• 한국환경과학회지
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• 제15권11호
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• pp.1053-1059
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• 2006

This study was performed to investigate the possible uses of waste sludge for the removal of heavy metal ions. The adsorption experiments were conducted with wastes such as sewage treatment sludge, water treatment sludge and oyster shell to evaluate their sorption characteristics. Heavy metals selected were cadmium, copper and lead. in the sorption experiments on the sewage treatment sludge, water treatment sludge, oyster shell and soil, sorption occurred in the beginning and it reached equilibrium after 40 minutes on the oyster shell and 4 hour on the sewage treatment sludge and water treatment sludge. Results of Freundlich isotherms indicated that sewage treatment sludge could be properly used as an adsorbent for heavy metals and sorption strength of heavy metals was in the order of Pb > Cu > Cd. In the influence of pH on the adsorbents, sorption rate was more than 80% in pH 4 and most of heavy metals were adsorbed in pH 9. Adsorption rate of Cd decreased with decreasing pH and then adsorption rate of Cu was lower in soil.

• 한국토양환경학회지
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• 제5권3호
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• pp.25-33
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• 2001

새만금 간척으로 인해 변화된 조류흐름이 갯벌의 조성에 미치는 영향을 조사하였으며, 이에 따른 물리적 특성이 중금속의 오염도에 미치는 영향을 분석하였다. 또한 회분실험을 통하여 중금속의 종류와 농도 변화에 따른 흡착특성을 알아보고, 흡착등온식을 적용시켰다. 분석결과에 따르면, 해류의 흐름변화로 강 하구 부분에 퇴적현상이 일어나고 있었으며, 이 현상은 중금속의 함량에 영향을 미치고 있었다. 특히 입도 분포와 유기물 함량 그리고 양이온 치환능력의 영향이 크게 작용하고 있음을 알 수 있었다. 중금속 흡착능력은 30분 이내에 주입농도의 90%이상이 흡착되는 것으로 나타났다. 그러므로 새만금의 흐름 양상은 토양 입도를 변화시킬 것이며, 역시 중금속의 흡착능력의 변화가 일어날 것이다.

• 한국환경보건학회지
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• 제18권2호
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• pp.106-116
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• 1992

In order to examine the influences of diluent, DVB, and ligand content, in the adsorption velocities and capacities of chelating resins to heaw metal ions, the chelating resins containing the PO$_3$H, amide, and PO$_3$H+amide were prepared from AN-STR-DVB copolymer. The adsorption capacities of chelating resins were measured by ICP-AES. The major results of the studies are as follows: The optimized compositions of the chelating resins having the highest adsorptivity for the heavy metal ions were found to be DVB=7 wt%, toluene= 100 vol%. The adsorption rate of the chelating resins to the heaw metal ions was PO$_3$H > PO$_3$H+Amide > Amide in order.

• Environmental Engineering Research
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• 제12권1호
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• pp.1-7
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• 2007

Most of the herb residue producing from oriental medical clinics(OMC) and hospitals(OMH) is wasted in Korea. To develop of adsorbent for removing heavy metal from wastewater, the various pre-treatment methods of the herb residue were evaluated by potentiometric titration, Freundlich isotherm adsorption test and the kinetic adsorption test. The herb residue was pre-treated for increasing the adsorption capacity by cleaning with distilled water, 0.1 N HCl and 0.1 N NaOH and by heating at $370^{\circ}C$ for 30 min. It showed a typical weak acid-weak base titration curve and a short pH break like commercial activated carbon during photentiometric titration of pre-treated herb residue. The log-log plots in the Freundlich isotherm test were linear on the herb residue pre-treated with NaOH or HCl like commercial activated carbon. The adsorption capacity(qe) in the Freundlich isotherm test for $Cr^{6+}$ was 1.5 times higher in the pre-treated herb residue with HCl than in activated carbon. On the other hand the herb residue pre-treated with NaOH showed the good adsorption capacities for $Pb^{2+}$, $Cu^{2+}$ and $Cd^{2+}$ even though those adsorption capacities were lower than that of activated carbon. In kinetic test, most of heavy metals removed within the first 10 min of contact and then approached to equilibrium with increasing contact time. The removal rate of heavy metals increased with an increase of the amount of adsorbent. Likewise, the removal rates of heavy metals were higher in the herb residue pre-treated with NaOH than in that pre-treated with HCl. The adsorption preference of herb residues pre-treated with NaOH or HCl was $Pb^{2+}>Cu^{2+}$ or $Cd^{2+}>Cr^{6+}$ in the order. Conclusively, the herb residue can be used as an alternative adsorbent for the removal of heavy metals depending on pr-treatment methods.

