Sonochemically synthesized mesoporous pyrophanite- MnTiO3/TiO2 nanoparticles: An Adsorbent for removal of commercial Malachite green dye

Abstract

Malachite green (MG) dye belongs to the triphenylmethane class, extensively employed in textile industries and its presence in aqueous environment exhibits a noxious impact on living beings. Thus, it’s being immensely important to remove the dye/residues from the environment matrix. Herein, the sonochemical synthesized adsorbent material -pyrophanite-MnTiO3/TiO2 nanoparticles (NPs) was utilized to expel the commercial Malachite green (MG) dye from the solution. The adsorption efficacy data indicates the maximum removal of MG (90.2%) is obtained for the NPs calcinated at 1000 °C (MT1). The adsorption material (MT1) is characterized by using different techniques including XRD, FE-SEM, EDX, FTIR, BJH, and BET. The XRD analysis indicates the formation of divergent phases viz. rutile TiO2 and MnTiO3. The FE-SEM depicts the formation of a nano-rod-like structure. The average size and percentage of void space of MT1 NPs are evaluated by using IMAGE J software. The hysteric loops from BET and BJH plots revealed the existence of type H3 hysteresis, confirming the mesoporous structure for MT1 NPs. The surface area, pore-volume, and pore size are found to be 61.245 m2/g, 0.139 cm3/g, and 2.0178 nm respectively. The pH, dye concentration, and temperature of the solution are optimized for the maximum removal of MG using MT1 NPs. Further, the adsorption isotherms, kinetics studies, and intra-particle studies indicative of the existence of monolayered second-order diffusion onto the surface of MT1 NPs. The adsorption process is endothermic, thermodynamically driven, and accompanied by an increase in entropy.