• Title/Summary/Keyword: adsorption separation of metals

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Removal of Se(IV) by the Fe(III)-impregnated Sea sand - Zeta potential approach to depict the binding between Fe(III) and Sea sand (표면 처리한 Sea sand를 이용한 Se(IV) 제거 - Zeta potential을 통한 Fe(III)간의 반은 메카니즘 연구)

  • 박상원;강혜정
    • Journal of Environmental Science International
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    • v.8 no.2
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    • pp.205-209
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    • 1999
  • Iron hydroxides are good adsorbents for uncomplexed metals, some metal-ligand complexes and many metal oxyanions. However, their adsorption properties of these precipitations are not fully exploited in wastewater treatment operations because of difficulties associated with their separation from the aqueous phase. This study describes experiments in which iron hydroxides were coated onto the surface of ordinary adsorbents(Sea sand) that are very resistant to acids, The coated adsorbents were used in adsorption of oxyanionic metals. The process was successful in removing some anions such as $SeO_3(-II)$ over a wide range of metal concentrations and sorption of oxyanionic metals increased with decreasing pH. Formation of two surface complexes for oxyanionic metals adsorption on iron hydroxides comprise (1) complexation of the free anion by a positively charged surface site, and (2) protonation of the adsorbed anion (or alternatively adsorption of a protonated form from solution) The coated adsorbents are inexpensive to prepare and could serve as the basis of a useful oxyanionic metal removal.

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Adsorption behavior of platinum-group metals and Co-existing metal ions from simulated high-level liquid waste using HONTA and Crea impregnated adsorbent

  • Naoki Osawa;Seong-Yun Kim;Masahiko Kubota;Hao Wu;Sou Watanabe;Tatsuya Ito;Ryuji Nagaishi
    • Nuclear Engineering and Technology
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    • v.56 no.3
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    • pp.812-818
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    • 2024
  • The volume and toxicity of radioactive waste can be decreased by separating the components of high-level liquid waste according to their properties. An impregnated silica-based adsorbent was prepared in this study by combining N,N,N',N',N",N"-hexa-n-octylnitrilotriacetamide (HONTA) extractant, N',N'-di-n-hexyl-thiodiglycolamide (Crea) extractant, and macroporous silica polymer composite particles (SiO2-P). The performance of platinum-group metals adsorption and separation on prepared (HONTA + Crea)/SiO2-P adsorbent was then assessed together with that of co-existing metal ions by batch-adsorption and chromatographic separation studies. From the batch-adsorption experiment results, (HONTA + Crea)/SiO2-P adsorbent showed high adsorption performance of Pd(II) owing to an affinity between Pd(II) and Crea extractant based on the Hard and Soft Acids and Bases theory. Additionally, significant adsorption performance was observed toward Zr(IV) and Mo(VI). Compared with studies using the Crea extractant, the high adsorption performance of Zr(IV) and Mo(VI) is attributed to the HONTA extractant. As revealed from the chromatographic experiment results, most of Pd(II) was recovered from the feed solution using 0.2 M thiourea in 0.1 M HNO3. Additionally, the possibility of recovery of Zr(IV), Mo(VI), and Re(VII) was observed using the (HONTA + Crea)/SiO2-P adsorbent.

Formation of iron oxides from acid mine drainage and magnetic separation of the heavy metals adsorbed iron oxides

  • Kwon, Hee-won;Kim, JeongJin;Ha, Dong-Woo;Kim, Young-Hun
    • Progress in Superconductivity and Cryogenics
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    • v.18 no.1
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    • pp.28-32
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    • 2016
  • There are a few thousand abandoned metal mines in South Korea. The abandoned mines cause several environmental problems including releasing acid mine drainage (AMD), which contain a very high acidity and heavy metal ions such as Fe, Cu, Cd, Pb, and As. Iron oxides can be formed from the AMD by increasing the solution pH and inducing precipitation. Current study focused on the formation of iron oxide in an AMD and used the oxide for adsorption of heavy metals. The heavy metal adsorbed iron oxide was separated with a superconducting magnet. The duration of iron oxide formation affected on the type of mineral and the degree of magnetization. The removal rate of heavy metal by the adsorption process with the formed iron oxide was highly dependent on the type of iron oxide and the solution pH. A high gradient magnetic separation (HGMS) system successfully separated the iron oxide and harmful heavy metals.

