TY - JOUR
T1 - Sorption of acidic organic solute onto kaolinitic soils from methanol-water mixtures
AU - Kim, Juhee
AU - Kim, Minhee
AU - Hyun, Seunghun
AU - Kim, Jeong Gyu
AU - Ok, Yong Sik
N1 - Funding Information:
This work was supported, in part, by the Basic Science Research Program through the National Research Foundation of Korea (NFR), funded by the Ministry of Education, Science and Technology (2010-0008507) and, in part, by a Korea University Grant.
PY - 2012/1
Y1 - 2012/1
N2 - The fate of the acidic organic solute from the soil-water-solvent system is not well-understood. In this study, the effect of the acidic functional group of organic solute in the sorption from cosolvent system was evaluated. The sorption of naphthalene (NAP) and 1-naphthoic acid (1-NAPA) by three kaolinitic soils and two model sorbents (kaolinite and humic acid) were measured as functions of the methanol volume fractions (f c ≤ 0.4) and ionic compositions (CaCl 2 and KCl). The solubility of 1-NAPA was also measured in various ionic compositions. The sorption data were interpreted using the cosolvency-induced sorption model. The K m values (= the linear sorption coefficient) of NAP with kaolinitic soil for both ionic compositions was log linearly decreased with f c. However, the K m values of 1-NAPA with both ionic compositions remained relatively constant over the f c range. For the model sorbent, the K m values of 1-NAPA with kaolinite for the KCl system and with humic acid for both ionic compositions decreased with f c, while the sorption of 1-NAPA with kaolinite for the CaCl 2 system was increased with f c. From the solubility data of 1-NAPA with f c, no significant difference was observed with the different ionic compositions, indicating an insignificant change in the aqueous activity of the liquid phase. In conclusion, the enhanced 1-NAPA sorption, greater than that predicted from the cosolvency-induced model, was due to an untraceable interaction between the carboxylate and hydrophilic soil domain in the methanol-water system. Therefore, in order to accurately predict the environmental fate of acidic pesticides and organic solutes, an effort to quantitatively incorporate the enhanced hydrophilic sorption into the current cosolvency-induced sorption model is required.
AB - The fate of the acidic organic solute from the soil-water-solvent system is not well-understood. In this study, the effect of the acidic functional group of organic solute in the sorption from cosolvent system was evaluated. The sorption of naphthalene (NAP) and 1-naphthoic acid (1-NAPA) by three kaolinitic soils and two model sorbents (kaolinite and humic acid) were measured as functions of the methanol volume fractions (f c ≤ 0.4) and ionic compositions (CaCl 2 and KCl). The solubility of 1-NAPA was also measured in various ionic compositions. The sorption data were interpreted using the cosolvency-induced sorption model. The K m values (= the linear sorption coefficient) of NAP with kaolinitic soil for both ionic compositions was log linearly decreased with f c. However, the K m values of 1-NAPA with both ionic compositions remained relatively constant over the f c range. For the model sorbent, the K m values of 1-NAPA with kaolinite for the KCl system and with humic acid for both ionic compositions decreased with f c, while the sorption of 1-NAPA with kaolinite for the CaCl 2 system was increased with f c. From the solubility data of 1-NAPA with f c, no significant difference was observed with the different ionic compositions, indicating an insignificant change in the aqueous activity of the liquid phase. In conclusion, the enhanced 1-NAPA sorption, greater than that predicted from the cosolvency-induced model, was due to an untraceable interaction between the carboxylate and hydrophilic soil domain in the methanol-water system. Therefore, in order to accurately predict the environmental fate of acidic pesticides and organic solutes, an effort to quantitatively incorporate the enhanced hydrophilic sorption into the current cosolvency-induced sorption model is required.
KW - 1-Napthoic acid
KW - cosolvency
KW - kaolinitic soil
KW - sorption
UR - http://www.scopus.com/inward/record.url?scp=84863337956&partnerID=8YFLogxK
U2 - 10.1080/03601234.2012.601949
DO - 10.1080/03601234.2012.601949
M3 - Article
C2 - 22022785
AN - SCOPUS:84863337956
VL - 47
SP - 22
EP - 29
JO - Journal of Environmental Science and Health - Part B Pesticides, Food Contaminants, and Agricultural Wastes
JF - Journal of Environmental Science and Health - Part B Pesticides, Food Contaminants, and Agricultural Wastes
SN - 0360-1234
IS - 1
ER -