Anchored Iron Ligands as an Efficient Fenton-Like Catalyst for Removal of Dye Pollutants at Neutral pH

The development of a pH-tolerant Fenton-like catalyst is an active and challenging research front in the area of environmental engineering. In the present work, a novel catalyst iron-gamma-aminopyridine ligand (FeAPy) was prepared and immobilized on activated carbon fibers (ACFs) by a covalent bond to obtain a heterogeneous FeAPy-ACFs. FeAPy-ACFs present a pH-tolerant microenvironment for the Fenton-like oxidation process, which exhibits remarkable catalytic ability across a wide pH range from acidic to alkaline. At neutral pH, employing hydrogen peroxide as an oxidant, the FeAPy-ACFs showed enhanced catalytic ability to degrade hazardous environmental pollutants Acid Red 1 (AR1) dyes and avoid secondary pollution with regard to FeAPy. FeAPy-ACFs are stable and remain efficient in repetitive test cycles with no obvious decrease of catalytic activity. Moreover, in comparison to most reported supports for Fenton-like catalyst, the introduction of ACFs contributed specifically to the activity improvement of FeAPy. Probe studies combined with electron paramagnetic resonance experiments were conducted to ascertain the role of several reactive species (center dot OH, HO2 center dot, and Fe-IV=O) on dye decolorization.