Simultaneous adsorption and immobilization of As and Cd by birnessite-loaded biochar in water and soil
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A novel biochar was prepared by loading birnessite to improve its capability to simultaneously adsorb As(III), As(V), and Cd(II) in water and soil. Layer sheet–structured birnessite was successfully loaded onto the biochar surface with increased functional groups. SEM, XRD, and FTIR combining with XPS analysis were utilized to characterize birnessite-loaded biochar and its adsorption mechanisms for As and Cd(II). The saturated adsorption capabilities of the birnessite-loaded biochar (BRB) for As(III), As(V), and Cd(II) were as large as 3543, 2412, and 9068 mg/kg (calculated by Langmuir isotherm model), much higher than for the corresponding non-loaded biochar (no adsorption of As, 4335 mg/kg for Cd). Adsorption of Cd and As onto BRB was controlled by multi mechanisms; Cd(II) appeared to coordinate to vacant sites of birnessite, while As formed surface complex with functional groups. Furthermore, BRB showed higher abilities for co-adsorption of As(III) and Cd or As(V) and Cd, which may be due to the formation of Cd3(AsO4)2 surface precipitate as well as synergistic reaction between anions and cations. After conditioning to soil, BRB showed potential for Cd and As remediation under both flooded and unflooded conditions. These results suggested that BRB can be used as an effective sorbent for simultaneous immobilization of heavy metals, especially As and Cd, in environmental and agricultural systems.
KeywordsBirnessite-loaded biochar Arsenic Cadmium Co-adsorption Soil
This study was financially supported by the National Key Research and Development Program of China (2016YFD0800400, 2017YFD0800303) and the National Natural Science Foundation of China (No. 41571130062).
- ATSDR Substance priority list, 2017. Accessed December 18, 2017Google Scholar
- Beesley L, Marmiroli M, Pagano L, Pigoni V, Fellet G, Fresno T, Vamerali T, Bandiera M, Marmiroli N (2013) Biochar addition to an arsenic contaminated soil increases arsenic concentrations in the pore water but reduces uptake to tomato plants (Solanum lycopersicum L.). Sci Total Environ 454:598–603CrossRefGoogle Scholar
- Matocha CJ, Elzinga EJ, Sparks DL (2001) Reactivity of Pb(II) at the Mn(III, IV) (oxyhydr)oxide− water interface. Environ Sci Technol 35(14):2967-2972Google Scholar
- Toner B, Manceau A, Webb SM, Sposito G (2006) Zinc sorption to biogenic hexagonal-birnessite particles within a hydrated bacterial biofilm. Geochim Cosmochim Ac 70(1):27-43Google Scholar
- Wang S, Gao B, Zimmerman AR, Li Y, Ma L, Harris WG, Migliaccio KW (2015b) Removal of arsenic by magnetic biochar prepared from pinewood and natural hematite. Bioresour Technol 175b:391–395Google Scholar