• Journal of the Korean Society of Mineral and Energy Resources Engineers
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• v.55 no.6
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• pp.527-537
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• 2018

Column tests of a sulfate reducing bacteria (SRB) bioreactor were conducted to determine the design factors for sulfate-rich mine drainage. Various substrates were applied to the bioreactor, including cow manure and its mixture with a mushroom compost, with rice straw and limestone as subsidiary materials. This procedure provided a removal efficiency of up to 82% of the total sulfur with the mixture of cow manure (70%), mushroom compost (10%) and rice straw (20%), and higher efficiencies were observed after 2 days of retention time. In the downflow condition of the flow direction, oxygen supply and re-oxidation of the sulfates occurred, causing a decrease in sulfate removal efficiency. The addition of an inorganic sludge containing heavy metals, which was intended for production of metal-sulfides in the bioreactor, had a negative effect on the long-term operation owing to arsenic release and toxicity to the SRB. The results thus show that a bioreactor using a mixed substrate with cow manure and operating in the downflow direction could reduce sulfates and total dissolved sulfur content; this process confirms the applicability of the SRB bioreactor to sulfate-rich saline drainage.

• Journal of Environmental Science International
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• v.19 no.11
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• pp.1385-1390
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• 2010

Repeated additions of untreated slurry to soil affected ecology and caused high levels of heavy metal in soil and ground water. The objective of this study was to evaluate heavy metal from hanwoo slurry with ferrous sulfate ($FeSO_4{\cdot}7H_2O$), aluminum sulfate [$Al_2(SO_4)_3{\cdot}14H_2O$, alum] and aluminum chloride ($AlCl_3{\cdot}6H_2O$) as a way to improve environmental management in hanwoo industry. The treatment rates, which were incorporated totally within the hanwoo slurry, were 1.0 g and 1.5 g of ferrous sulfate, alum and aluminum chloride/25 g of hanwoo slurry. The various rates of chemical additives significantly increased dry matter (9.98~13.94%) and decreased pH (3.48~6.52) compared with the controls. The use of chemical additives decreased Fe (11~29%), Al (7~12%), Zn (13~36%), and Cu (4~32%) contents, except for Fe in hanwoo slurry with ferrous sulfate and Al in hanwoo slurry with alum and aluminum chloride. In addition, the reduction in heavy metal should be associated with reduction in pH. In conclusion, the results of this study suggest that alum and aluminum chloride additives at rate of 1.5 g were cost-effective management practice that significantly reduces heavy metal from hanwoo slurry, while it may be improved environmental management.

• Journal of Periodontal and Implant Science
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• v.32 no.2
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• pp.325-338
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• 2002

Bone graft using growth factors and guided tissue regeneration have been used for the regeneration of infrabony defects which caused by periodontal disease. Calcium sulfate which is one of the resorbable barrier materials used for guided tissue regeneration. Platelet rich plasma which is a easy method to obtain the growth factors had many common points but, platelet rich plasma was still studying. This study was the comparative study between bone graft using platelet rich plasma and guided tissue regeneration using calcium sulfate barrier material in clinical view. For the study, 28 sites(2 or 3 wall infrabony defects) were treated. 14 infrabony defects were received surgical implantation of BBP-calcium sulfate composite with a calcium sulfate barrier and the others received BBP mixed with platelet rich plasma. Clinical outcome was accessed 3 and 6 months of postsurgery. 1. There was no statistical difference between CS group and PRP group in pocket depth, gingival recession, clinical attachment level, and probing bone level at baseline. 2. There was statistically significant reduction in probing depth, clinical attachment level, and probing bone level at 3 and 6 months postsurgery(p<0.05). 3. In the probing depth and clincial attachment level PPR group had less improvement than CS group, but there was no statistically difference at 3 and 6 months postsurgery. 4. In the recession PPR group had less recession than CS group, but there was no statistically difference at 3 and 6 months postsurgery. 5. In the probing bone level PPR group had less improvement than CS group, but there was no statistically difference at 6 months postsurgery. In conclusion bone graft using platelet rich plasma and guided tissue regeneration using calcium sulfate barrier showed similar clinical improvement for the treatment of 2 or 3 wall infrabony defects.

• Journal of Korean Society on Water Environment
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• v.21 no.4
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• pp.403-409
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• 2005

Methyl tert-butyl ether (MTBE) contamination in groundwater often coexists with benzene, toluene, ethylbenzene, and xylene (BTEX) near the source of the plume. Then, groundwater contamination problems have been developed in areas where the chemical is used. Common sources of water contamination by BTEX and MTBE include leaking underground gasoline storage tanks and leaks and spills from above ground fuel storage tanks, etc. In oil-contaminated environments, anaerobic biodegradation of BTEX and MTBE depended on the concentration and distribution of terminal electron acceptor. In this study, effect of electron acceptor on the anaerobic biodegradation for BTEX and MTBE-contaminated soil was investigated. This study showed the anaerobic biodegradation of BTEX and MTBE in two different soils by using nitrate reduction, ferric iron reduction and sulfate reduction. The soil samples from the two fields were enriched for 65 days by providing BTEX and MTBE as a sole carbon source and nitrate, sulfate or iron as a terminal electron acceptor. This study clearly shows that degradation rate of BTEX and MTBE with electron acceptors is higher than that without electron acceptors. Degradation rate of Ethylbenzene and Xylene is higher than that of Benxene, Toluene, and MTBE. In case of Benzene, Ethylbenzene, and MTBE, nitrate has more activation. In case of Toluene and Xylene, sulfate has more activation.

