Investigation on Adsorption Behavior of Some Pollutant Aromatic Acids onto Kaolinite by Spectrofluorometric Method

ABSTRACT

Polycyclic aromatic hydrocarbons are one of the most hazardous pollutants which can be degraded to aromatic acids (AAs) in the environment. These compounds are the main cause of soil pollution because of their solubility in water. In this work, the adsorption of some aromatic acids onto acid-activated kaolinite was studied in a batch process. The effects of contact time, initial pH, and amount of kaolinite were investigated on the adsorption process. The AAs removal enhances by increasing the contact time to 60 min at pH 6. Among the Langmuir, Freundlich, and Temkin models, the experimental isotherm data corresponding to the adsorption of the AAs onto kaolinite indicate an excellent agreement with the Langmuir equations. Three kinetic models including the pseudo-first- and second-order equations and the Elovich equation were selected to investigate the adsorption process. Kinetic parameters, namely, rate constants, equilibrium adsorption capacities, and correlation coefficients, for each kinetic equation were calculated and discussed. The investigations showed that the adsorption of AAs onto kaolinite can be described by the pseudo-second-order equation.

KEYWORDS:

• Acid activation
• adsorption
• aromatic acid
• kaolinite
• kinetics
• spectrofluorometry
• water purification

Additional information

Funding

The authors acknowledge financial support by the University of Birjand.