• Journal of Environmental Science International
• /
• v.23 no.6
• /
• pp.1157-1163
• /
• 2014

The solid phase extractant (PVC-D2EHPA bead) was prepared by immobilizing di-2-ethylhexyl-phosphoric acid (D2EHPA) with polyvinyl chloride (PVC). The prepared PVC-D2EHPA beads were characterized by using fourier transform infrared spectrometer (FTIR) and scanning electron microscopy (SEM). The removal experiments of Cu(II) by PVC-D2EHPA beads conducted batchwise. The removal kinetics of Cu(II) was found to follow the pseudo-second-order model. The equilibrium data fitted well with Langmuir isotherm model and the maximum removal capacity was 2.6 mg/g at $20^{\circ}C$. The optimum pH region was in the range of 3.5 to 6. and the standard free energy (${\Delta}G^{\circ}$) was between -4.67~-4.98 kJ/mol, indicating the spontaneous nature of Cu(II) removal by PVC-D2EHPA beads.

• Applied Chemistry for Engineering
• /
• v.27 no.1
• /
• pp.21-25
• /
• 2016

When copper alloy is used in etching process for the production of lead frame, the high concentration of heavy metals, such as iron, nickel and zinc may be included in the etching waste. Those etching waste is classified as a specified one. Therefore a customized design was designed for the purification process of the lead frame etching waste liquid containing high concentrations of heavy metals for the production of an electroplating copper(II) oxide. Since the lead frame etching waste solution contains highly concentrated heavy metal species, an ion exchange method is difficult to remove all heavy metals. In this study, a copper(I) chloride was manufactured by using water solubility difference related to the reduction-oxidation method followed by the reunion of copper(II) chloride using sodium sulfate as an oxidant. The hydrazine was chosen as a reducing agent. The optimum added amount was 1.4 mol per 1.0 mol of copper. In the case of removal of heavy metals by using the combination of reduction-oxidation and ion exchange resin methods, 4.3 ppm of $Fe^{3+}$, 2.4 ppm of $Ni^{2+}$ and 0.78 ppm of $Zn^{2+}$ can be reused as raw materials for electroplating copper(II) oxide when repeated three times.

• Clean Technology
• /
• v.20 no.3
• /
• pp.251-255
• /
• 2014

PVA gel beads were made by immobilization of thenoyltrifluoroacetone (HTTA) and trioctylphoshineoxide (TOPO) with poly vinyl alcohol (PVA). The prepared PVA gel beads were used for the removal of $Cu^{2+}$ from aqueous solution. The removal characteristics of $Cu^{2+}$ by PVA gel beads was found to follow the pseudo-second-order kinetic equation. The maximum removal capacity calculated from Langmuir isotherm equation was 9.59 mg/g. The optimal pH was in the range of 3.5~6. Even when the PVA gel beads were reused 5 times, the leakage of extractant and the damage of PVA gel beads was not observed.

• 한국생물공학회:학술대회논문집
• /
• 2005.04a
• /
• pp.252-256
• /
• 2005

Removal of heavy metal ions from aqueous solution by brown sea weeds (Hizikia fusiformis, Laminaria, and Undaria pinnatifida) was 80-96% for lead, cadmium, chromium and copper ions. Fifty percent of the adsorption was completed in 4 min. The uptake of lead and cadmium ions followed Langmuir adsorption. In the adsorption experiments using single and multi metal ions 80-95% of metal ions were removed, and the removal efficiency was the best for lead ion.

• Journal of Environmental Science International
• /
• v.12 no.10
• /
• pp.1061-1069
• /
• 2003

The adsorption behaviors of strontium and cesium ions on fly ash, natural zeolites, and zeolites synthesized from fly ash were investigated. The zeolites synthesized from fly ash had greater adsorption capabilities for strontium and cesium ions than the original fly ash and natural zeolites. The maximum adsorption capacity of synthetic zeolite for strontium and cesium ions was 100 and 154 mg/g, respectively, It was found that the Freundlich isotherm model could fit the adsorption isotherm. The distribution coefficients (K$\_$d/) for strontium and cesium ions were also calculated from the adsorption isotherm data, The distribution coefficients decreased with increasing equilibrium concentration of strontium and cesium ions in solution. By studying the removal of cesium and strontium ions in the presence of calcium, magnesium, sodium, potassium, sulfate, nitrate, nitrite, and EDTA (in the range of 0.01 - 5 mM) it was found that these coexistence ions competed for the same adsorption sites with strontium and cesium ions.

