• Journal of Korean Society of Water and Wastewater
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• v.26 no.3
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• pp.431-442
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• 2012

The purpose of this study, is to separate magnetic separation devices using permanent magnets by using magnetization characteristics remaining in treated water after adsorption and synthesizing phosphorus adsorbent capable of magnetic separation for efficient removal of phosphorus. The synthesis of the adsorbent which set Zirconium(Zr) having high friendly features for phosphorus as an element, and by synthesizing Iron Oxide($Fe_3O_4$, another name of $Fe_3O_4$ is magnetite) being able to grant magnetism to Zirconium Sulfate($Zr(SO_4)_2$), zirconium magnetic adsorbent(ZM) were manufactured. In order to consider the phosphorus adsorption characteristics of adsorbent ZM, batch adsorption experiment was performed, and based on the results, pH effect, adsorption isotherm, adsorption kinetics, and magnetic separation have been explore. As the experiment result, adsorbent ZM showed a tendency that the adsorption number was decreased rapidly at pH 13; however, it was showed a high amount of phosphorus removal in other range and it showed the highest amount of phosphorus removal in pH 6 of neutral range. In addtion, the Langmuir adsorption isotherm model is matched well, and D-R adsorption isotherm model is ranged 14.43kJ/mol indicating ion exchange mechanism. The result shown adsorption kinetics match well to the Pseudo-second-order kinetic model. The adsorbent ZM's capablility of regenerating NaOH and $H_2SO_4$, was high selectivity on the phosphorus without impacts on the other anions. The results of applying the treated water after adsorption of phosphorus to the magnetic separation device by using permanent magnets, shows that capture of the adsorbent by the magnetization filter was perfect. And they show the possibility of utilization on the phosphorus removal in water.

• Journal of Environmental Science International
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• v.27 no.9
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• pp.743-751
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• 2018

The objective of this study was to investigate the adsorption potential of chicken feathers for the removal of OrangeII (AO7) from aqueous solutions. Batch experiments were performed as a function of different experimental parameters such as initial pH, reaction time, feather dose, initial OrangeII concentration and temperature. The highest OrangeII uptake was observed at pH 1.0. Most of the OrangeII was adsorbed at 2 h and an adsorption equilibrium was reached at 6 h. As the amount of chicken feather was increased, the removal efficiency of OrangeII increased up to 99%, but its uptake decreased. By increasing the initial concentration and temperature, OrangeII uptake was increased. The experimental adsorption isotherm exhibited a better fit with the Langmuir isotherm than with the Freundlich isotherm, and maximum adsorption capacity from the Langmuir constant was determined to be 0.179244 mmol/g at $30^{\circ}C$. The adsorption energy obtained from the Dubinin-Radushkevich model was 7.9 kJ/mol at $20^{\circ}C$ and $30^{\circ}C$ which indicates the predominance of physical adsorption. Thermodynamic parameters such as ${\Delta}G^0$, ${\Delta}H^0$, and ${\Delta}S^0$ were -12.28 kJ/mol, 20.64 kJ/mol and 112.32 J/mol K at $30^{\circ}C$, respectively. This indicates that the process of OrangeII adsorption by chicken feathers was spontaneous and endothermic. Our results suggest that as a low-cost biomaterials, chicken feather is an attractive candidate for OrangeII removal from aqueous solutions.

• Journal of the Korean GEO-environmental Society
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• v.12 no.11
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• pp.31-37
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• 2011

This study investigated on the adsorption and photocatalysis of Reactive Black 5(RB5) by the hydroxyapatite(HAP)/Titanium dioxide($TiO_{2}$) media. The adsorption of RB5 on $TiO_{2}$, HAP and $TiO_{2}$/HAP was investigated during a series of batch adsorption experiments. The amounts adsorbed at equilibrium were measured. Langmuir and Freundlich isotherm models were tested for their applicability. The result of equilibrium studies of $TiO_{2}$, HAP and $TiO_{2}$/HAP adsorbent were found to follow Langmuir isotherm model. The adsorbed amounts(Qmax) were found to be 5.28mg/g on single $TiO_{2}$, 12.45mg/g on single HAP and 9.03mg/g on $TiO_{2}$/HAP, respectively. The experimental data were analysed using the pseudo-first-order adsorption and photocatalysis kinetic models. According to these models, RB5 degradation by $TiO_{2}$/HAP was affected by interaction effect of photocatalysis and adsorption.

