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Aquablok+Organoclay as Permeable Barriers
George R. Alther, Biomin Inc.,
Oak Park,
MI
Rheological Characteristics of Manufactured Gas Plant
Tars and Implications for Remediation
Pamela Schultz Birak, University of North Carolina at
Chapel Hill, Chapel Hill, NC
Scott C. Hauswirth, University of North Carolina at
Chapel Hill, Chapel Hill, NC
Cass T. Miller, University
of North Carolina at Chapel Hill, Chapel Hill, NC
In Situ Soil Washing by Sedimentation Method for
Contaminated Sandy Soil
Wawan Budianta, Gadjah Mada University, Yogyakarta,
Indonesia
Chris Salim, Tokyo Institute of Technology, Tokyo, Japan
Hirofumi Hinode, Tokyo Institute of Technology, Tokyo,
Japan
Hideki Ohta, Tokyo Institute of Technology, Tokyo, Japan
Remediation of
Acid Tar Lagoon
Branko Druzina, University of Ljubljana, Ljubljana,
Slovenia
Andrej Perc, University of Ljubljana, Ljubljana,
Slovenia
Remediation in Skykomish
Washington
Michael Byers, AECOM Environment,
Seattle,
WA
Mike Gardner, AECOM Environment,
Westford,
MA
Aimee Fitzpatrick, AECOM Environment,
Belmont,
NH
Optimization of a Multi-Well Groundwater Pump and Treat
System: Managing Hydraulic Stagnation Zones
Mark D.
Hilyard, CH2M HILL, Otis ANG Base, MA
Rose H. Forbes,
Air
Force Center
for Engineering and the Environment, Otis ANG Base, MA
Limited-Access Bioremediation in a Factory Setting
Deborah R.
Farnsworth, MyKroWaters, Inc.,
Concord,
MA
Willard Murray, ECC,
Inc.,
Marlborough,
MA
Daniel Bronson,
Bronson Drilling, Cambridge,
MA
EHC®
In
Situ Chemical
Reduction (ISCR) Technology for
In Situ
Treatment of Volatile Organic Compounds (VOCs)
Fayaz Lakhwala, Adventus Americas, Inc., Union, NJ
Ravikumar Srirangam, Adventus Americas, Inc., Union, NJ
Jim Mueller, Adventus Americas Inc.,
Freeport,
IL
Josephine Molin, The Adventus Group
John Valkenburg, The Adventus Group
Nitrate Removal from Synthetic High Nitrate Aaste by a
Denitrifying Bacterium
Rashmi R. Nair, Bhabha Atomic Research Centre,
Mumbai, India
Stanislaus F.
D’Souza, Bhabha Atomic Research Centre, Mumbai,
India
Comprehensive Study on Sorption of Polycyclic Aromatic
Hydrocarbons on Black Carbon
Hongwen Sun,
Nankai
University, Tianjin, P. R. China
Zunlong Zhou, Zhejiang University of
Technology, Zhejiang , P. R. China
The Capability of Binary Systems Containing
Water-soluble Ionic Liquids for Extraction of Typical
Endocrine Disrupting Chemicals from Sediments
Lei Wang, Ph.D,
Nankai
University, Tianjin, PR China
Guohua Zhang,
Nankai
University, Tianjin, PR China
Hongwen Nankai
University,
Tianjin,
PR China
Teng Tu,
Nankai University,
Tianjin, PR China
Aquablok + Organoclay as Permeable Barriers
George R. Alther,
Biomin Inc., 21641 Meyers Road,
Oak Park, MI 48237, Tel: 248-544-2552,
Fax: 248-544-3733, Email: biomin@aol.com
Aquablok is a patented, composite
aggregate technology resembling small stones and
typically comprised of a dense aggregate core. In this
application of the technology an organoclay coating is
utilized with polymers (Figure 1). In other AquaBlok+
applications, various alternative treatment materials
can be incorporated to meet project-specific needs
AquaBlok+ORGANOCLAY particles adsorb
oil and a wide range of hydrocarbon-based contaminants
when contact is made in sediments. As the particles
chemically bind the contaminants, the clay layer will
expand. At a point when the full mass of the organoclay
is achieved the particles coalesce into a continuous and
relatively soft body of material, decreasing the
permeability of the layer. The AquaBlok+ORGANOCLAY layer
can also be used in conjunction with a standard AquaBlok
cap layer to form an even lower permeability barrier
layer above the sediment if desired
Organoclays are a proven remediation
technology that addresses a wide range of
hydrocarbon-based contamination. The following is a
partial list of typical sites and/or contaminants where
AquaBlok+ORGANOCLAY cap can be a cost-effective
solution:
·
MGP
Plants
·
Wood
Treating Facilities
·
Creosote
·
Coal
Tar (BTEX)
·
PCBs
·
PAHs/NPL
Although it has been established that
similar weight of organoclay materials will remove, by
means of partitioning, up to 7 times the rate of
activated carbon, activated carbon can provide further
absorption of trace amounts that may not be fully
removed by organoclay. Thus, the materials can be used
in series in a complimentary manner in some applications
requiring very low levels of treatment.
