CCB-based encapsulation of pyrite for remediation of acid mine drainage

Bulusu, Sowmya; Aydilek, Ahmet H.; Rustagi, Neha

doi:10.1016/j.jhazmat.2007.01.035

Cited by 26 publications

(5 citation statements)

References 18 publications

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“…Further insights on the binding energy of Au and Pd after 10 cycles revealed that the AuPd alloy excellently maintained compositional and crystalline stability (Supporting Information Figure S12). In the real environment and actual wastewater, this superiority of AuPd/CNTs holds great feasibility for solving some practical problems, such as the pH fluctuation, the presence of other competitive metal ions (Fe, Cu, Pb, or Sb), 41 and the negative effects of ligands. 42 On the other hand, the AuPd/CNTs also show desirable settleability, indicating the ease of reuse and promise of economic benefits (Supporting Information Figure S11b).…”

Section: Environmental Science and Technologymentioning

confidence: 99%

Redox Conversion of Chromium(VI) and Arsenic(III) with the Intermediates of Chromium(V) and Arsenic(IV) via AuPd/CNTs Electrocatalysis in Acid Aqueous Solution

Sun

Zhang

Qin

et al. 2015

Environ. Sci. Technol.

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Simultaneous reduction of Cr(VI) to Cr(III) and oxidation of As(III) to As(V) is a promising pretreatment process for the removal of chromium and arsenic from acid aqueous solution. In this work, the synergistic redox conversion of Cr(VI) and As(III) was efficiently achieved in a three-dimensional electrocatalytic reactor with synthesized AuPd/ CNTs particles as electrocatalysts. The AuPd/CNTs facilitated the exposure of active Pd{111} facets and possessed an approximate two-electrontransfer pathway of oxygen reduction with the highly efficient formation of H 2 O 2 as end product, resulting in the electrocatalytic reduction of 97.2 ± 2.4% of Cr(VI) and oxidation of 95.7 ± 4% of As(III). The electrocatalytic reduction of Cr(VI) was significantly accelerated prior to the electrocatalytic oxidation of As(III), and the effectiveness of Cr(VI)/As(III) conversion was favored at increased currents from 20 to 150 mA, decreased initial pH from 7 to 1 and concentrations of Cr(VI) and As(III) ranging from 50 to 1 mg/L. The crucial intermediates of Cr(V) and As(IV) and active free radicals HO• and O 2 •− were found for the first time, whose roles in the control of Cr(VI)/As(III) redox conversion were proposed. Finally, the potential applicability of AuPd/CNTs was revealed by their stability in electrocatalytic conversion over 10 cycles. ■ INTRODUCTIONThe combined pollution of heavy metals in acid wastewater has become a formidable problem to environmental scientists and engineers for decades. As a consequence of improper treatment, effluents containing abundant heavy metal ions such as lead, nickel, copper, arsenic, or chromium may inflow into surface water or seep into groundwater, which pose great threats to aquatic life and drinking water sources.1,2 Thus, it is urgent to remove the heavy metals prior to their discharge into the environment.Arsenic and chromium, as priority pollutants, are highly toxic and frequently coexist with highly acidic wastewater (e.g., acid mine drainage).3 The valence states of arsenic or chromium have decisive impacts on their environmental fate and toxic effect.4,5 For example, As(III) is the most prevalent form of arsenic in the natural environment, which is more toxic than As(V) to mammals. 6 Additionally, As(III) is also more mobile than As(V), because As(III) is quite easier originated from the oxidative weathering or reductive dissolution of As-containing minerals, suggesting the immobilization of As(III) in acid solution more strictly depends on the redox conditions. 7 Therefore, it is advisible to preoxidize As(III) to As(V), coupled with a following adsorption or coprecipitation of the As(V) by using adsorbents or coagulants, to finally enhance the removal of arsenic species in acid aqueous solution. 8,9 Similarly, Cr(VI) is quite soluble and mobile in acid wastewater, 10 whileCr(III) is less toxic and insoluble, and can be effectively immobilized as the hydroxide in a wide pH range. 11,12 Thus, the prereduction of Cr(VI) to Cr(III) is conducive to the complete removal of ch...

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Section: Environmental Science and Technologymentioning

confidence: 99%

Redox Conversion of Chromium(VI) and Arsenic(III) with the Intermediates of Chromium(V) and Arsenic(IV) via AuPd/CNTs Electrocatalysis in Acid Aqueous Solution

Sun

Zhang

Qin

et al. 2015

Environ. Sci. Technol.

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show abstract

“…Pyrite (FeS 2 ), the most abundant phase in sulfide ore deposits, is the thermodynamically favored Fe-S mineral in most sediments and is an ubiquitous component in reduced environments where it acts as a reductant for hazardous oxidizing species and is capable for environmental application, especially for Cr(VI) reduction [19][20][21][22][23][24]. Natural pyrite is an abundant mineral resource, most of which is lean ore with a low sulfur content and is also a major mining waste product, which has a potential to treat contaminated aqueous solution as a reductant, such as Cr(VI) containing contaminated groundwater [25,26].…”

Section: Introductionmentioning

confidence: 99%

Cr(VI)-contaminated groundwater remediation with simulated permeable reactive barrier (PRB) filled with natural pyrite as reactive material: Environmental factors and effectiveness

Liu

Mou

Chen

et al. 2015

Journal of Hazardous Materials

104

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“…Thus, high cost of conventional clean up technologies has produced economic pressure and has caused engineers to search for creative, cost-effective and environmentally sound ways to treat AMD (Grady and Ackers, 1976;Simonyi et al, 1977;Gabr and Bowders, 2000;Zilberchmidt et al, 2004;Bulusu et al, 2007). As the coal mine drainage sludge contains a large amount of heavy metals, the residue obtained from the sedimented sludge can be used as an inorganic pigment (Kirby et al, 1999;Hedin, 2003;Xinchao et al, 2005;Wei and Viadero Jr., 2007).…”

Section: Introductionmentioning

confidence: 99%

Inorganic pigments made from the recycling of coal mine drainage treatment sludge

Marcello

Galato²,

Peterson

et al. 2008

Journal of Environmental Management

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CCB-based encapsulation of pyrite for remediation of acid mine drainage

Cited by 26 publications

References 18 publications

Redox Conversion of Chromium(VI) and Arsenic(III) with the Intermediates of Chromium(V) and Arsenic(IV) via AuPd/CNTs Electrocatalysis in Acid Aqueous Solution

Redox Conversion of Chromium(VI) and Arsenic(III) with the Intermediates of Chromium(V) and Arsenic(IV) via AuPd/CNTs Electrocatalysis in Acid Aqueous Solution

Cr(VI)-contaminated groundwater remediation with simulated permeable reactive barrier (PRB) filled with natural pyrite as reactive material: Environmental factors and effectiveness

Inorganic pigments made from the recycling of coal mine drainage treatment sludge

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