., 52 (10), 5911–5919 (2018); DOI: 10.1021/acs.est.8b00735.
• Thermal Air Oxidation Changes Surface and Adsorptive Properties of Black Carbon (Char/biochar), Feng Xiao*, Alemayehu H. Bedane, Julia Xiaojun Zhao, Michael D. Mann, Joseph J. Pignatello, Science of The Total Environment, 618, 276-283 (2018).