• Journal of the Korea Concrete Institute
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• v.27 no.6
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• pp.641-649
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• 2015

The purpose of this study was to assess the durability of high-strength concrete with high volume mineral admixture (HVMAC) derived from previous studies within ternary blended concrete (TBC) and normal concrete (NC). Four durability evaluation types such as chloride penetration resistance, freezing and thawing resistance, carbonation resistance in two pre-treatment conditions, and sulfuric acid and sulfate resistance using 5% sulfuric acid ($H_2SO_4$), 10% sodium sulfate ($Na_2SO_4$), and 10% magnesium sulfate ($MgSO_4$) solution were selected and performed in this study. HVMAC showed the excellent chloride penetration resistance in any age and the freezing and thawing durability close to 100%. In addition, HVMAC affected more reduction in carbonation resistance than TBC. When the curing time was increased, to create a concrete internal organization densely improved resistance to carbonation. HVMAC also showed the most superior in sulfuric acid and sulfate resistance. As the reduction of calcium hydroxide and $C_3A$ to apply a large amount of admixture reduced the swelling and cracking of concrete, the strength reduction and mass change of concrete was found to be small indicated.

• Proceedings of the Korea Concrete Institute Conference
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• 2002.10a
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• pp.27-32
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• 2002

In this research influences of type and concentration of alkali activator and curing condition on the hydration, and properties of alkali activated blast furnace slag(AAS) concrete were investigated. Sodium carbonate and sulfate were used as alkali activators and their concentration were 4~10 weight percent with Na$_2$O equivalent to binder. The curing conditions were standard curing using 23$^{\circ}C$ water and activated curing chamber at $65^{\circ}C$. Results show that in case of sodium carbonate addition high early strengths were gained by activation of early hydration, but later strength gained was slight. On the other side sodium sulfate strengths were continuously increased with adding amount and ages. Steam curing activated early hydration so that early strengths were improved but later strengths were similar to standard curing. The strength reduction of AAS mortar with sodium sulfate was less than OPC mortar in 5% sulfuric acid solution so that AAS concrete can be useful for acid-resistance concrete.

• Journal of Korean Society for Atmospheric Environment
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• v.14 no.4
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• pp.313-320
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• 1998

The most desirable diesel oxidation catalyst (DOC) should have the properties of oxidibing CO and HC effectively at low exhaust gas temperature while minimizing the formation of sulfate at high exhaust gas temperature. Precious metals such as platinum and palladium have been known to be sufficiently active for oxidizing CO and HC and also to have high activity for the oxidation of sulfur dioxide (SO2) to sulfor trioxide (SO3). There is a need to develop a highly selective catalyst which can promote the oxidation of CO and HC efficiently, but, on the other hand, suppress the oxidation of SO2. One approach to solve this problem is to load a base metal such as vanadium in Pt-based catalyst to suppress sulfate formation. In this study, a Pt-V catalyst was prepared by impregnating platinum and vanadium onto a Ti-Si wash coated catalyst in a laboratory reactor by changing the formulations and reaction temperatures.

• Journal of Environmental Science International
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• v.13 no.1
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• pp.69-77
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• 2004

In this study, sulfate reduction reaction was used to increase the decomposition of organics, which is the most critical factor for the stabilization of a landfill site. Composite of sewage sludge, papers, and incineration ashes was used in the column. The experimental results indicated that out of 10 reactors, the reactors 3, 4, 8. and 9 showed higher organics (i.e., TOC) removal rate than that in the absence of sulfate. The organics removal rates (K) in R3 and R9 were 8.65e$\^$-4/d and 3.82e$\^$-4//d, respectively. The times to reach 10％ of initial concentrations in R3 and R9 was 7.3 and 16.5 years, respectively, showing faster organics decomposition rates in these reactors.

• Journal of the Korean Ceramic Society
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• v.44 no.11
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• pp.618-621
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• 2007

In this study, flint glass batches with blast furnace slag (BFS) were prepared and the contribution of the BFS to the fining of melts was studied through investigations of the melting and fining characteristics. Additionally, a sulfur redox reaction for BFS-doped melts was examined by square wave voltammetry (SWV). The results of the melting & fining test showed that BFS improved the fining of the melts. In a voltammogram of BFS-doped melts, two reduction peaks were shown at high frequencies while only one peak appeared at low frequencies. The peaks were located at a potential that was similar to those of melts fined by sulfate. From those results it was concluded that sulfide ($S^{2-}$) in BFS has effects in glass melts that are identical to those of sulfate ($SO_4^{2-}$).

• Korean Journal of Metals and Materials
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• v.46 no.12
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• pp.823-829
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• 2008

The solvent extraction process for the recovery of vanadium from leaching solution of SCR(selective catalytic reduction) spent catalyst was investigated by using Alamine336 as an extractant. The effects of experimental conditions, such as initial pH and concentration of sulfate ion, and ammonia concentration of stripping solution were studied. The extraction percentage of vanadium were increased with the increase of initial pH of leaching solution and decreased with the increase of sulfate ion. More than 99% of vanadium in leaching solution were extracted and stripped at the A/O ratio of 1.0 in 2 stages. On the basis of these results, an optimum solvent extraction process which vanadium was effectively recovered from SCR spent catalyst was proposed.