• Journal of the Korea Organic Resources Recycling Association
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• v.16 no.3
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• pp.75-82
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• 2008

Two UASB reactors were operated to investigate the effect of high concentration of sulfate on anaerobic digestion of propionate using an upflow anaerobic sludge blanket (UASB) reactor. An organic loading rate of $1.2kg\;COD/m^3{\cdot}d$ and a hydraulic retention time of 1.6 d were maintained during this study. In the absence of sulfate, the UASB reactor achieved about 95% removal of chemical oxygen demand whereas in the presence of $2,000\;SO_4^{2-}mg/L$, the COD removal rate decreased to 83% due probably to the inhibition of dissolved sulfide inhibition. Interactions between the methane producing bacteria (MPB) and sulfate reducing bacteria (SRB) were measured to investigate the competition between MPB and SRB. The MPB consumed average 58% of the available electron donors at $COD/SO_4^{2-}$ ratio of 1. Propionate was consumed mainly by SRB, converting sulfate into sulfide and suppressing the methane production. The specific methanogenic activity (SMA) using acetate and propionate increased as microorganism acclimated to the substrate.

• Korean Journal of Soil Science and Fertilizer
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• v.19 no.2
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• pp.107-113
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• 1986

Laboratory experiments were carried out to investigate the effects of pH, gibbsite, and organic matter on sulfate adsorption by soils. Samples of five soil series (Songjeong, Gopyung, Yeasan, Gyorae, and Namwon), different in physical and chemical properties, were used in this study. The results obtained from sulfate adsorption experiment with sulfate solutions of the concentrations ranging from 50 to 400 ppm were as follows: 1. The adsorption phenomena for five soils were well described by the Freundlich adsorption isotherm over a given range of sulfate concentration. 2. The amounts of sulfate adsorbed and K value of Freundlich adsorption isotherm increased as the initial pH of the suspension decreased. 3. Although the changes in pH of the suspension on the adsorption equilibrium were hardly observed in the soil treated with gibbsite, the sulfate adsorption rates were increased with amount of gibbsite treated. 4. The effects of pH of the suspension on the adsorption rates in the soils treated with gibbsite were remarkable at the level of 0.1% but were little at the level of 1.5%. 5. The adsorption rates of soils, treated with organic matter and incubated for three weeks, were in the order: starch > straw > compost. At the relatively high levels (5 and 10%) of treatments, compost treatment resulted in the sulfate desorption phenomena.

• Journal of the Korean Ceramic Society
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• v.35 no.12
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• pp.1286-1293
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• 1998

${SO_4}^{2-}$ ions present in industrial waste water if combined with other metal ions in the water can cause serious scale problem in a transporting pipe. In this study therefore ${SO_4}^{2-}$ ions in an acidic solution have been removed by using surface active glasses. Glasses with various compositions of $SiO_2-Na_2O-B_2O_3-RO$ (R=Mg, Ca, Sr, Ba) system were reacted in a ${SO_4}^{2-}$ ion-containing solution with various pHs ranging from 1 to 4 for various time the reacted glass surfaces were analyzed by XRD and SEM and all ions in the reacted solution were also measured ${SO_4}^{2-}$ ions in the solution were combined with divalent ions leached out of glass and precipitated on the glass surface as sulfate crystals. In this was the surface ion could be removed from the acidic solution. The sulfate ion removal capacity is closely related to the solubility product con-stants of the newly formed sulfate crystals. Almost no sulfate crystal was formed on the MgO-containing glass while sulfate crystals were easily formed on the glass containing either SrO or BaO This indicates that those glasses have strong removal efficiency of ${SO_4}^{2-}$ ions from the solution.

