Impact of mechanical activation and mechanochemical activation on natural pyrite dissolution

Akhgar, B.N.; Pourghahramani, Parviz

doi:10.1016/j.hydromet.2015.02.010

Cited by 37 publications

(7 citation statements)

References 19 publications

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“…Mechanochemical activation of the precursors can be considered as another method for fabrication of AC. Ball-milling has proved to be effective for preparing ceramic powders [18] and nanomaterials [19], for conducting solvent-free organic reactions [20] and for degradation of waste materials [21]. Mechanochemistry offers several benefits over traditional solvent-based protocols like simplicity, mild/short reaction conditions, ease of scale-up and the ability to synthesize metastable phases [22].…”

Section: Introductionmentioning

confidence: 99%

Mechanochemical and chemical activation of lignocellulosic material to prepare powdered activated carbons for adsorption applications

et al. 2016

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This work presents a solvent-free mechanochemical approach toward controlled preparation of powdered activated carbons from lignocellulosic residue (horse chestnut shell, CS). The physicochemical changes of the biomass during mechanochemical and chemical activation with K2CO3 and the properties of the final materials obtained after pyrolysis at 700 ºC have been investigated by means of thermogravimetric analysis (TG-DTG), scanning electron microscopy (SEM), X-ray diffraction (XRD), N2 adsorptiondesorption, infrared and micro-Raman spectroscopy. The results indicated that the mechanochemical activation is superior to the traditional chemical activation in terms of specific surface area, pore development and the degree of structural order of the activated carbons. Furthermore, it has been observed that the later parameters depend on the milling time and the maximal BET surface area (1040 m 2 /g) and total pore volume (1.01 cm 3 /g) of the resulting mesoporous material can be obtained after 3h milling of the raw material/K2CO3 mixture. In addition, malachite green oxalate (MGO) adsorption capacities of the carbons were also examined and adsorption uptake up to 250 mg/g is observed. This study demonstrates the potential use of CS as a precursor in the preparation of activated carbon for adsorption applications and opens up new ways for activation of lignocellulosic materials under ball-milling conditions.

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Section: Introductionmentioning

confidence: 99%

Mechanochemical and chemical activation of lignocellulosic material to prepare powdered activated carbons for adsorption applications

et al. 2016

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“…To test this hypothesis, we evaluated the role of pyrite with varying amounts of SVs in the degradation of SMX. Ball milling, a technique commonly used to expose internal structures and increase vacancies in sulfide minerals, was employed (detailed in Text S6). The variation of the surface composition before and after ball milling was investigated by XPS spectra (Figure a).…”

Section: Resultsmentioning

confidence: 99%

Sulfur Vacancies in Pyrite Trigger the Path to Nonradical Singlet Oxygen and Spontaneous Sulfamethoxazole Degradation: Unveiling the Hidden Potential in Sediments

Zhu,

Wang,

Sun

et al. 2024

Environ. Sci. Technol.

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Pharmaceutical residues in sediments are concerning as ubiquitous emerging contaminants. Pyrite is the most abundant sulfide minerals in the estuarine and coastal sediments, making it a major sink for pharmaceutical pollutants such as sulfamethoxazole (SMX). However, research on the adsorption and redox behaviors of SMX on the pyrite surface is limited. Here, we investigated the impact of the nonphotochemical process of pyrite on the fate of coexisting SMX. Remarkably, sulfur vacancies (SVs) on pyrite promoted the generation of nonradical species (hydrogen peroxide, H 2 O 2 and singlet oxygen, 1 O 2 ), thereby exhibiting prominent SMX degradation performance under darkness. Nonradical 1 O 2 contributed approximately 73.1% of the total SMX degradation. The SVs with high surrounding electron density showed an advanced affinity for adsorbing O 2 and then initiated redox reactions in the sediment electron-storing geobattery pyrite, resulting in the extensive generation of H 2 O 2 through a two-electron oxygen reduction pathway. Surface Fe(III) (hydro)oxides on pyrite facilitated the decomposition of H 2 O 2 to 1 O 2 generation. Distinct nonradical products were observed in all investigated estuarine and coastal samples with the concentrations of H 2 O 2 ranging from 1.96 to 2.94 μM, while the concentrations of 1 O 2 ranged from 4.63 × 10 −15 to 8.93 × 10 −15 M. This dark-redox pathway outperformed traditional photochemical routes for pollutant degradation, broadening the possibilities for nonradical species use in estuarine and coastal sediments. Our study highlighted the SV-triggered process as a ubiquitous yet previously overlooked source of nonradical species, which offered fresh insights into geochemical processes and the dynamics of pollutants in regions of frequent redox oscillations and sulfur-rich sediments.

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“…X-ray diffraction patterns of the dry mineral sample were obtained with a D8 Advance diffractometer (Drucker, Germany) applying a Cu -K Kα radiation (wavelength = 15.41 nm) at 50 kV and 150 mA in a 2θ range of 5º -90º. The diffractograms were created using a step size of 0.02º and a measurement speed of 1º/min as suggested by Akhgar and Pourghahramani (2015). In addition, inductively coupled plasma (ICP) analysis was carried out by ICP -OES (iCAP 7000, Thermo Scientific, USA ® ) by the SGS company to find the initial and final concentration in the soil sample submitted to evaluation.…”

Section: Chemical Analysis and Characterization Of Mine Tailingsmentioning

confidence: 99%

Bioleaching of As from mine tailings using an autochthonous Bacillus cereus strain

Cabrales-González

Martínez-Prado²,

Núñez-Ramírez³

et al. 2022

RMIQ

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Impact of mechanical activation and mechanochemical activation on natural pyrite dissolution

Cited by 37 publications

References 19 publications

Mechanochemical and chemical activation of lignocellulosic material to prepare powdered activated carbons for adsorption applications

Mechanochemical and chemical activation of lignocellulosic material to prepare powdered activated carbons for adsorption applications

Sulfur Vacancies in Pyrite Trigger the Path to Nonradical Singlet Oxygen and Spontaneous Sulfamethoxazole Degradation: Unveiling the Hidden Potential in Sediments

Bioleaching of As from mine tailings using an autochthonous Bacillus cereus strain

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