• Journal of Korean Society of Environmental Engineers
• /
• v.39 no.7
• /
• pp.385-390
• /
• 2017

This study investigated removal characteristic of soluble Cs in water by RPT (Radioactivity pollutant treatment) with coagulation and sedimentation. The RPT conducted with various chemical and natural coagulants to remove the soluble Cs which consisted pre-adsorption, Sedimentation and post-adsorption. Natural absorbent included Illite and zeolite. Especially, Illite divided LPI (Large Particle Illite) and SPI (Small Particle Illite) by grain size. Also, Chemical coagulants included high basicity PAC (poly aluminum chloride). The adsorbent had a plate structure mainly composed of quartz, albite and muscovite. The surface area were $4.201m^2/g$ and $4.227m^2/g$ and the particle sizes were $197.4-840.9{\mu}m$ and $3.28-53.57{\mu}m$, respectively. The adsorption efficiency of the natural Illite was 82.8% for LPI and 85.6% for SPI. The removal efficiency of turbidity, which was an indirect indicator of adsorbent recovery, was 96.4% and 98.3%, respectively.

• Corrosion Science and Technology
• /
• v.22 no.3
• /
• pp.201-213
• /
• 2023

Corrosion management of an aircraft and its engine relies on rinsing and cleaning using tap water. Few studies have reported effects of tap water species on corrosion behaviors of structural materials. In this study, a series of experiments were conducted based on the design of experiment. Solutions with different levels of chloride and sulfate ions were prepared using a full factorial design. Two structural materials (aluminum alloy and steel) were used for an alternate immersion test. Weight loss was then measured. In addition, a silver specimen was utilized as a sensor for chloride deposition measurement. The silver specimen was examined using the electrochemical reduction method, XPS, and SEM-EDS. Surface analysis revealed that levels of chloride and sulfate ions were sufficient for the formation of silver chloride and silver surface. Statistical analysis of weight loss and chloride deposition rate showed significant differences in measured values. Concentration of chloride ions greatly affected corrosion behaviors of structural materials. Sulfate ion hindered the adsorption reaction. These results emphasize the importance of controlling ion concentration of tap water used for cleaning and rinsing an aircraft.

• Bulletin of the Korean Chemical Society
• /
• v.33 no.5
• /
• pp.1669-1674
• /
• 2012

A novel superabsorbent composite was prepared by intercalation polymerization of acrylic acid (AA) and 2-acrylamido-2-methyl-1-propane sulfonic acid (AMPS) in the presence of montmorillonite (MMT), using ammonium persulfate (APS) as an initiator and $N,N'$-methylenebisacrylamide (MBA) as a cross linker. The superabsorbent composite was characterized by Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), X-ray diffraction (XRD) and thermogravimetric analysis (TGA). Maximum absorbency of the composite in distilled water and 0.9% sodium chloride solution was 722 and 108 g/g, respectively. The composite was used for removal of heavy metal ions from aqueous solutions. Maximum amount of adsorption for $Ni^{2+}$, $Cu^{2+}$ and $Pb^{2+}$ was 211.0, 159.6 and 1646.0 mg/g, respectively, and the adsorption was in accordance with both Langmuir and Freundlich model. The composite could be regenerated and reused in wastewater treatment.

• Korean Journal of Materials Research
• /
• v.26 no.6
• /
• pp.298-305
• /
• 2016

In this work, recent progress on graphene/metal oxide composites as advanced materials for $HgCl_2$ and $CO_2$ capture was investigated. Density Functional Theory calculations were used to understand the effects of temperature on the adsorption ability of $HgCl_2$ and water vapor on $CO_2$ adsorption on CaO (001) with reinforced carbon-based nanostructures using B3LYP functional. Understanding the mechanism by which mercury and $CO_2$ adsorb on graphene/CaO (g-CaO) is crucial to the design and fabrication of effective capture technologies. The results obtained from the optimized geometries and frequencies of the proposed cluster site structures predicted that with respect to molecular binding the system possesses unusually large $HgCl_2$ ($0.1-0.4HgCl_2g/g$ sorbent) and $CO_2$ ($0.2-0.6CO_2g/g$ sorbent) uptake capacities. The $HgCl_2$ and $CO_2$ were found to be stable on the surface as a result of the topology and a strong interaction with the g-CaO system; these results strongly suggest the potential of CaO-doped carbon materials for $HgCl_2$ and $CO_2$ capture applications, the functional gives reliable answers compared to available experimental data.

• Journal of Korea Technical Association of The Pulp and Paper Industry
• /
• v.42 no.2
• /
• pp.1-11
• /
• 2010

The possibility of applying birchwood xylan in papermaking process to improve dry strength of paper was investigated. Unmodified xylan barely adsorbed onto pulp fibers while cationically modified xylan adsorbed substantially. Adsorption of cationically modified xylan by quaternarization with 3-chloro-2-hydroxypropy trimethylammonium chloride improved dry strength of paper. Chemical structure and degree of substitution of the cationically modified xylan was determined by 400 MHz 13CNMR spectroscopy and elemental analyzer. The amount of adsorbed xylan on cellulose fibers was greater when the cationicity was moderate, and it was interpreted that the conformation of this cationic xylan adsorbed on fiber surface was more favorable for greater adsorption due to its greater loop formation tendency while highly cationic xylan tends to adsorbed in stretched conformation. The physical properties of handsheets increased as the amount of adsorbed cationic xylan increased. On the other hands, the optical properties decreased with xylan adsorption.

