• 청정기술
• /
• 제17권2호
• /
• pp.150-155
• /
• 2011

본 연구에서는 수용액상의 금속이온을 기능화된 구형의 실리카 담체를 이용하여 제거하는 공정에 대하여 유한 차분법을 이용하여 모사하였다. 평형 모델과 비평형 모델을 수립하여 무차원 변수와 각종 변수에 대한 영향을 살펴보았으며 평형 모델과 비평형 모델의 결과를 비교하였다. 평형모델의 경우 Freundlich 등온식을 사용하였으며 비평형 모델의 경우 1차 반응속도를 가정하였다. 평형모델과 비평형 모델의 경우 변수값에 따라 비슷한 경향을 나타내었으며 금속이온 제거공정의 효율을 예측할 수 있었다. 문헌에 제시된 실험값을 활용하여 평형 모델의 예측 결과를 비교한 결과 부합되는 결과를 나타내었다.

• Advances in environmental research
• /
• 제7권3호
• /
• pp.225-237
• /
• 2018

The sorption of metal ions with low-cost adsorbents plays an important role in sustainable development. In the present study, the efficacy of sugarcane bagasse, rain tree fruits (samaneasaman), banana stem and their mixtures, used as bio-sorbents, in the removal of Cu(II) and Pb(II) ions from aqueous solution is evaluated. Batch studies are conducted, and residual ions were measured using Inductively Coupled Plasma (ICP)-atomic spectrometer. Effect of pH, initial metal ion concentration, reaction time and adsorbent dosage are studied. The Pb(II) removal efficiency was observed to be 97.88%, 98.60% and 91.74% for rain tree fruits, banana stem and a mixture of adsorbents respectively. The highest Cu(II) ion removal was observed for sugarcane bagasse sorbent with an efficiency of 82.10% with a pH of 4.5 and a reaction time of 90 min. Finally, desorption studies were carried out to study the leaching potential of adsorbent, and it was found that the adsorbent is stable in water than the other leaching agents such as HCl, ammonium acetate, Sodium EDTA. Hence, these adsorbents can be effectively used for the removal of these heavy metals.

• Bulletin of the Korean Chemical Society
• /
• 제34권6호
• /
• pp.1871-1874
• /
• 2013

• 대한화학회지
• /
• 제19권6호
• /
• pp.471-474
• /
• 1975

• Bulletin of the Korean Chemical Society
• /
• 제24권7호
• /
• pp.1032-1034
• /
• 2003

• 한국환경과학회지
• /
• 제13권4호
• /
• pp.435-440
• /
• 2004

The thiophene or furan-containing hexadentate ligands 1, 12-bis (2-theophene )-2,5,8,ll-tetraazadodecane(Thiotrien ㆍ 4HCl) and 1,12-bis (2-furan)-2,5,8,11-tetraazadodecane(Furatrienㆍ4HC1) were synthesized as their tetrahydrochloride salt and characterized by EA, IR, NMR, and Mass spectrum. Their protonation constants (logK$_{nH}$) and stability constants (logK$^{M}_{L}$ for Cd$^{2+}$, Pb$^{2+}$, $Zn^{2+}$ and Cu$^{2+}$ ions were determined in aqueous solution by potentiometry and compared with 1, 12-bis(2-pyridyl)-2,5,8, 11-tetra-azadodecane(Pytrien) of pyridyl-containing ligand. The effect stability constants of ligands and metal ion for removal of heavy metals in aqueous solution were described.

• 한국환경과학회:학술대회논문집
• /
• 한국환경과학회 2003년도 International Symposium on Clean Environment
• /
• pp.109-112
• /
• 2003

A method to determine As(V) ions in aqueous solution by chemiluminescence method has been studied using a stopped flow system. The method is based on the increased chemiluminescence intensity with the addition of As(V) ion to a solution of lucigenin and hydrogen peroxide. The effects of KOH concentration, $H_2O_2$ concentration and flow rate of reagents on the chemiluminescence intensity have been investigated. The calibration curve for As(V) was linear over the range from $1.0{\times}l0^{-6}$M to $1.0{\times}l0^{-4}$M, the coefficient of correlation was 0.997 and the detection limit was $3.3{\times}l0^{-7}$M under the optimal experimental conditions.