• Korean Journal of Microbiology
• /
• v.37 no.3
• /
• pp.197-203
• /
• 2001

An ubiquitous bacterium, Pseudomonar cepacia KH410 was isolated from fresh water plant root and identified. Adsorption of heavy metals of lead, cadmium and copper by this strain was investigated. Optimal conditions foradsorption was 1.0 dry g-biomass, at pH 4.0 and temperature of $40^{\circ}C$. Adsorption equilibrium reached max-imum after 120 min in 1000 mg/l metal solutions. The adsorption capacity (K) of lead was 5.6 times higher thancadmium and 4.0 times higher than that of copper. Adsorption of lead was applicable for Langmuir modelwhereas Freundlich model for cadmium and copper, respectively. Adsorption strength (1/n) of heavy metal ionswere in the order of lead>copper>cadmium. Uptake capacity of lead, cadmium and copper by dried cell was83.2,42.0,65.2 mg/g-biomass, respectively. Effective desorption was induced 0.1 M HCI for lead and 0.1 $HNO_3$ for cadmium and copper. Pretreatment to increase ion strength was the most effective with 0.1 M KOH.Uptake by immobilized cell was 77.8,58.5,71.2 mg/g-biomass for lead, cadmium and copper, respectively. Theimmobilized cell was more effective than ion exchange resin on removal of heavy metals in solution containinglight metals.

• Environmental Engineering Research
• /
• v.17 no.3
• /
• pp.125-132
• /
• 2012

The removal of Cd(II) and Cu(II) from aqueous solution by an agricultural solid waste biomass prepared from Moringa oleifera bark (MOB) was investigated. The biosorbent was characterized by Fourier transform infrared spectroscopy and elemental analysis. Furthermore, the effect of initial pH, contact time, biosorbent dosage, initial metal ion concentration and temperature on the biosorption of Cd(II) and Cu(II) were studied using the batch sorption technique. Kinetic studies indicated that the biosorption process of the metal ions followed the pseudo-second order model. The biosorption data was analyzed by the Langmuir, Freundlich, Dubinin-Radushkevich, and Temkin isotherm models. Based on the Langmuir isotherm, the maximum biosorption capacities for Cd(II) and Cu(II) onto MOB were 39.41 and 36.59 mg/g at 323 K, respectively. The thermodynamic parameters, Gibbs free energy (${\Delta}G^o$), enthalpy (${\Delta}H^o$), and entropy (${\Delta}S^o$) changes, were also calculated, and the values indicated that the biosorption process was endothermic, spontaneous and feasible in the temperature range of 303-323 K. It was concluded that MOB powder can be used as an effective, low cost, and environmentally friendly biosorbent for the removal of Cd(II) and Cu(II) ions from aqueous solution.

• Journal of the Korea Organic Resources Recycling Association
• /
• v.15 no.4
• /
• pp.107-114
• /
• 2007

A study on the removal of heavy metals using alginic acid, a kind of polysaccharides, was performed. Alginic acid adsorbed 480 mg Pb/g dry mass at pH 4, which was about twice as high as uptake capacity of other biosorbents. Isothermal adsorption curve for lead ions was described by the Langmuir model equation and the experimental data well fitted to model equation. The adsorption of lead ions was an endothermic process since binding strength increased with temperature. The effect of alkali metal ions ($Ca^{2+}$ and $Mg^{2+}$) on lead sorption capacity was negligible and most adsorption process was completed in 30min. The uptake capacity of other metals such as, copper, mercury, strontium, and cesium ions using alginic acid was also investigated.

• Journal of Environmental Science International
• /
• v.25 no.11
• /
• pp.1485-1491
• /
• 2016

PSf/D2EHPA/CNT beads were prepared by immobilizing di-(2-ethylhexyl)-phosphoric acid (D2EHPA) and carbon nanotubes (CNT) on polysulfone (PSf) and used to remove Cu(II) from aqueous solutions. Optimum pH was in the range of 4 to 6. The removal kinetic of Cu(II) by the prepared PSf/D2EHPA/CNT beads was mainly governed by internal diffusion, and the diffusion coefficient of Cu(II) by PSf/D2EHPA/CNT beads was found to be $2.19{\times}10^{-4}{\sim}2.64{\times}10^{-4}cm^2/s$. The Langmuir isotherm model predicted the experimented data well. The maximum removal capacity of Cu(II) obtained from this isotherm was 7.32 mg/g. Calculated thermodynamic parameters such as ${\Delta}G^o$, ${\Delta}H^o$ and ${\Delta}S^o$ showed that the adsorption of Cu(II) ions onto PSf/D2EHPA/CNT beads was feasible, spontaneous and endothermic at 293-323 K.

• Transactions of the Korean Society of Automotive Engineers
• /
• v.22 no.1
• /
• pp.135-141
• /
• 2014

$NH_3$-SCR has high NOx removal efficiency approximately 80~90%. Recently, the copper or iron ion-exchanged zeolite catalysts are widely used as automobile SCR catalysts. In this paper, the effect of the space velocity, temperature of reaction and $NO_2$ addition on the $NH_3$-SCR reaction were studied using various zeolite SCR catalysts. The test was conducted with small sized fresh catalysts in a laboratory fixed-bed flow reactor system using simulated gases. It is found that the activity of the BEA is better than MFI. It seems that three-dimensional framework and a wide pore entrance of BEA enhances the SCR activity. It is also found that low temperature activity of Cu-zeolites was better than Fe-zeolites. Once $NO_2$ was added, the NOx conversion activity of the Cu-zeolite was slightly enhanced, whereas remarkable improvement was achieved by Fe-zeolite.