Rheological Characteristics
of
Manufactured Gas
Plant Tars and Implications for Remediation
Student Presenter
Pamela Schultz Birak,
University of North Carolina at Chapel Hill, 148 Rosenau
Hall CB 7431, Chapel Hill, NC 27599-7431, U.S.A., Tel:
919-966-6332,
Fax: 919-966-7911,
Email: pamela_birak@unc.edu
Scott C. Hauswirth, University of North Carolina at
Chapel Hill, 148 Rosenau Hall CB 7431, Chapel Hill, NC
27599-7431, U.S.A., Tel:
919-966-6332, Fax:
919-966-7911,
Email: shauswirth@unc.edu
Cass T. Miller, University of North Carolina at Chapel
Hill, 148 Rosenau Hall CB 7431, Chapel Hill, NC
27599-7431, U.S.A., Tel:
919-966-1024, Fax:
919-966-7911,
Email: casey_miller@unc.edu
Thousands of former manufactured gas plants (MGPs) are
located across the
U.S.
At these sites, one of the most significant
sources of contamination is by-product tar.
The viscosity of MGP tars can vary several orders
of magnitude and plays an important role in affecting
the migration and distribution of these dense
non-aqueous phase liquids in the subsurface.
Understanding the flow or rheological behavior of
a particular tar is critical for designing effective
pumping strategies and for understanding potential
further migration of subsurface tar plumes.
In this work, we conducted a rheological analysis
of tars recovered from two former MGPs, as well as a
recently produced coal tar.
Viscosity was
measured using a rotational viscometer, where both
temperature and shear rate can be controlled.
Data from the rotational viscometer were fit to
standard functions to allow for the prediction of
viscosity for various temperatures and shear rates.
At low shear rates and temperatures relevant to
subsurface systems, tars were found to be non-Newtonian
such that the viscosity was no longer constant and
increased with decreasing shear rate.
Thus, the movement of a creeping tar plume could
be over- predicted by relying on viscosity measurements
in the Newtonian range.
Viscosity was also found to be very sensitive to
temperature and decreased by orders of magnitude from 5
to 80 degrees C.
This decreased viscosity could be useful for
thermal approaches to remediation when the mobilization
of trapped residual is a desired effect.
In Situ Soil Washing by Sedimentation Method for
Contaminated Sandy Soil
Wawan Budianta,
Department of Geological Engineering, Faculty of
Engineering, Jl. Grafika 2 Kampus UGM, Gadjah Mada
University, Yogyakarta 55281, Indonesia. Tel:
+62-274-513668, Fax: +62-274-513668, Email:
wbudianta@ugm.ac.id
Chris Salim, Department of International Development
Engineering, Tokyo Institute of Technology, I4-406,
2-12-1 Ookayama, Meguro-Ku, Tokyo 152-8550, Japan, Tel:
+81-3-5734-3245, Fax: +81-3-5734-3245, Email:
salim.c.aa@m.titech.ac.jp
Hirofumi Hinode, Department of International Development
Engineering, Tokyo Institute of Technology, I4-406,
2-12-1 Ookayama, Meguro-Ku, Tokyo 152-8550, Japan, Tel:
+81-3-5734-3245, Fax: +81-3-5734-3245, Email:
hinode@ide.titech.ac.jp
Hideki Ohta, Department of International Development
Engineering, Tokyo Institute of Technology, S6-3, 2-12-1
Ookayama, Meguro-Ku, Tokyo 152-8550, Japan, Tel:
+62-3-5734-3583, Fax: +62-3-5734-3189, Email:
ohta@ide.titch.ac.jp
We propose a new method of in situ soil remediation
called in situ washing by sedimentation (IWS),
accomplished by injecting a high air-pressure into a
mixture of saturated water-sandy soil at a certain depth
and hydraulically separating the soil particles based on
their particle size and density. This physical
segregation exploits the distribution of contaminant in
the soil by physically separating a selected
contaminant-rich fraction. For the in situ application,
the physical segregation by sedimentation and on-site
water wash treatment happen as an integrated process.
