Non-destructive separation of metal ions from wastewater containing excess aminopolycarboxylate chelant in solution with an ion-selective immobilized macrocyclic material

Hasegawa, Hiroshi; Rahman, Ismail M.M.; Kinoshita, Sanae; Maki, Teruya; Furusho, Yoshiaki

doi:10.1016/j.chemosphere.2010.01.065

Cited by 37 publications

(18 citation statements)

References 44 publications

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“…Soil decontamination by washing treatment can be accomplished through either in situ or ex situ operations. Aminopolycarboxylate chelants (APCs) such as, EDTA and its homologs are commonly utilized in the ex situ soil washing processes due to their ability to interact with the majority of toxic metals (Leštan et al, 2008;Hasegawa et al, 2010;Hasegawa et al, 2011). However, the ecoenvironmental consequences due to the release of APCs to the surroundings become an issue of concern .…”

Section: Introductionmentioning

confidence: 99%

Remediation of toxic metal contaminated soil by washing with biodegradable aminopolycarboxylate chelants

et al. 2012

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Ex situ soil washing with synthetic extractants such as, aminopolycarboxylate chelants (APCs) is a viable treatment alternative for metal-contaminated site remediation. EDTA and its homologs are widely used among the APCs in the ex situ soil washing processes. These APCs are merely biodegradable and highly persistent in the aquatic environments leading to the post-use toxic effects.Therefore, an increasing interest is focused on the development and use of the eco-friendly APCs having better biodegradability and less environmental toxicity. The paper deals with the results from the lab-scale washing treatments of a real sample of metal-contaminated soil for the removal of the ecotoxic metal ions (Cd, Cu, Ni, Pb, Zn) using five biodegradable APCs, namely [S,S]-ethylenediaminedisuccinic acid, imminodisuccinic acid, methylglycinediacetic acid, DL-2-(2-carboxymethyl)nitrilotriacetic acid (GLDA) and 3-hydroxy-2,2'-iminodisuccinic acid. The performance of those biodegradable APCs was evaluated for their interaction with the soil mineral constituents in terms of the solution pH and metal-chelant stability constants, and compared with that of EDTA. Speciation calculations were performed to identify the optimal conditions for the washing process in terms of the metal-chelant interactions as well as to understand the selectivity in the separation ability of the biodegradable chelants towards the metal ions. A linear relationship between the metal extraction capacity of the individual chelants towards each of the metal ions from the soil matrix and metal-chelant conditional stability constants for a solution pH greater than 6 was observed. Additional considerations were derived from the behavior of the major potentially interfering cations (Al, Ca, Fe, Mg, and Mn), and it was hypothesized that use of an excess of chelant may minimize the possible competition effects during the single-step washing treatments.Sequential extraction procedure was used to determine the metal distribution in the soil before and after the extractive decontamination using biodegradable APCs, and the capability of the APCs in removing the metal ions even from the theoretically immobilized fraction of the contaminated soil was observed. GLDA appeared to possess the greatest potential to decontaminate the soil through ex situ washing treatment compared to the other biodegradable chelants used in the study. KeywordsSoil remediation; Toxic metals; Ex situ washing; Aminopolycarboxylate chelants; Biodegradable; Sequential extraction 3 IntroductionSoil contamination with heavy metals derived from various anthropogenic activities, including agricultural practices, industrial activities and waste disposal is a worldwide concern. Soil washing is one of the few enduring treatment alternatives, which uses either or both physical and chemical processes, to confine the contaminants in soils (Peters, 1999;Dermont et al., 2008). Soil decontamination by washing treatment can be accomplished through either in situ or ex situ operations. Aminopolycarboxylate c...

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Section: Introductionmentioning

confidence: 99%

Remediation of toxic metal contaminated soil by washing with biodegradable aminopolycarboxylate chelants

et al. 2012

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“…The lower pH of EDTA in solution is also mentioned as a reason for the lesser metal extraction capability of DTPA than the EDTA [37]. Such sub-standard metal-DTPA complex formation rate compared to the NTA or EDTA was also mentioned in the literatures [38,39].…”

Section: Extraction Behavior Of the Chelants Under The Influence Of Mmentioning

confidence: 96%

“…Strong basic mesoporous and macroporous anion exchange resins (Cl -form) can be used for the sequestration of indium [16], while the chelant used for the indium extraction in the proposed process might obstruct the separation behavior of the ion-exchange resins due to the competition effect [39]. A MRT-SPE, AnaLig TE-01, showed better separation efficiency than the chelating resins and the ion-exchange resins for the separation of toxic metal ions from the washing effluent containing APCs [25].…”

