Recent advances and perspectives of tannin-based adsorbents for wastewater pollutants elimination: A review

Abstract

A considerable volume of wastewater is generally dumped into bodies of water, which has severe negative consequences on aquatic habitats. While various traditional methods are available in wastewater treatment, the development of new technologies is critical for wastewater treatment and recycling. Synthesis of biomass-based adsorbents due to their environmentally friendly properties can help sustain our lifestyles. Polymers have lately been extensively used in numerous sectors due to their unique properties. Biopolymers are a natural alternative to synthetic polymers that can be created by covalently linking monomeric units. Among these biopolymers, tannin-based biopolymers as bio sorbents are one of the potential candidates in the field of wastewater treatment. Among these studies, tannin-based biopolymers as biosorbents are one the potential candidates in the field of wastewater treatment and are considered one inexpensive adsorbent with a relatively easy combination with effective performance in water and wastewater treatment. Due to the high content of adjacent phenolic hydroxides, tannins show a high tendency to chelate against various metal ions in water. Also have a good adsorption capacity to remove dyes by establishing electrostatic interactions, ion exchange, and covalent bonds. Due to the importance of these compounds as promising materials in various applications, in this article, the classification of tannins based on structural properties, preparation methods and some of their important properties and applications in the field of adsorption are reviewed.