Advancements in the use of filtration materials for the removal of heavy metals from multicontaminated solutions

Granular materials can be used in the context of different technologies for the treatment of contaminated solutions, such as groundwater, stormwater, wastewater, water intended for potable use, or leachate. For all such technologies, it is essential that the filtering media guarantee reactivity and permeability over a reasonably long time, avoiding the rapid replacement of the materials or the failure of the treatment goals. This mini-review provides an update on materials recently tested at the laboratory scale for heavy metal removal during batch or column tests. A recent trend in this field of research is the use of reactive materials derived from agricultural and industrial waste, alone or in combination with other conventional materials, such as zerovalent iron. Lack of knowledge of their long-term behavior is the main challenge related to the use of these new active materials, and therefore, long-term column tests are strongly recommended to correctly simulate the filtration process.