title: Geochemical and spectroscopic investigations of Cd and Pb sorption mechanisms on contrasting biochars: engineering implications.
abstract: Biochars prepared from nut shells, plum stones, wheat straws, grape stalks and grape husks were tested as potential sorbents for Cd and Pb. Mechanisms responsible for metal retention were investigated and optimal sorption conditions were evaluated using the RSM approach. Results indicated that all tested biochars can effectively remove Cd and Pb from aqueous solution (efficiency varied between 43.8% and 100%). The removal rate of both metals is the least affected by the biochar morphology and specific surface but this removal efficiency is strongly pH-dependent. Results of variable metal removal combined with different optimized conditions explain the different metal sorption mechanisms, where the predominant mechanism is ion exchange. In addition, this mechanism showed very strong binding of sorbed metals as confirmed by the post-desorption of the fully metal-loaded biochars. Finally, these biochars could thus also be applicable for metal contaminated soils to reduce mobility and bioavailability of Cd and Pb.
authors.affiliation: Department of Environmental Geosciences, Faculty of Environmental Sciences, Czech University of Life Sciences Prague, Kamycka 129, Praha 6 Suchdol 16521, Czech Republic. Electronic address: trakal@fzp.czu.cz.
authors.forename: Lukáš
authors.initials: L
authors.lastname: Trakal
authors.affiliation: Department of Chemistry, Faculty of Sciences and Arts, Kocaeli University, Umuttepe Campus, 41380 Kocaeli, Turkey.
authors.forename: Deniz
authors.initials: D
authors.lastname: Bingöl
authors.affiliation: Environmental Process Engineering Laboratory, Institute of Chemical Process Fundamentals, Academy of Sciences of Czech Republic, v.v.i., Rozvojova 135, Praha 6 Suchdol 16502, Czech Republic.
authors.forename: Michael
authors.initials: M
authors.lastname: Pohořelý
authors.affiliation: Department of Environmental Geosciences, Faculty of Environmental Sciences, Czech University of Life Sciences Prague, Kamycka 129, Praha 6 Suchdol 16521, Czech Republic.
authors.forename: Miroslav
authors.initials: M
authors.lastname: Hruška
authors.affiliation: Department of Environmental Geosciences, Faculty of Environmental Sciences, Czech University of Life Sciences Prague, Kamycka 129, Praha 6 Suchdol 16521, Czech Republic.
authors.forename: Michael
authors.initials: M
authors.lastname: Komárek
mesh_terms: D000327:Adsorption; D002104:Cadmium / Q000737:chemistry*; D002606:Charcoal / Q000737:chemistry*; D006863:Hydrogen-Ion Concentration; D007700:Kinetics; D007854:Lead / Q000737:chemistry*; D008855:Microscopy, Electron, Scanning; D008956:Models, Chemical; D014874:Water Pollutants, Chemical / Q000032:analysis*; D018508:Water Purification / Q000379:methods*
chemical_list: D014874:Water Pollutants, Chemical; C540010:biochar; D002104:Cadmium; D002606:Charcoal; D007854:Lead
keywords: Biochar; Desorption; Metals; Response Surface Methodology (RSM); Sorption mechanisms