• Korean Chemical Engineering Research
• /
• v.56 no.3
• /
• pp.356-360
• /
• 2018

The negative effects on ecosystem are getting serious due to the increase of particulate matters (PM) in the air by the increase of the number of population and the industrial activities. Thus, there have been a lot of environmental policies and researches of air purification system and filter mask to relieve the environmental problem. In this research, activated carbon impregnated cellulose acetate fiber filters produced using an electrospinning technique are studied for air purification. NaCl aqueous solution was used to generate PM and the humid air with NaCl PM was dried using a dehumidifier for the filter performance test. Filtration efficiency was increased with the increase of activated carbons, and acetone adsorption capacity was enhanced.

• Resources Recycling
• /
• v.10 no.4
• /
• pp.18-23
• /
• 2001

Air pollutants, phenol was generated in case of thermal regeneration of used activated carbon loaded with phenol and because of this problem, removal process of phenol were studied. Electrolytic oxidation of samples, used S.company granular activated carbon (WS-GAC), used C.company granular activated carbon (WC-GAC) and used L.company granular activated carbon (WL-GAC) loaded with phenol carried out by potentiostatic method in this study. In case of experiment was to come into operation in condition of samples containing 100 mg/g phenol, supporting electrolyte was 1.0% sodium chloride solution, Ti-Ir (10$\times$10$\textrm{cm}^2$) electrode and electrode distance was 2 cm, current density was $1.25 A/dm^2$, Obtained from the results of electrolytic oxidation experiments were not detected residual phenol. And then we knew about reaction time of electrolytic oxidation, current density, concentration of supporting electrolyte and electrode and electrode distance were 60 minutes, 1.25 A/dm$^2$, 1.0%, 2 cm.

• Analytical Science and Technology
• /
• v.10 no.2
• /
• pp.126-130
• /
• 1997

Electrochemical behavior of 1.0mM bis(2,2'-bipyridyl)copper( II )(${Cu(bpy)_2}^{2+}$) in 100mM NaCl+27mM $MgCl_2$ solution with and without sodium dodecyl sulfate(SDS) is investigated. In the presence of SDS, $E_{pa}$ and $E_{1/2}$ of ${Cu(bpy)_2}^{2+/1+}$ shifts to the positive direction compared to the SDS free. Teh intersection of two lines on ${\Delta}E_p$ vs. -log[SDS] plot for 1.0mM $Cu(bpy)_2(NO_3)_2$ in 100mM NaCl+27mM $MgCl_2$ solution is a critical micelle concentration(CMC). Reduced form ${Cu(bpy)_2}^{1+}$ in the presence of $MgCl_2$ is more easily associated to dodecyl sulfate anion($DS^-$) than oxidized ${Cu(bpy)_2}^{2+}$. As the ionic strength is increased by the addition of multiply charged cations($MgCl_2$), the double layer becomes more compact and micelle formation is more difficult.

• Korean Chemical Engineering Research
• /
• v.54 no.4
• /
• pp.510-518
• /
• 2016

Ethyl cellulose-g-poly(ethylene glycol) (EP) was synthesized by esterification of carboxylic acid functionalized methoxy polyethylene glycol (MPEG-COOH) with ethyl cellulose (EC) in order to develop a hydrophilic substrate for thin-film composite (TFC) membrane in a forward osmosis (FO) system. A porous EP substrate, fabricated by a non-solvent induced phase separation method, was found to be more hydrophilic than the EC substrate due to the presence of polyethylene glycol (PEG) side chains in the EP. Since the EP substrate exhibits smaller water contact angles and higher porosity, the structural parameter (S) of TFC-EP is smaller than that of TFC-EC, indicating that internal concentration polarization (ICP) within porous substrates can occur less when TFC-EP is used as a membrane. For example, the water flux value of the TFC-EP is 15.7 LMH, whereas the water flux value of the TFC-EC is only 6.6 LMH. Therefore, we strongly believe that the TFC-EP could be a promising candidate with good FO performances.

