Remediation of Cr (VI) Using Clay Minerals, Biomasses and Industrial Wastes as Adsorbents

Acharya, Rashmi; Martha, Satyabadi; Parida, Kulamani

doi:10.1002/9781119407805.ch5

Cited by 25 publications

(11 citation statements)

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“…The aqueous environment mostly contains Cr(III) and different Cr(VI) species like HCrO 4 − , Cr 2 O 7 2− , CrO 4 2− and H 2 CrO 4 . The speciation of these Cr(VI) species depends on pH and concentration of the solution [4–5]. Fig.…”

Section: Introductionmentioning

confidence: 99%

Cr(VI) remediation from aqueous environment through modified-TiO₂-mediated photocatalytic reduction

Acharya

Naik

Parida

2018

Beilstein J. Nanotechnol.

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111

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Cr(VI) exhibits cytotoxic, mutagenic and carcinogenic properties; hence, effluents containing Cr(VI) from various industrial processes pose threat to aquatic life and downstream users. Various treatment techniques, such as chemical reduction, ion exchange, bacterial degradation, adsorption and photocatalysis, have been exploited for remediation of Cr(VI) from wastewater. Among these, photocatalysis has recently gained considerable attention. The applications of photocatalysis, such as water splitting, CO2 reduction, pollutant degradation, organic transformation reactions, N2 fixation, etc., towards solving the energy crisis and environmental issues are briefly discussed in the Introduction of this review. The advantages of TiO2 as a photocatalyst and the importance of its modification for photocatalytic reduction of Cr(VI) has also been addressed. In this review, the photocatalytic activity of TiO2 after modification with carbon-based advanced materials, metal oxides, metal sulfides and noble metals towards reduction of Cr(VI) was evaluated and compared with that of bare TiO2. The photoactivity of dye-sensitized TiO2 for reduction of Cr(VI) was also discussed. The mechanism for enhanced photocatalytic activity was highlighted and attributed to the resultant properties, namely, effective separation of photoinduced charge carriers, extension of the light absorption range and intensity, increase of the surface active sites, and higher photostability. Advantages and limitations for photoreduction of Cr(VI) over modified TiO2 are depicted in the Conclusion. The various challenges that restrict the technology from practical applications in remediation of Cr(VI) from wastewater were addressed in the Conclusion section as well. The future perspectives of the field presented in this review are focused on the development of whole-solar-spectrum responsive, TiO2-coupled photocatalysts which provide efficient photocatalytic reduction of Cr(VI) along with their good recoverability and recyclability.

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Section: Introductionmentioning

confidence: 99%

Cr(VI) remediation from aqueous environment through modified-TiO₂-mediated photocatalytic reduction

Acharya

Naik

Parida

2018

Beilstein J. Nanotechnol.

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111

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“…The Langmuir and Freundlich isotherm models were applied to the mq and river water experiments to characterize the sorption of Cr (VI) onto kaolin under these conditions. The Langmuir isotherm model assumes single layer adsorption on a finite number of homogeneous adsorption sites and is expressed in the following equation (Acharya et al, ; Ajouyed et al, ):

\frac{C_{e}}{q_{e}} = \frac{1}{(Q_{m} \times b)} + \frac{C_{e}}{Q_{m}}

…”

Section: Resultsmentioning

confidence: 99%

“…The Freundlich isotherm model assumes multilayer adsorption onto a heterogeneous surface and is expressed in the following equation (Acharya et al, ; Ajouyed et al, ):

log q_{e} = log K_{f} + \frac{1}{n} \times log C_{e}

…”

Section: Resultsmentioning

confidence: 99%

“…However, thus far, it is unknown whether the sorption of Cr onto clay minerals is associated with an isotopic fractionation. Cr (VI) readily adsorbs on clay minerals through electrostatic attraction between the positively charged surface areas and negatively charged Cr (VI) species (CrO 4 2− and HCrO 4 − ; Acharya et al, ; Covelo et al, ). At neutral and alkaline pH, however, clay minerals commonly have a negatively charged surface area resulting in a rather low adsorption capacity for Cr (VI) at naturally occurring pH ranges (Acharya et al, ; Marjanović et al, ; Taylor, ).…”

