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1.
Appointed
to National Academies Committee On Examination of the Disposal of
Activated Carbon from the Heating, Ventilation and Air Condition Systems
at Chemical Agent Disposal Facilities (May 2008- May 2009). 2.
On
the Editorial Board of Adsorption Science and Technology (2005-present) 3.
On
the Editorial Board of Journal of Colloid and Interface Science
(2008-2010) 4.
On
The Advisory Board of American Carbon Society (2010- present). 5.
On
Scientific Committee of Pacific Basin Conference on Adsorption Science and
Technology II, Australia, May 2000. 6.
On
the Scientific Committee of IV International Symposium on Surface
Heterogeneity in Adsorption and Catalysis, August 2006 7.
On
the Scientific Committee of 2nd Carbon for Environmental
Protection Conference, October 2009. 8.
On the Advisory Board of 1st
United Arab Emirates Conference on Pure and Applied Chemistry
(ECPAC11)-American University of Sharjah, February 2011. 9.
On the Scientific Committee of Colloids and
Materials, Amsterdam 2011. 10.
On
the Advisory Committee of International Carbon Conference, Krakow, Poland
2012 11.
Session
Organizer /Chair at Annual ACS Meetings in Philadelphia (2004) and San
Diego (2005). 12.
Editor
“Activated Carbon Surfaces in Environmental Remediation”, Elsevier,
2006. 13.
Visiting
Professor, Department of Chemical Engineering, The University of
Queensland, Australia; Fall 2006 14.
Guest
Professor/ Sky Scholar, Dalian University of Technology, China 2006-2009. 15.
Visiting
Professor, University of Orleans, France, Fall 2009. 16.
Plenary
Lecturer at Brazilian Institute of Chemical Engineers Meeting, Iguassu
Falls, Brazil, September 2010. 17.
Plenary
Lecturer of Carbon in Catalysis, CarboCat4, Conference, Dalian, China,
November 2010. 18.
Invited
speaker to 1st International Symposium on Chemistry of Energy
Conversion and Storage (Germany; February 2001). 19.
Invited
Keynote speaker to Carbon for
Energy storage and Environment Protection
IV (France, September 20011) 20.
Discussion
leader at Hydrocarbon Resources Gordon Conference (January 2009) 21. Excellence in Review Award; Environmental Science and Technology, 2005 22. Excellence in Review Award; Carbon, 2008 |
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Featured in New York Times: "Secret Weapon Against Sludge: Sludge" by Antoni DePalama; February 21, 2005. |
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Environmental Application of Adsorption |
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Modification of materials |
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New sorbents and catalysts |
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Surface characterization |
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Methane/natural gas/hydrogen storage |
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Adsorption/desorption phenomena |
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Gas separation |
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Deep desulfurization of fuels |
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Catalytic photooxidation |
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Graphite oxide based composite adsorbents |
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Graphene/MOF composites as adsorbents |
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Gas sensors |
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Carbon materials based supercapacitors for energy storage |
DESCRIPTION OF RESEARCH
Study of Granular Activated Carbons as Adsorbents of Hydrogen Sulfide
We are working on monitoring the performance of activated carbons used to remove hydrogen sulfide odor in the City of New York Water Pollution Control Plants. So far mainly caustic-impregnated carbons have been used for air deodorization. Such carbons are expensive, create a risk of self ignition and require special precaution. That is why we are carrying out laboratory experiments along with pilot and fill-scale tests to study the possibility of replacement of caustic carbons with unmodified ones. Since the surface of activated carbons is very complicated from the point of view of chemistry and porous structure we are trying to define factors which enhance the adsorption of hydrogen sulfide and its oxidation to water soluble species that may make the regeneration of exhausted carbons using water feasible.
Mechanism of Mercaptan Adsorption on Activated Carbons
The process of removal of hydrogen sulfide and mercaptans is of great scientific and practical importance. It is because many natural raw materials, including copper ores and energy sources (oil, gas, coal, geothermal vapor, etc.) contain considerable amounts of sulfur derivatives. Those derivatives are formed in biological or chemical reactions such as thermal or anaerobic decomposition of organic materials. Sulfur derivatives are also considered as strong pollutants emitted to the atmosphere from various industries such as petroleum, paper, viscose, and food industries. From those, the most desirable to remove are hydrogen sulfide and thiols (mercaptans). They are odorous gases with significant toxicity. Since scientific reports describing sorption of methyl mercaptan which have been published so far do not discuss the influence of the carbon surface on the removal/oxidation of thiols, major goals of the proposed research are: (a) to study the performance of various commercial activated carbons as adsorbents of methyl mercaptane; (b) to modify the surface of carbons toward increasing their performance as adsorbents of methyl mercaptan; (c) to derive the mechanism of adsorption of methyl mercaptan on activated carbons. Since many odoriferous compounds have sulfur in their chemical formulas, investigation of the mechanism of methyl mercaptan removal will shed some light on the process of removal of odoriferous species in general.
