Sorption of Phenanthrene onto Diatomite under the Influences of Solution Chemistry: A Study of Linear Sorption based on Maximal Information Coefficient

Abstract

The effectiveness of diatomite as the low-cost sorbent in the removal of polycyclic aromatic hydrocarbons (PAHs) from water was investigated. The effects of ionic strength, pH, dissolved organic matter, and temperature on sorption of phenanthrene (PHE) to two types of diatomite clay (DM 545 and DM 577) were systematically studied. The maximal information coefficient (MIC) was calculated to reveal the linearity/nonlinearity in the sorption process under the influences of aqueous chemistry parameters. Results indicated that the solution parameters played an essential role in the PHE sorption behavior at the aqueous/diatomite interface. The sorption isotherms of PHE on diatomite at different temperatures could well fit the Freundlich equation. Thermodynamic studies confirmed that the sorption behavior of PHE on diatomite was spontaneous and exothermic from 283 to 303 K. The calculation of MIC revealed the linear relationship between the aqueous PAHs and sorbed PAHs at the water/diatomite interface. The results can be used to support the potential application of diatomite for the treatment of PAH-contaminated effluents.