Materials and Methods Characterization:
• Inductively coupled plasma (ICP) Cu2+ concentration
• Brunauer-Emmett-Teller (BET) surface area
• Fourier transform infrared spectroscopy (FTIR)
functional groups
• Zeta Potential Analyzer surface charge
Process Design:
• Breakthrough Flow-through column design
Conclusions/Future Work Characterization: • High surface area, due to high processing temperatures,
had the greatest effect on the adsorption capacity.
Process Design:
• The best operating capacity was 50% of the batch test
adsorption density: combustion char.
• Test scaled model of the industrial filtration design for
flow characteristics and ability to remove copper (II).
Process Design Results
A continuous filtration system was designed based on column
breakthrough tests and the resulting operating capacity of the
biochar.
Project Opportunity Increased copper (II) levels in stormwater is the driving concern of our project. It is a common industrial pollutant and is
released onto highways through car brake pad use. Increased copper (II) concentrations in waterways negatively affect
salmon olfactory systems, reducing their ability to return to their birthplace and spawn.
With three industrially produced biochars, we will:
• Catalog their physical and chemical characteristics to determine the major mechanism of copper (II) removal.
• Design a filtration system for the remediation of copper from industrial stormwater runoff.
What is Biochar?
Biochar, similar to charcoal, is an organic material made through the thermal digestion of biomass.
Biomass is processed at high temperatures, which increases the porosity of the biochar.1 High porosity, or high surface
area, results in better contact with contaminated stormwater. Chemical functional groups and increased biochar surface
charge are two other mechanisms in which copper (II) can be removed.2 The adsorption characteristics are dependent on
the biochar process temperature and feedstock.3 The processing conditions of the three biochars are listed.
Characterization Results
The following four tests were performed to characterize the
biochar. The adsorption density determines the biochar
performance, while the last three results help explain why.
Characterization of Biochars and Process Development for Stormwater RemediationRobert Hannah, Tyler Kimmel, Sunny Ovesen, Greg Stearns
School of Chemical, Biological, and Environmental Engineering
Literature Cited 1. Keiluweit, M., Nico, R. (2010). “Dynamic Molecular Structure of Plant
Biomass-Derived Black Carbon (Biochar).” Environmental Science
Technology 44. 1247-1253.
2. Uchimiya, M., Bannon, D., Wartelle, H. (2012). "Retention of Heavy
Metals by Carboxyl Functional Groups of Biochars in Small Arms Range
Soil." Journal of Agricultural and Food Chemistry 60. 1798-1809.
3. Mukherjee, A., Zimmerman, A.R. (2011). “Surface chemistry variations
among a series of laboratory-produced biochars.” Geoderma 163. 247-
255.
Figure 1: The adsorption density (qe) isotherm measures copper (II) removal with respect to
the equilibrium copper (II) concentration.
Figure 2: Surface area quantifies
the biochar’s porosity. The high
surface area of the gasification char
suggests more available sites for
copper (II) removal.
Figure 3: The similar
functional groups between the
biochars excludes surface
chemistry as a cause for
differing adsorption capacities.
Figure 5: A simple filtration schematic of continuous Cu2+ removal in a bed of biochar
Filtration Systemmbc = 100 kg biochar
qe (Adsorption Density) ≈ 4 mg Cu2+/g charContaminated Stormwater
Qx = 4000 m3/yr
Ce = 100 ppb Cu2+
Treated Water
Qx = 4000 m3/yr
< 7 ppb Cu2+
Biochar
Figure 6: Continuous adsorption of copper (II) for all three biochars was tested at 5 mL/min.
Combustion outperforms both gasification and pyrolysis for continuous copper (II) removal.
The average operating capacity was between 14 and 50% of the batch test adsorption density.
Figure 4: A larger surface
charge suggests a larger
amount of copper (II)
flocculating around a
particle of biochar.
Biochar Types Surface Area (m2/g)
Combustion 392 ± 15
Gasification 806 ± 22
Pyrolysis 283 ± 12
Figure 7: The in-drain filtration system has a hard outer shell with a geotextile
biochar bag inside. The over flow weir relieves excess stormwater, and the system
increases residence times for more complete copper (II) removal.
Qx (Flowrate through Storm Drain)
Ce (Copper Concentration in Water)
Mbc (Mass of Biochar)
qe (Adsorption Density)
Our biochar: (Feedstock, Processing Temperature)
• Combustion: (Redwood, 1300 C)
• Gasification :(Doug fir, 900 C)
• Pyrolysis: (Redwood, 600 C)
Processing Unit
Under-drain Funnel
View of
biochar
Removable biochar
sack
Overflow WeirMaximum
Water Level
Primary
Stormwater Drain
Surface Storm Grate
Geotextile Mesh Bag
Flow-Packed
Biochar
Glass Wool
Post-Biochar
Glass Wool
Pre-Biochar
Column
Effluent
To Waste
Contaminated
Stormwater Inlet
Scale-Up
Acknowledgments Dr. Jeff Nason, John Miedema, Justin Provolt, Brian Smith,
Nick Wannemacher, Brian Rowbatham, Matt Adams,
Tyler Deboodt, Dr. Mohammad Azizian, Malachi Bunn, Danny Phipps,
Cameron Oden, Andy Brickman, Dr. Phil Harding, Andy Ungerer
Iron
50 m 100 m 40 m 200 m Combustion Char Gasification Char Gasification Char Pyrolysis Char
Surface Area
Adsorption Density
Functional Groups
Surface Charge
Flow through Filtration Concept
Continuous Adsorption Results
Column Design and In-Drain Schematic:
Iron
50 m 100 m 40 m 200 m Combustion Char Gasification Char Gasification Char Pyrolysis Char