Immobilization of chitosan-templated MnO 2 nanoparticles onto filter paper by redox method as a retrievable Fenton-like dip catalyst

By exploiting the hydrophilicity of cellulose filter paper (FP) and the excellent chelating property of chitosan (CH) for Mn , we have designed an efficient and retrievable dip catalyst MnO /CH-FP for Fenton-like degradation of methylene blue (MB) over a wide pH range from 2.8 to 11.2. The MnO nanoparticles were uniformly immobilized in the CH-FP matrix by in-situ redox precipitation method where Mn(NO ) was treated with KMnO at mild conditions. A series of MnO /CH-FP hybrids with different MnO loading were fabricated via varying concentration of Mn(NO ) solution, and their structure-function relationships were discussed based on detailed characterization. The optimal catalyst 1.0MnO /CH-FP could cooperate with multiple low-concentration dosages of H O to efficiently degrade 95.6% MB in 90 min (50 mg L MB, 1 g L catalyst, 30 mg L H O , pH 7). It is also shown that 1.0MnO /CH-FP could still keep 83.3% degradation efficiency of MB after six cycles. Moreover, the activity of this composite greatly surpassed that of bare MnO for nearly 50%, owing to its larger surface area and more accessible active sites. This method for preparing MnO /CH-FP could effectively avoid the agglomeration of MnO nanoparticles and make the reaction turn on/off almost instantaneously by mere insertion/removal.