• Title/Summary/Keyword: 층상이중수산화물

Search Result 22, Processing Time 0.016 seconds

Hydrothermal Synthesis and Exfoliation of Mg/Al Layered Double Hydroxide with Tailored Aspect Ratio (수열 합성 및 박리에 의한 Mg/Al 층상 이중 수산화물의 종횡비 제어)

  • Hwang, Sung-Hwan;Kim, Donghyun;Kim, Yewon;Jung, Hyunsung
    • Journal of the Korean Institute of Electrical and Electronic Material Engineers
    • /
    • v.30 no.12
    • /
    • pp.822-827
    • /
    • 2017
  • Mg/Al layered double hydroxide with two-dimensional (2D) nanostructures was synthesized by a hydrothermal technique. The morphology and aspect ratio of $Mg_4Al_2(OH)_{14}3H_2O$ were controlled by the concentration and kinds of the hydrolysis agent, and temperature. The aspect ratio of $Mg_4Al_2(OH)_{14}3H_2O$ layered double hydroxides with the 2D hexagonal crystal structure was tailored from about 12.6 to about 45.7. The intercalated $CO{_3}^{2-}$ anions of the synthesized 2D $Mg_4Al_2(OH)_{14}3H_2O$ layered double hydroxides were exchanged to $NO_3{^-}$ anions. The bulk 2D $Mg_4Al_2(OH)_{14}3H_2O$ layered double hydroxides with the increased space between two layers due to the anion exchange were exfoliated in a formamide solution. The aspect ratio of the exfoliated 2D $Mg_4Al_2(OH)_{14}3H_2O$ layered double hydroxides increased to 570.3.

Arsenic removal from artificial arsenic water using CaAl-monosulfate and CaAl-ettringite (CaAl-monosulfate와 CaAl-ettringite를 이용한 인공비소폐수의 비소 제거 연구)

  • Shim, Jae-Ho;Kim, Ki-Baek;Choi, Won-Ho;Park, Joo-Yang
    • Journal of Korean Society of Water and Wastewater
    • /
    • v.26 no.1
    • /
    • pp.141-148
    • /
    • 2012
  • The objective of this study is to remove arsenate from artificially contaminated wastewater using CaAl-ettringite and CaAl-monosulfate which were synthesized in laboratory. The study was carried on the basis of solidification/stabilization of waste using cement. Monosulfate and ettringite are constituents of cement paste. The CaAl-ettringite has a chemical formula of $Ca_6Al_2O_6(SO_4)_3{\cdot}32H_2O$ and has a needle like morphology. Whereas CaAl-monosulfate $Ca_4Al_2O_6(SO_4){\cdot}12H_2O$ has layered double hydroxide structure (LDH) in which the mainlayer consists of Ca and Al and S as interlayer. Ettringite and monosulfate were synthesized by reaction of tricalcium aluminate and gypsum and hydrating this mixture at elevated temperature. The synthesized mineral were characterized by PXRD and FESEM to ensure purity. It was found that concentrations of As(V) in contaminated water were reduced from initial concentration of 1.335 mmol/L to 0.054 mmol/L and 0.300 mmol/L by CaAl-monosulfate and CaAl-ettringite respectively. The post experimental results of PXRD and FESEM analysis indicate that arsenate removal was by ion exchange.