• 한국환경과학회지
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• 제5권6호
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• pp.779-783
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• 1996

Cation exchange distribution coefficients of poly(dithiocarbamate) were presented for $Cd^{2+}$, $Cr^{3+}$, and $Pb^{2+}$ in HCI. The distribution coefficients were determined tv using the batch method. Based on these distribution data, the separation possibilities of the heavy metal ions were discussed. The distribution coefficients of three heavy metal ions on dithiocarbamate resin were decreased as HCI concentrations were increased. The selective separation of $Cr^{3+}$ and $Cd^{2+}$ was possible by using 0.1M HCl in dithiocarbamate resin and the reproducibility test showed that the average absorptivity of resin was 90% in the case of $Cd^{2+}$ ion by the column method.

• 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+/.

• Journal of the Korean Wood Science and Technology
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• 제28권2호
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• pp.49-56
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• 2000

본 연구는 용액의 처리조건에 따른 미처리 수피에 의한 중금속 흡착을 연구하기 위하여 계획되었다. 흡착에 미치는 용액의 온도와 pH, 수피의 입자크기, 경금속 첨가의 영향이 연구되었고, 또한 중금속간의 흡착경쟁도 평가되었다. 용액의 온도를 $-5^{\circ}C$에서 $10^{\circ}C$까지 증가시킴에 따라 $Cu^{2+}$와 $Zn^{2+}$의 흡착율이 증가하였다. 그러나, 이 흡착은 $10^{\circ}C{\sim}55^{\circ}C$에서는 거의 일정하였다. $Cr^{6+}$은 용액의 온도를 증가시킴에 따라 계속적으로 증가하였다. $Cu^{2+}$, $Zn^{2+}$ 및 $Pb^{2+}$의 최대 흡착율은 pH 6~7에서 나타났다. 그러나, 이 흡착율은 최적 pH 의 양 영역에서는 급격하게 감소하였다. $Cr^{6+}$의 흡착율은 용액의 pH를 증가시킴에 따라 계속적으로 감소하였다. 수피의 입자크기가 작을수록 흡착율은 감소하였다. 소나무 수피와 상수리나무 수피 간의 흡착 경향은 차이가 거의 없었다. $Ca^{2+}$이나 $Mg^{2+}$(10~25 ppm)의 첨가에 의해 $Cu^{2+}$, $Zn^{2+}$의 흡착율이 증가되었다. 흡착율의 증가는 소나무 수피보다 상수리나무 수피에서 더 높았다. 그러나 $Pb^{2+}$와 $Cr^{6+}$은 경금속의 첨가에 영향을 받지 않았다. 2~3종류의 중금속 혼합용액 ($Cu^{2+}$, $Pb^{2+}$, $Zn^{2+}$)을 미처리 수피로 처리할 경우, $Zn^{2+}$의 흡착은 중금속 이온간의 흡착경쟁 때문에 현저하게 감소되었다. 또한, $Cu^{2+}$의 흡착도 다소간 감소되었다. 그러나 $Pb^{2+}$의 흡착은 다른 중금속 이온의 존재에 의해서 영향받지 않았다.

• Bulletin of the Korean Chemical Society
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• 제21권7호
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• pp.685-689
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• 2000

The complexation reaction between Pb2+,TI and Cd2+ions and macrocyclic ligands, 18-crown-6 ( 18C6) and dibenzo- 18-crown-6 (DB 18C6), was studied in dimethylsulfoxide (DMSO)-nitromethane (NM) and dimethyl-formamide (DMF)-nitromethane binary system s by square wave polarography (SWP) technique. The stoichiometry and stability of the complexes were determined by monitoring the shifts in half-waves or peak potentials of the polarographic waves of metal ions against the Iigand concentration. In most cases, the stability constants of complexes increase with increasing amounts of the nitromethane in mixed binary solvents used in this study. The complexes formed between 18C6 and DB18C6 and these metal cations in all cases had a stoichiometry of 1 : 1. The results obtained show that there is an inverse relationship between the formation constant of complexes and the donor number of solvents based on a Gatmann donocity scale and the stability constants show a high sensitivity to the composition of the mixed solvent systems. A linear behavior was observed for variation of log Kf of I8C6 complexes vs the composition of the mixed solvent systems in NM/DMSO and NM/DMF,but a non-linear behavior was observed in the case of DB 18C6 complexes in these binary systems. In most of the systems investigated, the Pb2+ cation forms a more stable complex with the 18C6 than other two cations and the order of selectivity of this Iigand for cations is: Pb2+ > TI+,Cd2+.

• 환경위생공학
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• 제23권1호
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• pp.57-65
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• 2008

Resins were synthesized with 1-aza-15-crown-5 macrocyclic ligand attached to styrene(dangerous matter) divinylbenzene(DVB) copolymer with crosslink of 1, 2, 6 and 15% by substitution reaction. The synthesis of these resins was confirmed by content of chlorine, element analysis, and IR-spectrum. The effects of pH, time and crosslink on adsorption of metal ion　from water fire extinguishing agent by the synthetic resin adsorbent were investigated. The metal ion was showed fast adsorption on the resins above pH 3. The optimum equilibrium time for adsorption of metallic ions was about two hours. The adsorption selectivity determined in water was in increasing order of $Mg^{2+}>Al^{3+}>Pb^{2+}$. The adsorption was in the order of 1, 2, 6, and 15% crosslink resin.