• Textile Coloration and Finishing
• /
• v.12 no.3
• /
• pp.192-198
• /
• 2000

Influence of the fluorescent whitening agent(FWA)'s adsorption on the whiteness of cotton and on the color change of the dyed fabrics was investigated by repeating wash cycles. Cotton 100% and cotton60/polyester40 blended fabrics were dyed pink, blue and yellow, and cyanuric chloride diamino stilbene(CC/DAS) and distyryl bisphenyl(DSBP) were used for the FWA with laundry detergents. Fabrics were washed at $20^\circ{C}$ with Terg-o-tometer. The FWA adsorption amount was measured by the absorption intensity for the pyridine-water extracted solution. The FWA adsorption increased on the cotton fabric with the wash cycles. Though adsorption of CC/DAS continuously increased up to the 20th cycle, that of DSBP increased sharply before the 10th cycle and reached an equilibrium. The whiteness of the fabrics dried in the shade was greater than that dried under the sunlight through window glass. The color change of dyed fabrics was increased by the number of wash cycles. Pink changed more greatly than blue, yellow or grey cloth. The color change(\Delta{E)}$ of dyed fabric washed repeatedly up to the 20th cycle with the detergent without FWA was less than 1. It is recommended to wash pale colored fabric with the detergent free of FWA.

• Membrane and Water Treatment
• /
• v.13 no.3
• /
• pp.129-137
• /
• 2022

In this study, the removal of Ciprofloxacin (CPX) from aqueous solutions was investigated by a new activated carbon adsorbent prepared from orange peel (ACOP) with chemical activation using ZnCl₂. The physicochemical properties of orange peel activated carbon were characterized by proximate and ultimate analysis, scanning electron microscopy, BET surface area determination and Fourier transformation infrared spectroscopic studies. According to Brunauer-Emmett-Teller isotherm and non-local-density functional theory, the cumulative surface area, pore volume and pore size of ACOP were determined as 1193 m² g^-1, 0.83 cc g^-1 and 12.7 Å, respectively. The effects of contact time, pH, temperature and ACOP dose on the batch adsorption of CPX were studied. Adsorption equilibrium data of CPX with ACOP were found to be compatible with both the Langmuir and Freundlich isotherms. CPX adsorption capacity of ACOP was calculated as 181.8 mg g^-1 using Langmuir isotherm. The CPX adsorption kinetics were found to be harmonious with the pseudo-second-order kinetic model. Conclusively, ACOP can be assessable as an effective adsorbent for the removal of ciprofloxacin (CPX) from aqueous solutions.

• Analytical Science and Technology
• /
• v.24 no.2
• /
• pp.94-104
• /
• 2011

Mesoporous silica was synthesized in a water solvent and in an ethanol solvent with the non and cationic cetyltrimethyl ammonium chloride (CTAC) by varying the amount of the amphiphilic acrylic urethane oligomer (AAU) and the pH of the solution. The adsorption of the MX (3-chloro-4 (dichloromethyl)-5-hydroxy-2-(5H)-furanone) in drinking water was studied using the synthesized mesoporous silica as an adsorbent. The most appropriate silica was synthesized in acidic conditions in the water solvent and in alkali conditions in the ethanol solvent. The average pore sizes of the synthesized mesosilica were 3 nm and more. The mesoporous silica synthesized by the addition of the AAU oligomer showed excellent adsorption characteristics. With respect to the co-surfactant, the best adsorption characteristics were obtained when the P64,a non-ionic surfactant with a high molecular weight, was used to synthesize the silica than when other co-surfactants were used. The adsorption rate decreased as the MX concentration in the water increased. Different adsorption equilibrium conditions were reached depending on the adsorbate MX concentration in the adsorbent and the solution. It was seen that perfect adsorption does not occur due to such equilibrium conditions.

• Journal of Soil and Groundwater Environment
• /
• v.13 no.3
• /
• pp.21-26
• /
• 2008

Nitrate adsorption from aqueous solutions onto zinc chloride ($ZnCl_2$) treated coconut Granular Activated Carbon (GAC) was studied in a batch mode at two different initial nitrate concentrations (25 and 50 mg/L). The rate of nitrate uptake on prepared media was fast in the beginning, and 50% of adsorption was occurred within 10 min. The adsorption equilibrium was achieved within one hour. The mechanism of adsorption of nitrate on $ZnCl_2$ treated coconut GAC was investigated using four simplified kinetic models : the rate parameters were calculated for each model. The kinetic analysis indicated that pseudo-second-order kinetic with pore-diffusion-controlled was the best correlation of the experimental kinetic data in the present adsorption study.

• Applied Chemistry for Engineering
• /
• v.24 no.1
• /
• pp.49-54
• /
• 2013

We fabricated a composite carbon electrode to remove nitrate ions selectively from a mixed solution of anions. The electrode was fabricated by coating the surface of a carbon electrode with the nitrate-selective anion exchange resin (BHP55, Bonlite Co.) powder. We performed capacitive deionization (CDI) experiments on a mixed solution containing chloride, nitrate, and sulfate ions using a BHP55 cell constructed with the fabricated electrode. The removal of nitrate ions in the BHP55 cell was compared to that of a membrane capacitive deionization (MCDI) cell constructed with ion exchange membranes. The total quantity of ions adsorbed in BHP55 cell was $38.3meq/m^2$, which is 31% greater than that of MCDI cell. In addition, the number of nitrate adsorption in the BHP55 cell was $15.9meq/m^2$ (42% of total adsorption), 2.1 times greater than the adsorption in the MCDI cell. The results showed that the fabricated composite carbon electrode is very effective in the selective removal of nitrate ions from a mixed solution of anions.