Tannic Acid Hydrogels

Tannic Acid is a widely available from plants, and its extraction has low costs associated to it. Where previously hydrogels could only reach up to 30% TA content, we can report an approach for the preparation of a majority plant polyphenol hydrogel. These hydrogels have a TA content of a never seen 75%. A minority seaweed alginate (Alg) matrix is used to bind the TA into conveniently handled beads. Experiments also show that application is quite convenient as the beads were rehydrated directly during use. Further we also found that the hydrogels had an increased water swelling, sorption of a suite of PTEs, and antimicrobial activity with increasing TA content.

figure 3. the ATR-FTIR graph showing different levels of Ta in the gels.

The incorporation of Iron(Fe) creating an Alg-TA-Fe matrix has shown increased sorption of the Cr(VI) ion. Further the Ta allows for better binding to the Alg based gel.

Figure 6. Data showing the increased sorption of Cr(VI) using the gels with Fe incorporated.

Figure 5. XPS scans showing the increased Fe content.

Figure 4. Alg-TA gel with Fe incorporated into it, with Ta contents at 55%(left) and 75%(right) respectively.

Figure 1. 75% TA gel, in dry, and saturated state

figure 2. Bar graph showing the ion removal in % for different pHs and %TA content in the gels