Smectite-supported metal nanoparticles: current trends and approaches

The latest trend in environmental sustainability is nanoparticle applications in environmental monitoring. Consequently, the rapid increase in toxic waste from various industries, medical and agricultural sector can be altered by environmental friendly materials. One of the cost-effective and peculiar mineral namely 2:1 smectite clay mineral is proven to be effective in such sectors. This review surveys the work developed in the field of clay nanoparticles, categorically smectite clay nanoparticles in the combination of metals in its nano-form where smectite clay acts as a support for metal nanoparticles. The synthesis of smectite-supported metal nanoparticles are discussed with a comparison to different methods among which reduction and wet impregnation is the most performed process which includes a wide array of reducing agents. An interpretative research reveals significant advancements revealing the usage of similar clay minerals for the adsorption of different pollutants in water treatment such as bentonite-Fe3O4 NPs for the removal of Cu(II) and bentonite-nZVI for the removal of Cr(VI). The study ascertained that an increase in the surface area allows effective catalytic reaction with improvement in the rate of reaction. It was found that qualitative detection can be done by smectite-supported metal nanoparticles. Though the non-toxic and inexpensive factors of metal-supported smectite nanoparticles prove to be a cornerstone for the medical and industrial sector, a limited variety of studies is found. A compendium of literatures since 2010 to 2022 is presented in this review. This study proves the exclusive efficiency of metal nanoparticles supported by smectite over smectite nanoparticles.