• Korean Journal of Environmental Biology
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• v.18 no.1
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• pp.33-39
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• 2000

Gordona sp. MS6, desulfurizing petroleum, can convert dibenzothiophene (DBT) to 2-hydroxybiphenyl (2-HBP) and sulfate. In this study, the effect of DBT degradation product on DBT desulfurization activity was investigated. When $Na_2$SO$_4$ and DBT were simultaneously added in the medium sulfur sources, specific growth rate of strain MS6 was doubled compared to not adding $Na_2$SO$_4$. But, sulfate inhibited DBT desulfurization rate, furthermore, when 0.05 g/L $Na_2$SO$_4$ was supplied DBT desulfurization rate decreased down to 40%. When 2-HBP and its derivative, 2, 2'-dihydroxybiphenyl (DHBP) were not added, DBT desulfurization rate was 5.0 $\mu$mol L$^{-1}$ㆍh$^{-1}$. With the increase of 2-HBP and DHBP concentration, DBT desulfurization rate was decreased. No DBT desulfurization activity of Gordona sp. MS6 was observed when initial concentration was over 0.15 mM 2-HBP and 0.8 mM DHBP [Gordona sp., Desulfurization, Dibenzothiophene, 2-Hydroxybiphenyl, Sulfate].

• Korean Chemical Engineering Research
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• v.51 no.2
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• pp.195-202
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• 2013

$TiO_2$ powders were prepared from titanium (IV) sulfate ($Ti(SO_4)_2$) solution using ammonia solution at low reaction temperature ($80{\sim}100^{\circ}C$) and atmospheric pressure by hydrothermal precipitation method without calcination. The effect of reaction conditions, such as reaction temperature, initial concentration of titanium (IV) sulfate ($Ti(SO_4)_2$) solution, pH of mixture solution and the physical properties of the prepared $TiO_2$, such as crystallite structure, crystallite size were investigated. The photocatalytic activity of prepared $TiO_2$ was tested by the photolysis of brilliant blue FCF (BB-FCF) under the UV and the analysis of UV-VIS diffuse reflectance spectroscopy (DRS). The physical properties of prepared $TiO_2$ were examined by X-ray diffraction (XRD), scanning electron microscopy (SEM), photoluminescence spectrometer (PL), particle size distribution measurements. The crystallite size and crystallinity of prepared $TiO_2$ increased with increasing titanium (IV) sulfate ($Ti(SO_4)_2$) concentration, but photocatalytic activity decreased. The crystallite size decreased with increasing pH of mixture solution, but photocatalytic activity increased. The crystallinity and photocatalytic activity increased with increasing reaction temperature. The results showed that anatase type $TiO_2$ could be prepared by hydrothermal precipitation method using titanium (IV) sulfate ($Ti(SO_4)_2$) solution and ammonia solution at low reaction temperature and atmospheric pressure without calcination.

• Korean Journal of Materials Research
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• v.2 no.1
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• pp.3-11
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• 1992

Aluminum sulfate hydrate was prepared using sulfuric acid from Ha-dong kaolin. The effects of calcination-temperature and calcination-time of kaolin, reaction-temperature and reaction-time, and sulfuric acid concentration on the formation of aluminum sulfate hydrate were investigated. The precipitation condition of aluminum sulfate hydrate from sulfuric acid solution was determined. Also, the products heat-treated at different temperatures have been investigated by X-ray diffraction, thermogravimetry, differential thermal analysis, Fourier transform infrared spectrophotometer, scanning electron microscopy, particle size distribution analysis and chemical analysis. In the optimum condition, the conversion of aluminum oxide in kaolin to aluminum sulfate hydrate was 60%. From the results of XRD, TG-DTA, and FT-IR, it is suggested that the aluminum sulfate hydrate is thermally decomposed as follows ; $Al_2(SO_4)_3{\cdot}18H_2O{\rightarrow}Al_2(SO_4)_3{\cdot}6H_2O{\rightarrow}Al_2(SO_4){\rightarrow}\;amorphous\;alumina{\rightarrow}{\gamma}-alumina{\rightarrow}{\delta}-alumina{\rightarrow}{\theta}-alumina{\rightarrow}{\alpha}-alumina$. The purity of alumina powder prepared by calcining aluminum sulfate hydrate at $1200^{\circ}C$ was 99.99 percent.

