TY - JOUR
T1 - Humic substances as a washing agent for Cd-contaminated soils
AU - Meng, Fande
AU - Yuan, Guodong
AU - Wei, Jing
AU - Bi, Dongxue
AU - Ok, Yong Sik
AU - Wang, Hailong
N1 - Funding Information:
Valuable discussion with and editorial help from Dr BKG Theng of Landcare Research, New Zealand, was greatly appreciated. This work was supported by Chinese National Key Research and Development Program (2016YFD0200303), the National Natural Science Foundation of China (21577131), the Special Funding for the Introduced Innovative R&D Team of Dongguan Municipal Government (2014607101003), and Key Research and Development Program of Shandong Province (2016CYJS05A01-1).
Publisher Copyright:
© 2017 Elsevier Ltd
PY - 2017
Y1 - 2017
N2 - Cost-effective and eco-friendly washing agents are in demand for Cd contaminated soils. Here, we used leonardite-derived humic substances to wash different types of Cd-contaminated soils, namely, a silty loam (Soil 1), a silty clay loam (Soil 2), and a sandy loam (Soil 3). Washing conditions were investigated for their effects on Cd removal efficiency. Cadmium removal was enhanced by a high humic substance concentration, long washing time, near neutral pH, and large solution/soil ratio. Based on the tradeoff between efficiency and cost, an optimum working condition was established as follows: humic substance concentration (3150 mg C/L), solution pH (6.0), washing time (2 h) and a washing solution/soil ratio (5). A single washing removed 0.55 mg Cd/kg from Soil 1 (1.33 mg Cd/kg), 2.32 mg Cd/kg from Soil 2 (6.57 mg Cd/kg), and 1.97 mg Cd/kg from Soil 3 (2.63 mg Cd/kg). Cd in effluents was effectively treated by adding a small dose of calcium hydroxide, reducing its concentration below the discharge limit of 0.1 mg/L in China. Being cost-effective and safe, humic substances have a great potential to replace common washing agents for the remediation of Cd-contaminated soils. Besides being environmentally benign, humic substances can improve soil physical, chemical, and biological properties.
AB - Cost-effective and eco-friendly washing agents are in demand for Cd contaminated soils. Here, we used leonardite-derived humic substances to wash different types of Cd-contaminated soils, namely, a silty loam (Soil 1), a silty clay loam (Soil 2), and a sandy loam (Soil 3). Washing conditions were investigated for their effects on Cd removal efficiency. Cadmium removal was enhanced by a high humic substance concentration, long washing time, near neutral pH, and large solution/soil ratio. Based on the tradeoff between efficiency and cost, an optimum working condition was established as follows: humic substance concentration (3150 mg C/L), solution pH (6.0), washing time (2 h) and a washing solution/soil ratio (5). A single washing removed 0.55 mg Cd/kg from Soil 1 (1.33 mg Cd/kg), 2.32 mg Cd/kg from Soil 2 (6.57 mg Cd/kg), and 1.97 mg Cd/kg from Soil 3 (2.63 mg Cd/kg). Cd in effluents was effectively treated by adding a small dose of calcium hydroxide, reducing its concentration below the discharge limit of 0.1 mg/L in China. Being cost-effective and safe, humic substances have a great potential to replace common washing agents for the remediation of Cd-contaminated soils. Besides being environmentally benign, humic substances can improve soil physical, chemical, and biological properties.
KW - Cadmium
KW - Calcium hydroxide
KW - Leonardite
KW - Soil remediation
KW - Soil washing
UR - http://www.scopus.com/inward/record.url?scp=85018335311&partnerID=8YFLogxK
U2 - 10.1016/j.chemosphere.2017.04.127
DO - 10.1016/j.chemosphere.2017.04.127
M3 - Article
C2 - 28458221
AN - SCOPUS:85018335311
SN - 0045-6535
VL - 181
SP - 461
EP - 467
JO - Chemosphere
JF - Chemosphere
ER -