• Journal of Korean Society of Water and Wastewater
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• v.35 no.6
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• pp.455-463
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• 2021

The adsorption process using GAC is one of the most secured methods to remove of phosphate from solution. This study was conducted by impregnating Cu(II) to GAC(GAC-Cu) to enhance phosphate adsorption for GAC. In the preparation of GAC-Cu, increasing the concentration of Cu(II) increased the phosphate uptake, confirming the effect of Cu(II) on phosphate uptake. A pH experiment was conducted at pH 4-8 to investigate the effect of the solution pH. Decrease of phosphate removal efficiency was found with increase of pH for both adsorbents, but the reduction rate of GAC-Cu slowed, indicating electrostatic interaction and coordinating bonding were simultaneously involved in phosphate removal. The adsorption was analyzed by Langmuir and Freundlich isotherm to determine the maximum phosphate uptake(q_m) and adsorption mechanism. According to correlation of determination(R²), Freundlich isotherm model showed a better fit than Langmuir isotherm model. Based on the negative values of q_m, Langmuir adsorption constant(b), and the value of 1/n, phosphate adsorption was shown to be unfavorable and favorable for GAC and GAC-Cu, respectively. The attempt of the linearization of each isotherm obtained very poor R². Batch kinetic tests verified that ~30% and ~90 phosphate adsorptions were completed within 1h and 24 h, respectively. Pseudo second order(PSO) model showed more suitable than pseudo first order(PFO) because of higher R². Regardless of type of kinetic model, GAC-Cu obtained higher constant of reaction(K) than GAC.

• Journal of Welding and Joining
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• v.24 no.5
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• pp.37-42
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• 2006

The robotic arc welding is widely employed in the fabrication industry fer increasing productivity and enhancing product quality by its high processing speed, accuracy and repeatability. Basically, the bead geometry plays an important role in determining the mechanical properties of the weld. So that it is very important to select the process variables for obtaining optimal bead geometry. In this paper, the possibilities of the Infrared camera in sensing and control of the bead geometry in the automated welding process are presented. Both bead width and thermal images from infrared thermography are effected by process parameters. Bead width and isotherm radii can be expressed in terms of process parameters(welding current and welding speed) using mathematical equations obtained by empirical analysis using infrared camera. A linear relationship exists between the isothermal radii producted during the welding process and bead width.

• Journal of Korean Society of Water and Wastewater
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• v.23 no.1
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• pp.113-119
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• 2009

The feasibility of using cork oak bark for phosphorus removal from wastewater was evaluated in this study. Recently, development of more cost-effective media while maintaining high efficiency in pollutants removal has received concern. Barks have a negative surface charge and, hence, tend to show a high affinity to bind cations, and they need to undergo chemical modification to increase their adsorption capacity of anions. Bark was hydrolyzed by HCl solution and it received modification using an aqueous solution of high molecular weight polyethylenimine(PEI). Surface modification with HCl and PEI resulted in a decrease of specific surface area of the bark from $1.932 m^2/g$ to $1.094 m^2/g$. The adsorption experiments were carried out in batch tests and the data were fitted to the Langmuir isotherm and Freundlich isotherm equations. Phosphate removal rate was higher at the lower solution pH possibly due to the form of phosphate ion in solution. For the initial phosphate concentration of 10 mg/L, maximum adsorption was 20.88 mg P/g at pH 3 and 12.02 mg P/g at pH 5. Mechanism of phosphorus sorption onto the HCl-PEI bark was examined through FT-IR spectrometer. Ion exchange between $NH^+$ and $H_2PO_4{^-}$ appeared to be a key mechanism of phosphate adsorption onto the HCl-PEI bark surface.