• 한국표면공학회:학술대회논문집
• /
• 한국표면공학회 2018년도 춘계학술대회 논문집
• /
• pp.33.1-33.1
• /
• 2018

pH is expressed mathematically as $pH=-{\log}[H^+]$, is a measure of the hydrogen ion concentration, [$H^+$] to specify the acidity or basicity of an aqueous solution. The pH scale usually ranges from 0 to 14. Every aqueous solution can be measured to determine its pH value. The pH values below 7.0 express the acidity, above 7.0 are alkalinity and pH 7.0 is a neutral solution. The solution pH can be determined by indicator or by measurement using pH sensor, which measuring the voltage generated between a glass electrode and a reference electrode according to the Nernst Equation. The pH value of solutions depends on the temperature and the activity of contained ions. In nickel electroless plating process, the controlled pH value in some limited ranges are extremely important to achieve optimal deposition rate, phosphorus content as well as solution stability. Basically, nickel electroless plating solution contains of $Ni^{2+}ions$, reducing agent, buffer and complexing agents. The plating processes are normally carried out at $82-92^{\circ}C$. However, the change of its pH values with temperatures does not follow any rule. Thus, the purpose of study is to understand the relationship between pH and temperature of some based solutions and electroless nickel plating solutions. The change of pH with changing temperatures is explained by view of the thermal dynamic and the practical measurements.

• 한국진공학회:학술대회논문집
• /
• 한국진공학회 2016년도 제50회 동계 정기학술대회 초록집
• /
• pp.290.1-290.1
• /
• 2016

Grapehen, a single atomic layer of graphite, has been in the spotlight and researched in vaious fields, because its fine mechanical, electrical properties, flexibility and transparence. Synthesis methods for large-area graphene such as chemical vaper deposition (CVD) and mechanical, chemical exfoliation have been reported. In particular, chemical exfoliation method receive attention due to low cost process. Chemical exfoliation method require reduction of graphene oxide in the process of exfoliation such as chemical reduction by strong reductant, thermal reduction on high temperature, and optical reduction via ultraviolet light exposure. Among these reduction methods, optical reduction is free from damage by strong reductant and high temperature. However, optical reduction is economically infeasible because the high cost of short-wavelength ultraviolet light sorce. In this paper, we make graphene-oxide and lanthanoid ion mixture aqueous solution which has highly optical absorbency in selective wevelength region. Sequentially, we synthesize reduced graphene oxide (RGO) using the solution and visible laser beam. Concretely, graphene oxide is made by modified hummer's method and mix with 1 ml each ultraviolet ray absorbent Gd3+ ion, Green laser absorbent Tb3+ ion, Red laser absorbent Eu3+ ion. After that, we revivify graphene oxide by laser exposure of 300 ~ 800 nm layser 1mW/cm2 +. We demonstrate reproducibility and repeatability of RGO through FT-IR, UV-VIS, Low temperature PL, SEM, XPS and electrical measurement.

• 한국환경과학회지
• /
• 제1권1호
• /
• pp.69-76
• /
• 1992

The effects of $Ca_{2+}$ ion on the formation of micelle colloid of nonionic surfactants, nonylphenol-(ethylene oxide)n [NP-(EO)n: n= 11, 40, 100) were investigated by the iodine solubilization method. The characteristics of spectra depended on the concentration of $Ca_{2+}$ ion and the number of EO unit. Above CMC(critical micelle concentration), the intensity of the CT (charge transfer) band by the addition of $Ca_{2+}$ ion for the NP-(EO)11 and NP-(EO)40 increased and when decreased and for the NP-(EO)In continuously increased. The increase in the intensity of CT band were attributed to the compactness of micelle in the presence of $Ca_{2+}$ ion. These phenomena may be explained by the fact that the linear ethylene oxide (EO) chain, relatively free to assume various configuration in aqueous solution, could form a pseudo-crown ether structures capable of forming complexes with $Ca_{2+}$ ion.