Adsorption Characteristics and Mechanism of Cr(VI)by Nanoscale Zerovalent Iron Particles Supported on Tamarisk Biochar
The tamarash biochar(TBC)was prepared from typical agricultural and forestry waste tamarash branches,and the biochar supported nano zero-valent iron composite(nZVI@TBC)was synthesized by liquid phase reduction method for Cr(Ⅵ)re-moval from water.Static adsorption experiments were used to study the adsorption characteristics and influencing factors of Cr(Ⅵ)in water,and the removal mechanism of nZVI@TBC on Cr(Ⅵ)has been conducted by SEM,FTIR,XRD and XPS.The results show that the TBC promoted uniform distribution and dispersion level of nZVI on the surface of biochar and its pore structure.The adsorption process of nZVI@TBC on Cr(Ⅵ)fitted the Langmuir isotherm model and the pseudo-second-order kinetic model.When the initial concentration of Cr(Ⅵ)was 50 mg/L,the initial pH was 3,the adsorption time was 120 min and the dosage was 4 g/L,the maximum theoretical adsorption capacity was 32.53 mg/g.The removal mechanism of Cr(Ⅵ)by nZVI@TBC involved electrostatic interaction,reduction,co-precipitation,complexation and"π-π"interaction with SiO2.Therefore,the nZVI@TBC can be used as an promising material for Cr(Ⅵ)removal from aqueous solution.
tamariskbiocharnano zero valent ironchromiummechanism
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