Biological Approaches for Synthesis of Silver Nanoparticles for Environmental Applications - A Review

Nanotechnology is an emerging field in the area of interdisciplinary research, especially in biotechnology. Over the past few decades, nanoparticles of noble metals such as silver exhibited significantly distinct physical, chemical, and biological properties from their bulk counterparts. Silver nanoparticles are particles of silver that are in the range of 1 and 100 nm in size. Several products of colloidal silver are already available in the market. The major methods used for silver nanoparticles synthesis are the physical and chemical methods. The chemical and physical methods are that the synthesis is expensive and can also have toxic substances absorbed onto them. To overcome this, the biological method provides a reliable, economic, eco-friendly, and feasible alternative. The major biological systems involved in this are bacteria, fungi, and plant extracts. Silver nanoparticles have broad-spectrum applications due to their advanced properties such as the high surface area to volume ratio, smaller size than bulk silver. It is possible to solve the environmental pollution problem like drinking water, wastewater, removal of pathogenic microorganisms, heavy metal removal, textile dye removal, pesticide mineralization, food preservation, as a disinfectant, etc. using such nanoparticles. Apart from these, silver nanoparticles are also proved very efficient sensors to detect heavy metals from the environment. This review article provides some information about different modes of silver nanoparticles synthesis using a biological system, and also its fascinating environmental applications.