Effects of hydrogen-peroxide supply rate on schwertmannite microstructure and chromium(VI) adsorption performance

Zhang, Zhuo; Guo, Guanlin; Li, Xintong; Zhao, Qianchen; Bi, Xue; Wu, Kening; Chen, Honghan

doi:10.1016/j.jhazmat.2018.12.116

Cited by 65 publications

(24 citation statements)

References 35 publications

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“…A better performance of the Langmuir model was confirmed by Anandaraj et al [54] using native and chemically modified green macroalgae Codium tomentosum biomass as a sorbent. Similar results were obtained by Mikhaylov et al [8] using Al/Fe oxyhydroxide composite powders, Sutkowy and Klosowsky [55] using the green alga Pseudopediastrum boryanum and many other authors using minerals [40,56], synthetized materials [1,7,10,20,57,58] or biosorbents [26,27,48,59].…”

Section: Sorption Isothermssupporting

confidence: 82%

“…Cr(VI) sorption capacity of schwertmannite attained a maximum at pH 6.0 [40]. Cr(VI) sorption by schwertmannite was mainly attributed to ion exchange between Cr(VI) and structural SO 4 2− , a process possible because the Cr(VI) species and SO 4 2− have the same charge and similar sizes.…”

Section: Cr(vi) Behavior In Solution and Proposed Sorption Mechanisms: Effect Of Phmentioning

confidence: 97%

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Cr(VI) Sorption from Aqueous Solution: A Review

et al. 2020

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Hexavalent chromium (Cr(VI)) in water systems is a major hazard for living organisms, including humans. The most popular technology currently used to remove Cr(VI) from polluted water is sorption for its effectiveness, ease of use, low cost and environmental friendliness. The electrostatic interactions between chromium species and the sorbent matrix are the main determinants of Cr(VI) sorption. The pH plays a central role in the process by affecting chromium speciation and the net charge on sorbent surface. In most cases, Cr(VI) sorption is an endothermic process whose kinetics is satisfactorily described by the pseudo second-order model. A critical survey of the recent literature, however, reveals that the thermodynamic and kinetic parameters reported for Cr(VI) sorption are often incorrect and/or erroneously interpreted.

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Section: Sorption Isothermssupporting

confidence: 82%

Section: Cr(vi) Behavior In Solution and Proposed Sorption Mechanisms: Effect Of Phmentioning

confidence: 97%

Cr(VI) Sorption from Aqueous Solution: A Review

et al. 2020

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Section: Resultsmentioning

confidence: 78%

“…As reported by several authors, Cr(VI) adsorption on schwertmannite can be mainly attributed to ion exchange with SO 4 2 − groups [ 22 , 25 , 52 , 71 ]. Due to the same charge and a similar radius of SO 4 2 − (0.23 nm) and CrO 4 2 − (0.24 nm) ions, the replacement of sulphate groups with chromate groups occurs without changing the crystal structure of the schwertmannite [ 52 ]. No change in the structure of synthetic schwertmannite is observable when analysing FTIR spectra before and after adsorption of Cr(VI) and SEM images of schwertmannite after adsorption of Cr(VI).…”

Section: Resultsmentioning

confidence: 78%

“…Additionally, at alkaline pH conditions, inhibition of Cr(VI) hydrolysis may be one of the reasons for reduced adsorption [ 51 ]. Zhang and co-workers reported that an increase in pH may also release sulphate groups through higher concentration of OH − ions, converting schwertmannite to goethite, and this may decrease the adsorption efficiency of Cr(VI) [ 52 ].…”

Section: Resultsmentioning

confidence: 99%

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Comparison of Cr(VI) Adsorption Using Synthetic Schwertmannite Obtained by Fe3+ Hydrolysis and Fe2+ Oxidation: Kinetics, Isotherms and Adsorption Mechanism

Ulatowska¹,

Stala²,

Polowczyk³

2021

IJMS

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Good sorption properties and simple synthesis route make schwertmannite an increasingly popular adsorbent. In this work, the adsorption properties of synthetic schwertmannite towards Cr(VI) were investigated. This study aimed to compare the properties and sorption performance of adsorbents obtained by two methods: Fe3+ hydrolysis (SCHA) and Fe2+ oxidation (SCHB). To characterise the sorbents before and after Cr(VI) adsorption, specific surface area, particle size distribution, density, and zeta potential were determined. Additionally, optical micrographs, SEM, and FTIR analyses were performed. Adsorption experiments were performed in varying process conditions: pH, adsorbent dosage, contact time, and initial concentration. Adsorption isotherms were fitted by Freundlich, Langmuir, and Temkin models. Pseudo-first-order, pseudo-second-order, intraparticle diffusion, and liquid film diffusion models were used to fit the kinetics data. Linear regression was used to estimate the parameters of isotherm and kinetic models. The maximum adsorption capacity resulting from the fitted Langmuir isotherm is 42.97 and 17.54 mg·g−1 for SCHA and SCHB. Results show that the adsorption kinetics follows the pseudo-second-order kinetic model. Both iron-based adsorbents are suitable for removing Cr(VI) ions from aqueous solutions. Characterisation of the adsorbents after adsorption suggests that Cr(VI) adsorption can be mainly attributed to ion exchange with SO42− groups.

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