The advantage of IWS that the washing and segregation
processes take place simultaneously during the
remediation process, quick, effective and cheap since
there are no costs for excavation of contaminated soil
from the site. The effect of soil-water ratio and
diameter geometry of the column on the effectiveness of
segregation by IWS was investigated. A series of
laboratory test were conducted to optimize the soil
water ratio for the best segregation process. Soil-water
ratio 1:2 (v/v) was found to be optimum for particle
segregation produced by IWS and generally the diameter
geometry column will not affect on the particle
segregation on IWS. The suitability of IWS for Heavy
Metals such as Copper, Zinc, Lead and Cadmium and also
for Polycyclic Aromatic Hydrocarbons (PAHs) remediation,
such as Napthalene, Phenantrene and Pyrene, were
examined by batch sedimentation column experiment. The
laboratory experiment was effective to produce a
distinct size segregation of the contaminated soil into
the coarse and fine fractions, as well as the wash
water, indicating that a significant reduction in Heavy
Metals and PAHs (90%) may be achieved. The experimental
results show that the removal efficiencies depend on the
initial concentration of Heavy Metals and PAHs in the
soil sample, the duration of washing and the addition of
biosurfactant in the washing solution.
Remediation of
Acid Tar Lagoon
Branko Druzina,
University College of Health, University of Ljubljana,
Poljanska cesta 26 a, Ljubljana, Slovenia, Tel: 00386 1
300 11 15, Fax.: 00386 1 300 11 19, Email:
branko.druzina@vsz.uni-lj.si
Andrej Perc, University College of Health, University of
Ljubljana, Poljanska cesta 26 a, Ljubljana, Slovenia,
Tel: 00386 1 300 11 15, Fax.: 00386 1 300 11 19, Email:
perc.andrej@gmail.com
Slovenia
(20,000 km2, 2 million inhabitants, 750,000
in employment) is industrialised to a medium extent.
Many ecological problems have remained from past periods
(‘old ecological burdens’).
Many of them are legal waste dumps resulting from the
technology used in these past periods. One of these is
the acid tar waste dump in the northeast of the country,
close to the border with Austria (‘Pesnicki Dvor’, in
operation from 1966 to 1983).
In addition to mineral and sulphanated mineral oils,
acid tar also contains well dispersed heavy metal salts
of lead, zinc copper, arsenic and barium.
The surface area of the acid tar at the dump was between
3,000 and 3,500 m2. The total thickness of
the acid tar and water was 5 m, and the pH value of the
water below acid tar was approx. 1.5.
In 2006 the clean-up of the dump began:
- Excavation of the tar and contaminated earth;
- Technological process of solidification of the tar;
- Loading and removal of the solidificate or the product
of the incineration process;
- Capture and cleaning of waste acid gases;
- Cleaning of water from the dump at a treatment
facility.
The process of solidification of the acid tar took place
in a plate mixer (approx. 80 tonnes a day), the addition
of active additives (CaO, Ca(OH)2, CaC03)
amounted to approx. 25 tonnes a day, and the total daily
volume of all additives used was approx. 20–50m3.
The daily production of solidificate from acid tar and
contaminated earth was 90 m3.
More detailed results of the clean-up and cleaning from
the polluted water process will be shown by individual
stage of the process, with a timescale and the relevant
measurements and data.
The end result of the clean-up is the removal of all
acid tar and polluted soil, the removal of all surfaces
and facilities used during the clean-up, the
introduction of clean earth and the re-cultivation of
the area (‘greening’).