• Journal of the Korean Society of Marine Environment & Safety
• /
• v.24 no.2
• /
• pp.203-214
• /
• 2018

Ballast water treated by sodium dichloroisocyanurate (NaDCC) injection method in ballast water management system (BWMS) contains reactive bromine, chlorine species and disinfection by-products (DBPs). In this study, we conducted whole effluent toxicity (WET) testing and ecological risk assessment (ERA) to investigate its ecotoxicological effects on the marine environment. WET testing was carried out for eight marine and fresh water organisms, i.e. diatom, Skeletonema costatum, Navicula pelliculosa, green algae, Dunaliella tertiolecta, Pseudokirchneriella subcapitata, rotifer, Brachionus plicatilis, Brachionus calyciflorus and fish, Cyprinodon variegatus, Pimephales promelas. The WET test revealed that diatom and green algae were the only organisms that showed apparent toxicity to the effluent; it showed no observed effect concentration (NOEC), lowest observable effect concentration (LOEC) and effect concentration of 50 % (EC50) values of 25.0 %, 50.0 % and over 100.0 %, respectively, in seawater conditions. In contrast, rotifer and fish showed no toxicities to the effluent in the all salinity conditions. Meanwhile, chemical analysis revealed that the BWMS effluent contained total of 25 DBPs such as bromate, isocyanuric acid, formaldehyde, chloropicrin, trihalomethanes (THMs), halogenated acetonitriles (HANs) and halogenated acetic acids (HAAs). Based on ERA, the 25 DBPs were not considered to have persistency, bioaccumulation and toxicity (PBT) properties. The ratio of predicted environmental concentration (PEC) to predicted no effect concentration (PNEC) of the all DBPs did not exceed 1.0 for general harbour environments, but isocyanuric acid, tribromomethane, chloropicrin and monochloroacetic acid exceed 1.0 for near ship environments. However, when NOEC (25.0%) of the WET test results where actual effluent was applied, it was concluded that the NaDCC injection method did not have unacceptable ecological risks to the general harbor including near ship environments.

• Korean Journal of Food Science and Technology
• /
• v.17 no.2
• /
• pp.65-70
• /
• 1985

To recover proteins from antarctic krill(Euphausia superba) for the use of food material, some factors affecting the extraction of protein were investigated. The protein solubility profile showed a minimum solubility level(33.2-38.8%) within the range of pH4.0-4.5 and very high solubility levels as 56.8% at pH2.0 and 80.7% at pH11.0. The extraction yield increased as the solvent-to-krill ratios increase in which a ratio of 5:1(volume of solvent/weight of krill) was found to be preferable from the point of handling convenience and extraction yield. The extraction temperatures did not seem to be important variables on extraction of protein. The extraction of krill protein occurred fairly rapidly with little further extraction of protein after 30 minutes. The extraction of protein was slightly decreased at both acidic(pH2.0) and alkaline(pH11.0) conditions with the increasing concentration of sodium chloride. The extractibility of krill protein at strong alkaline condition(pH11.0) was higher than at strong acidic condition(pH2.0) under the same concentration range as 1-6% of sodium chloride. In phosphate treatments, the extraction of protein was slightly influenced by presence of sodium chloride as the concentration range of 3-4% in the aqueous solvent by which maximize the extraction yield as over 80%.

• Proceedings of the Korean Society of Soil and Groundwater Environment Conference
• /
• 2001.02a
• /
• pp.29-48
• /
• 2001

일반적인 폐수처리 시 여러 광물들이 사용되는 데 예를 들면, 수산화칼슘 및 탄산나트륨은 중화제, 점토는 응집제, 알룸(alum) 및 염화철은 인 제거제로 사용되고 있다. 산성광산배수인 경우에는 알칼리성의 중화제로 석회 (CaO), 석회석 (CaCO$_3$), 가성소다 (NaOH), 탄산나트륨 (NaCO$_3$) 등이 사용된다. 그러나, 설비비 및 유지비가 많이 들어 몇 십년 동안 계속해서 침출되는 산성광산배수를 처리하기에는 문제가 있다. 산성광산배수 (Acid Mine Drainage, AMD)는 pH가 6.0 미만이고 총산도 (totalacidity)가 총알카리도 (total alkalinity)를 초과하는 물로서 노천광이 가행되었던 지역, 가행중이거나 휴광 또는 폐광된 광산에서 유출된다. 또한 도로사면 절개부나 지하철 터널에서도 황철석(pyrite)이나 백철석 (marcasite)을 함유하는 층이 공기 중에 노출되면 산성수가 침출되어 나오기도 한다. 산성광산배수에 의한 하천수의 오염이 매우 극심하여 때로는 미생물마저도 그 속에 살 수 없게 된다. 산성광산배수에 의해 오염된 하천수의 오염범위는 산성수의 양, 농도, 하천에 유입되는 산성수의 분포, 상류에서 흘러드는 오염되지 않은 물의 양, 지류에서 유입되는 물의 양에 따라 좌우된다. 산성광산배수 오염이 문제시되고 있는 나라는 미국을 포함하여 호주, 일본, 한국, 러시아, 남아연방 등이다. 산성광산배수는 환원환경에서 생성된 석탄층 및 접촉교대 또는 열수에 의해 생성된 금속광이 공기 및 물에 노출되어 생성되는 자연적인 현상이다. 그러나 국지적인 지역에서 인간이 이 광상들을 환경영향을 고려하지 않고 대규모로 개발할 때 인간 생활에 심각한 영향을 미치는 것이다. 광산산성배수를 처리하기 위해 상기와 같이 여러 기술이 도입 적용되었으며 일부 기술들은 현재도 사용되고 있다. 각 기술마다 일장일단이 있으므로 경비의 과다, 유지 및 관리에 대한 지속성 여부, 공간의 확보 여부, 지역적 특수성에 맞춰 가장 적합한 방법을 채택하여야 하며 꾸준히 채택한 기술의 개량 및 새로운 기술의 첨가가 요구되고 있다. 따라서, 산성광산배수 오염지대에 대해 획일적으로 같은 처리방법을 채택하여 사용하는 것보다 각 지역 또는 광산산성폐수가 유출되어 나오는 광산폐기물의 특성 등을 고려하여 거기에 맞는 기술들을 복합적으로 또는 단독으로 사용하되 처리방법 채택 시 신중을 기할 것이 요망된다.

