Iron impregnated biochars as heterogeneous Fenton catalyst for the degradation of acid red 1 dye

In the present work, Acid Red 1 (AR1) dye degradation by two heterogeneous Fenton catalysts, namely iron loaded rice husk biochar (Fe-RHB) and coir pith biochar (Fe-CPB) are studied. Biochar prepared from RHB and CPB were sonicated in the presence of ferric nitrate for the synthesis of Fe-RHB and Fe-CPB by incipient impregnation method. Effect of operational parameters such as pH, the dosage of catalyst, H₂O₂ concentration and temperature were examined. Characterization of the synthesized Fenton catalyst, Fe-RHB and Fe-CPB were analysed by SEM, EDS, XRD and XPS techniques. In Fe-RHB Fenton system, maximum dye removal efficiency of 97.6% and TOC removal efficiency of 84.2% were obtained at pH 3 for 50 mg L^-1 of AR1 concentration, with 16 mM of H₂O₂ and 5 g L^-1 of catalyst dosage within 120 min reaction time. Similarly, for Fe-CPB, maximum dye removal efficiency of 99.1% and TOC removal efficiency of 86.7% were obtained with 16 mM of H₂O₂ and 4 g L^-1 of dosage for 50 mg L^-1 of initial dye concentration at pH 3. The prepared catalysts can be reused for successive cycles as the catalyst materials are highly stable and have very less iron leaching property.