Bioleaching of metallic nanoparticles from e-waste and their environmental application

The e-waste disposal methods have been a great challenge. The toxic substances of electronic devices including heavy metals and plastics put the lives of living organisms into danger. So their removal from the natural environment seems to be necessary. There are different disposal methods like landfilling and incineration which cause a great deal of damage to the environment. For instance emission of hazardous gases or the leakage of heavy metals into the soil. On the other hand, the need for precious metals recovery like gold and silver from e-waste, the use of recycling methods seems to be necessary. But these methods are generally expensive. So applying a new alternative method is required.The purpose of this article is to introduce bioleaching as an alternative to conventional disposal and recycling methods. This method is used to remove the heavy and toxic metals and also produce metallic nanoparticles at the same time. Then the application of nanoparticles in wastewater treatment and microplastics degradation is mentioned.The conversion of insoluble metals to the soluble one by chemolithoautotrophic microorganisms is called bioleaching. The Mesophilic and thermophilic bacteria like Chromobacterium violaceum, Pseudomonas species, Sulfobacillus thermosulfidooxidans, and Acidiphilium acidophilum can bioleaching gold, silver, nickel, and copper of electronic wastes. There are different fungi like Aspergillus niger,Penicillium simplicissimum, Aspergillus fumigatus, and Aspergillus flavus generate organic acid to leach out metals like copper, lead, nickel, and aluminum. Morganella can produce copper nanoparticles from waste materials. Different factors like the type of microorganisms, particle sizes, temperature, and PH affect the bioleaching process. Bioleaching is a substitution for recycling methods of electronic wastes. Various microorganisms are used for bioleaching according to the type of desired metallic nanoparticles. Wastewater treatment and photocatalytic degradation of microplastics are two important applications of produced nanoparticles.

کلیدواژه ها:

Biodegradation ، Bioleaching ، Metallic nanoparticle ، Wastewater treatment