Evaluation of sorptive capacity of natural clay, pillared clay, and alga-modified clay to contain oil spills in soil

Abstract

This paper describes the characterization of natural Patagonian clay (ARC), composed mainly of montmorillonite and illite, and two modifications: one with alga Codium fragile (ARC-ALG) and other ironpillared (ARC-PIL), as oil sorbents. The textural characterization of samples was performed by nitrogen adsorption isotherms at 77K, obtaining 36, 2 and 105 m2/g of BET surface area, respectively. The pore size distribution was calculated from isotherms data by the method of density functional (NLDFT). Oil sorption capacities were determined and expressed in g oil/g sorbent by tests in batch, sorption isotherms were obtained in a concentration range of 50 to 300 mg/L of oil in organic solvent. The quantification of remnant concentrations in solution was performed by UV-Vis spectrophotometric techniques. The results of sorption capacity are consistent with the BET surface area for ARC and ARC-PIL, but are not in agreement with ARC-ALG, since it has the lowest BET surface area and the highest sorption capacity; this would be mainly due to the organic nature of this material. This information together with the analysis of the respective isotherms, gives the possibility of making inferences about of the action mechanisms for the selection of new sorbents in treating soils spills.