Remediation in Skykomish
Washington
Michael Byers, AECOM Environment,
1011 SW Klickitat Way, Ste 207,
Seattle, WA 98137, USA, 206-624-9349, Email:
Mike.Byers@aecom.com
Mike Gardner, AECOM Environment, 2
Technology Park Drive, Westford, MA 01886, USA,
978-589-3000, Email: Mike.Gardner@aecom.com
Aimee Fitzpatrick, AECOM Environment, 171 Daniel Webster Highway, Ste 11,
Belmont,
NH
03220,
USA,
603-524-8866, Email: Aimee.Fitzpatrick@aecom.com
Skykomish
Washington, incorporated in
1909, has 250 people. Skykomish situated on the
west-facing slopes of the northern Cascade Mountains in
northwest Washington.
The early development of Skykomish was shaped by
the railroad, regional resource-based industries (i.e.,
logging and mining) and commercial needs of the
residents.
When the rail line was completed in 1893, the town
became the location for a variety of facilities for
storage, maintenance, and repair of engines and track.
The facilities changed as railroad technologies
evolved: fueling facilities changed from support for
steam power, bunker-C fuel, diesel power and electrical
power.
The industrial history of Skykomish and the railyard
resulted in below-ground petroleum hydrocarbon (LNAPL)
contamination that extends from the railyard to below
approximately half of the town, as LNAPL followed
groundwater to seep out in the North Fork of the Skykomish River.
First phase of cleanup, in 2006, included
removing and replacing the main flood control levee,
moving five residential structures to facilitate removal
of impacted soil, and removal/replacement of about
20,000 cubic yards of impacted sediment from the
Skykomish
River.
Second phase of remediation, in the summer of
2008, included the relocation of three buildings
(including the historic train depot) and removal of
impacted soil from below the main street.
This phase also included the installation of a
1,100-foot barrier wall with four large subsurface
passive treatment vaults to reduce dissolved petroleum
in groundwater flowing out the railyard and onto
adjacent property.
Remediation is anticipated to continue through
2011 with different parts of the town being affected in
different years.
Monitoring and maintenance activities will
continue beyond the active remediation.
Optimization of a Multi-Well Groundwater Pump and Treat
System: Managing Hydraulic Stagnation Zones
Mark D.
Hilyard,
CH2M HILL, 318C East Inner Road, Otis ANG Base, MA
02542-5028, United States, Tel: 508-968-4670 x 5604,
Fax: 508-968-4916, Email: Mark.Hilyard@ch2m.com
Rose H. Forbes, P.E., Air Force Center for Engineering
and the Environment, 322 East Inner Road, Otis ANG Base,
MA 02542-5028, Tel: 508-968-4670 x 5613, Fax:
508-968-4476, Email:
rose.forbes@brooks.af.mil
In September 1997, a groundwater pump and treat system
began operating to remediate the Fuel Spill-12 (FS-12)
groundwater plume at the Massachusetts Military
Reservation.
The primary contaminant of concern within the
FS-12 plume is ethylene dibromide (EDB), which is a
remnant of an approximately 70,000 gallon release of
both aviation gasoline and jet-fuel to the subsurface in
the 1970s.
At startup, the treatment system was comprised of 25
extraction wells pumping at a combined flow rate of 772
gallons per minute.
The extracted groundwater is piped to a treatment
plant where contaminants are removed using granular
activated carbon filtration.
Treated water is returned to the aquifer through
23 reinjection wells.
A significant reduction in both the contaminant
mass and volume of the FS-12 plume has occurred since
start up in 1997; primarily due to the operation of the
remedial system.
Therefore, the remedial system has been optimized
several times since 1997 to improve plume recovery,
reduce predicted cleanup time, and reduce operational
costs.
Since 2006 the mass removal efficiency of the treatment
system has steadily declined.
A 2008 field investigation, which included
collection of groundwater vertical profile data from
boreholes installed between extraction wells using sonic
drilling techniques, identified several potential
hydraulic stagnation zones within the composite capture
zone of the FS-12 treatment system.
Such stagnation zones are thought to inhibit the
movement of EDB impacted groundwater to the operating
extraction wells due to competing hydraulic stresses.
