Polyaniline/FeOOH composite for removal of Acid Orange II from aqueous solutions

The synthesized polyaniline/FeOOH composite characterized by SEM, HRTEM, XRD , FT-IR and BET, was used as adsorbent for Acid Orange II (AOII). The kinetics, isotherm and thermodynamics of AOII adsorption by polyaniline/FeOOH were studied by batch experiments. And effects of pH and coexisting ions on AOII removals were also investigated. Adsorption kinetics and isotherm well fitted pseudo second-order kinetic model and Langmuir isotherm model, respectively. The maximum adsorption capacity of polyaniline/FeOOH for AOII could reach 155.8 mg g −1 . It showed that polyaniline/FeOOH composite could rapidly and efficiently remove AOII from aqueous solutions. In addition, thermodynamic result indicated that the adsorption was a spontaneous endothermic process. Removal ratio of AOII (100 mg/L) increased as pH decreased and could reach 98.6% at pH3. And anions coexisting in the solutions could inhibit the adsorption effect, while the cations have negligible influence. Also, PANI/FeOOH had better applicability to the different types of anionic dyes. The regeneration of polyaniline/FeOOH loading 98.6% of AOII evaluated for three cycles and there was about 70% of AOII loaded on final adsorbent.