• Korean Journal of Materials Research
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• v.9 no.9
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• pp.872-877
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• 1999

The purpose of this research was to investigate the characteristics and the cleaning efficiency on HN(sub)4OH solutions added with H(sub)2O(sub)2 and surfactants. NH(sub)4OH solutions added with surfactants did not show much changes in pH and redox potential (Eh) as a function of NH(sub)4OH concentration compared with NH(sub)4OH solution. However H(sub)2O(sub)2 added NH\ulcornerOH solutions showed the decrease of pH and the increase of Eh as the concentration of NH(sub)4OH increased. The decrease of surface tension from 72 dynes/cm to 38 dynes/cm was observed in solutions added with surfactant but not in H(sub)2O(sub)2. The etch rates of silicon in NH(sub)4OH solutions(NH(sub)4OH:H(sub)2O= 1 : 5) showed at least 50 times higher than those in H(sub)2O(sub)2 and surfactant added NH(sub)4OH solutions(NH(sub)4OH:H(sub)2O(sub)2= 1 : 1 : 5) solution removed the PSL particles (0.67$\mu\textrm{m}$ in diameter) on Si wafers effectively at all temperatures investigated. NH(sub)4OH solution added with a surfactant could not remove particles at room temperature, however it was possible to remove particles at higher temperatures, 5$0^{\circ}C$ and 8$0^{\circ}C$.

• Applied Chemistry for Engineering
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• v.5 no.2
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• pp.199-208
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• 1994

In this study, the ultrasound which provides the properties of mixing, and surface cleaning effect, the increase of the effective reaction surface area and the enhancement of the effective collision frequency, was used to enhance the recovering efficiency of Cu from the Cu-ion containning waste water. The ultrasonic reactor used in this study was designed and constructed for improving the disadvantage of the existing ultrasonic reactor. From the experimental result and its analysis, we obtained following conclusions. 1. The ultrasound increased the rate of electrochemical deposition to 582.2% in maximum at the condition of $0.1M-CuSO_4$, and 2.1 V-overpotential. 2. The enhancement effect of ultrasound induced by the reduction of diffusion layer thickness was 277.8% in maximum and induced by the other effect except for the reduction effect of the diffusion layer thickness was 253.6% in maximum at $0.1M-CuSO_4$ and 2.1V overpotential. 3. This study gave the possibility of the scale-up of ultrasonic reactor and in particular, ultrasonic reactor would be effective in the treatment of waste water containning a low concentration of Cu ion.

• Composites Research
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• v.33 no.2
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• pp.68-75
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• 2020

Recently, the use of TiO₂ as a phtocatalyst has been diversely investigated due to its excellent durability performance and high photocatalytic reaction efficiency. Active researches have particularly focused on the development of TiO₂-incorporated cementitious composites in order to remove the atmospheric pollutants. Furthermore, the potential utilization of TiO₂-incorporated cementitious composites as road accessories such as tunnels, road median separators and soundproof walls in the form of tiles, blocks and structural components has been widely examined. In this regard, a thorough understanding on the material characteristics of TiO₂-incorporated cementitious composites should be preceded. The present overview article, therefore, revisits previous studies of TiO₂-incorporated cementitious composites and summarizes their various physicochemical properties and atmospheric pollutants removal performance.

• Journal of Animal Environmental Science
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• v.12 no.3
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• pp.133-140
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• 2006

The climate of stall significantly influences on animal production ability. High concentration of ammonia gas, $CO_2$ and lots of dust are found in modern densely raising stall system, as results, they provide a negative influence on animal and farmer health, and production ability. Therefore, it is necessary to keep clean the inside air of stall to increase the productivity. An air cleaner of wet type, consisting of a fan, a motor, rotating discs, a dust collector, a water bowl, an ozone generator etc, has been developed to clean the stall air. The work principle is that the inside air is sucked through the fan, and the rotating discs make water into fineness spray and blow into the stall. The rest water flows down to the dust collector. In the present study, we measured the dust, ammonia gas, odor, temperature and humidity in a swine stall that were installed two wet air cleaners with 700 fattening swine with On-mode and Off-mode of wet air cleaners. The dust measure was divided into 3 categories, TSP, $PM_{10}$, and $PM_{2.5}$. In summer, the TSP in on-mode were maximum $0.259mg/m^3$ and minimum $0.128mg/m^3$, and the average was $0.195mg/m^3$. These are comparable to the data from Off-mode stall that maximum $0.308mg/m^3$, minimum $0.139mg/m^3$, and average $0.277mg/m^3$. However, $PM_{10}$ and $PM_{2.5}$ showed any significant differences between the tests. The concentrations of ammonia gas in Off-mode stall were maximum 13.8 ppm and minimum 5.9 ppm, and the average was 8.47 ppm. However in On-mode stall the ammonia gas concentrations were maximum 10.5 ppm and minimum 5.5 ppm, and the average was 7.63 ppm. The concentration of ammonia gas in On-mode was 10% in average lower than off-mode stall. Odor was measured by olfactometer. In the Off-mode stall, the odor unit were maximum 420 $Ou/m^3$ and minimum $300\;OU/m^3$, and the average was $367\;OU/m^3$, but in the On-mode stall the odor unit were maximum $330\;OU/m^3$ and minimum $210\;OU/m^3$, and the average was $253\;OU/m^3$. Odor removal efficiency was about 31% in On-mode stall.