• 공업화학
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• 제30권5호
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• pp.536-545
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• 2019

An experiment was conducted to evaluate the adsorptive removal of Pb(II) from an aqueous solution using a mixture of spent coffee grounds and chitosan on beads (CC-beads). Various parameters affecting the adsorption process of Pb(II) using CC-beads were investigated. Based on the experimental data, the adsorption kinetics and adsorption isotherms were analyzed for their adsorption rate, maximum adsorption capacity, adsorption energy and adsorption strength. Moreover, the entropy, enthalpy and free energy were also calculated by thermodynamic analysis. According to the FT-IR analysis, a CC-bead has a very suitable structure for easy heavy metal adsorption. The process of adsorbing Pb(II) using CC-beads was suitable for pseudo-second order kinetic and Langmuir model, with a maximum adsorption capacity of 163.51 (mg/g). The adsorption of Pb(II) using CC-beads was closer to chemical adsorption than physical adsorption. In addition, the adsorption of Pb(II) on CC-beads was exothermic and spontaneous in nature. CC-beads are economical because they are inexpensive and also the waste can be recycled, which is very significant in terms of the continuous circulation of resources. Thus, CC-beads can compete with other adsorbents.

• 한국환경보건학회지
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• 제29권3호
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• pp.50-58
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• 2003

Removal of heavy metal ions (Cd$^{2+}$, Cr$^{3+}$, Cu$^{2+}$, Pb$^{2+}$) by several chitosans was studied and the molecular weight of chitosan was investigated in order to examine the effect of autoclaving. Chitosan were divided into 3 groups (A type, controlled chitosan; B type, autoclaved for 15 min; C type, autoclaved for 60 min). The heavy metal removal capacity and rate of B type chitosan were higher than those of A type and B type chitosan. The molecular weight of chitosan was decreased by the increase of autoclaving time. Therefore, the heavy metal capacity was not well correlated to the molecular weight. Freundlich and Langmuir isotherm was determined from the experimental results of equilibrium adsorption for individual heavy metal ions on chitosan. Langmuir isotherm was well fitted to this experimental data. The heavy metal removal capacity of B type chitosan was in the order of Pb$^{2+}$ > Cu$^{2+}$ > Cd$^{2+}$> Cr$^{3+}$.3+/.$.3+/.

• 분석과학
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• 제12권3호
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• pp.196-202
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• 1999

갈조류인 Sargassum horneri를 중금속 흡착제로 사용하여 중금속 Cd(II) 및 Pb(II)이온을 제거하였다. Sargassum horneri는 동해안에서 채취하였고, 풍건 건조시켜 40~60 mesh의 입자 크기로 흡착제를 만들어 사용하였다. batch법은 진탕 시간에 따른 흡착량을 측정함으로써 흡착속도를 조사하였고, column법은 해조 분말을 충진 시킨후 일정농도의 중금속용액을 1 mL/min의 속도로 흘려보내면서 흡착시키고 흡착량을 알아 보았다. 중금석 흡착에 미치는 pH의 영향은 batch법과 column법 모두, pH 10.5>7.0>3.5순으로 나타났다. Pb(II)이온이 Cd(II)이온보다 높은 흡착량을 보였다. 특히 batch법에서는 모든 pH의 조건하에서 5분이내에 최대 흡착량에 도달하였다. 회수율은 batch법에 의해 흡착된 중금속의 회수율이 column법에 의해 흡착된 중금속의 회수율 보다 조금 높게 나타났다.