Activated Carbons as Adsorbents of Traces of Odoriferous Compounds
Major goals of the research are: (a) to study the performance of various commercial activated carbons as odor adsorbents; (b) to modify the surface of carbons toward increasing their performance as adsorbents of specific odor compounds; (c) to study the mechanisms of adsorption of representative volatile constituents of human odor on activated carbons. The following analytical methods are used to characterize the pore structure and surface chemistry: potentiometric titration (pKa distribution), Boehm titration, volumetric sorption experiments (gas and vapor) with modern DFT analysis, FTIR, DTA/TG analysis, thermometric titration, and inverse gas chromatography with MS detector. We expect our work to throw new light on a number of unanswered questions regarding the application of carbons as deodorants. This includes: (1) what is the mechanism by which adsorption/immobilization occurs ?; (2) how is the adsorption affected by type, density and placement of the active sites on the surface?; (3) is there an optimum density, type, and geometric arrangement of sites that give a maximum adsorption of odorous species? Based on the answers to those questions the mechanism of adsorption will be proposed.
Activated of Organic Pollutants from Aqueous Phase on Activated Carbons
The mechanisms of adsorption of polar molecules such as water, methanol or chlorophenol on activated carbons are still not fully understood. The description of these molecules behavior at low relative pressure is important since activated carbons are widely used in the chemical, oil, gas and pharmaceutical industries for separations and purification of process streams, and for treatment of waste streams. However, it was previously found that the adsorption of polar molecules is strongly influenced by surface chemistry of carbon, the experimental results presenting adsorption at very low pressure region where surface groups - adsorbate interaction are significant have not been abandoned in the literature. The aim of this project is to develop improved models of polar molecules adsorption on activated carbons at low relative pressure. Experimental measurements will be done on carbons having a variety of well described surface chemical groups (carboxylic, lactonic, phenolic, etc.) and relatively homogeneous pore structures. The surface of carbon will be characterized by the variety of analytical methods based on titration, thermal analysis and spectroscopy. The isotherms of polar molecules will be measured at various temperatures (p/po 0.001-0.3). From the isotherms the isosteric heats of adsorption will be calculated. Then their values and changes with surface coverage will be analyzed in conjunction with the detailed characteristics of the carbon surface. The work is expected to throw new light on understanding the mechanism of adsorption of polar molecules and how adsorption is influenced by the type, placement and density of various surface chemical groups
COMPOSITE ADSORBENTS BASED ON INDUSTRIAL/MUNICIPAL WASTES
Industrial sludges/wastes/ ashes often contain transition metals which can work as catalysts in many processes such as hydrogen sulfide oxidation or desulfurization of liquid fuel. Pyrolyzing those wastes in various proportions with carbonaceous "fillers" results in materials with high capacity for removal of sulfur from gas or liquid phase via reactive adsorption. This happens owing to high dispersion of catalysts significant volume of pores.
As a result of the technology applied a new class of composite materials is obtained.
On those materials following processes are tested:
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Removal of hydrogen sulfide from air |
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Desulfurization of bio gas |
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Desulfurization of liquid fuels |
METAL CONTAINING CARBONS FOR REACTIVE ADSORPTION
Nanoporous carbon are obtained from metal containing polymers via carbonization either as a bulk materials or within inorganic templates (silica, ordered silica, alumina, zeolites). By changing the kind of polymer , its functional groups and the kind of metals new catalyst are obtained and tested in various reactions.
SORBENTS AND MECHANISMS OF REMOVAL
Various sorbents are tested as adsorbents of industrial toxic gases such as NH3, NOx, SO2, Ethylene oxides, etc. Depending on the properties of adsorbates and the mechanism of surface reaction expected various surface modifications are targeted towards surface retention of toxic species.
GRAPHITE OXIDES BASED COMPOSITE ADSORBENTS
A new class of adsorbents for removal of toxic gases is prepared from graphite oxide using their interactions with inorganic catalytic phases.
NANOENGINEERED ADSORBENTS
A major goal of
this project is the synthesis of composites, which will combine the favorable
attributes of activated carbons, graphite oxides, MOFs and transition metal
based catalysts; in particular the graphene component will lead to strong
adsorption, and the MOF or catalytic species of nanosize dimensions - to surface
reactions enhancing removal of TICs.
Syntheses will be followed by characterization. We plan to study NOX
(NO2/NO), AsH3 and PH3 interactions with the
nanocomposites. MOF chosen for the study will include those water stable with
potentially active Cu and Fe sites. For incorporation of nanocrystal species,
silver, iron, copper, and their oxides will be used.
