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