• Title/Summary/Keyword: Aluminum Hydrolysis

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Removal Mechanism of Phosphorus in Wastewater Effluent using Coagulation Process (응집공정을 이용한 하수처리수 중의 인 제거 Mechanism)

  • Han, Seung-Woo;Kang, Lim-Seok
    • Journal of Korean Society of Environmental Engineers
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    • v.32 no.8
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    • pp.774-779
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    • 2010
  • The experimental results for the analysis of aluminum hydrolysis species with PACls (polyaluminum chloride) prepared by different basicity (r value) showed that monomeric Al species were reduced while polymeric Al species were increased with an increase in basicity for PACls. The PACl with 2.2 of r value contained the highest amount of polymeric Al species. According to the experimental results for the phosphorus removal, the alum and PACl (r=0), which consisted of mainly monomeric Al species, were the most effective for phosphorus removal. Therefore, it was concluded that the Al coagulant containing higher amount of monomeric or lower molecular Al species would be more beneficial for phosphorus removal.

Effects of Artificial Acid Precipitation on Forest Soil Buffer Capacities (인공산성우(人工酸性雨)가 삼림토양(森林土壤)의 완충능(緩衝能)에 미치는 영향(影響))

  • Min, Ell Sik;Lee, Soo Wook
    • Journal of Korean Society of Forest Science
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    • v.79 no.4
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    • pp.376-387
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    • 1990
  • A research effort has been made to determine soil buffer capacity in forest soils nearby urban and industrialized regions. Buffer capacities of soils from four regions were measured by different pH levels of artificial acid precipitation. The following conclusions have been drawn in response to the overall research objectives. Soil Suffer capacity was the highest in Kangwondo followed by Uisan, Yeochon and Seoul when simulated acid precipitation were treated at the level of pH 3.0-5.7. With the acid precipitation treatment below pH 2.0 level, however, the capacity dropped seriously with no significant differences between the regions. In Kangwondo region soils weathered from granite and limestone showed significant differences in the buffer capacities. Soil collected in Seoul and Ulsean revealed that the capacities tended to increase with the distance from the pollution sources when treated at pH 3.0, 4.5 and 5.7 level of acid precipitation. The major mechanism of soil buffer observed during simulated acid precipitation experiment was canon exchange for Kangwondo forest soils. In Seoul region canon exchange also played an important role in soil buffering under artificial acid precipitation between 3.0 and 5.7 pH levels, yet under pH 2.0 level aluminum and silicate hydrolysis. In Ulsan canon exchange was a msjor determinant for the buffer capacity above pH 4.5 level, between pH 3.0-4.5 aluminum hydrolysis and below pH 3.0 aluminum and silicate hydrolysis. In Yeochon silicate hydrolysis led buffer capacity above pH 4.5 and below pH 4.5 aluminum hydrolysis.

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Evaluation of effect of rapid mixing intensity on chemical phosphorus removal using Al hydrolysis speciation (가수분해 산물 분포를 이용한 급속혼화강도가 화학적 인 제거 효율에 미치는 영향의 규명)

  • Kim, Seung-Hyun;Yoon, Dong-Soo;Moon, Byung-Hyun
    • Journal of Korean Society of Water and Wastewater
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    • v.25 no.3
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    • pp.367-373
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    • 2011
  • Mechanism of rapid mixing effect on chemical phosphorus removal is evaluated in this study. Assuming that chemical phosphorus removal is unaffected by mixing time, only rapid mixing intensity is evaluated. In order to find out the mechanism, it is hypothesized that rapid mixing affects the Al hydrolysis speciation, and that formation of more monomeric species ($Al^a$) results in better removal of phosphorus. According to a ferron assay, more $Al^a$ formed at higher mixing intensity than at lower intensity. Subsequent experiments revealed that better phosphorus removal was obtained at higher intensity than at lower intensity, in terms of the molar ratio of $Al_{added}/P_{removed}$. The proposed hypothesis was proved in this study. Chemical phosphorus removal is affected by rapid mixing intensity due to its effect on the Al hydrolysis speciation.

Formation of an Aluminum Hydroxide Fiber by a Hydrolysis of Aluminum Nano Powder (알루미늄 나노 분말의 수화반응에 의한 수산화알루미늄 형성)

  • Lee Geunhee;Oh Young Hwa;Rhee Chang Kyu;Kim Whung Whoe
    • Korean Journal of Materials Research
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    • v.15 no.3
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    • pp.172-176
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    • 2005
  • Formation of aluminum hydroxide by a hydrolytic reaction of nano aluminum powder synthesized by a pulsed wire evaporation (PWE) method has been studied. The type and morphology of the hydroxides were investigated with various initial temperatures and pHs. The nano fibrous boehmite (AlOOH) was formed predominantly over $40^{\circ}C$ of the hydrolytic temperature in acid solution, while the bayerite $(Al(OH)_3)$ was formed predominantly below $30^{\circ}C$ in alkali solution with a faceted crystalline structure. As a result the boehmite showed a much larger specific surface area (SSA) than that of bayerite. The highest SSA of the boehmite was about $409\;m^2/g$.

Influence of inorganic compounds on nanofiltration membrane fouling with Al hydrolysis products (알루미늄 수화물 나노여과 막오염에 대한 공존염의 영향에 관한 연구)

  • Choi, Yang-Hun;Kweon, Ji-Hyang
    • Journal of Korean Society of Water and Wastewater
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    • v.25 no.4
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    • pp.479-488
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    • 2011
  • Nanofiltration was performed with polyaluminium chloride solutions at different pH conditions to understand effects of inorganic compounds on aluminum hydrolysis products, i.e., three distinctive groups of aluminum species: polymeric Al at low pH; $Al(OH)_3$ at neutral pH; and ${Al(OH)_4}^-$ at high pH. The PACl solution was prepared to be approximately 4.0mM and adjusted to the designated pH. The influence of inorganic compounds on Al species fouling was investigated with 4.9mM $CaCl_2$ and 3.5mM $MgSO_4$ because $Ca^{2+}$, $Mg^{2+}$, $Cl^-$, ${SO_4}^{2-}$ are the most common inorganics in the drinking water. NF membrane fouling was measured by flux decline rate. The impact of $CaCl_2$ was not significant on the individual Al hydrolysis products fouling. However, the flux decline rate was drastically changed in the presence of $MgSO_4$. The concentration of particulate matters was considerably increased possibly due to interaction between Al species and ${SO_4}^{2-}$ where $MgSO_4$ was introduced. The particulates were accumulated on the membrane and enhanced the hydraulic resistance of the cake layer. In addition, conductivity removal of the membrane was decreased when Al-hydroxide was dominant due to reduction of membrane surface charge. The rejection of $Ca^{2+}$and $Mg^{2+}$ were considerably different, which implys that composition of inorganics paly a role on conductivity removal.