Removal and recovery of metals by biosorbents and biochars derived from biowastes

The production of biosorbents and biochars from various biowastes (such as the agricultural and food industries and algal and fungal biomass) has received considerable attention because of their potential use in the removal and recovery of elements, such as precious metals and heavy metals from water and wastewater. Recovery of these metals from their aqueous solutions has emerged as an exciting area of research as a result of increasing or fluctuating prices of metals (eg, precious metals), limited availability of their deposits, and the ever-increasing demand and time- and energy-consuming processes needed to mine metal deposits. This review will summarize the various sources of metals, the available biowastes of the agricultural and food industries, and preparation methods for biosorbents and biochars from biowastes. We will focus on metal and heavy metal removal and recovery from waste and wastewater, methods for metal recovery, pretreatment and modification of biosorbents and biochars for enhanced metal sequestration, and strategies to provide stability to biosorbents and biochars to maximize resource recovery. © 2016 Elsevier Inc. All rights reserved.