TY - JOUR
T1 - Adsorption of mono- and di-butyltin by a wheat charcoal
T2 - pH effects and modeling
AU - Fang, Liping
AU - Borggaard, Ole K.
AU - Christensen, Jan H.
AU - Holm, Peter Engelund
AU - Hansen, Hans Chr. Bruun
PY - 2012/10
Y1 - 2012/10
N2 - Understanding adsorption processes of butyltins (BTs) such as monobutyltin (MBT) and dibutyltin (DBT) by black carbons is important for the evaluation of BT exposure risks to organisms and humans. However, relevant knowledge is scarce. In this study, the acidity constants pKa,1=2.3, pKa,2=3.5 and pKa,3=5.9 for MBT and pKa,1=3.0 and pKa,2=5.1 for DBT are estimated via potentiometric titration. Additionally, adsorption isotherms of BTs to a wheat charcoal were determined. The adsorption behavior was observed to be pH-dependent due to BT speciation and the pH-dependent surface charge of the charcoal. MBT adsorption to the charcoal decreases with increasing pH from 4 to 8, while the highest adsorption occurs at pH 6 for DBT. Adsorption of the BTs is successfully described in the pH range of 3-10 by using a newly developed pH-dependent Dual Langmuir model. The model has the potential to predict the interaction of BT species with charcoal, which can contribute to the risk assessments of BTs in the environment.
AB - Understanding adsorption processes of butyltins (BTs) such as monobutyltin (MBT) and dibutyltin (DBT) by black carbons is important for the evaluation of BT exposure risks to organisms and humans. However, relevant knowledge is scarce. In this study, the acidity constants pKa,1=2.3, pKa,2=3.5 and pKa,3=5.9 for MBT and pKa,1=3.0 and pKa,2=5.1 for DBT are estimated via potentiometric titration. Additionally, adsorption isotherms of BTs to a wheat charcoal were determined. The adsorption behavior was observed to be pH-dependent due to BT speciation and the pH-dependent surface charge of the charcoal. MBT adsorption to the charcoal decreases with increasing pH from 4 to 8, while the highest adsorption occurs at pH 6 for DBT. Adsorption of the BTs is successfully described in the pH range of 3-10 by using a newly developed pH-dependent Dual Langmuir model. The model has the potential to predict the interaction of BT species with charcoal, which can contribute to the risk assessments of BTs in the environment.
U2 - 10.1016/j.chemosphere.2012.05.010
DO - 10.1016/j.chemosphere.2012.05.010
M3 - Journal article
C2 - 22664389
SN - 0045-6535
VL - 89
SP - 863
EP - 868
JO - Chemosphere
JF - Chemosphere
IS - 7
ER -