Multipurpose Kieselguhrbots to Mitigate Micro-Nanoplastics and Energy Harvesting.

Micro and nanoplastics (MNPs), along with oil spills (OSs), have emerged as among the most pervasive contaminants in the environment, posing significant threats to the aquatic ecosystem and human health. In this work, we employ a strategy using microbots to target large-scale remediation of such pollutants in water resources. In particular, this study explores the transformation of diatomaceous earth (DE) into functional microscale robots, namely, kieselguhrbots, for an efficient water purification. By combining DE with Fe3O4 nanoparticles, we enhance the surface activity, porosity, and catalytic properties of the composite material. The surface modification with hexadecyltrimethoxysilane (HDTMS) improves the ability of kieselguhrbots to target hydrophobic pollutants. The high surface area, enhancement of hydrophobicity, and oleophilic nature of the bots provide a promising, scalable, and environmentally friendly solution for such a complex water decontamination. These bots help in effective removal of the MNPs and OSs from the contaminated water resources. The natural abundance of the materials used for the synthesis of the bots promises a frugal large-scale production and mitigation of MNPs and OSs with the help of the proposed methodology in the near future. Further, the enhanced catalytic activity of such kieselguhrbots has been utilized for fuel cell application. In a way, this study suggests that the proposed multipurpose bots are not only capable of mitigating the widespread impact of environmental MNPs and OSs but can also be employed for energy harvesting applications, generating H2 and O2 gases from H2O2 and HCOOH to power a fuel cell.