A review on the synthesis of silica nanoparticles and their applications in environmental remediation

Environmental remediation deals with the removal of contaminants from environment for maintaining and restoring the quality of soil, water, and air and, more in general, for protecting human health. At present, a wide range of silica products is manufactured for applications in microelectronics, medicine, pharmacy and so on. A more ambitious use of nanosilicas is remediation of contaminated environments and, recently, their application in wastewater treatment has emerged as a fast-developing and attractive area of interest. Because of high surface area, silica nanoparticles show a very good adsorption capacity and a large specific reactivity. Recent studies have shown that hydrophilic and hydrophobic silica nanoparticles are very efficient in removing pollutants such as dyes, metallic species, and pesticides from water, and wastewaters. Another interesting benefit of silica nanoparticles as adsorbents is that they are considered non-toxic and not harmful to the environment. Moreover, nanosilica based technology shows an attractive cost-effectiveness ratio as it requires relatively cheap processing of raw materials. This paper has reviewed the recent progresses in remediation by silica nanoparticles and their synthesis methods.