Adsorption has been proved as an efficient process to remove a multiplicity of solutes from aqueous
solution. Various biosorbents have found promising applications in wastewater treatment and in the
recovery of critical metals that is, nowadays, the spotlight due to the promotion of environmental and
economic sustainability. Tannins are excellent candidates to produce biosorbents. These ubiquitous
and inexpensive natural biopolymers are of easy extraction and conversion into insoluble (tannin gels
and tannin foams) or immobilized matrices. Tannin-based adsorbents (TBAs) have a natural affinity to
uptake heavy metals, dyes, surfactants and pharmaceutical compounds from contaminated waters, and
to accumulate selectively precious and critical metals from aqueous streams. Furthermore, chemically
modified forms, such as iron-loaded and amine-modified tannin gels can be produced with relative ease
and enhance the adsorption ability of many substances. In this paper, the literature about the production
of different types of TBAs (resins, foams, immobilized tannins on support matrices, iron and amine
treatments) is revised. The actual state of knowledge, in respect to TBAs application for water remediation
and recovery of substances is presented.