A Review of Empirical Models of Sorption Isotherms of Hydrophobic Contaminants

Renewed focus on empirical models of sorption isotherms of hydrophobic organic contaminants (HOCs) onto mineral surfaces and soil components is required because of the importance attached to numerous pollutants released into the environment. This examines the various models and isotherms with their assumptions by different scholars on the contribution of sorption of contaminants onto clay mineral sorbents and soil organic matter with the possible ways of prevention of environmental contamination by HOCs. Literature indicated that empirical models and isotherms have been used to ascertain several surfaces that can be sorbed by hydrophobic organic contaminants. These models also show that soils can retain HOCs even at low soil organic levels and the extent depends on the structure of the pollutant type and concentration of clay minerals in the sorbent. It also revealed the important role played by soil organic carbon in the sorption of contaminants onto soils and how it is strongly affected by the nature and structure of the organic soil matter. Contamination by different pollutants required a renewed approach in the context of the sorption of organic pollutants onto clay minerals from aqueous and non-aqueous solutions.