Effect of the pH on the interaction of hydrotalcite with dyes from textile wastewater

The increase in textile fibre production volume is expected to result in a corresponding rise in untreated wastewater, highlighting the need for effective and affordable wastewater treatment methods. This study explored the potential of hydrotalcite, a product in cement hydration, which can be used as a low-cost adsorbent, in treating wastewater containing Reactive Blue 19 or Acid Green 1 dyes. The effect of pH on the decolourization properties was studied using HCl, HNO3, H2SO4, NaOH, KOH, Ca(OH)2, and Ba(OH)2. The results showed that both dyes had significantly different decolourization properties with hydrotalcite in acidic and basic dye solutions, with acidic environments enhancing dye uptake. The ions present in the dye solution have no significant impact on the decolourization properties. Zeta potential analysis supported these findings, with acidic dye solutions exhibiting higher zeta potential. An intercalation of dye molecules into the layered structure of the hydrotalcite could not be detected. The study shows that hydrotalcite is most effective as an adsorbent in acidic environments. © 2023 The Authors. Published by Ernst & Sohn GmbH.