Sorption of Aqueous Organics by Aquifer Material: Correlation of Batch Sorption Parameters with Octanol-Water Partition Coefficient

Abstract

A study of sorption of aqueous organics by aquifer materials was undertaken with an objective to correlate sorption parameters with the octanol-water partition coefficient (KOW) of aqueous samples. In the first phase, synthetic samples were equilibrated with the aquifer material collected from the river bank filtration (RBF) site located on the bank of the river Alaknanda at Srinagar, Uttarakhand, India. In the second phase, water from the river Hindon at Barnawa, Uttar Pradesh, India, was stirred with the Srinagar aquifer material, and a sample of water from the Elbe River was mixed with the aquifer material from the RBF site in Torgau, Germany. The fraction of organic carbon content (foc) in the aquifer material from Srinagar and Torgau was 0.018 and 0.0027 mg/mg, respectively. The hydrophilic and hydrophobic nature of the synthetic samples and the water samples from the rivers Hindon and Elbe were determined by measuring KOW and specific ultraviolet absorbance (SUVA). Empirical correlations between log KOW and (1) adsorption capacity (Qm), (2) soil-water partition coefficient (Kd), and (3) organic carbon-water partition coefficient (logKOC) for hydrophilic and hydrophobic samples have been developed. The values predicted from the model and experimental observations were statistically analyzed by the regression analysis model (RAM) and analysis of variance (ANOVA). The analysis did not indicate a significant difference between the experimental data and computed data of sorption parameters from log KOW. The similarity between log KOC from (1) Kd (slope of the sorption isotherm) and (2) log KOW was within a 95% confidence limit. The Freundlich isotherm constant (KF) has been found to increase with an increase in KOW, whereas no such correlation was noted for the Langmuir isotherm constant (KL). A correlation between the sorption parameters (Qm, Kd, and KOC) and SUVA was not observed.