• Journal of Microbiology and Biotechnology
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• v.19 no.7
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• pp.698-708
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• 2009

High rate sulfate reduction under acidic conditions opens possibilities for new process flow sheets that allow the selective recovery of metals from mining and metallurgical waste and process water. However, knowledge about high-rate sulfate reduction under acidic conditions is limited. This paper investigates sulfate reduction in a membrane bioreactor at a controlled pH of 5. Sulfate and formate were dosed using a pH-auxostat system while formate was converted into hydrogen, which was used for sulfate reduction. Sulfide was removed from the gas phase to prevent sulfide inhibition. This study shows a high-rate sulfate-reducing bioreactor system for the frrst time at pH 5, with a volumetric activity of 188 mmol $SO_4^{2-}$/I/d and a specific activity of 81 mmol $SO_4^{2-}$volatile suspended solids/d. The microbial community at the end of the reactor run consisted of a diverse mixed population including sulfate-reducing bacteria.

• Applied Microscopy
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• v.37 no.4
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• pp.219-230
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• 2007

The morphological effects of intranasal zinc sulfate(5% solution) irrigation on the mouse olfactory epithelium and the regeneration process of olfactory receptor cells following nasal irrigation were studied with scanning and transmission electron microscope. The results were as follows: 1. The septal epithelium except some basal cells was wholly detached from the basement membrane, during the first 6 to 24 hours after 5% zinc sulfate irrigation. 2. 3 days after $ZnSO_4$ treatment, two layered septal epithelium was formed from basal cells. And microvilli were observed in the apical epithelium of newly formed olfactory epithelial cells. 3. 5 days after treatment, a lot of centrosomes and basal bodies were observed in the olfactory receptor cells, and cilia were lined up between microvilli on the apical membrane of olfactory receptor cells. And immature olfactory knob was first observed in the newly formed olfactory receptor cells. Mature olfactory knob was observed 1 week after treatment. 4. There are very many mature olfactory knobs in the olfactory receptor cells 2 weeks after intranasal zinc sulfate irrigation. These results support that treatment with 5% zinc sulfate is a good experimental model for the regeneration of mammalian nervous tissues because this method could thoroughly detach the septal epithelium. During the regeneration of olfactory receptor cells, the surface membrane of the olfactory receptor cells widen the surface with the microvilli. Then cilia, which arranged in a line, substituted for the microvilli. The part of the surface membrane with cilia protruded and finally formed the olfactory vesicle.

• Journal of the Korean Ceramic Society
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• v.24 no.5
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• pp.417-422
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• 1987

Kinetic studies were made on the thermal decomposition of hydrated magnesium aluminum double sulfate by a nonisothermal TG method. Thermal analyses of the dehydration of tricosahydrate showed that the reaction proceeded via decahydrate to the anhydrous MgAl2(SO4)4 in the range 50$^{\circ}$to 400$^{\circ}C$. Decomposition of MgAl2(SO4)4 occurred as the two-step between 650$^{\circ}$ and 970$^{\circ}C$. Dehydration of MgAl2(SO4)4$.$23H2O and a 2D diffusion controlled with an activation energy of 16.6kcal/mole, respectively. MgAl2(SO4)4 fitted the contracting volume model with an activation energy of 10.5kcal/mole, and MgSO4 fitted a contracting area model with an activation of 4.5kcal/mole.

• Resources Recycling
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• v.31 no.2
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• pp.49-55
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• 2022

In the present study, the thermodynamic evaluation of the sulfate-roasting process was conducted to extract vanadium from the Korean vanadium titano-magnetite ore. The leaching efficiency of vanadium and other impurities was analyzed for varying roasting temperatures and addition of Na₂SO₄. In the case of sulfate roasting, the roasting temperature was 200 ℃ higher than that previously observed Na₂CO₃ roasting. However, the higher leaching efficiency of vanadium and lower leaching efficiency of other impurities, such as aluminum and silicon, were observed. The high selectivity for the extraction of vanadium in sulfate roasting would result from the reaction mechanism between SO₂ gas and vanadium concentrate.