Synthesis of β-FeOOH/polyaniline heterogeneous catalyst for efficient photo-Fenton degradation of AOII dye.

Discharge of the untreated dye-containing wastewaters will induce water source pollution and further harm aquatic organisms. In this study, the akaganéite/polyaniline catalyst (β-FeOOH/PANI, about 1.0 μm) could be successfully composed by polyaniline (PANI, (C6H7N)n, 200-300 nm) and akaganéite (β-FeOOH, FeO(OH)1-xClx, less than 200 nm), according to the identification and characterization results of XRD, Ramon, FTIR, XPS, SEAD, EDS, and FESEM (or HRTEM). Due to PANI providing more photogenerated electrons, the β-FeOOH/PANI composite (compared with β-FeOOH) in photo-Fenton system had the more highly catalytic degradation capacity to Acid Orange II (AOII) under an optimal condition (7.5 mmol/L of H2O2 oxidant, 40 mg/L of AOII, 0.2 g/L of catalyst dosage, and pH 4.0). The AOII degradation kinetics could be well fitted by pseudo-first-order model. In photo-Fenton catalytic process of AOII dye, the ∙OH and h+ were the main reaction substances. The AOII in solutions could be gradually mineralized into non-toxic inorganic H2O molecule and CO2. The β-FeOOH/PANI catalyst also had a good reusable ability of about 91.4% AOII degradation after 4 runs. These results can provide a reference for synthesis of catalyst used in photo-Fenton system and the applications in degradation removal of organic dye from wastewaters.