Adsorbent tannin foams: New and complementary applications in wastewater treatment

•We present novel adsorbents derived from tannin extracts.•Multiple adsorbates were tested: pharmaceuticals, dyes and surfactants.•Kinetic studies showed high r2 correlation. Equilibrium studies presented high q.•We also developed structural and physical characterization of adsorbents. Tannin rigid foams were synthesized at lab scale in order to confirm their feasibility in wastewater treatment. Different water samples containing three emerging contaminants (Methylene blue, Polyoxyethylene (3.5) sodium lauryl ether sulfate and Trimethoprim) were subjected to adsorption process with these novel products. The experimental results confirmed the ability of these foams for removing anionic and cationic contaminants through adsorption process. Kinetic data were adjusted to Lagergren, Ho and Elovich model. Both the second and the third one presented an average r2 above 0.96. Equilibrium studies on the three studied systems revealed Langmuir and Freundlich models were also adequate for predicting the behavior of the adsorption process. High adsorption capacities were reached (ca. 215, 65 and 25mgg−1 for dye, surfactant and pharmaceutical respectively), which were comparable to other commercial adsorbents already available and functional in wastewater treatments. Therefore, this new ability must be added to the list of advantages these new materials seem to present.