Characterization of metal binding sites onto biochar using rare earth elements as a fingerprint
نویسندگان
چکیده
The ability of biochar to immobilize metals relies on the amount of functional groups at its surface but the contribution of each functional groups (e.g. carboxylic, phenolic) to metal bonding is poorly known. Using a new approach based on previous works on rare earth element (REE) interactions with humic substances, we aim at elucidating the relative contribution of these binding sites to metal sorption under various conditions (i.e. pH and ionic strengths, IS). Using batch experiments, REE sorption onto biochar was analyzed from pH 3 to 9 and IS 10-1 mol/L to 10-3 mol/L. Rare earth element patterns show a Middle REE (MREE) downward concavity at acidic pH and low ionic strength. These patterns are in good agreement with existing datasets quantifying REE binding with humic substances. Indeed, the MREE downward concavity displayed by REE-biochar complexation pattern compares well with REE patterns with various organic compounds. This similarity in the REE complexation pattern shapes suggests that carboxylic groups are the main binding sites of REE in biochar. Overall, our results indicate that the strength of the metal bonding with biochar increases when pH and IS increase, suggesting that biochar is more efficient for long-term metal immobilization at near neutral pH and high ionic strength.
منابع مشابه
Characterization of rare earth elements by coupling multivariate analysis, factor analysis, and geostatistical simulation; case-study of Gazestan deposit, central Iran
The traditional approaches of modeling and estimation of highly skewed deposits have led to incorrect evaluations, creating challenges and risks in resource management. The low concentration of the rare earth element (REE) deposits, on one hand, and their strategic importance, on the other, enhances the necessity of multivariate modeling of these deposits. The wide variations of the grades and ...
متن کاملRare earth element sorption onto hydrous manganese oxide: a modeling study.
Manganese oxides are important scavengers of rare earth elements (REE) in hydrosystems. However, it has been difficult to include Mn oxides in speciation models due to the lack of a comprehensive set of sorption reactions consistent with a given surface complexation model (SCM), as well as discrepancies between published sorption data and predictions using the available models. Surface complexa...
متن کاملScreening biochars for heavy metal retention in soil: role of oxygen functional groups.
Oxygen-containing carboxyl, hydroxyl, and phenolic surface functional groups of soil organic and mineral components play central roles in binding metal ions, and biochar amendment can provide means of increasing these surface ligands in soil. In this study, positive matrix factorization (PMF) was first employed to fingerprint the principal components responsible for the stabilization of heavy m...
متن کاملAssessment of the Binding of Protons, Al and Fe to Biochar at Different pH Values and Soluble Metal Concentrations
Biochar can retain large amounts of protons and metals in the drainage water from acid sulfate soils and mine sites. Metal sorption can, however, be influenced by many factors, such as pH and metal composition. This study investigated proton, Al, and Fe retention capacity of eucalyptus biochar (1% w/v) at different pH and metal concentrations. In the absence of metals, the biochar had a high pr...
متن کاملIsolation and Structural Characterization of Alkali and Alkaline Earth Metal Salts with Synthetic Non Cyclic Ionophores
In the present study, an investigation on the complex formation between mono- and divalent metal ions (Na+, K+, Li+ and Mg2+) in the form of salt with different podands using various solvents has been carried out. Isolated complexes were characterized by different spectroscopic techniques viz. IR, NMR and elemental analysis. On the basis of ...
متن کامل