• Journal of the Korean Society of Marine Environment & Safety
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• v.27 no.6
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• pp.898-904
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• 2021

This experimental study aims to investigate the use of a wet electrostatic precipitator as a post-treatment device to satisfy the strict emission regulations for sulfur oxides and particulate matter (PM). The inlet/outlet of a wet electrostatic precipitator was installed in a funnel using a marine four-stroke diesel engine (STX-MAN B&W) consuming marine heavy fuel oil (HFO) with a sulfur content of about 2.1%. Measurements were then obtained at the outlet of the wet electrostatic precipitator; an optical measuring instrument (OPA-102), and the weight concentration measurement method (Method 5 Isokinetic Train) were used for the PM measurements and the Fourier transform infrared (FT-IR; DX-4000) approach was used for the sulfur oxide measurements. The experimenst were conducted by varying the engine load from 50%, to 75% and 100%; it was noted that the PM reduction efficiency was a high at about 94 to 98% under all load conditions. Additionally, during the process of lowering the exhaust gas temperature in the quenching zone of the wet electrostatic precipitator, the sulfur dioxide (SO₂) values reduced because of the cleaning water, and the reduction rate was confirmed to be 55% to 81% depending on the engine load.

• Resources Recycling
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• v.30 no.5
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• pp.38-48
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• 2021

In this study, we determine the optimal process conditions for selectively recovering Si from a solar cell surface by removal of impurities (Al, Zn, Ag, etc.). To selectively recover Si from solar cells, leaching is performed using HCl solution and an ultrasonic cleaner. After leaching, the solar cells are washed using distilled water and dried in an oven. Decompression filtration is performed on the HCl solution, and ICP-OES (Inductively Coupled Plasma Optical Emission spectroscopy) full scan analysis is performed on the filtered solution. Furthermore, XRD (X-ray powder diffraction), XRF (X-ray fluorescence), and ICP-OES are performed on the dried solar cells after crushing, and the purity and recovery rate of Si are obtained. In this experiment, the concentration of acid solution, reaction temperature, reaction time, and ultrasonic intensity are considered as variables. The results show that the optimal process conditions for the selective recovery of Si from the solar cells are as follows: the concentration of acid solution = 3 M HCl, reaction temperature = 60℃, reaction time = 120 min, and ultrasonic intensity = 150 W. Further, the Si purity and recovery rate are 99.85 and 99.24%, respectively.

• Membrane Journal
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• v.34 no.1
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• pp.38-49
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• 2024

Wastewater treatment using membrane bioreactors has been extensively used to alleviate water shortage and pollution by improving the quality of the treated water discharged into the environment. However, membrane biofouling persistently holds back an MBR process by reducing the process efficiency. Herein, we synthesized carbon nanospheres (CNSs) with many hydrophilic oxygen groups and utilized them as an additive to prepare high-performance ultrafiltration (UF) membranes with hydrophilicity and porous pore structure. CNSs were found to form crescent-shaped pores on the membrane surface, increasing the mean surface pore size by about 40% without causing significant defects larger than bubble points, as the CNS content increased by 4.6 wt%. In addition, the porous pore structure of CNS composite membranes was also attributable to the CNS's isotropic morphologies and relatively low particle number density because the aforementioned properties contributed to preventing the polymer solution viscosity from soaring with the loading of CNS. However, too porous structure compromised the mechanical properties, such that CNS2.3 was the best from a comprehensive consideration including the pore structure and mechanical properties. As a result, CNS2.3 showed not only 2 times higher water permeability than CNS0 but also 5 times longer operation duration until membrane cleaning was required.

