A novel approach in bioleaching of metals from e waste by construction of a batch reactor and extraction of metals by adsorption using low cost adsorbents

Abstract

Electronic waste is the waste electrical and electronic equipment which when disposed in an open environment untreated could bring out lot of harmful gases and effluent The important part of electronic device is the Printed Circuit Board PCB which contributes 3 of the total electronic devices The Waste Printed Circuit Board WPCB when turned into waste as a source of metals as there is a huge depletion of natural resources Bioleaching is the process of solubilization of metals with the help of microorganisms Though there are various techniques for the extraction of metals bioleaching was opted because it is eco friendly and does not emit harmful gases that causes health problem to the user Various researchers stated that smaller the size of the particle larger the metal recovery efficiency but the consumption of energy for the pulverization or shredding of the WPCB is high Therefore an alternate idea has been originated for better leaching which could also be eco friendlier Moreover there is no proper reactor set up which would be easily adapted by the local informal recyclers who turns into an unhealthy human After the leaching of metals by bioleaching there are various techniques for the removal of metals from the lixiviant pool but they are either expensive or difficult to be implemented in large scale Considering all these an attempt has been made to fulfill the needs of extraction and to remove the metals in a compatible way The WPCB were cut into pieces and powdered to find out the difference in leaching efficiency in a lab scale study An initial pretreatment of removal of epoxy coating has been done prior to the bioleaching process which enhances the metal recovery Various chemical has been tried and finally the WPCB has been soaked in a solution of 5 N of NaOH for 8 hours which removed the entire epoxy coating of the WPCB when subjected to 5 minutes of bath sonication newline