pH-Dependent Leaching Characteristics of Major and Toxic Elements from Red Mud

Cui, Yulong; Chen, Jiannan; Zhang, Hongjie; Peng, Daoping; Huang, Tao; Sun, Chunwei

doi:10.3390/ijerph16112046

Cited by 50 publications

(32 citation statements)

References 54 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Leaching of Pb is controlled by Pb (OH) 2 in accordance with previous studies appearing on the literature [57,60]. Such a mechanism corresponds to cationic element mobilizing in the form of Pb +2 .…”

Section: Geochemical Modelingsupporting

confidence: 89%

“…The adsorption due to iron has a different effect on the elements studied, although it is mainly reflected by retaining the metal by surface adsorption and decreasing its concentration in the leachate [58]. This behavior differs from that of other wastes whose Fe content is lower, and whose leaching is described by solubility-precipitation models [57,59], especially at alkaline pH [60]. Elements that are close to oxygen in electronegativity tend to form oxyanions i.e., the transition metal Mo which from MoO 2− 4 [58].…”

Section: Geochemical Modelingmentioning

confidence: 92%

See 1 more Smart Citation

Coal Fly Ash–Clay Based Geopolymer-Incorporating Electric Arc Furnace Dust (EAFD): Leaching Behavior and Geochemical Modeling

et al. 2021

View full text Add to dashboard Cite

The recent recovery processes of electric arc furnace dust (EAFD) include stabilization within materials with potential uses in the construction sector. The stabilization of EAFD by alkaline activation of different alumina-silicates, resulting in low-cost and environmentally friendly materials. The leaching standards within the different European regulations allow evaluating waste materials and products. This work aims to study the introduction of EAFD in FA–clay geopolymers, assessing the environmental and geochemical behavior in two different scenarios, disposal, and utilization. For it, the compliance equilibrium-based batch test (EN 12457-2) and pH dependence test (EN 14429) have been used. The dosages of EAFD in the geopolymeric matrix are 5% to 20% with curing temperatures of 75 °C and 225 °C. The introduction of EAFD favors the development of the flexural strength. From the environmental point of view, metals related to EAFD, such as Zn, Pb, or Cu, are retained in the matrix. While As or Se, comes mainly from clay, present a high concentration. Therefore, the role of clay should be analyzed in future research. As expected by the high iron content in the EAFD, the iron complexes on the surface of the material are responsible for immobilization of metals in this type of matrix.

show abstract

Section: Geochemical Modelingsupporting

confidence: 89%

Section: Geochemical Modelingmentioning

confidence: 92%

Coal Fly Ash–Clay Based Geopolymer-Incorporating Electric Arc Furnace Dust (EAFD): Leaching Behavior and Geochemical Modeling

et al. 2021

View full text Add to dashboard Cite

show abstract

“…Red mud has an alkaline nature because of the presence of NaOH, a strong base used in producing alumina [ 72 ]. The high alkalinity of red mud can increase pH drastically as we observed in this study.…”

Section: Discussionmentioning

confidence: 99%

Oyster Shell Powder, Zeolite and Red Mud as Binders for Immobilising Toxic Metals in Fine Granular Contaminated Soils (from Industrial Zones in South Korea)

Torres-Quiroz

Dissanayake

Park

2021

IJERPH

View full text Add to dashboard Cite

Low-cost absorbent materials have elicited the attention of researchers as binders for the stabilisation/solidification technique. As, there is a no comprehensive study, the authors of this paper investigated the performance of Oyster shell powder (OS), zeolite (Z), and red mud (RM) in stabilising heavy metals in three types of heavy metal-contaminated soils by using toxicity characteristic leaching procedure (TCLP). Samples were collected from surroundings of an abandoned metal mine site and from military service zone. Furthermore, a Pb-contaminated soil was artificially prepared to evaluate each binder (100× regulatory level for Pb). OS bound approximately 82% of Pb and 78% of Cu in real cases scenario. While Z was highly effective in stabilizing Pb in highly polluted artificial soil (>50% of Pb) at lower dosages than OS and RM, it was not effective in stabilising those metals in the soils obtained from the contaminated sites. RM did not perform consistently stabilising toxic metals in soils from contaminated sites, but it demonstrated a remarkable Pb-immobilisation under dosages over than 5% in the artificial soil. Further, authors observed that OS removal efficiency reached up to 94% after 10 days. The results suggest that OS is the best low-cost adsorbent material to stabilize soils contaminated with toxic metals considered in the study.