The goal of this most recent optimization was to adjust
well-field pumping conditions in an effort to eliminate
these hydraulic stagnation zones.
A capture zone analysis using an existing
groundwater flow model was completed to assess whether
the remedial goal of plume capture was still being met
under the new operating conditions.
Limited-Access Bioremediation in a Factory Setting
Deborah R. Farnsworth,
President, MyKroWaters, Inc., P.O. Box 1088,
Concord,
MA
01742, Tel:
978-369-3037, Email: deborahf@mykrowaters.com|
Willard Murray, Ph.D., P.E.,. ECC, Inc., 33 Boston Post Road West,
Marlborough,
MA
01752, Tel:
508-229-2270, Email: wmurray@ecc.net
Daniel Bronson, President, Bronson Drilling, P.O. Box 400013,
Cambridge,
MA
02140, Tel:
617-610-1801, Email: dan@bronsondrilling.com
A factory in
New Hampshire had a volatile
organic compound (VOC) release detected in a storm-water
outfall pipe. Hydrogen Release Compound (HRC) injection
was determined to be the best remedial solution. Tight
soils, shallow water table, access limitations, and
pending property sale complicated remediation. The
groundwater contamination was addressed through
bioremediation using HRC. Application required many
injection points and applications, due to the low
permeability of the soil. An trench was cut into the
concrete floor slab between each injection point and the
wall. Piping ran from the injection point to the wall,
terminating at a standpipe with a quick-connect fitting.
Each trench was then fillled with concrete to restore
the floor slab. Since starting HRC treatment, VOC levels
at the outfall have dropped to below the state
regulatory standard. One well had levels of 1800 ug/L
and 1200 ug/L of Cis-1,2 Dichloroethene
and Vinyl Chloride in April, 2008. By January,
2009, both were below MCLs.
Site closure is expected to be completed in a
reasonable timeframe. The treatment has not interfered
with Site activities or with sale of the Site.
EHC®
In
Situ Chemical
Reduction (ISCR) Technology for
In Situ
Treatment of Volatile Organic Compounds (VOCs)
Fayaz Lakhwala, Adventus Americas, Inc. 1435 Morris
Avenue, 2nd Flr., Union, NJ 07083, Tel: 908-688-8543,
Fax: 908-688-8563,
Email: Fayaz.Lakhwala@AdventusGroup.com
Ravikumar Srirangam,
Adventus Americas, Inc. 1435 Morris Avenue, 2nd Flr.,
Union, NJ 07083, Tel: 908-688-8543, Fax: 908-688-8563,
Email: Ravi.Srirangam@AdventusGroup.com
Jim Mueller, Adventus Americas Inc., 2871 W. Forest
Road, Suite #2, Freeport, IL
61032,
Tel: 815-235-3503, Email: jim.mueller@adventusgroup.com
Josephine Molin, The Adventus Group – USA, Email:
josephine.molin@AdventusGroup.com
John Valkenburg, The Adventus Group – USA, Email:
john.valkenburg@AdventusGroup.com
The
Adventus Group (Adventus) has developed a combination of
controlled-release solid carbon and zero valent iron
(ZVI) particles to yield a highly effective material for
stimulating the reductive dechlorination of otherwise
persistent organic solvents present in groundwater. The
materials are known as EHC® and can be
employed as fill material for permeable reactive
barriers or injected into groundwater and contaminant
source zones in a variety of ways. Following placement
of EHC into the subsurface environment, indigenous
heterotrophic bacteria consume the organic component of
EHC (processed fibrous organic material) and consume
dissolved oxygen thereby reducing the redox potential in
groundwater. In addition, these bacteria ferment carbon
and release a variety of volatile fatty acids (acetic,
propionic, butyric) into the groundwater plume which
serve as electron donors for other bacteria, including
dehalogenators and halorespiring species. Finally, the
small ZVI particles (i.e., between 10 and 50
mm)
provide substantial reactive surface area that
stimulates direct chemical dechlorination and an
additional drop in the redox potential of the
groundwater. These physical, chemical, and biological
processes combine to create a strongly reducing (e.g.,
up to -550 mV Eh) environment that stimulates
both chemical and microbiological dechlorination of
solvents in groundwater.