Section: Introductionmentioning

confidence: 99%

“…Cr (VI) readily adsorbs on clay minerals through electrostatic attraction between the positively charged surface areas and negatively charged Cr (VI) species (CrO 4 2− and HCrO 4 − ; Acharya et al, ; Covelo et al, ). At neutral and alkaline pH, however, clay minerals commonly have a negatively charged surface area resulting in a rather low adsorption capacity for Cr (VI) at naturally occurring pH ranges (Acharya et al, ; Marjanović et al, ; Taylor, ). Alternatively, Cr (VI) can be reduced to Cr (III) by natural reducing agents (e.g., Fe (II) or organic matter) and subsequently sorbed through cation exchange (Brookshaw et al, ; Covelo et al, ; Koppelman, ).…”

Section: Introductionmentioning

confidence: 99%

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Fractionation Behavior of Chromium Isotopes during the Sorption of Cr (VI) on Kaolin and its Implications for Using Black Shales as a Paleoredox Archive

Frank

Klaebe

2019

Geochem Geophys Geosyst

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Chromium stable isotope variations in marine black shales are increasingly used to constrain redox changes though time. However, how well black shale δ53Cr values represent ambient seawater δ53Cr values is difficult to assess as black shales contain both detrital and authigenic mineral phases, of which only authigenic phases are expected to mirror seawater, while detrital silicate phases are expected to show igneous δ53Cr values. In order to correct for detrital contamination, it is thus imperative to know whether detrital minerals are in fact characterized by igneous δ53Cr values. To investigate this further, three sets of Cr (VI) batch sorption experiments were conducted, reacting kaolin with (1) with a synthetic Cr (VI) solution, (2) with Cr (VI) doped river water, and (3) with Cr (VI) doped seawater. Further, sequential leaches were applied to reacted kaolin to evaluate how well sorbed Cr (VI) can be leached. The experiments revealed that Cr (VI) readily sorbs on kaolin, changing its Cr concentration and isotopic composition. In river water, kaolin sorbed up to 36 μg of Cr (VI) per gram of kaolin and recorded a negative offset in bulk δ53Cr of up to 0.26‰ relative to unreacted kaolin, while no sorption was observed in seawater. Our leaching experiments revealed that already a weak acid leach (0.5M HCl) readily mobilizes some of the sorbed Cr from kaolin, which when applied to black shales will likely contaminate leachates designed to release authigenic Cr. This has major implications for the application of Cr stable isotopes in black shales as marine paleoredox archives.

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BiFeO₃‐Based Materials For Augmented Photoactivity

Acharya

Parida

2022

Perovskite Materials for Energy and Environmental Applications

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Remediation of Cr (VI) Using Clay Minerals, Biomasses and Industrial Wastes as Adsorbents

Cited by 25 publications

References 105 publications

Cr(VI) remediation from aqueous environment through modified-TiO₂-mediated photocatalytic reduction

Cr(VI) remediation from aqueous environment through modified-TiO₂-mediated photocatalytic reduction

Fractionation Behavior of Chromium Isotopes during the Sorption of Cr (VI) on Kaolin and its Implications for Using Black Shales as a Paleoredox Archive

BiFeO₃‐Based Materials For Augmented Photoactivity

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Remediation of Cr (VI) Using Clay Minerals, Biomasses and Industrial Wastes as Adsorbents

Cited by 25 publications

References 105 publications

Cr(VI) remediation from aqueous environment through modified-TiO2-mediated photocatalytic reduction

Cr(VI) remediation from aqueous environment through modified-TiO2-mediated photocatalytic reduction

Fractionation Behavior of Chromium Isotopes during the Sorption of Cr (VI) on Kaolin and its Implications for Using Black Shales as a Paleoredox Archive

BiFeO3‐Based Materials For Augmented Photoactivity

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Cr(VI) remediation from aqueous environment through modified-TiO₂-mediated photocatalytic reduction

Cr(VI) remediation from aqueous environment through modified-TiO₂-mediated photocatalytic reduction

BiFeO₃‐Based Materials For Augmented Photoactivity