Fundamental study on volume reduction of heavy metal-contaminated soil by magnetic separation

  • Konishi, Yusuke;Akiyama, Yoko;Manabe, Yuichiro;Sato, Fuminobu
    • Progress in Superconductivity and Cryogenics
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    • v.22 no.2
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    • pp.1-6
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    • 2020
  • Large-scale civil engineering works discharge a large amount of soil suspension contaminated with natural heavy metals. Most of the heavy metal ions due to industrial activities and minings are accumulated in the soils and the sediments of lakes and inner bays through the rivers. It is necessary to remove heavy metals from the soils and the sediments, because some of these heavy metals, such as arsenic and cadmium, have significant biological effects even in small amounts. This study proposes a new volume reduction method of the contaminated soils and sediments by superconducting magnetic separation. Our process can remove the specific minute minerals selectively, which adsorbs heavy metals depending on pH. As a fundamental study, the adsorption behaviors of arsenic and cadmium on minute minerals as a function of pH were investigated, and the adsorption mechanism was discussed based on the crystal structure and pH dependence of surface potential in each minute minerals.

Removal of heavy metals using waste sludge by biosorptive flotation (폐슬러지를 이용한 흡착·부상 공정에 의한 중금속 제거)

  • Lee Chang-Han;Ahn Kab-Hwan
    • Journal of Environmental Science International
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    • v.14 no.7
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    • pp.691-697
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    • 2005
  • Waste sludge may be used to recovery wastewater contaminated with heavy metals. The waste sludge is an inexpensive readily available source of biomass for biosorption with metal-bearing wastewater. The biosorption of heavy metals such as Pb(II), Cu(II), Cr(II), and Cd(II) onto waste sludge was investigated in batch ex­periments and waste sludge loaded heavy metals was separated by dissolved air flotation. The biosorption equi­bria of heavy metals could be described by Langmuir and Freundich isotherms. The adsorption capacity for waste sludge was in the sequence of Pb(II)>Cr(II)>Cu(II)>Cd(II). The system attained equilibrium about 20 min. The Langmuir and Freundlich adsorption model effectively described the biosorption equilibrium of Cu(II) and Cr(II) ions on waste sludge. Maximum adsorption capacity of Cu(II) and Cr(II) were 196.08 and 158.73 mg/g, respectively. Solid-liquid separation efficiencies were kept above $95\%$ on waste sludge loaded heavy metals, and were decreased with pH increasing.

Pd-based metallic membranes for hydrogen separation and production

  • Tosti, Silvano;Basile, Angelo
    • Proceedings of the Membrane Society of Korea Conference
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    • 2003.07a
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    • pp.25-28
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    • 2003
  • Low cost composite metallic membranes for the hydrogen separation and production have been prepared by using thin Pd-Ag foils reinforced by metallic (stainless steel and nickel) structures. Especially, “supported membranes” have been obtained by a diffusion welding procedure in which Pd-Ag thin foils have been joined with perforated metals (nickel) and expanded metals (stainless steel): in these membranes the thin palladium foil assures both the high hydrogen permeability and the perm-selectivity while the metallic support provides the mechanical strength. A second studied method of producing "laminated membranes" consists of coating non-noble metal sheets with very thin palladium layers by diffusion welding and cold-rolling. Palladium thin coatings over these metals reduce the activation energy of the hydrogen adsorption process and make them permeable to the hydrogen. In this case, the dense non-noble metal has been used as a support structure of the thin Pd-Ag layers coated over its surfaces: a proper thickness of the metal assures the mechanical strength, the absence of defects (cracks, micro-holes) and the complete hydrogen selectivity of the membrane. membrane.

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Feasibility Study with Several Sorption Materials to Treat Road Runoff Pollutions (흡착 소재별 도로 노면 유출 오염원의 저감성 비교 연구)

  • Park, Sangwoo;Oh, Jeill;Choi, Younghwa
    • Journal of Korean Society of Water and Wastewater
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    • v.20 no.5
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    • pp.709-717
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    • 2006
  • This research was conducted to figure out the feasibility of several sorption materials to treat various pollutants in road runoff. In advance of the major feasibility test with various sorption materials, the separation process with $1.2{\mu}m$ filter was conducted and showed that slight portion of pollutants was removed(Orgamic pollutant - 20%, Nutrient salt - 50%, Heavy metals - 0~30%). To remove dissolved pollutants in runoff, various materials were tested through an isotherm sorption experiment. As a result, GAC showed most effective material among them to lessen most contaminants such as organic compounds and nutrients. On the other hand, ion-exchange resin and Zeolite showed limited usefulness on the some heavy metals. Freundlich model was most suitable for the current experiment data, and the amount of adsorbent (GAC) could calculated based on this model.

