Adsorption Of Reactive Brilliant Red X-3b From Aqueous Solution By Polypyrrole/Calcium Rectorite Composites: Adsorption Behavior And Mechanism

In this study, polypyrrole/calcium rectorite clay composites (PPy/REC composites) were prepared by in-situ polymerization of pyrrole monomer to adsorb reactive brilliant red X3B from aqueous solution. The results of XRD showed that the clay flakes exfoliated in the prepared composites. The SEM results showed that PPy had good dispersibility on clay sheets. The adsorption mainly depended on the initial pH value of the solution, and the optimal adsorption of reactive brilliant red X-3B was achieved when the pH value was 2.0. The removal rate of PPy/REC composite was much higher than that of PPy homopolymer. The adsorption kinetic data of reactive brilliant red X-3B at three initial concentrations (100, 150 and 200 mg/L) were best fitted by the pseudo-second-order model, indicating that the concentration gradient of the adsorbent was the driving force of the adsorption process. The adsorption isotherm accorded with the Langmuir isotherm model, and the maximum adsorption capacity was 232.56 mg/g at 298 K. The PPy/REC composites could be regenerated and reused for 5 continuous adsorption-desorption cycles without losing the removal efficiency of the original reactive brilliant red X-3B. XPS, zeta potential and FT-IR results showed that the removal mechanism of reactive brilliant red X-3B was related to electrostatic interaction and ion exchange.