Influence of pH on photocatalytic reduction, adsorption, and deposition of metal ions: speciation modeling

Thakur, Rajesh; Chaudhary, Rubina; Singh, Chandan Kumar

doi:10.1080/19443994.2014.944222

Cited by 11 publications

(5 citation statements)

References 24 publications

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“…In suitable conditions, UV and visible light can reduce a variety of metal ions in different environments (Monico et al, 2015;Oster and Oster, 1959;Thakur et al, 2015). Photoreduced metal compounds may further act as effective chemical reductants (Ola and Maroto-Valer, 2015;Xu et al, 2015), and the oxidized compounds such as hydroxyl radicals or chlorine atoms can further act as effective oxidants.…”

Section: Oxidation Of Methane and Other Ghgsmentioning

confidence: 99%

Climate engineering by mimicking natural dust climate control: the iron salt aerosol method

et al. 2017

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Abstract. Power stations, ships and air traffic are among the most potent greenhouse gas emitters and are primarily responsible for global warming. Iron salt aerosols (ISAs), composed partly of iron and chloride, exert a cooling effect on climate in several ways. This article aims firstly to examine all direct and indirect natural climate cooling mechanisms driven by ISA tropospheric aerosol particles, showing their cooperation and interaction within the different environmental compartments. Secondly, it looks at a proposal to enhance the cooling effects of ISA in order to reach the optimistic target of the Paris climate agreement to limit the global temperature increase between 1.5 and 2 • C.Mineral dust played an important role during the glacial periods; by using mineral dust as a natural analogue tool and by mimicking the same method used in nature, the proposed ISA method might be able to reduce and stop climate warming. The first estimations made in this article show that by doubling the current natural iron emissions by ISA into the troposphere, i.e., by about 0.3 Tg Fe yr −1 , artificial ISA would enable the prevention or even reversal of global warming. The ISA method proposed integrates technical and economically feasible tools.

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Section: Oxidation Of Methane and Other Ghgsmentioning

confidence: 99%

Climate engineering by mimicking natural dust climate control: the iron salt aerosol method

et al. 2017

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“…Consequently, those ions could be effectively adsorbed on the surface of the catalyst owing to the electrostatic interaction. 58,59 Unlike the photocatalytic degradation of MO, the chromium reduction is therefore a proximal process and occurs on the surface of the catalyst.…”

Section: Resultsmentioning

confidence: 99%

“…Notably, the hexavalent chromium exists in the aqueous medium mainly in the form of Cr 2 O 7 2– which comes into close proximity of the catalyst due to its positive surface charge as evident from Zeta potential measurements (SI Figure S5). Consequently, those ions could be effectively adsorbed on the surface of the catalyst owing to the electrostatic interaction. , Unlike the photocatalytic degradation of MO, the chromium reduction is therefore a proximal process and occurs on the surface of the catalyst.…”

Section: Resultsmentioning

confidence: 99%

Flower-Like BiOI Microspheres Decorated with Plasmonic Gold Nanoparticles for Dual Detoxification of Organic and Inorganic Water Pollutants

Chatterjee

Kar

Wulferding

et al. 2020

ACS Appl. Nano Mater.

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The development of bismuth-based photocatalysts in response to emerging demand for solving environmental problems has attracted immense interest over the past few years. This is owed to their low cost, nontoxicity, and high stability. Here, we report the synthesis of a nanohybrid consisting of 3D flower-like BiOI microspheres decorated with plasmonic gold nanoparticles (∼15 nm) to experience enhanced photocatalytic activity. Various characterization tools such as scanning electron microscopy (SEM), transmission electron microscopy (TEM), and X-ray diffraction (XRD) have been used to investigate the morphology and crystallinity of the photocatalyst. The formation of the nanohybrid by the gold nanoparticles and BiOI microspheres has been confirmed by Raman as well as picosecond resolved ultrafast spectroscopy. The as-synthesized nanohybrid exhibits a superior photocatalytic activity toward the detoxification of organic (methyl orange) as well as inorganic (hexavalent chromium) water pollutants under visible and red light (λ > 600 nm) irradiation. Our detailed ultrafast spectroscopic studies link the enhanced photocatalytic activity of the nanohybrid to an improved charge carrier separation in the metal−semiconductor interface. In addition, we find that the degradation process of the dye and the reduction of hexavalent chromium [Cr(VI)] are based on two completely different mechanisms. Moreover, our synthesized nanohybrid efficiently retains its activity as well as its structural stability after several cycles of light irradiation, which highlights it as a promising candidate for environmental remediation.

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“…In contrast, at higher pH values the biosorbent becomes more negatively charged and therefore repels the negatively charged species (Jung et al 2017;Vu et al 2017). In contrast, since Cr is an amphoteric metal (Thakur et al 2015), there was no variation in the biosorption capacity with changes in pH for Cr, except for PP bead where it significantly increased at 6.5 and 8.5 compared to neutral pH (Fig. 3c).…”

Section: Effect Of Initial Phmentioning

confidence: 94%

Simultaneous removal of heavy metals from drinking water by banana, orange and potato peel beads: a study of biosorption kinetics

et al. 2021

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Banana, orange and potato peels (BP, OP and PP, respectively) were immobilised to produce biosorbent beads that were employed for the biosorption of heavy metals from a cocktail solution containing As(V), Cd(II), Cr(VI), Cu(II), Hg(II) and Ni(II) ions. Drinking water conditions were maintained with neutral initial pH and low concentration of the ions. Batch experiments were performed for evaluating the effect of pH in the drinking water range (6.5–8.5). Results showed a significant increase in the biosorption capacity of the beads with respective to the uptake of As and Pb, whereas it decreased significantly for Cd, Cu, Hg and Ni ions at basic pH values. Approximate equilibrium biosorption of Cd, Cu, Hg and Ni was 89–92%, 79–87%, 84% and 71–80% by BP, OP and PP beads. The physisorption-based PFO model was the most suitable for the ions with biosorption capacities closer to the experimental values. BP and OP beads had better biosorption efficiencies relative to PP bead due to the higher surface heterogeneity observed by scanning electron microscopy coupled with energy-dispersive spectroscopy. An increase in the biosorbent concentration from one to ten BP beads significantly increased the biosorption percentage of the ions. The biosorption capacities of Cd, Hg and Ni uptake by one BP bead from a 1 mgL−1 cocktail solution were 3.4 ± 0.0, 5.3 ± 0.1 and 3.0 ± 0.0 mgg−1, respectively. Thus, BP beads were the most effective than for the simultaneous removal of heavy metals from drinking water.

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Influence of pH on photocatalytic reduction, adsorption, and deposition of metal ions: speciation modeling

Cited by 11 publications

References 24 publications

Climate engineering by mimicking natural dust climate control: the iron salt aerosol method

Climate engineering by mimicking natural dust climate control: the iron salt aerosol method

Flower-Like BiOI Microspheres Decorated with Plasmonic Gold Nanoparticles for Dual Detoxification of Organic and Inorganic Water Pollutants

Simultaneous removal of heavy metals from drinking water by banana, orange and potato peel beads: a study of biosorption kinetics

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