• Bulletin of the Korean Chemical Society
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• 제19권2호
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• pp.218-222
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• 1998

Removal of Cd(Ⅱ), Zn(Ⅱ) and Cu(Ⅱ) from aqueous solutions using the adsorption process on magadiite has been investigated. It was found that the removal percentage of metal cations at equilibrium increases with increasing temperature, and follows the order of Cd(Ⅱ) > Cu(Ⅱ) > Zn(Ⅱ). Equilibrium modeling of adsorption showed that the adsorptions of Cd(Ⅱ), Cu(Ⅱ), and Zn(Ⅱ) were fitted to Langmuir isotherm. Kinetic modeling of the adsorption showed that first order reversible kinetic model fitted to experimental data. From kinetic model and equilibrium data, the overall rate constant (k) and the equilibrium constant (K) for the adsorption process were calculated. The overall rates of adsorption of metal ions follow the order of Cd(Ⅱ) > Cu(Ⅱ) > Zn(Ⅱ). From the results of thermodynamic analysis, standard Gibbs free energy (ΔG°), standard enthalpy (ΔH°), and standard entropy (ΔS°) of adsorption process were calculated.

• 한국지반신소재학회논문집
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• 제11권1호
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• pp.1-9
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• 2012

본 연구에서는 PRE의 반응물질로 음식물 쓰레기 처리과정에서 발생하는 음식물 쓰레기 탄화재(CFW, Carbonized Foods Waste)를 적용하고자 회분석 흡착실험(Batch test)을 실시하였다. 중금속 구리와 아연에 대한 흡착특성 분석을 위해 CFW를 이용한 개별 및 경쟁흡착 특성을 확인하고자 하였다. 개별흡착 실험에서는 Langmuir와 Freundlich 모델에 적용하여 흡착평형을 예측한 결과 Langmuir의 모델에 더 일치하였고 최대흡착량은 구리가 더 많았다. 유사일치반응과 유사이차반응모델을 이용한 흡착물질의 흡착속도를 비교한 결과 아연의 반응속도가 구리보다 빨랐다. CFW를 이용한 중금속 제거는 구리보다 아연이 먼저 제거가 될 것으로 판단된다. 한편 구리와 아연과의 경쟁흡착 비율이 유사하면 아연의 흡착량이 떨어지는 특성을 보였다. 구리용액에 이연을 혼합한 경우, CFW에 구리의 흡착은 86%이고, 아연용액에 구리를 혼합한 경우에는 이연의 흡착이 19%로 나타났다. 따라서, 복합 중금속으로 오염된 지반의 효율적인 오염제거를 위해서는 각 중금속의 정화특성이 고려되어야 할 것으로 판단된다.

• 한국물환경학회지
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• 제38권2호
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• pp.82-94
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• 2022

In this study, chemically modified biochar (NSBP500, KSBP500, OSBP500) derived from starfish was utilized to improve the adsorption ability of the SBP500 (Starfish Biochar Pyrolyzed at 500℃) in a solution contaminated with heavy metals. According to the biochar modification performance evaluation batch tests, the removal rate and adsorption amount of NSBP500 increased 1.4 times for Cu, 1.5 times for Cd, and 1.2 times for Zn as compared to the control sample SBP500. In addition, the removal rate and adsorption amount of KSBP500 increased 2 times for Cu, 1.8 times for Cd, and 1.2 times for Zn. The removal rate and adsorption amount of OSBP500 increased 5.8 times for Cu. The FT-IR analysis confirmed the changes in the generation and movement of new functional groups after adsorption. SEM analysis confirmed Cu in KSBP500 was in the form of Cu(OH)₂ and resembled the structure of nanowires. The Cd in KSBP500 was densely covered in cubic form of Cd(OH)₂. Lead(Pb) was in the form of Pb₃(OH)₂(CO₃)₂ in a hexagonal atomic layer structure in NSBP500. In addition, it was observed that Zn was randomly covered with Zn₅(CO₃)₂(OH)₆ pieces which resembled plates in KSBP500. Therefore, this study confirmed that biochar removal efficiency was improved through a chemical modification treatment. Accordingly, adsorption and precipitation were found to be the complex mechanisms behind the improved removal efficiency in the biochar. This was accomplished by electrostatic interactions between the biochar and heavy metals and ion exchange with Ca²⁺.