• Membrane Journal
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• v.29 no.6
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• pp.355-361
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• 2019

We studied the removal of barium ions that may be contained in industrial wastewater using the existing capacitive deionization (CDI). The 30 mg/L BaCl₂ (barium chloride dihydrate) solution was used as the feed solution, and the flow rate was set to 10 mL/min. The adsorption conditions were varied from 1.2 V to 3, 5 and 7 min, and the desorption conditions were -1, -1.5, -2 V and 1, 2 and 3 min, respectively, to select the most efficient conditions. As a result, barium ion removal efficiency of 64.4% was obtained under the adsorption conditions of adsorption of 1.2 V/7 min and the desorption -1 V/1 min. For the desorption voltages and time, under the same experimental conditions, the removal efficiency of CDI for 30 mg/L NaCl aqueous solution with the same concentration as barium showed 69.9% removal efficiency under the adsorption conditions of and the desorption conditions of 1.2 V/7 min desorption -1 V/1 min, respectively.

• KCI Concrete Journal
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• v.11 no.3
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• pp.175-180
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• 1999

In order to predict the onset of the corrosion of steel bars in concrete, a mathematical model was presented to observe the diffusion of chloride ion in aqueous phase, the adsorption and desorption of chloride ions to and from the surface of solid phase of concrete, and the chemical reaction or chloride ions with solid phase. The finite element method was employed to carry out the numerical analysis. The chlorides enetrating through the wall of the concrete structure from the external environment and the chlorides contained in the concrete admixture were confirmed to be two important factors to determine the onset of the corrosion of steel bars.

• Environmental Engineering Research
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• v.13 no.2
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• pp.98-104
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• 2008

In this study, chromate and cetylperidinium chloride (CPC) removal from artificial wastewater was monitored by using micellar enhanced ultrafiltration (MEUF) and activated carbon fibre (ACF) adsorption hybrid processes. For the efficient chromate removal, molar concentration of the CPC should be five times that of chromate and it should be at least one critical micelle concentration (CMC). The MEUF was found to be effective in the chromate removal while ACF in the CPC adsorption to produce chromate and CPC free effluents. The chromate and CPC removal was 99.8% from MEUF-ACF process. Effluent chromate concentration was exponentially correlated with molar ratio of CPC to chromate and pH.

• Journal of the Korean Chemical Society
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• v.57 no.2
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• pp.264-271
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• 2013

Corrosion inhibition of mild steel used in water station in 35 ppm aluminum sulfate and 10 ppm chloride solution by Camellia sinensis leaves extract was studied using weight loss, potentiodynamic polarization and electrochemical impedance spectroscopy techniques at $30^{\circ}C$. Results show that the inhibition efficiency increases with increasing concentration of the extract and decreases with increasing temperature. Inhibitive effect was afforded by adsorption of the extract's components which was found to accord with Langmuir adsorption isotherm. Inhibition mechanism is deduced from the temperature dependence of the inhibition efficiency and was further corroborated by the values of activation parameters obtained from the experimental data.

• Journal of Industrial and Engineering Chemistry
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• v.67
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• pp.132-139
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• 2018

A cost-effective preparation method is proposed to prepare nanoporous alumina (NA) using aluminum chloride as a precursor with a lower cost than aluminum butoxide. In addition, the surfactant template was replaced with magnesium stearate, which has a lower unit cost in stearate acid. The adsorption isotherm test for the CO gas was carried out to compare the adsorption performance of the NA adsorbents prepared using post-hydrolysis (NA) and cost-effective precipitation (C-NA). In addition, C-NA exhibited a similar uptake capacity as NA, and the maximum uptake capacity of Pd/C-NA increased 1.3 times via Pd nanodots loading.

