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. Graphical abstract

Bisphenols have drawn increasing attention from regulatory agencies and scientific communities due to their widespread occurrences, distribution and endocrine disrupting effects, and severe toxicity. As one of the bisphenol A (BPA) substitutes, bisphenol S (BPS) is most frequently detected in the environment. Although numerous studies have shown its occurrence, distribution, and toxicity to certain aquatic species, investigation on BPS removal from aqueous environments is lacking. Thus, in this review, we summarize the state-of-art about BPS removal approaches including biodegradation, sorption, and advanced oxidation processes. Particular attention has been paid to the BPS sorption mechanisms, active species for BPS biodegradation, and the corresponding degradation pathways. The primary degradation intermediates formed during BPS oxidation (e.g. p-hydroxybenzenesulfonic acid) are discussed. The effects of solution chemistry (pH, ionic strength, anion, and surfactants) on BPS decontamination are also emphasized. In addition, knowledge gaps, current challenges, and future research needs of BPS decontamination in real environments have been discussed briefly. Through this review we demonstrate the overarching scientific opportunities for a comprehensive understanding of the efficiency and mechanisms of the bio-and chemical remediation approaches of BPS contaminated water. Graphical Abstract