Porous Pd-loaded IRMOF-9 as Highly Efficient Recyclable Material towards the Reduction of Nitroaromatics in Aqueous Media.

ABSTRACT

Nitroaromatic compounds (NACs) cause severe hazardous impacts on human health as well as on the environment. Therefore, there is dire need to develop a robust material to reduce the toxicity of these organic pollutants. In this regard, our group developed a series of porous MOF materials viz., Pdx@IRMOF-9 (x=2%, 5% and 10%) by loading different concentration of Pd(II) on IRMOF-9 and explored them towards reduction of different nitroaromatic compounds. Pd10%@IRMOF-9 showed ~30% greater efficiency for the reduction of 4-NP as compared to Pd2%@IRMOF-9. Pd10%@IRMOF-9 showed excellent reduction ability (>85%) towards 4-NP, 2-NP, 2-NA, 3-NA and 2,4-DNPH. The kinetic studies indicates that the reduction follows the pseudo-first-order kinetics. Moreover, the rate constant value for reduction of 3-NA was ~9 times higher than that of 2-NP. Based on the kinetic parameters, the t1/2 values for all the nitroaromatics have been calculated. The kinetic parameters, Km and Vmax have been calculated from double reciprocal Lineweaver-Burk plot and found 65.984 µM and 116 x10-6 Mmin-1 respectively. Pd10%@IRMOF-9 showed excellent recyclability towards the reduction of 4-NP for few consecutive cycles without any remarkable loss in its activity. Thus, highly efficient, porous and robust material for reduction of nitroaromatic compounds in aqueous media have been demonstrated.