Value of biochars from Miscanthus x giganteus cultivated on contaminated soils to decrease the availability of metals in multicontaminated aqueous solutions

Abstract

The objective of this study was to evaluate the sorption efficiency of eight biochars, made from Miscanthus x giganteus cultivated on contaminated agricultural soil, in aqueous solutions contaminated with metals alone or mixed with polycyclic aromatic hydrocarbons. These biochars were produced in different pyrolysis conditions (temperature, 400/600 °C; heating rate, 5/10 °C min; duration, 45/90 min) and compared with an uncontaminated commercialized biochar made of wood. The physicochemical characterization of the Miscanthus biochars confirmed the impact of the pyrolysis on the biochar parameters with substantial differences between the biochars in terms of pH, cation exchange capacity, and specific surface area. The sorption experiment showed higher sorption efficiency of Cd, Pb, and Zn for the Miscanthus biochars produced at 600 °C compared with the biochars produced at 400 °C when the aqueous solutions were mono- or multicontaminated. Furthermore, the desorption study showed that the sorption process was largely irreversible. Therefore, the high sorption capacity of Miscanthus biochars and the low sorption reversibility confirmed that these biochars are a suitable sorbent for metals.

Characterization of Chemically Activated Carbons Prepared from Miscanthus and Switchgrass Biomass

“…The global cultivation area of these crops may be easily expanded, since these grasses are able to grow on marginal lands [20][21][22]. In fact, miscanthus and switchgrass biomass have already been grown to produce biochar of potential use for soil and groundwater remediation or improvement [23][24][25][26]. However, making ACs for industrial or medicinal and other applications requires additional processing of crude carbonizate and the evaluation of obtained products.…”

Toward a New Way for the Valorization of Miscanthus Biomass Produced on Metal-Contaminated Soils Part 1: Mesocosm and Field Experiments

“…The production of plant biomass, not dedicated to human consumption, in marginal and contaminated agricultural areas has been recently suggested as a potential solution for the rehabilitation and reconversion of contaminated soils [8]. Modifications of the plant biomass to produce fibers, oil, biofuels, mulch, animal bedding and biochars are topical and of particular interest to manufacturers and researchers because these advances are part of the circular economy and design processes [9][10][11][12][13][14]. For instance, miscanthus is a promising example of biomass for which there are still new applications to discover.…”