Comparisons of metal leachability for various wastes by extraction and leaching methods

Chang, E. E.; Chiang, Pen‐Chi; Lu, Pi‐Hsien; Ko, Ya‐Wen

doi:10.1016/s0045-6535(01)00002-9

Cited by 72 publications

(32 citation statements)

References 4 publications

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“…Many testing procedures have been developed to simulate the leaching process of hazardous wastes in landfill or natural environments in order to evaluate the possibility of human health hazard threats by such wastes (Brunori et al, 2001;Chang et al, 2001), because the potential risk of heavy metals in solid waste, with respect to their mobility and ecotoxicological significance, is determined by their solid-solution partitioning rather than the total heavy metal content. Among various factors affecting leaching of metals from fly ash, pH and temperature might play major roles in leaching of metals.…”

Section: Introductionmentioning

confidence: 99%

Temperature and pH Dependence of Some Metals Leaching from Fly Ash of Municipal Solid Waste

Gupta¹,

Kawahata²,

Takeuchi³

et al. 2005

Resource Geology

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Abstract. Municipal solid waste combustion leads to concentration of various metals in the solid residue (fly ash) remaining after combustion. These metals pose serious environmental hazard and require proper handling and monitoring in order to control their harmful effects. Leachability of some metals from fly ash was examined in fly ash and Milli‐Q water mixture (liquid‐to‐solid ratio, 100) under various temperature and pH conditions in the laboratory. The leaching experiments conducted for 24 hours showed that pH was generally more important than temperature in controlling the amount of metals leached out of the fly ash. However, at a given pH, rise in temperature led to different degree of (usually one to two fold) enhanced or reduced leaching of metals. Owing to amphoteric nature of oxides of Al, Cr, Pb and Zn, these metals often yielded typical pattern of increase and decrease in their concentrations with change in pH. The extent of leaching of Cr and Pb in our experiments suggests that decrease of pH to acidic range in the case of Pb and to neutral to acidic range for Cr over a long period of storage of fly ash at solid waste dumping site may facilitate leaching of these metals from fly ash, leading to contamination of groundwater to the level that exceeds beyond the level permitted by the environmental laws.

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Section: Introductionmentioning

confidence: 99%

Temperature and pH Dependence of Some Metals Leaching from Fly Ash of Municipal Solid Waste

Gupta¹,

Kawahata²,

Takeuchi³

et al. 2005

Resource Geology

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“…The degree of mobilisation and dissolution of the constituents in the leachate is of interest for different purposes such as waste treatment and disposal, soil clean-up and reuse of cleaned soil, sludge treatment and use of secondary materials in construction (van der Sloot, Heasman, & Quevauviller, 1997). Leaching tests are widely used (for example Benito, Ruiz, Cosmen, & Merino, 2001;Chang, Chiang, Lu, & Ko, 2001;Choi, Lee, Song, & Moon, 2002;Dreesen et al, 1977;Eighmy et al, 1995;Fytianos & Tsaniklidi, 1998;Janos, Wildnerova, & Loucka, 2002;Kim, Kazonich, & Dahlberg, 2003;Querol et al, 2001) as indicators to estimate the release potential of these elements from fly ash in order to assess environmental impacts of utilisation or deposition of the fly ash under laboratory conditions. In general, possible reasons for carrying out a leaching test for coal fly ash are (Jones, 1995):…”

mentioning

confidence: 99%

Design of a Leaching Test Framework for Coal Fly Ash Accounting for Environmental Conditions

Zandi

Russell

2006

Environ Monit Assess

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Fly ash from coal combustion contains trace elements which, on disposal or utilisation, may leach out, and therefore be a potential environmental hazard. Environmental conditions have a great impact on the mobility of fly ash constituents as well as the physical and chemical properties of the fly ash. Existing standard leaching methods have been shown to be inadequate by not representing possible disposal or utilisation scenarios. These tests are often criticised on the grounds that the results estimated are not reliable as they are not able to be extrapolated to the application scenario. In order to simulate leaching behaviour of fly ash in different environmental conditions and to reduce deviation between measurements in the fields and the laboratories, it is vital to study sensitivity of the fly ash constituents of interest to major factors controlling leachability. pH, liquid-to-solid ratio, leaching time, leachant type and redox potential are parameters affecting stability of elements in the fly ash. Sensitivity of trace elements to pH and liquid to solid ratio (as two major overriding factors) has been examined. Elements have been classified on the basis of their leaching behaviour under different conditions. Results from this study have been used to identify leaching mechanisms. Also the fly ash has been examined under different standard batch leaching tests in order to evaluate and to compare these tests. A Leaching Test Framework has been devised for assessing the stability of trace elements from fly ashes in different environments. This Framework assists in designing more realistic batch leaching tests appropriate to field conditions and can support the development of regulations and protocols for the management and disposal of coal combustion by-products or other solid wastes of environmental concern.

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“…In the United States, TCLP has generally been used as a general method for assessing the toxicity of contaminants in ecosystems [3,31,30]. The detailed leaching procedures of the average soil samples and incinerated soil samples included the following: (1) two different buffered acidic leaching extraction fluids (Fluid 1: CH 3 COOH, pH 4.93 AE 0.05 for sample pH < 5 and Fluid 2: CH 3 COOH, pH 2.88 AE 0.05 for pH > 5) were prepared for TCLP.…”

Section: Tclp Leaching Experimentsmentioning

confidence: 99%

“…[6,2,5,18,19,21]. Chemical leaching may destroy the soil structure and may require the addition of some inorganic acids (e.g., H 2 SO 4 , HNO 3 , HCl), organic acids (e.g., citric acid, malic acid, oxalic acid) or organic chelating agents (e.g., EDDS, EDTA) [2,36], which may lead to secondary pollution. Heavy metals in contaminated soils may be transported to ambient environment through biochemical processes if these soils are covered by unpolluted soils.…”

Section: Introductionmentioning

confidence: 99%

Influence of thermal treatment on fixation rate and leaching behavior of heavy metals in soils from a typical e-waste processing site

Wang

Quan

et al. 2016

Journal of Environmental Chemical Engineering

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Comparisons of metal leachability for various wastes by extraction and leaching methods

Cited by 72 publications

References 4 publications

Temperature and pH Dependence of Some Metals Leaching from Fly Ash of Municipal Solid Waste

Temperature and pH Dependence of Some Metals Leaching from Fly Ash of Municipal Solid Waste

Design of a Leaching Test Framework for Coal Fly Ash Accounting for Environmental Conditions

Influence of thermal treatment on fixation rate and leaching behavior of heavy metals in soils from a typical e-waste processing site

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