• Nuclear Engineering and Technology
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• 제41권8호
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• pp.1101-1108
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• 2009

The ocean contains around eighty elements of the periodic table and uranium is also one among them, with a uniform concentration of 3.3 ppb and a relative abundance factor of 23. With a large coastline, India has a large stake in exploiting the 4 billion tonnes of uranium locked in seawater. The development of radiation grafting techniques, which are useful in incorporating the required functional groups, has led to more efficient adsorbent preparations in various geometrical configurations. Separation based on a polymeric adsorbent is becoming an increasingly popular technique for the extraction of trace heavy metals from seawater. Radiation grafting has provided definite advantages over chemical grafting. Studies related to thermally bonded non woven porous polypropylene fiber sheet substrate characterization and parameters to incorporate specific groups such as acrylonitrile (AN) into polymer back bones have been investigated. The grafted polyacrylonitrile chains were chemically modified to convert acrylonitrile group into an amidoxime group, a chelating group responsible for heavy metal uptake from seawater/brine. The present work has been undertaken to concentrate heavy metal ions from lean solutions from constant potential sources only. A scheme was designed and developed for investigation of the recovery of heavy metal ions such as uranium and vanadium from seawater.

• 한국환경과학회지
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• 제7권6호
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• pp.803-809
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• 1998

Heavy metal ions in water were removed using algal biomass as adsorbents. Absorbents were dried for 3 days, ground them by 40~60 mesh and then were swelled in a buffer solution for 1hr. After being packed in the column, commercially available standard solution of Cd(II) and Pb(II) ions were diluted to get the suitable concentration and then it was eluted with the rate of 1mι/min. Heavy metals on the adsorbents were recovered with nitric acid. More amounts of Cd(II) or Pb(II) ions in green algae, Ulva pertusa, than in brown algae, Sargassum horneri, were adsorbed. Pb(II) ion was adsorbed more than Cd(II) ion in both algae. The pH effect of adsorbed amounts of Cd(II), Pb(II) ions on the biomass was shown the following order ; pH 10.5 ＞ 8.5 ＞ 7.0 ＞ 5.5 ＞ 3.5. Recovery ratio of metal ions front algae is shown higher in acidic or neutral conditions than it in alkalic ones. Pb(II) ion is recovered relatively more than Cd(II) ion in our system.

• 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.

• 분석과학
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• 제14권6호
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• pp.530-534
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• 2001

Effect of stripping solutions on the Duolite GT-73 chelating resin for ten elements, Ag(I), Al(III), Ca(II), Cd(II), Cu(II), Fe(II), Hg(II), Mn(II), Pb(II), and Zn(II), was investigated. Relation between affinities of the metal ions and solubility products of metal sulfides was studied. The smaller the solubility product of metal sulfideis, the larger the affinitie with the ionsis. The ions which have the solubility products larger than $10^{-23}$ could be effectively desorbed with nitric acid. Complexation with chloride ion enhanced the desorption efficiencies of the ions having moderately strong affinity with the resin. The ions which have very strong affinity by the chelating resin can be desorbed by complextion with thiourea and hydrochloric acid.

• Korean Chemical Engineering Research
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• 제53권2호
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• pp.243-246
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• 2015

색센서는 액상 내 존재하는 특정 물질에 대하여 선택적인 색상변화를 통하여 대상물질을 검지할 수 있다. 기존 유기염료를 이용한 색센서는 단일종의 중금속 이온만을 검지한다는 단점이 있지만, 디티존(dithizone, DTZ)은 최소 5개 이상의 중금속 이온을 서로 다른 색상 변화로 검지해 낼 수 있다는 장점이 있다. 즉 다중검지용 색센서 물질로 사용할 수 있다. 그러나 디티존은 액상에서 주로 사용되어서 종이나 분말형태로 제조된 사례가 없어서 활용범위가 제한적이다. 이에 본 연구에서는 폴리스티렌(polystyrene, PS)과 디티존을 결합시켜 DTZ/PS 펠렛을 제조하여 10가지 중금속 이온에 대한 선택적인 색상변화를 관찰하였다. 제조한 DTZ/PS 펠렛에 대하여 10 ppm의 중금속 이온의 노출 결과, 수은과 코발트가 뚜렷한 색상 변화를 보였으며 선택적인 중금속 이온 검지에 활용할 수 있음을 확인하였다.

• Journal of the Korean Wood Science and Technology
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• 제12권3호
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• pp.9-14
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• 1984

The removal and readsorption effects of pine and oak bark grown in Korea on water pollution caused by heavy metal ions have been investigated. Bark saturated with heavy metal ions is refleshed with 0.1 N ammonium acetate and then its readsorption has been done. The results obtained are as follows: 1. Adsorption effect of pine bark is similiar to that of oak bark, and 20-40 meshed bark gives the best results. 2. 0.1 N amonium acetate of pH 7 shows more elutriative than the others such as pH 3 hydrochloric acid, pH 10 ammonium hydroxide and pH 7 water. 3 Pine bark refleshed with 0.1 N ammonium acetate gets two times as effective in adsorption as raw bark, and shows more effective than oak bark.

• 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.

• 산업기술연구
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• 제27권A호
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• pp.19-24
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• 2007

This research was done for possible treatment of impermeable surfaces rainwater runoff containing heavy metal ions by manganese oxide coated on polypropylene support. Manganese oxide was coated by Birnessite Coating Methods(BCM)and the coating analyzed by SEM and FT-IR techniques. The efficiency of heavy metal ions adsorption was also assessed via both batch and column tests. Adsorption efficiencies of Cd, Zn, Cu, and Pb were 99.4%, 98.9%, 96.7%, and over 95.7%, respectively. The adsorption progress pattern reveals quite fast adsorption at initial periods of treatment and change to slower rates at later times.

• 공업화학
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• 제34권5호
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• pp.556-565
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• 2023

Fast industrial and agricultural expansion result in the production of heavy metal ions (HMIs). These are exceedingly hazardous to both humans and the environment, and the necessity to eliminate them from aqueous systems prompts the development of novel materials. In the present study, a UIO-66 (COOH)₂ metal-organic framework (MOF) containing free carboxylic acid groups was post-synthetically modified with L-glutamic acid via the solid-solid reaction route. Pristine and glutamic acid-treated MOF materials were characterized in detail using several physicochemical techniques. Single-ion batch adsorption studies of Pb(II) and Hg(II) ions were carried out using pristine as well as amino acid-modified MOFs. We further examined parameters that influence removal efficiency, such as the initial concentration and contact time. The bare MOF had a higher ion adsorption capacity for Pb(II) (261.87 mg/g) than for Hg(II) ions (10.54 mg/g) at an initial concentration of 150 ppm. In contrast, an increased Hg(II) ion adsorption capacity was observed for the glutamic acid-modified MOF (80.6 mg/g) as compared to the bare MOF. The Hg(II) ion adsorption capacity increased by almost 87% after modification with glutamic acid. Fitting results of isotherm and kinetic data models indicated that the adsorption of Pb(II) on both pristine and glutamic acid-modified MOFs was due to surface complexation of Pb(II) ions with available -COOH groups (pyromellitic acid). Adsorption of Hg(II) on the glutamic acid-modified MOF was attributed to chelation, in which glutamic acid grafted onto the surface of the MOF formed chelates with Hg(II) ions.

• Bulletin of the Korean Chemical Society
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• 제23권8호
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• pp.1169-1172
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• 2002