Section: Isolation Of Indium From the Chelant-rich Aqueous Solutionmentioning

confidence: 99%

Chelant-induced reclamation of indium from the spent liquid crystal display panels with the aid of microwave irradiation

Hasegawa¹,

Rahman²,

Egawa³

et al. 2013

Journal of Hazardous Materials

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“…EDTA is commonly utilized among the APCs for solid waste remediation [26,27] and, hence, employed as the reference chelant to regulate the operating variables (chelant concentration, solution pH) that may influence the dissolution of indium from the ITO-glass. The extraction yield of indium increased with the increase in the EDTA concentration until 0.05 M and remain constant thereafter (Fig.…”

Section: Effect Of Chelant Concentration and Solution Phmentioning

confidence: 99%

Recovery of indium from end-of-life liquid-crystal display panels using aminopolycarboxylate chelants with the aid of mechanochemical treatment

Hasegawa

Rahman

Egawa

et al. 2013

Microchemical Journal

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The metal indium termed as 'rare' in recent days due to its increasing demand in the formulations of electronic and energy-related gadgets and scarce supply resources. Hence, the attempts to recover indium from the secondary resources, such as recycling of the indium abundant waste materials, received increasing research focus. The major indium consumption happens in the form of indium tin oxide (ITO) that used for the fabrication of liquid-crystal displays (LCD). The end-of-life LCD screens, termed as ITO-glass hereafter, are an emerging contributor to the global e-waste load and can be an impending secondary source of indium.The present work introduces a new technique for the treatment of waste ITO-glass using aminopolycarboxylate chelants (APCs) in combination with a mechanochemical treatment process. APCs are capable of forming stable complexes with the indium deposited on the ITO-glass, whereas the rate of recovery was not substantial. The mechanochemical treatment induces the destruction of crystalline structure with which the ITO fragments are attached and facilitate the increased indium dissolution with the chelants. The increase was more prominent followed by a decrease in the cumulative processing time from 24 to 6 h when the vitrified ITO-glass was simultaneously crushed and washed with the chelants. The extraction of indium was better at the acidic pH condition, and it was further intensified when the operating temperature was raised to ≥ 120 °C. Keywords:Indium; Indium tin oxide; Liquid crystal display; Waste; Recovery; Mechanochemical treatment Microchemical Journal (In Press). DOI: http://dx.doi.org/10.1016/j.microc.2012.08.010 3 IntroductionIndium has emerged as an important strategic element in electronic and energy-related industries due to its specific applications [1,2]. The most important end use of indium in recent years is to manufacture indium-tin oxide (ITO) thin film, an optoelectronic material with the characteristics of transparency to visible light, electric conduction and thermal reflection [2,3]. ITO thin film is widely used in designing liquid-crystal displays (LCD), plasma displays and solar-energy cell [3], and consume about two-third of the global indium production [4].Indium has no ore of its own and is generally found in low concentrations in some sulphide ores of zinc, copper and lead, from which it is procured as a by-product [5]. The technology revolution created an increasing demand for indium while the boom in its price is due to the policies of the nations with indium reserves (e.g. China, South Korea). Hence, the recovery of indium from the waste resources received sincere focus from the researches [4-6].The ITO-scrap resulted from the ITO ceramic target during the conversion and application of ITO thin films on glass panels using the DC magnetron sputtering process is the most potential secondary resource of indium [2,3,6,7]. The other prospective waste resources of indium are the etching waste [1,8] and the LCD powder [6,9].The end-of-life (EoL) LCDs are a gr...

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Non-destructive separation of metal ions from wastewater containing excess aminopolycarboxylate chelant in solution with an ion-selective immobilized macrocyclic material

Cited by 37 publications

References 44 publications

Remediation of toxic metal contaminated soil by washing with biodegradable aminopolycarboxylate chelants

Remediation of toxic metal contaminated soil by washing with biodegradable aminopolycarboxylate chelants

Chelant-induced reclamation of indium from the spent liquid crystal display panels with the aid of microwave irradiation

Recovery of indium from end-of-life liquid-crystal display panels using aminopolycarboxylate chelants with the aid of mechanochemical treatment

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