We plan to address the following questions related to reactive adsorption of small molecule gases on Graphene/ MOF, graphene/ nanocrystal composites and on nonospecies modified carbons: 1) Which synthesis route leads to the most porous and most reactive nanocomposites? 2) Can we control the position and type of active centers groups to design the porosity and the exact location of the active centers? 3) Do the experimental conditions affect the molecular level interactions? 4) Can we design revolutionary optimal nanocomposites for air decontamination? 5) For such optimal materials, what is their performance in removal of TICs
Deep
desulfurization of Liquid fuel
Recent
environmental regulations set the limits of sulfur in gasoline to 30 ppm and in
diesel fuel to 15 ppm
(2006). Even though in the off-road fuel 500 ppm of sulfur is still an
acceptable level, the limits are set to be 15 ppm by 2010. Hydrodesulfurization
(HDS) is a method, which is able to remove the majority of sulfur-containing
compounds from fossil fuel. In spite of the high efficiency and established
technological importance of HDS it is not able to remove completely
dibenezothiophenes. Especially 4,6 – dimethyldibezothiophene is considered as
resistant to any chemical reactions.
In
the research program proposed here we seek to define the features of
carbonaceous adsorbents that govern the deep desulfurization process and to
develop efficient diesel fuel desulfurization media. The removal process we
target is based on reactive adsorption of DBT and 4, 6-DMDBT from very low
concentration of 20 ppm sulfur. In the “best case scenario”, thiophenic
molecules will first be specifically adsorbed on the catalytic metal center/
heteroatom containing groups and then the breaking of the carbon sulfur bond
will occur with retention of sulfur on the surface and a return of the
hydrocarbon molecule to the fuel stream.
In the “worse case scenario”, the DBT and 4,6-DMDBT molecules will be
specifically adsorbed in the pore system on metal oxides, sulfides, sulfur,
nitrogen, phosphorus or oxygen containing centers. Various scenarios of the
in-between interactions can exist.
We will provide the detailed experimental procedure for the preparation
of the most efficient removal media (from the point of view of the capacity,
selectivity and regeneration feasibility) along with the mechanism of the
process. The performance of adsorbents in desulfurization from liquid phase will
be linked to their surface features. This will open new routes for designing
more efficient and cost effective adsorbents and catalysts.
Our
review of the literature and research experience lead to the following research
questions related to achieving our objectives and to the development of new
technology: 1) Which temperature of carbonization does lead to the most
effective adsorbent/catalyst? 2) Which heteroatoms do enhance the capacity and
selectivity of adsorption? 3) Which metals/ surface groups or their combinations
are the most effective desulfurization catalysts? 4) Which content of metal does
result the highest capacity? 5) What are the products of surface reactions (if
any)? 6) What is the mechanism of
adsorption? 7) Can we efficiently regenerate the spent adsorbents? 8) Can we
design an adsorbent (based on the commercial carbonaceous precursors) with the
surface features leading to the effective deep desulfurization of diesel fuel?
Graphene
Oxide /MnO2 Composites: Investigation of energy storage capability
 | National Research Council/ National Academy of Sciences; Fall 1997 |
Travel grant to Ukraine to start collaboration with Ukrainian Academy of Sciences ---$ 2,000
| NYC DEP ; Jan. 98-Jan. 99 |
Study of Granular Activated Carbons ---$272,319
| PSC-CUNY; July 98- June 00 |
Effect of Surface Chemistry of Activated Carbons on Sorption of Polar Molecule---$7,910
| NASA (PAIR); (associate investigator) June 98-June 01 |
Remote Sensing and Environmental/Climate Research
| NYC DEP ; May 99-May 02 |
Study of Granular Activated Carbons--- $682,896
| CUNY Collaborative Incentive Grants Program; Sept.99-Aug.01 |
Activated Carbons Obtained from New York City Municipal Sludge as Sorbents for Sulfur Dioxide (with Prof.David Locke, QC)--- $32,000
| Graduate Research Technology Initiative: 1999 |
Evaluation of the levels of Contaminants and Pollutants in Water and Air in New York--- $50,000
| Petroleum Research Foundation; Sept.00-Aug.02 |
The Mechanism of Methyl Mercaptan Adsorption/Oxidation on Activated Carbons--- $60,000
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DuPont;
Feb. 01- Jan. 02 |
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NATO: April 2002-2004 |
Removal of H2S and CH3SH on Nitrogen Containing Activated Carbons--$ 20,000
| Synagro Corporation:
Oct. 01- Sept. 02 TERRENE® Modified with Spent Oil As A Precursor for Efficient Adsorbents for H2S and SO2 Removal---$10,000 |
| NYC DEP: May 02 -
May 05 Study on Granular Activated Carbons --- $ 476,490 |
| CRDF (USA - Moldavia):
March 02 - April 04 Activated Carbons for Water Treatment --- $ 5,800 |
| NYSERDA: Feb 04 -
June 04 Sewage Sludge Enriched Adsorbents Removal of Acidic Gases --- $ 41,000 |
| NYC DEP: May 05- May 07 |
Study of Granular Activated Carbon ----$ 562,000
| Army Research Office: Oct.05-Oct.09 |
Sorbents and Mechanism of Removal ---$ 370,000
| NYSERDA: April 06-April 07 |
Desulfurization of Biogas on Industrial Sludge Derived Materials---$50,000
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NSF
April 08-March 11 |
