Efficient removal of azo dyes with nano-flower formation using nano-basic resins

In this study, two new basic polymeric resins were prepared, characterized, and investigated for their usability as adsorbent for acidic dyes removal from aqueous solution. Basic resins (R1-Mod and R2-Mod) were prepared by modifying crosslinked polymers of MA-DVB (R1) and GMA-DVB (R2) with tetraethylenepentaamine (TEPA). Characterization studies showed that the R1-Mod resin prepared from R1 had a low surface area and its particle size was at the micron level but the R2-Mod resin prepared from R2 had a high surface area, and also its particle size was at the nano-level. In the adsorption studies, R1-Mod worked in a narrow pH and concentration range for just RR45, while R2-Mod worked in a wide pH and concentration range for both RR45 and dye mixture due to superior textural properties. It was observed that adsorption behavior of R1-Mod was in agreement with Freundlich isotherm model, but R2-Mod resin was in agreement with the Langmuir isotherm model. Kinetic results were consistent with the pseudo-second-order and intra-particle diffusion models for both resins. It was found that the adsorption process for both resins was exothermic, spontaneous and favorable at lower temperature. Also, it was observed that the resins did not lose their high removal affinity at five reusability for 400 ppm RR45. [GRAPHICS]

Automated summary

Two new basic polymeric resins were prepared and characterized for their effectiveness in removing acidic dyes from aqueous solutions. The R2-Mod resin showed superior adsorption properties compared to R1-Mod, working in a wider range of pH and concentration levels. Additionally, both resins exhibited exothermic, spontaneous, and favorable adsorption at lower temperatures.