The Multiple Roles of Diatoms in Environmental Applications: Prospects for Sol-Gel Modified Diatoms

Abstract

Diatoms, unicellular microalgae, have a characteristic ornate siliceous cell wall, referred to as the frustule. The elaborate architecture of the frustule, at both the nano- and micro-scale, lends these structures to proposed applications in catalysis, separation science, filtration and emerging nanotechnologies. In addition, the living diatom is a known indicator of water quality, due to the fact that both the cell morphology and cell physiology are sensitive to the presence of pesticides, herbicides, pharmaceuticals, polymers and personal care products. The potential of diatoms to bioaccumulate, biotransform or biodegrade compounds of concern including polycyclic aromatic hydrocarbons, non-steroidal anti-inflammatory pharmaceuticals, endocrine disrupting chemicals, phthalates and metal nanoparticles has been documented. Sol-gel modification of either the living diatom or harvested frustule enables the design of diatoms for bioremediation of these priority substances from the environment. Furthermore, diatoms can be prodigious producers of extracellular polymeric substances (EPS) that may find a role in decontamination of pollutants through the formation gel-like networks that sequester pollutants.