• Resources Recycling
• /
• v.26 no.3
• /
• pp.53-60
• /
• 2017

Black dross contains metallic aluminium, alumina, silica, MgO, soluble salts together with minor ingredients. Control of silica in black dross is important in transforming the black dross into usable materials. First, most of the soluble salts (KCl and NaCl) in black dross were dissolved in water at reaction temperature of $50^{\circ}C$. Leaching behavior of silica, alumina, MgO and $TiO_2$ from the residue after water treatment was investigated by varying NaOH concentration and reaction temperature. Reaction temperature ($25{\sim}95^{\circ}C$) was favorable to the leaching of alumina but an optimum temperature existed for silica. MgO was not dissolved at all in the NaOH concentration range from 2 to 6 M. At the leaching condition of 5 M NaOH and reaction temperature of $95^{\circ}C$, approximately 80% of alumina and 68% of silica was dissolved.

• Korean Chemical Engineering Research
• /
• v.46 no.6
• /
• pp.1107-1112
• /
• 2008

Crystallization of calcium carbonate was performed by using aqueous calcium chloride and sodium carbonate for operational simplicity. Reaction time, solute concentrations, pH, and organic additive were varied to get calcium carbonate crystals. Silk fibroin was used as the additive to understand the change of morphology of calcium carbonate crystal. The crystals were analyzed by FE-SEM, XRD, and FT-IR. Reaction time, and pH mainly affected the morphology of crystals. Besides, it was found that silk fibroin inhibited the formation of vaterite and promoted the calcite forms.

• Korean Journal of Environmental Agriculture
• /
• v.34 no.1
• /
• pp.30-37
• /
• 2015

BACKGROUND: During the winter, the use of deicers was rapidly increased for reduction of traffic accidents as well as injuries in Korea, whose components are largely comprised of calcium chloride and sodium chloride. Recently, to reduce the adverse effects of chloride-deciers such as pollution of water and soil, and decrease of agricultural productivity, the attention of eco-friendly deciers have been increased. This study aimed to investigate biological effects of magnesium chloride deicer (PC-10) and organic acid deicer (EFD-1) against wheat, barley, and spinach. METHODS AND RESULTS: We examined the effect of two deciers, PC-10 and EFD-1 on the seed germination and growth of wheat, barley and spinach. EFD-1 showed higher suppression of the germination than PC-10 among tested crop seeds. In demage index of the seedlings of the crops, there was no symptoms in spinach such as spotting and color change of leaves. EFD-1 showed much stronger inhibitory effect on the germination of tested crop seeds than PC-10 when crops were exposed continuously to tested deciers in soils. The growth and shoot and root in examined crops was relatively higher in PC-10 treatment than in EFD-1 treatment when compared to the control. The biomass decrease was found in all examined conditions of deciers. PC-10 showed 23-35% reduction of biomass whereas EFD-1 exhibited 39-84% loss in all examined crops at over 2% concentration. CONCLUSION: These results suggest that the effects of deicers used in this study by inputting into soil against growing tested crops cause the reduction of germination of seeds, growth, and biomass compared to the control.