• Title/Summary/Keyword: Hematite-coated sand

Search Result 3, Processing Time 0.017 seconds

나노 크기 적철석 입자 피복 모래를 이용한 지하수내 비소 3가와 5가의 제거 기술 개발

  • 고일원;이철효;이상우;김주용;김경웅
    • Proceedings of the Korean Society of Soil and Groundwater Environment Conference
    • /
    • 2003.09a
    • /
    • pp.78-82
    • /
    • 2003
  • Development of hematite-coated sand was evaluated for the application of the PRB (permeable reactive barrier) in the arsenic-contaminated subsurface of the metal mining areas. The removal efficiency of As(III) and As(V), the effect of anion competition and the capability of arsenic removal in the flow system were investigated through the experiments of adsorption isotherm, arsenic removal kinetics against anion competition and column removal. Hematite-coated sand followed a linear adsorption isotherm with high adsorption capacity at low level concentrations of arsenic (< 1.0 mg/l). When As(III) and As(V) underwent adsorption reactions in the presence of anions (sulfate, nitrate and bicarbonate), sulfate caused strong inhibition of arsenic removal, and bicarbonate and nitrate caused weak inhibition due to specific and nonspecific adsorption onto hematite, respectively. In the column experiments, high content of hematite-coated sand enhance the arsenic removal, but the amount of the arsenic removal decreased due to the higher affinity of As(V) than As(III) and reduced adsorption kinetics in the flow system, Therefore, the amount of hematite-coated sand, the adsorption affinity of arsenic species and removal kinetics determined the removal efficiency of arsenic in the flow system. arsenic, hematite-coated sand, permeable reactive barrier, anion competition, adsorption.

  • PDF

Removal of Arsenite and Arsenate by a Sand Coated with Colloidal Hematite Particl (나노 크기 적철석 입자 피복 모래를 이용한 비소 3가와 비소 5가의 제거)

  • 고일원;이상우;김주용;김경웅;이철효
    • Journal of Soil and Groundwater Environment
    • /
    • v.9 no.1
    • /
    • pp.63-69
    • /
    • 2004
  • Hematite-coated sand was examined for the application of the PRB (permeable reactive barrier) to the arsenic-contaminated subsurface in the metal mining areas. The removal efficiency of As in a batch and a flow system was investigated through the adsorption isotherm, removal kinetics and column experiments. Hematite-coated sand followed a linear adsorption isotherm with high adsorption capacity at low level concentrations of As (<1.0 mg/L). In the column experiments, high content of hematite-coated sand enhanced the removal efficiency, but the amount of the As removal decreased due to the higher affinity of As (V) than As (III) and reduced adsorption kinetics in the flow system. Therefore. the amount of hematite-coated sand, the adsorption affinity of As species and removal kinetics determined the removal efficiency of As in a flow system.

Microbial Removal Using Layered Double Hydroxides and Iron (Hydr)oxides Immobilized on Granular Media

  • Park, Jeong-Ann;Lee, Chang-Gu;Park, Seong-Jik;Kim, Jae-Hyeon;Kim, Song-Bae
    • Environmental Engineering Research
    • /
    • v.15 no.3
    • /
    • pp.149-156
    • /
    • 2010
  • The objective of this study was to investigate microbial removal using layered double hydroxides (LDHs) and iron (hydr)oxides (IHs) immobilized onto granular media. Column experiments were performed using calcium alginate beads (CA beads), LDHs entrapped in CA beads (LDH beads), quartz sand (QS), iron hydroxide-coated sand (IHCS) and hematite-coated sand (HCS). Microbial breakthrough curves were obtained by monitoring the effluent, with the percentage of microbial removal and collector efficiency then quantified from these curves. The results showed that the LDH beads were ineffective for the removal of the negatively-charged microbes (27.7% at 1 mM solution), even though the positively-charged LDHs were contained on the beads. The above could be related to the immobilization method, where LDH powders were immobilized inside CA beads with nano-sized pores (about 10 nm); therefore, micro-sized microbes (E. coli = 1.21 ${\mu}m$) could not diffuse through the pores to come into contact with the LDHs in the beads, but adhere only to the exterior surface of the beads via polymeric interaction. IHCS was the most effective in the microbial removal (86.0% at 1 mM solution), which could be attributed to the iron hydroxide coated onto the exterior surface of QS had a positive surface charge and, therefore, effectively attracted the negatively-charged microbes via electrostatic interactions. Meanwhile, HCS was far less effective (35.6% at 1 mM solution) than IHCS because the hematite coated onto the external surface of QS is a crystallized iron oxide with a negative surface charge. This study has helped to improve our knowledge on the potential application of functional granular media for microbial removal.