• Journal of the Korean Chemical Society
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• v.62 no.5
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• pp.364-371
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• 2018

Inhibition effects of alanine (Ala), histidine (His), methionine (Met) on the corrosion of aluminum were investigated in deaerated 0.5 M HCl and NaCl solution. In HCl solution the inhibition efficiency for the aluminum corrosion depended on the cathodic inhibition, and the inhibition efficiency was increased in the order of Met$10^{-4\;}M$ the adsorption process can be explained by Langmuir isotherm, however, in the case of higher concentration by Temkin logarithmic isotherm due to the interaction between the adsorbed molecules.

• Resources Recycling
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• v.8 no.1
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• pp.37-43
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• 1999

Studies have been conducted for the purpose of using manganese nodule and residue remained after extracting valuable metals [mm it as the adsorbent of cadmium wastewater. The study observed the adsorption percentage according to initial cadmium concentration and interpreted each adsorption systems by applying the Freundlich, Langmuir, and Temkin isotherms. The adsorption amounts increased as the initial concentration at cadmium ion increased, whereas the adsorption percentage decreased. Linearity was shown when applied to the Freundlich and Langmuir isotherms. The k value which evaluates the adsorption capacity of adsorbent in Freundlich isotherm, turned out to be 11.72, the highest in case of manganese nodule. The Xm value, the maximum adsorption amount of the adsorbate that adsorbs as a monolayer in Langmuir isotherm of manganese nodule, was estimated as 0.16, representing higher value compared with those of leached residue, leached residue-raw manganese nodule mixture, and activated carbon.

• Membrane and Water Treatment
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• v.15 no.1
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• pp.41-50
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• 2024

Presence of hazardous dyes in water cause considerable risks to the human health and environment due to their potential toxicity and ecological disruptions. Therefore, in the present research, to suggest an alternative method for the retention of toxic Azocarmine G (ACG) dye from aqueous media, natural and H₂SO₄-modified acacia sawdust were performed for the first time as low-cost and efficient adsorbents. Based on batch experiments, it was determined that the best conditions for the developed dye retention process were an initial pH of 2.0 and an equilibrium time of 240 min. Analysis of the data using both pseudo-first order and pseudo-second order kinetic models showed that the retention of ACG onto the adsorbents predominantly occurred through chemical adsorption. Langmuir, Freundlich, and Dubinin-Radushkevich isotherm models were employed to provide insights into the interaction between the adsorbate and adsorbent and the mechanism of the adsorption process. Maximum monolayer adsorption capacities of natural and H₂SO₄-modified acacia sawdust were determined as 28.01 and 64.90 mg g^-1, respectively by Langmuir isotherm model. Results of the study clearly indicated that the modification of acacia sawdust with H₂SO₄ leads to a substantial increase in the adsorption performance of anionic dyes.

• Journal of environmental and Sanitary engineering
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• v.14 no.4
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• pp.1-8
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• 1999

This study was aimed ultimately to develop an adsorption process treating heavy metal wastewater by utilizing activated carbon using flyash. The affecting factors in adsorption process on heavy metal by flyash adhesion-activated carbon are s follows. Factors such as pH, and quality of activated carbon, and reaction time made batch adsorption isotherm described adsorption capacity was made use of the investigation to evaluate adsorptive possibility of heavy metal.As the results of this study, H ion has influence on adsorption of heavy metal if pH is low. As reaction time is transformed, factors such as optimum reaction time is taken into consideration an adsorptive process of heavy metal because an adsorption and a reduction process occur. Adsorption isotherm of adhesion-activated carbon was generally obeyed to Freundlich formular than Langmuir formular and Freundlich constant, l/n were obtained in the range of 0.1~0.5.