In situ
chemical reduction (ISCR) is defined as the combined
effect of stimulated biological oxygen consumption (via
“fermentation” of complex organic carbon sources),
direct chemical reduction with reduced metals, and the
corresponding enhanced decomposition reactions that are
realized at the lowered redox (Eh)
conditions. These combined effects are unique to EHC®
technology. EHC can be safely and easily applied to the
subsurface environment in number of ways for the
treatment of chlorinated volatile organic compounds (CVOCs),
chlorinated organic pesticides, heavy metals and other
persistent compounds (e.g., perchlorate).
Case Study: Groundwater at a manufacturing facility in
Portland,
Oregon was impacted by chlorinated
volatile organic compounds (cVOCs) with concentrations
indicative of a dense nonaqueous–phase liquid (DNAPL)
release. An evaluation of the source-area and
downgradient plume treatment remedies identified insitu
bioremediation as most likely to be effective for the
CVOC plume.
Bench scale studies were performed to identify the most
appropriate technology which was further evaluated in a
field pilot study. The results of the testing
demonstrated that
enhanced bioremediation by in situ chemical
reduction (ISCR) using EHC® and KB-1®
was most
appropriate for this site , providing outstanding
results presented in this presentation.
Nitrate Removal from Synthetic High Nitrate Waste by a
Denitrifying Bacterium
Student Presenter
Rashmi R. Nair,
Nuclear Agriculture and Biotechnology Division, Bhabha
Atomic Research Centre, Trombay, Mumbai 400 085,
India.
Tel: +91-22-23091038, Fax: +91-22-25505151/25519-613,
Email: rushnair@gmail.com
Stanislaus F. D’Souza,
Nuclear Agriculture and Biotechnology Division, Bhabha
Atomic Research Centre, Trombay, Mumbai 400 085,
India.
Tel:
+91-22-25593632, Fax: +91-22-25505151/25519-613, Email:
sfdsouza@ barc.gov.in
The present work aims towards isolating organisms
capable of treating high nitrate wastewater and
optimizing the process for maximum denitrification rate.
A denitrifying bacterium strain, isolated from the
wastewater of a fertilizer denitrification plant (FDP),
was screened from a total of 160 isolated cultures based
on its high nitrate removal efficiency. Biochemical
tests and 16S rRNA sequence analysis showed the
bacterium genus to be
Pseudomonas
and close to
aeruginosa species. The culture on acclimatization
to high strength nitrate waste [10000 ppm NO3
(2258 ppm NO3-N)] in a sequence batch
reactor, showed complete degradation in a time period of
just 1.75 h. The specific nitrate and nitrite
degradation rate of the process using the acclimatized
culture was further increased by 54.4 % and 15 %
respectively on optimizing the process using orthogonal
array method. The applicability of this isolate for high
rate denitrification process was investigated in a 4 L
reactor and the two important enzymes involved in the
first two steps of denitrification process, NaR and NiR
were assayed. This provided an invitro index of
the ability of the cells to reduce nitrate and nitrite.
The reactor was run successfully for 2 months without
any change in the activity. Studies has now been
extended further by using this isolate for
denitrification of radioactive nuclear high nitrate
wastes, which is a common nuclear problem faced during
uranium extraction process.
Comprehensive Study on Sorption of Polycyclic Aromatic
Hydrocarbons on Black Carbon
Hongwen Sun,
Ph.D, MOE Key Laboratory of Pollution Processes and
Environmental Criteria, College of Environmental Science
and Engineering, Nankai University, Tianjin 300071, P.
R. China, Tel/Fax: 86-22-23509241, Email:
hongwen.sun@yahoo.com.cn
Zunlong Zhou, Ph.D, College of Biological and
Environmental Engineering, Zhejiang University of
Technology, Hangzhou, Zhejiang 310032, P. R. China,
Tel/Fax: 86-571-88320967, Email:
zhouzunlong@mail.zjut.edu.cn
Sorption of three polycyclic
aromatic hydrocarbons (PAHs) on three charcoals and
their precursor (sawdust) was studied. The charcoals
obtained by heating at 400
°C for different periods
were different in chemical composition and structure.
