TY - JOUR
T1 - Copyrolysis of Biomass with Phosphate Fertilizers to Improve Biochar Carbon Retention, Slow Nutrient Release, and Stabilize Heavy Metals in Soil
AU - Zhao, Ling
AU - Cao, Xinde
AU - Zheng, Wei
AU - Scott, John W.
AU - Sharma, Brajendra K.
AU - Chen, Xiang
N1 - Funding Information:
This study was supported by the National Natural Science Foundation of China (No. 21537002, 21577087, 21428702) and the Russell and Helen Dilworth Memorial Fund (USA).
Publisher Copyright:
© 2016 American Chemical Society.
PY - 2016/3/7
Y1 - 2016/3/7
N2 - Two phosphate fertilizers, triple superphosphate (TSP) and bone meal (BM), were premixed with sawdust and switchgrass biomass for pyrolytic biochar formation. Carbon retention, P release kinetics, and capacity of biochar for stabilizing heavy metals in soil were evaluated. Results show that TSP and BM pretreatment increased carbon retention from 53.5-55.0% to 68.4-74.7% and 58.5-59.2%, respectively. The rate constants (k2) of P release from the TSP- and BM-composite biochars are 0.0012-0.0024 and 0.89-0.91, respectively, being much lower than TSP and BM themselves (0.012 and 1.79, respectively). Copyrolysis with phosphate fertilizers enhanced biochar capability for stabilizing metals in soil significantly, especially the BM-composite biochar which increased Pb, Cu, and Cd stabilization rates by up to about 4, 2, and 1 times, compared to the pristine biochars. During the pyrolysis process, Ca(H2PO4)2 in TSP converted to Ca2P2O7 and reacted with biomass carbon to form C-O-PO3 or C-P, leading to greater carbon retention and lower P release. PO43- in both composite biochars could precipitate with heavy metals, resulting heavy metal immobilization in soil. This study indicates that copyrolysis of biomass with P-containing fertilizers could obtain multiple environmental benefits.
AB - Two phosphate fertilizers, triple superphosphate (TSP) and bone meal (BM), were premixed with sawdust and switchgrass biomass for pyrolytic biochar formation. Carbon retention, P release kinetics, and capacity of biochar for stabilizing heavy metals in soil were evaluated. Results show that TSP and BM pretreatment increased carbon retention from 53.5-55.0% to 68.4-74.7% and 58.5-59.2%, respectively. The rate constants (k2) of P release from the TSP- and BM-composite biochars are 0.0012-0.0024 and 0.89-0.91, respectively, being much lower than TSP and BM themselves (0.012 and 1.79, respectively). Copyrolysis with phosphate fertilizers enhanced biochar capability for stabilizing metals in soil significantly, especially the BM-composite biochar which increased Pb, Cu, and Cd stabilization rates by up to about 4, 2, and 1 times, compared to the pristine biochars. During the pyrolysis process, Ca(H2PO4)2 in TSP converted to Ca2P2O7 and reacted with biomass carbon to form C-O-PO3 or C-P, leading to greater carbon retention and lower P release. PO43- in both composite biochars could precipitate with heavy metals, resulting heavy metal immobilization in soil. This study indicates that copyrolysis of biomass with P-containing fertilizers could obtain multiple environmental benefits.
KW - Biochar
KW - Bone meal
KW - Carbon retention
KW - Heavy metals stabilization
KW - Phosphate release
KW - Triple superphosphate
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U2 - 10.1021/acssuschemeng.5b01570
DO - 10.1021/acssuschemeng.5b01570
M3 - Article
AN - SCOPUS:84960154301
VL - 4
SP - 1630
EP - 1636
JO - ACS Sustainable Chemistry and Engineering
JF - ACS Sustainable Chemistry and Engineering
SN - 2168-0485
IS - 3
ER -