• Journal of Korean Ophthalmic Optics Society
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• v.19 no.1
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• pp.51-57
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• 2014

Purpose: The present study was conducted to establish the experimental condition for the proper evaluation of protein removal efficacy when developing protein removal agents. Its protein removal efficacy was further analyzed and compared with the result from protein removal efficacy against protein deposition on contact lens to suggest the evaluation method for efficacy of protein removal agents. Methods: Protein digestibility assay presented in the Korean pharmacopoeia was selected to establish the evaluation method for efficacy of papain, pancreatin, subtilisin A and protease itself as a ingredient and protein removal tablets or solution containing those enzymes and find a suitable test conditions. Furthermore, the cleaning efficacy of commercially available protein removal tablets and solution on balafilcon A lens deposited with protein artificially was measured and the correlation between two evaluation methods was further analyzed. Results: When pancreatin itself and the product containing pancreatin was evaluated by protein digestibility assay, both reached 28 IU/mg, the standard value of protein digestibility suggested by the Korean pharmacopoeia. In case of protease and subtilisin A tested with trichloroacetic acid B solution, both of them met the enzyme activity level proposed by the manufacturers when they were evaluated by protein digestibility assay however, papain and subtilisin A tested with trichloroacetic acid A solution were not reached the enzyme activity level. Among protein removal agents, three products except a product containing pancreatin did not meet the enzyme activity value specified by the manufacturer when they were evaluated by protein digestibility assay. However, actual protein removal efficacy of three products except a papain-containing product on the lens was greater than 90% protein removal. In the case of papain-containing protein removal product, its effect was not measured by protein digestibility assay however, its actual protein removal efficacy on the lens reached 73.72%. Conclusions: From the results, it was confirmed that the efficacy of protein removal agents for contact lens should be evaluated by different method according to the type of proteolytic enzyme contained. That is, the protein removal agents containing pancreatin, protease and subtilisin A can be evaluated by protein digestibility assay and protein removal efficiency evaluation and the products containing papain can be effectively evaluated by only the evaluation method for protein removal efficiency employing the lens.

• Economic and Environmental Geology
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• v.43 no.2
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• pp.123-136
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• 2010

In order to remediate heavy metal contaminated Nong island, Maehyang-ri shooting range soils through the batch reactor scale washing were evaluated. The experiment texture soil of N3 in the Nong island at north side incline was (g)mS containing 12.9% gravel, 47.0% sand, 35.1% silt and 5.0% clay. And the N3 soil area was contaminated with Cd($22.5\pm1.9$ ppm), Cu($35.5\pm4.0$ ppm), Pb($1,279.0\pm5.1$ ppm) and Zn($403.4\pm9.8$ ppm). The EDTA(ethylene diamine tetra acetic acid, $C_{10}H_{16}N_2O_8$) in the N3 soil was observed as most effective extractants among the 5 extractants(citric acid, EDTA, phosphoric acid, potassium phosphate and oxalic acid) tested. And chemical partitioning of heavy metals after washing N3 soil with EDTA was evaluated. Removal efficiency of residual fractions was higher than that of non-residual fractions. To choose EDTA extractant which is the most effective in soil washing technology using batch reactor process cleaning Pb and Zn contaminated sits; Pb and Zn removal rates were investigated 92.4%, 94.0% removal(1,000 mM, soil:solution=5, $20^{\circ}C$, 24 hour shaking, pH=2, 200 RPM), respectively. The results of the batch test showed that the removal efficiency curve was logarithmic in soil was removal. Thus, EDTA washing process can be applied to remediate the Pb and Zn contaminated soil used in this study.

• Journal of Navigation and Port Research
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• v.39 no.1
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• pp.45-53
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• 2015

These days Container Terminals are focusing on increasing the quantity of containers and shipping lines choose Terminals by referring to the key elements of a terminal to perform the overall operation the fastest such as the location of the terminal, discharging ability, keeping environment, and other elements related to shipping in general. Container terminal is able to offer On-Dock service has become an important factor for shipping lines to choose that terminal. In this paper, we propose an algorithm for On-Dock system work algorithm, the algorithm Empty container exports, Full Container algorithm and The aim of our study focus on both container's gate out time and search for the effective terminal operation which is using the general On-Dock system through several algorithm like container batch priority, gate in and out job priority and empty container yard equipment allocation rule based on the automatic allocation method and manual allocation scheme for container. Gathering these information, it gives the priority and yard location of gate-out containers to control. That is, by selecting an optimum algorithm container, container terminals Empty reduces the container taken out time, it is possible to minimize unnecessary re-handling of the yard container can be enhanced with respect to the efficiency of the equipment. Operations and operating results of the Non On-Dock and On-Dock system is operated by the out work operations (scenarios) forms that are operating in the real Gwangyang Container Terminal derived results. Gwangyang Container terminal and apply the On-Dock system, Non On-Dock can be taken out this time, about 5 minutes more quickly when applying the system. when managing export orders for berths where On-Dock service is needed, ball containers are allocated and for import cargoes, D/O is managed and after carryout, return management, container damage, cleaning, fixing and controlling services are supported hence the berth service can be strengthened and container terminal business can grow.