Sorption characteristics were for the first time
described by Polanyi–Dubinin–Manes model combined with
poly-parameter linear free energy relationships on
charcoals. The results revealed that though partition
could not be neglected for sawdust and charcoal
containing large sawdust residue, adsorption controlled
the sorption of PAHs on matured charcoals, where π-π
electron donor–acceptor (EDA) exerted as a main specific
interaction besides to the nonspecific interaction.
Charring elevated partition coefficients
(Koc)
of the PAHs by more than one order of magnitude.
Adsorption increased with the aromaticity of the
charcoals, however, polar aromatic structure may
stimulate sorption of PAHs due to the presence of π-π
EDA interaction.
Then, comparative study was
conducted on the sorption of phenanthrene on charcoals
with and without the modification by humic acids as
single solute or in bi-solute system with pyrene. The
sorption of phenanthrene onto charcoals decreased and
became more linear with the addition of increasing
concentration of pyrene, which again proved that the
sorption of PAHs onto charcoals is controlled by
multi-processes. Competition between the two PAHs was
different for different charcoals due to their different
distribution of high/low-energy sites. It is proposed
that the sites induced by π-π EDA are low-energy sites,
which occur mainly at surface-adsorpiton process. The
sites controlled by hydrophobic interaction are
high-energy sites. Loading of humic acid on charcoals
also led to a reduction in phenanthrene adsorption.
After loading with humic acid, the difference in surface
properties between different charcoals was mitigated,
and competition effect of pyrene on phenanthrene
sorption became similar on the two modified charcoals.
The Capability of Binary Systems Containing
Water-soluble Ionic Liquids for Extraction of Typical
Endocrine Disrupting Chemicals from Sediments
Lei Wang, Ph.D, Key Laboratory
of Pollution Processes and Environmental Criteria,
Nankai University, Ministry of Education, Tianjin
300071, PR China. Tel: 86-22-2350-4821, Email:
L.wang@live.com
Guohua Zhang, Master student, College of
Environmental Science and Engineering, Nankai
University, Tianjin 300071, PR China, Tel:
86-22-2350-4362, Email: weally2008@126.com
Hongwen Sun, Ph.D, Key Laboratory of Pollution
Processes and Environmental Criteria, Nankai University,
Ministry of Education, Tianjin 300071, PR China, Tel:
86-22-2350-9241,
Email: hongwen.sun@yahoo.com.cn
Teng Tu, Bachelor student, College of Environmental
Science and Engineering, Nankai University,Tianjin
300071, PR China, Tel: 86-22-2350-4362, Email:
tuteng0921@mail.nankai.edu.cn
Binary systems containing water and
different water-soluble ionic liquids (WSILs) were
considered for extraction of three typical endocrine
disruptor chemicals (EDCs), 17β-estradiol (17β-E2),
bisphenol A (BPA), and nonylphenol (NP), from three
model sediments. Imidazolium and pyridinium based ionic
liquids with different anions (tetrafluoroborate or
chloride) were selected as representative WSILs to
assess the extraction of EDCs from different sediments
by the binary system containing water and WSILs at
different molecular ratio. Compared with extraction of
EDCs by water, the presence of 1-butyl-3-methyl
imidazolium tetrafluoroborate ([bmim]PF4) or
N-butyl-3-methyl pyridinium tetrafluoroborate ([bmpy]PF4)
in the binary system at low molecular ratio could
decrease the extraction of EDCs. However, at high
molecular ratios, WSILs in binary system significantly
increased the extraction of EDCs, especially for those
from sediments with high organic matter content. At a
molecular ratio of 5: 5 (WSIL: water), extraction by the
binary system containing [bmim]PF4 was more efficient
than that by [bmpy]PF4. However, at a molecular ratio of
1: 9, contrary results occurred. Cation-π, π-π, and
hydrogen bond interaction of phenolic hydroxyl and
“-N=C(H)-N-” are proposed to be the major interactions
between WSILs and EDC molecules, while these
interactions were greatly inhibited when water molecule
presented in the binary system at high ratio. Moreover,
the adsorption of WSILs on sediments could affect the
extraction efficiency when they presented at low ratio.
At the same molecular ratio, the presence of [bmim]PF4
and 1-butyl-3-methyl imidazolium chloride ([bmim]Cl)
resulted in similar extraction efficiencies, which might
suggest that anions of WSILs play minor role for the
extraction of EECs in this study.
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