Separation of cadmium and chromium heavy metals from industrial wastewater by using Ni-Zn nanoferrites

  • Thakur, Atul;Punia, Pinki;Dhar, Rakesh;Aggarwal, R.K.;Thakur, Preeti
    • Advances in nano research
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    • v.12 no.5
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    • pp.457-465
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    • 2022
  • The potentials of NixZn1-xFe2O4 (x = 0.0, 0.2, 0.4, 0.6, 0.8 and 1.0) nanoadsorbents were investigated for removal of Cd and Cr from contaminated water from an electroplating industry in Himachal Pradesh, India. Optimal values were recorded under batch adsorption experiments performed to remove dissolved heavy metal ions from industrial wastewater. The specific surface area (SSA) of nanoadsorbents perceived to vary in a range 35.75-45.29 cm2/g and was calculated from the XRD data. The influence of two operating parameters, contact time and dopant (Ni) concentration was also investigated at pH ~7 with optimum dosage. Kinetic studies were conducted within a time range of 2-10 min with rapid adsorption of cadmium and chromium ions onto Ni0.2Zn0.8Fe2O4 nanoadsorbents. Pseudo-second-order kinetic model was observed to be well fitted with the adsorption data that confirmed the only existence of chemisorption throughout the adsorption process. The maximum adsorption efficiency values observed for Cd and Cr were 51.4 mg/g and 40.12 mg/g, respectively for different compositions of prepared series of nanoadsorbents. The removal percentage of Cd and Cr was found to vary in a range of 47.7%-95.25% and 21%-50% respectively. The prepared series of nanoferrite found to be suitable enough for adsorption of both heavy metal ions.

Adsorption and Preconcentration of Some Heavy Metals by Resorcinol-Formaldehyde Resin (Resorcinol-formaldehyde 수지에 의한 중금속 이온의 흡착과 농축)

  • Park, Chan-Il;Cha, Ki-Won
    • Analytical Science and Technology
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    • v.11 no.3
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    • pp.174-178
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    • 1998
  • A chelating resin was prepared by the reaction of formaldehyde and resorcinol. It possesses high adsorption selectivity for transition metal ions such as Pb(II) and Ni(II). The adsorption and desorption yields of Pb(II), Ni(II), Co(II), Fe(II) and Zn(II) were determined using batch method. The significant characteristics of the chelating resin is the exchange processes between its hydrogen and metal ions. The mechanism of metal adsorption and desorption seems to be the competing protonation and complexation reaction of the functional group of the resin. This resin was applied to the rapid concentration of trace amounts of these metal ions and to the separation of Pb(II) from other metal ions in bulk solution.

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Effective Use of Orange Juice Residue for Removing Heavy and Radioactive Metals from Environments

  • Inoue, Katsutoshi;Zhu, Yushan;Ghimire, Kedar-Nath;Yano, Masayuki;Makino, Kenjiro;Miyajima, Tohru
    • Proceedings of the IEEK Conference
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    • 2001.10a
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    • pp.264-269
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    • 2001
  • Large amounts of orange juice are produced in Japan every yea.. Accompanied by the production of orange juice, large amount of juice residues are also generated in nearly the same amounts with juice. Although, at present, some of these residues are marketed as a feed for cattle after drying and mixing with lime, the marketing price is lower than its production cost and the difference is paid by the consumers as a part of the price of orange juice. In the present work, we developed new innovative use of orange juice residue, a biomass waste, as adsorption gel for removing toxic heavy metals such as lead. arsenic, selenium and so on as well as radioactive elements such as uranium and thorium from environments. The major components of orange juice residue are cellulose. hemicellulose and pectin, which are converted into pectic. acid, an acidic polysaccharide, by means of saponification with concentrated sodium hydroxide solution. In the previous work, we found that crosslinked pectic acid gel strongly an selectively adsorbs lead over other metals such as zinc an copper. On the other hand. it is well known that polysaccharides such as cellulose can be easily phosphorylated and that phosphorylated polysaccharides have high affinity to uranium and thorium as well as some trivalent metals such as ferric iron and aluminum. Taking account of the noticeable characteristics of these polysaccharides, 2 types of adsorption gels were prepared from orange juice residue: one is the gel which was prepared by saponificating the residue followed by crosslinking with epichlorohydrin and another is that prepared by crosslinking the residue followed by phosphorylation. The former gel exhibited excellent adsorptive separation behavior for lead away from zinc owing to high content of pectic acid while the latter gel exhibited that for uranium and thorium. Both types of adsorption gels exhibited high affinity to ferric iron, which enables selective and strong adsorption for some toxic oxo-anions of arsenic (V and III), . selenium and so on via iron loaded on these gels. These results demonstrate that biomass wastes such as orange juice residue can be effectively utilized fer the purpose of removing toxic heavy or radioactive metals existing in trace or small amounts in environments.

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