development of in-situ extraction for point-of-use trace...
Post on 19-Oct-2020
6 Views
Preview:
TRANSCRIPT
Development of In-Situ Extraction for Point-of-Use Trace Metal Sensor in New
Jersey SedimentPhilip Sontag1, Katherine Dawson2, Mikayla Byron2, Matthew Esteves2, Azam Gholizadeh3, Malcolm X Shabazz Biogeochemistry Team4, Andrew D. Steen5,
Ali Maher1, Mehdi Javanmard6, and Robert Miskewitz1
1Center for Advanced Infrastructure and Technology, Rutgers University 2Department of Environmental Sciences, Rutgers University 3Virginia Tech University 4Malcolm X Shabazz High School, NJ 5University of Tennessee, Earth and Planetary Sciences 6Department of Electrical Engineering, Rutgers University
Directions for Future Research• Analyze lead (Pb) concentrations using sensor and traditional laboratory
techniques in sediment from NY/NJ harbor• Determine the impact of the microbial community on enzyme-sediment
digestion through 16S (DNA) and response of bacteria through expressionof RNA transcripts
• Determine the need for regional or broad-scale chemical speciationmodels to determine modeled total Pb concentrations in sediment
• Move from point-of-use sensor application to autonomous deploymentfor real-time sediment measurements in estuarine ecosystems
Acknowledgements
Discussion• Iron (Fe)-bound and residual (sulfide)-bound lead (Pb) controls the
majority of the Pb fractions in New Jersey sediment• Addition of β-glucosidase exoenzyme increased Pb signal in most samples
of digested sediment• Bacterial communities and metabolisms may impact enzyme-sediment
digestion at varying salinities in estuarine watersheds• Good agreement between sensor signal and modeled total Pb
concentrations was achieved in Fe-replete New Jersey sediment
We would like to thank: Dr. Reinfelder at Rutgers University, Dr. Steen atUniversity of Tennessee, and the Malcolm X Shabazz High School andPat Murray.
0
5
10
15
20
25
-1 -0.9 -0.8 -0.7 -0.6 -0.5 -0.4 -0.3 -0.2 -0.1 0
Cu
rren
t (µ
A)
Voltage vs Ag/AgCl (V)
Pb measurment without enzyme digestion
Pb measurment with enzyme digestion
ICP-OES Sediment [Pb] (mg/kg)Nitric Acid alone (control): 1.2
+Enzyme Extraction: 2.2
CC7B
Square wave anodic stripping voltammogram (SWASV) of lead (Pb) ion in enzyme digested sediment sample
0
1
2
3
4
5
6
-1 -0.9 -0.8 -0.7 -0.6 -0.5 -0.4 -0.3 -0.2 -0.1 0
Cu
rren
t (µ
A)
Voltage vs Ag/AgCl (V)
Pb measurment without enzyme digestion
Pb measurment with enzyme digestion
ICP-OES Sediment [Pb] (mg/kg)Nitric Acid alone (control): 4.4
+Enzyme Extraction: 4.3
CC5A
ICP-OES Sediment [Pb]
(mg/kg)
Nitric Acid alone (control):
1.2
+Enzyme Extraction: 2.2
ICP-OES Sediment [Pb]
(mg/kg)
Nitric Acid alone (control):
4.4
+Enzyme Extraction: 4.3
SedimentOrganic Matter
Extracellular Enzymes, Hydrolysis Reactions
Stimulate Microbial
Metabolism
Liberate Trace
Metals
Breakdown of Sediment Organic Matter (OM)
y = 27.789ln(x) + 143.58R² = 0.8248
y = 26.176ln(x) + 144.23R² = 0.9768
0
20
40
60
80
100
120
140
160
180
200
0.00 0.50 1.00 1.50 2.00
To
tal [P
b]
(pp
m)
Sensor [Pb] (ppm)
Relationship between Sensor [Pb] and Total [Pb]
(Measured and Modeled)
Stacked bar chart of archaeal and bacterial diversity in Raritan River-Bay sediment samples3D Printed Sample
Preparation Cartridge with
ElectrodesLaboratory Setup
% of Lead (Pb) Bound – Four Sediment Fractions –
Cheesequake CreekSample
Name
F1-
Carbonates %
of Total
F2- Fe Oxides
% of Total
F3- OM
% of Total
Residual-
Sulfides % of
Total
SC1A 3.1 34.6 15.9 46.4
CC2B 2.9 27.6 4.4 65.1
CC7B 4.4 40.1 ND 55.5
CC5A 9.6 40.7 4.7 45.0
SC2A 6.1 39.3 4.2 50.4
Results
Contact InformationPhilip Sontag – Postdoctoral Associate – Center for Advanced
Infrastructure and Technology - Email: philip.sontag@rutgers.edu
AbstractCollaborative research efforts between the Center for Advanced Infrastructure and Technology, Electrical Engineering, and Environmental Science Departments at Rutgers University have yielded a graphene oxide sensor capable of measuring lead (Pb) in sediment at part per billion levels. Parallel measurements of total Pb and Pb speciation in various sediment fractions were used to produce modeled total Pb concentration from the sensor’s electrochemical response. Addition of exoenzyme (β-glucosidase) increased sensor’s signal (factor of 2 to 10) and is likely attributed to natural chemical and microbial reduction fueled by the breakdown of complex organic matter. Future project aims include the evaluation of microbial communities in New Jersey and New York sediment and response of microbial metabolisms to exoenzyme additions in enzyme-sediment digestion.
Project Goals• Point-of-use lead (Pb) detection in less than five minutes at part per
billion (ppb) levels• Model total Pb concentrations from sensor signal within 15% of measured
total concentrations in New Jersey and New York sediment• Optimize enzyme-sediment digestion with different exoenzyme additions• Characterize microbial community and activity in response to exoenzyme
additions
top related