Photodegradation of Ammonia Using MIL-125 as a Potential Photocatalyst

Abstract

Metal Organic frameworks have shown promises in adsorption, gas separation, gas storage, catalysis, drug delivery and sensing. MOFs have shown potential as heterogenous catalysts as well. Their high surface area, tunable porosity, diversity in metal and functional groups, pore volume and active metal sites make them attractive proposition to be used as catalysts. Heterogeneous photocatalysis is a one of the a most attractive technologies for the degradation of organic substances present in wastewater. Literature reports conclude MIL-125(Titanium based MOF) has a great potential in photocatalysis. In our present area of research, we report a novel rapid synthesis procedure of MIL-125. Detailed characterizations were carried out using various techniques like SEM, PXRD,TGA,BET surface area analysis, FTIR and UV reflectance study. A detailed aqueous phase stability study followed which showed its stability under various pH conditions. The specific surface area of approx. 371 m2/g showed the porous nature of the synthesized samples whereas the corresponding band gap energy value was found to be 3.18 eV. Ammonia degradation study was carried out using MIL-125 and the results were found to be consistent. The final degradation of ammonia was found to be approx. 70% and the experimental data were best fit pseudo first order kinetic a model where the a rate constant was a found to a be 0.03189. Two more variants of MIL-125 were synthesized viz. Fe doped and MIL-125 Solvothermal. Both the products were found to be porous with an experimental measured surface areas of 246 m2/g and 240m2/g, respectively. The corresponding band a gapa energy were 3.4 eV and a 3.2 eV. These preliminary evaluation shows the potential of both the samples and further investigation are necessary to find their effectiveness.