Interactions between organic matter and Fe (hydr)oxides and their influences on immobilization and remobilization of metal(loid)s: A review

Fe (hydr)oxides and organic matter (OM) are two of the main active substances ubiquitously occurring in natural environments. Fe (hydr)oxides rarely exist as a discrete component in natural environments, but they can interact readily with OM and are usually associated with OM to form Fe-OM associations. The interaction of Fe (hydr)oxides with OM will significantly change the binding characteristics of Fe (hydr)oxides toward metal(loid)s. In this review paper, firstly, interaction mechanisms, including the adsorption of OM onto Fe (hydr)oxides and the co-precipitation of OM and Fe (hydr)oxides, and factors affecting these interactions are summarized. Secondly, the characteristics of Fe-OM associations via adsorption and co-precipitation processes are compared. Then, the immobilization and remobilization of metal(loid)s influenced by interaction with OM and Fe (hydr)oxides are discussed. Finally, suggestions for future studies concerning the interactions between Fe (hydr)oxides and OM and their influences on immobilization and remobilization of metal(loid)s are offered. Therefore, this review provides helpful guidance for better evaluation of the bioavailability and mobility of metal(loid)s as impacted by Fe-OM associations in the natural environment.

Automated summary

This review paper summarizes the interaction mechanisms between Fe (hydr)oxides and organic matter, compares the characteristics of Fe-OM associations, and discusses the immobilization and remobilization of metal(loid)s influenced by these interactions. Suggestions for future studies concerning the interactions between Fe (hydr)oxides and OM and their influences on immobilization and remobilization of metal(loid)s are also offered in the review.