Mg-Fe 이중층수산화물로 제조한 분말상과 입상 안정화제의비소 오염토양 안정화 기작 (Stabilization Mechanisms of Powdered and Bead Type Stabilizer Made of Mg-Fe Layered Double Hydroxide (LDH) for the Arsenic Contaminated Soil)

서지정보

· 발행기관 : 한국지하수토양환경학회
· 수록지 정보 : 지하수토양환경 / 27권 / 4호 / 49 ~ 62페이지
· 저자명 : 김선희, 김경태, 오유나, 한이경, 이민희

초록

The magnesium and iron-based layered double hydroxide (Mg-Fe LDH) was synthesized by the co-precipitation processand the bead type LDH (BLDH, 5~6 mm in diameter) was manufactured by using the Mg-Fe LDH and the starch as abinder. To evaluate the feasibility of the BLDH as the As stabilizer in the soil, various experiments were performed andthe As stabilization efficiency of the BLDH was compared to that of powdered type LDH (PLDH, <149 μm in diameter).
For the As sorption batch experiment, the As sorption efficiency of both of the PLDH and the BLDH showed higher than99%. For the stabilization experiment with soil, the As extraction reducing efficiency of the PLDH was higher than 87%,and for the BLDH, it was higher than 80%, suggesting that the BLDH has similar the feasibility of As stabilization for thecontaminated soil, compared to the PLDH. From the continuous column experiments, when more than 7% BLDH wasadded into the soil, the As stabilization efficiency of the column maintained at over 91% for 7 pore volume flushing(simulating about 21 months of rainfall) and slowly decreased down to 64% after that time (to 36 months) under the nonequilibriumconditions. Results suggested that more than 7% of BLDH added in As-contaminated soil could be enough tostabilize As in soil for a long time. The main As fixation mechanisms on the LDH were also identified through the X-rayfluorescence (XRF), the X-ray diffraction (XRD), and the Fourier transform infrared (FT-IR) analyses. Results showedthat the LDH has enough of an external surface adsorption capacity and an anion exchange capability at the interlayerspaces. Results of SEM/EDS and BET analyses also supported that the Mg-Fe LDH used in this study has sufficientporous structures and outer surfaces to fix the As. The reduction of carbonate (CO32-) and sulfate (SO42-) anions in theLDH after the reaction between As and the LDH was observed through the FT-IR, the XRF, and the XRD analyses,suggesting that the exchange of some of these anions with the arsenate (H2AsO4- or HAsO42-) occurs at the LDHinterlayers during the stabilization process in soil.

영어초록

The magnesium and iron-based layered double hydroxide (Mg-Fe LDH) was synthesized by the co-precipitation processand the bead type LDH (BLDH, 5~6 mm in diameter) was manufactured by using the Mg-Fe LDH and the starch as abinder. To evaluate the feasibility of the BLDH as the As stabilizer in the soil, various experiments were performed andthe As stabilization efficiency of the BLDH was compared to that of powdered type LDH (PLDH, <149 μm in diameter).
For the As sorption batch experiment, the As sorption efficiency of both of the PLDH and the BLDH showed higher than99%. For the stabilization experiment with soil, the As extraction reducing efficiency of the PLDH was higher than 87%,and for the BLDH, it was higher than 80%, suggesting that the BLDH has similar the feasibility of As stabilization for thecontaminated soil, compared to the PLDH. From the continuous column experiments, when more than 7% BLDH wasadded into the soil, the As stabilization efficiency of the column maintained at over 91% for 7 pore volume flushing(simulating about 21 months of rainfall) and slowly decreased down to 64% after that time (to 36 months) under the nonequilibriumconditions. Results suggested that more than 7% of BLDH added in As-contaminated soil could be enough tostabilize As in soil for a long time. The main As fixation mechanisms on the LDH were also identified through the X-rayfluorescence (XRF), the X-ray diffraction (XRD), and the Fourier transform infrared (FT-IR) analyses. Results showedthat the LDH has enough of an external surface adsorption capacity and an anion exchange capability at the interlayerspaces. Results of SEM/EDS and BET analyses also supported that the Mg-Fe LDH used in this study has sufficientporous structures and outer surfaces to fix the As. The reduction of carbonate (CO32-) and sulfate (SO42-) anions in theLDH after the reaction between As and the LDH was observed through the FT-IR, the XRF, and the XRD analyses,suggesting that the exchange of some of these anions with the arsenate (H2AsO4- or HAsO42-) occurs at the LDHinterlayers during the stabilization process in soil.

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