• 대한환경공학회지
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• 제27권11호
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• pp.1146-1152
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• 2005

개시제로 potassium persulfate($K_2S_2O_8$)를 사용하여 methylcellulose(MC)에 중금속 이온과 친화력이 우수한 carboxyl(-COOH)기를 도입하기 위하여 acrylic acid(AA)를 그라프트 공중합시켜 얻어낸 반응생성물(MC-g-AA)을 중금속 이온 흡착제로 적용하였다. MC-g-AA의 그라프트율은 개시제 및 단량체의 농도가 높을수록 증가하였으며 그라프트율 19.7% 이상의 MC-g-AA는 물에 용해되지 않았다. MC-g-AA의 중금속 흡착 특성을 평가하기 위해 MC-g-AA의 기라프트율, 폐수의 pH, 흡착시간, MC-g-AA의 주입량 및 폐수내 $Pb^{2+}$, $Cu^{2+}$ 이온의 농도에 따른 흡착실험을 진행하였다. 흡착실험 결과 MC-g-AA는 pH $4{\sim}6$ 범위에서 $Pb^{2+}$, $Cu^{2+}$ 이온에 대한 높은 흡착량을 나타내었으며 그라프트율 및 초기 중금속 이온의 농도가 높을수록 MC-g-AA의 중금속 흡착량은 증가하였으나 MC-g-AA의 주입량이 늘어날수록 MC-g-AA 단위 무게당 흡착량은 감소하였다. MC-g-AA에 의한 중금속 흡착을 Freundlich 등온흡착 모델로 표현한 $Pb^{2+}$, $Cu^{2+}$ 이온의 l/n은 각각 0.4294, 0.3453로 나타났다.

• Current Photovoltaic Research
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• 제11권3호
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• pp.87-95
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• 2023

As the demand for the Internet of Things grows, research into indoor photovoltaics for wireless power is becoming important. In particular, perovskite has attracted considerable attention due to its superior performance compared to other candidates. However, various surface defects present in perovskite are a limiting factor for high performance. In particular, deep-level surface defects caused by uncoordinated Pb²⁺ ions directly limit charge transport. In low light environments, this appears to be a more significant hurdle. In this study, ethylenediamine, which can provide covalent bonding to uncoordinated Pb²⁺ ions through nitrogen, was used as a surface treatment material for indoor photovoltaics. X-ray photoelectron spectroscopy confirmed that the uncoordinated Pb²⁺ ions were effectively passivated by the terminal nitrogen of ethylenediamine. As a consequence, a V_OC of 0.998 V, a JSC of 0.139 mA cm^-2 and a fill factor of 83.03% were achieved, resulting in an indoor photoelectric conversion efficiency of 38.02%.

• 한국환경과학회지
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• 제7권5호
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• pp.697-705
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• 1998

$Pb^{2+}$ removal capacity and initial $Pb^{2+}$ removal rate were compared between non-biomaterials (granular activated carbon, powdered activated carbon, ion exchange resin, zeolite) and biomaterials (activated sludge, Aureobasidium pullulans, Saccharomyces cerevisiae). The $Pb^{2+}$ removal capacity of biomaterials were greater than that of non-biomaterials, generally. The $Pb^{2+}$ removal capacities of non-biomaterials and biomaterials were shown on the order of ion exchange resin ＞ zeolite ＞ granular activated carbon ＞ powdered activated carbon and A. pullulans ＞ S. cerevisiae ＞ activated sludge, respectively. In the initial $Pb^{2+}$ removal rate, the non-biomaterials showed powdered activated carbon ＞ granular activated carbon ＞ zeolite ＞ ion exchange resin and the biomaterials showed A. pullulans ＞ activated sludge ＞ S. cerevisiae. Comparing the $Pb^{2+}$ removal capacity and initial $Pb^{2+}$ removal rate of activated sludge with those of other non-biomaterials and biomaterials, activated sludge may have an availability on the removal of heavy metal ions by the economical and pratical aspects.

• 한국환경과학회지
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• 제8권3호
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• pp.393-397
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• 1999

Among various reactions which metal sulfides can undergo in the reducing environment, the lattice exchange reaction was examined in a attempt to selectively remove heavy metal ions contained in the Fe-Coagulants acid solution. We have examined Zeta potential along with pHs to investigate surface characteristics of ${FeS}_{(s)}$. As a result of this experiment, zero point charge(ZPC) of FeS is pH 7 and zeta potential which resulted from solid solution reaction between Pb(II) and ${FeS}_{(s)}$ is similar to that of ${PbS}_{(s)}$. Solubility characteristics of ${FeS}_{(s)}$ is appeared to that dissolved Fe(II) concentration increased in less than pH 4, and also increased with increasing heavy metal concentration. Various heavy metal ions(Pb(II), Cu(II), Zn(II)) contained in Fe-coagulants acid solution were removed selectively more than ninety-five percent in the rang of pH 2.5~10 by ${FeS}_{(s)}$. From the above experiments, therefore, We could know that the products of reaction between heavy metal ions and $FeS_{(S)}$ are mental sulfide such as $PbS_{(S)}$, $CuS_{(S)}$ and $ZnS_{(S)}$.

• 한국응용과학기술학회지
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• 제15권3호
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• pp.13-19
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• 1998

This study was carried out to investigate characteristics and Pb(II) removal effect of natural Muan, Seosan, Kangjin clays in the batch mode test to develope the low-priced treatment agent of wastewater which contain heavy metals in order structural, optical properties and chemical compositions of natural clays from domestic have been investigated to have high specific surface area and have minerals such as $SiO_2$ and $Al_2O_3$. As a result, removal effects of Pb(II) ions on clays were reached at equilibrium in aqueous solutions by stirring about 20minutes. The removal effect of Pb(II) ions was best for Seosan clay than Muan or Kangjin clays in terms of fixed time. The results show the possibility of continuous treatment system of wastewater which contain heavy metals by using natural clays from domestic.