• Bulletin of the Korean Chemical Society
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• v.34 no.8
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• pp.2358-2366
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• 2013

Iron oxide (ferrihydrite, hematite, and magnetite) coated silica gels were prepared using a low-cost, easily-scalable and straightforward method as the adsorbent material for arsenic removal application. Adsorption of the anionic form of arsenic oxyacids, arsenite ($AsO^{2-}$) and arsenate ($AsO{_4}^{3-}$), onto hematite coated silica gel was fitted against non-linear 3-parameter-model Sips isotherm and 2-parameter-model Langmuir and Freundlich isotherm. Adsorption kinetics of arsenic could be well described by pseudo-second-order kinetic model and value of adsorption energy derived from non-linear Dubinin-Radushkevich isotherm suggests chemical adsorption. Although arsenic adsorption process was not affected by the presence of sulfate, chloride, and nitrate anions, as expected, bicarbonate and silicate gave moderate negative effects while the presence of phosphate anions significantly inhibited adsorption process of both arsenite and arsenate. When the actual efficiency to remove arsenic was tested against 1 L of artificial arsenic-contaminated groundwater (0.6 mg/L) in the presence competing anions, the reasonable amount (20 g) of hematite coated silica gel could reduce arsenic concentration to below the WHO permissible safety limit of drinking water of $10{\mu}g/L$ without adjusting pH and temperature, which would be highly advantageous for practical field application.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2022.11a
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• pp.73-74
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• 2022

The corrosion inhibitive effect of a new hydrazone-based heterocyclic compound for steel in simulated concrete pore solution with 3.5 wt.% sodium chloride was investigated by experimental and computational techniques. Electrochemical studies, up to 30 days of immersion, and surface analysis (X-ray photoelectron spectroscopy (XPS), atomic force microscopy (AFM), and scanning electron microscope (SEM)) were performed to assess the corrosion protection abilities of investigated compound for steel rebar. Results showed that adding the organic compound to the chloride contaminated concrete pore solution decreased the corrosion rate of the steel rebar thanks to the effective adsorption of inhibitor molecules. After 30 days of immersion of steel rebar in inhibited chloride contaminated synthetic concrete pore solution, the inhibition efficiency exceeded 80% at low concentration of 1 mmol/L. Computational studies by Density Functional based Tight Binding (DFTB) method revealed the formation of covalent bonds between the hydrazone molecule and the iron surface.

• Journal of the Korean Wood Science and Technology
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• v.42 no.4
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• pp.491-498
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• 2014

In order to obtain basic data for concentration control of alkaline copper quat (ACQ) solution in wood preservative treatment, this study investigates the change of concentration and adsorption of treating solution and active ingredient, copper oxide (CuO) and didecyldimethyl ammonium chloride (DDAC), in the process of recycling of ACQ solution. Japanese larch (Larix leptolepis), Douglas-fir (Psedotsuga menziesii) and Radiata pine (Pinus radiata) were treated with ACQ solution. The active ingredient concentration of ACQ solution was decreased continuously with increase of recycling. There are differences between extent of concentration decrease of Cu (as CuO) and DDAC. DDAC was decreased more quickly and to a higher degree than Cu for all recycling. The extent of DDAC concentration decrease was remarkable than that of Cu for wood species. The amount of DDAC adsorbed into wood decreased with the increase of ACQ solution recycling, but adsorption of Cu was little difference regardless of recycling. The adsorption of Cu into wood increased as DDAC concentration decrease by recycling of ACQ solution. This is likely due to decrease of DDAC competition with Cu for the same reaction site in wood.

• Journal of the Society of Cosmetic Scientists of Korea
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• v.11 no.1
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• pp.32-52
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• 1985

• Carbon letters
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• v.7 no.3
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• pp.188-195
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• 2006

Phosphoric acid-activated carbon WP's and zinc chloride-activated carbons WZ's were developed from wild cherry stones. The textural properties of the activated carbons were determined from nitrogen adsorption data at 77 K and the chemistry of the carbon surface, i.e. the surface carbon-oxygen groups (type and amount) was determined from the base and acid neutralization capacities (Boehm method). The adsorption of phenol, p-nitrophenol, p-chlorophenol, dinitrophenol and dichlorophenol was followed at 298 K. The activated carbons obtained were characterized by high surface area and large pore volumes as well as by high surface concentration of C-O groups. The investigated carbons exhibited high adsorption capacities towards phenols with these capacities increased with the increase of molecular weight and the decrease of the solubility of phenol in water. However, no general relationship could be observed between the adsorption capacities of carbons and any of their textural parameters or their surface chemistry. This may be attributed to the many factors controlling phenol adsorption and the different types and mechanisms of adsorption involved.