show abstract

“…The conditions were chosen to reflect potential application as a reactive lining material where the infiltrating moisture was acidic. A pH of 4.2 was selected for the testing as it represented the pH of acid rain, furthermore it was noted that at a pH of 4.2 initiated the maximum release of heavy metals (Cui et al., 2019).…”

Section: Introductionmentioning

confidence: 99%

Determining distribution coefficients for low cost adsorbents

Das

Alibrandi²

2021

Remediation Journal

View full text Add to dashboard Cite

As with other construction materials, coal fly ash contains trace metals that can leach into the natural environment. As part of a broader effort to encourage appropriate coal combustion product use in infrastructure applications (e.g., road construction, stabilization, and structural fill), this study evaluated traditional and low-cost adsorbent alternatives for their capacity to attenuate trace metals. Batch sorption tests were used as a preliminary screen for a wide variety of low cost (e.g., steel byproducts, rubber dust, and compost) and innovative materials (e.g., kudzu, biofilm, and pond weed) as well as conventional materials (activated carbon, alumina, and zeolites). The removal rates were demonstrated in this study by observing the calculated distribution coefficient (K d) which were determined using a program called MATLAB. Limestone and steel byproducts were found to be particularly effective with large K d values of 15,740, 1,520, and 540 L kg −1 for cadmium, chromium, and selenium and, for ladle refractory and mill scale, K d values of 3,910, 670, and 1,760 L kg −1 were observed. Among the three metals tested for this study, it was observed that most low cost and innovative materials removed cadmium quite efficiently; however, the removal of selenium and chromium depended on the substrate and prevailing pH. In general, these results suggest that alternative materials may have relevance in niche applications where leaching is a concern that can be addressed through enhanced attenuation capacity via blending or layering of adsorbents. K E Y W O R D S distribution coefficients, heavy metals, low cost adsorbents, MATLAB 1 | INTRODUCTION Coal fly ash (CFA) is commonly used in structural fills and embankments, with such applications representing second only to concrete in terms of amount used (ACAA, 2016). A structural fill or embankment may be defined as a raised mass of material that is used as part of an engineered facility (USEPA, 2013). When used in these applications, CFA is typically placed in direct contact with existing soil or even after excavation. Fill materials can be used for a variety of different applications such as roadways, earth retaining walls, abutments for bridges, and even parking lots. Fill material is generally required to raise the height of the existing topography to some design elevation. CFA is particularly attractive as a fill material because of its low unit weight and reasonably high strength. Less weight translates into less deflection or settlement in each application. It has been observed that the mechanical properties of a Class F CFA are similar to those of natural sandy soils (Kim & Prezzi, 2008). Numerous projects have been completed using CFA without geotechnical or environmental concerns. For example, the Federal Highway Administration (FHWA) summarized data from 21 construction projects that used two million or more cubic yards of fly ash without any significant adverse environmental concern (FHWA, 1998). Many other product categories involve placing or blending ...

show abstract

pH-Dependent Leaching Characteristics of Major and Toxic Elements from Red Mud

Cited by 50 publications

References 54 publications

Coal Fly Ash–Clay Based Geopolymer-Incorporating Electric Arc Furnace Dust (EAFD): Leaching Behavior and Geochemical Modeling

Coal Fly Ash–Clay Based Geopolymer-Incorporating Electric Arc Furnace Dust (EAFD): Leaching Behavior and Geochemical Modeling

Oyster Shell Powder, Zeolite and Red Mud as Binders for Immobilising Toxic Metals in Fine Granular Contaminated Soils (from Industrial Zones in South Korea)

Determining distribution coefficients for low cost adsorbents

Contact Info

Product

Resources

About