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RESEARCH POSTER PRESENTATION DESIGN © 2012
www.PosterPresentations.com
This study reports the concentration of water and acid soluble elements in
the biochar samples produced through slow pyrolysis of various herbaceous
and ligneous feedstocks. Biochar samples were produced from red cedar,
pine, oak, willow, corn stover, miscanthus giganteus and switchgrass. The
information reported in this study in part explains the role biochar plays in
promoting plant growth and its enhancing effect on soil quality. The results
demonstrate that biochar chemical composition reflects the composition
of its biomass precursor. The DI water extractable N, P, K, Ca, Mg, and S of
biochar produced from coniferous biomass were found to be generally
lower than those of the herbaceous and deciduous biomass feedstocks. The
giant miscanthus and switchgrass in this study contained more K than the
ligneous feedstocks. Among the trace elements, B and Zn were
omnipresent in acid digested biochar samples but unlike B, the amount of
Zn significantly varied among samples.
Abstract
The objectives of this study were:
1. To better understand the soluble component of biochar produced from
the lignocellulosic biomass through slow pyrolysis
2. To estimate the trace elemental composition of biochar.
3. To compare the soluble elements present in biochar samples.
4. To estimate proportion of the DI water and weak acid extractable
chemical elements in biochar sample
Objectives
In this study biochar was produced from the following biomass: Oak
(Quercus ellipsoidalis), willow (Salix amygdaloides), cedar (Juniperus
virginiana), pine (Pinus strobus), corn (Zea mays) stover, giant miscanthus
(Miscanthus giganteus) and switchgrass (Panicum vergatum).
The biomass was air-dried and was placed in an inner steel drum enclosed
in an outer drum. Cedar wood blocks were ignited in the space between
the two drums. The temperature was monitored via a thermocouple.
Biochar was produced between 400 C and 600 C.
Biochar samples were ground and passed through a 2-mm sieve. 10-gram
samples were rinsed with known volume of DI water, 0.01 M or 0.1 M HCl.
The effluent was collected for analysis using ICP-MS (2). 200.0 milligram
biochar samples were digested in a mixture of 10 ml trace metal grade
nitric acid (67-70% concentration) and 3 ml trace metal grade perchloric
acid (67-70% concentration) for 20 minute at 800 watt power level to a
temperature of 180 C at 2000 kP (20 bars) pressure. The digested samples
were transferred to 25 ml flasks and brought to volume with Millipore
water. The elemental analyses were done by ICP-MS. The Nitrogen content
of biochar was determined by the Kjeldahl method (1).
Materials and Methods
Results and Conclusions
The elemental composition of biochar varied significantly among biochar
samples generated from different biomass feedstocks through the slow
pyrolysis. The DI water extractable N, P, K, Ca, Mg, and S of biochar
produced from coniferous biomass were generally lower than those of the
herbaceous and deciduous biomass feedstocks. The herbaceous biomass
(Miscanthus giganteus and Panicum virgatum) in this study contained more
K than the ligneous feedstocks. The weak solution of HCl (0.01 M)
extracted slightly more solutes from biochar as compared to DI water and
the concentration of macro elements increased when the concentration of
HCl increased to 0.1 M.
The extractable trace elements in biochar samples showed a trend similar
to macro elements. The B and Zn were found to be present in all biochar
samples. When biochar samples were digested in a mixture of nitric and
perchloric acid, the switchgrass and miscanthus biochar samples found to
contain more S, P, and Mg than other samples. The amount of other
elements in biochar samples varied significantly. The willow biochar
contained the maximum amount of Ca followed by oak and switchgrass.
Among the trace elements, B and Zn were omnipresent in biochar samples
but unlike B, the amount of Zn significantly varied among samples.
The N content of the herbaceous biomass was significantly higher than the
ligneous biomass. The giant miscanthus biochar contained similar amount
of N as other biochar samples produced from herbaceous species despite
the fact that the giant miscanthus plots had not been fertilized.
References
1. Jones, M. & D. Bradshaw. 1989. Copper: An alternative to mercury;
more effective than zirconium in kjeldahl digestion of ecological
materials. Commun. Soil Sci. Plant Anal. 20:1513.
2. U.S. Environmental Protection Agency. 1998. Inductively coupled
plasma-mass spectrometry, Method 6020. In: Solid Waste Methods. SW846,
Update 4, U.S. EPA, Environmental Monitoring Systems Lab., Cincinnati,
Ohio.
3. Yin Chan, K. and Zhihong Xu. 2009. Biochar: Nutrient Properties and
Their Enhancement. In: Biochar for Environmental Management (Editors:
Johannes Lehmann and Stepehen Joseph. Earthscan 416 pages.
Acknowledgements
The data presented here is part of a broader research project that is being
supported by the USDA/NIFA/Evans-Allen (Project No. MOX-BAYAN). The
author is grateful for the support he has received from the USDA/NIFA.
M. R. Bayan, Ph.D., Ph.D. Department of Agriculture and Environmental Sciences - Lincoln University in Missouri
Elemental Composition of Biochar from Various Biomass Feedstocks
Na
S
P
Mg Ca
K
0.00
2000.00
4000.00
6000.00
8000.00
D.I. Water
Na
S
P
Mg Ca
K
0.00 1000.00 2000.00 3000.00
4000.00
5000.00
6000.00
7000.00
8000.00
P
p
m
0.01 M HCl
Na
S
P
Mg Ca
K
0.00
2000.00
4000.00
6000.00
8000.00
10000.00
P
p
m
0.1 M HCl
Sb
As
Cd
Cu Mo
Se B Zn
0.00 2.00 4.00 6.00 8.00
10.00 12.00 14.00 16.00 18.00 20.00
P
p
m
0.01 M HCl
Sb
As
Cd
Cu Mo
Se Zn
B
0.00 0.50 1.00 1.50 2.00 2.50 3.00 3.50
4.00
4.50
P
p
m
D.I. Water
Sb
As
Cd Cu
Mo Se
B Zn
0.00
20.00
40.00
60.00
80.00
100.00
P
p
m
0.1 M HCl
Na
S
P Mg
Ca K
0.00
5000.00
10000.00
15000.00
20000.00
P
p
m
Acid Microwave Digestion
Sb
As
Cd
Cu Mo
Se Zn B
0.00
50.00
100.00
150.00
200.00
P
p
m
Acid Microwave Digestion
P
K
N 0.00
5000.00
10000.00
15000.00
P
p
m
Acid Digestions
