The performance of nCaO<sub>2</sub> for BTEX removal: Hydroxyl radical generation pattern and the influences of co‐existing environmental pollutants

Sun, Xuecheng; Sun, Yong; Lyu, Shuguang; Qiu, Zhaofu; Sui, Qian

doi:10.1002/wer.1257

Cited by 7 publications

(8 citation statements)

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“…Making nCaO 2 or Fe(III) constant and increasing another concentration could not contribute to a better BTEX degradation. This result was also reported in the nCaO 2 /Fe(II) system on BTEX removal (Sun et al 2020). As the concentration of L-cys changed from 1.0 to 10.0 mM, more nCaO 2 and Fe(III) were needed to achieve the same BTEX removal (Fig.…”

Section: Resultssupporting

confidence: 81%

“…This means that the oxidizing capacity of the combined Fenton-like process is varied with the different target pollutants. Moreover, nanoscale CaO 2 (nCaO 2 ) were synthesized and displayed better dispersion and transportation ability than commercial CaO 2 from our previous study, owing to their smaller particle size and larger surface area (Qian et al 2013(Qian et al , 2016Mosmeri et al 2019;Ali et al 2020;Sun et al 2020). Therefore, nCaO 2 have been showing great perspective and attraction to scientists and engineers.…”

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confidence: 99%

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Degradation of BTEX in groundwater by nano-CaO2 particles activated with L-cysteine chelated Fe(III): enhancing or inhibiting hydroxyl radical generation

et al. 2021

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The simultaneous oxidation performance of benzene, toluene, ethylbenzene, and xylene (BTEX) by nanoscale calcium peroxide particles (nCaO2) activated with ferric ions (Fe(III)) and the mechanism of the enhancement of BTEX degradation by L-cysteine (L-cys) were investigated. The batch experimental results showed that the nCaO2/Fe(III)/L-cys process was effective in the destruction of BTEX in both ultrapure water and actual groundwater. A proper amount of L-cys could enhance BTEX degradation due to the promotion of Fe(II)/Fe(III) redox cycles by the participation of L-cys, but excessive presence of L-cys would cause inhibition. Adding 1.0 mM L-cys to the nCaO2/Fe(III) system, the concentration of Fe(II) increased to 1.15 mM instantly. Simultaneously, the yield of HO• produced by 1.0 mM L-cys-containing system was 0.066 mM at 180 min reaction, higher than that without L-cys (0.049 mM). When excess L-cys (5.0 mM) was added to the system, the amount of Fe(II) increased to 3.73 mM because excessive L-cys caused a large number of Fe(III) in the system to be reduced. However, the yield of HO• decreased to 0.043 mM since excessive Fe(II) could conversely scavenge HO• to produce Fe(III) again. EPR tests and quenching results indicated that HO• was the dominant reactive species in the nCaO2/Fe(III)/L-cys system. For the removal of BTEX, the optimal molar ratio of nCaO2/Fe(III)/L-cys was 10.5/20/1 based on the calculation by RSM. Finally, the BTEX destruction pathway was proposed according to the detected intermediates by LC-MS.

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Section: Resultssupporting

confidence: 81%

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confidence: 99%

Degradation of BTEX in groundwater by nano-CaO2 particles activated with L-cysteine chelated Fe(III): enhancing or inhibiting hydroxyl radical generation

et al. 2021

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“…For example, the removal efficiencies of CaO 2 and nCaO 2 for treating BTEX (∼40 mg L −1 at pH 3) were ∼60 and 96% in 180 min, respectively. 98 Similar to CaO 2 , the change in the molar ratio of nCaO 2 and Fe 2+ affected the generation rate of ˙OH. In practical settings, the influence of surfactants on the efficiency of nCaO 2 /Fe 2+ was investigated.…”

Section: Advanced Oxidation Processesmentioning

confidence: 95%

“…Accordingly, nano-CaO 2 (nCaO 2 ) was prepared by the hydrolysis precipitation method. 98 The smaller particle size of nCaO 2 (109 nm) increased the ˙OH production and subsequently showed higher removal efficiency than CaO 2 . For example, the removal efficiencies of CaO 2 and nCaO 2 for treating BTEX (∼40 mg L −1 at pH 3) were ∼60 and 96% in 180 min, respectively.…”

Section: Advanced Oxidation Processesmentioning

confidence: 95%

Sorptive removal versus catalytic degradation of aqueous BTEX: a comprehensive review from the perspective of life-cycle assessment

Vellingiri

Choudhary

Kumar

et al. 2022

Environ. Sci.: Water Res. Technol.

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“…The accidental leakages of diesel fuel and gasoline from underground storage tanks are the main reasons for aromatic hydrocarbons pollution in the soil and groundwater (Tabani et al, 2016; Usman et al, 2020). Benzene, toluene, ethylbenzene, and xylenes (BTEX), four typical aromatic compounds, are listed as the priority pollutants by the United States Environmental Protection Agency (US‐EPA) because of their high carcinogenicity and toxicity (Akmirza et al, 2017; Dong et al, 2017; Sun et al, 2019). Currently, many techniques are applied in groundwater remediation polluted by BTEX such as bioremediation, bioelectrochemical oxidation, photo catalysis, radiolysis, and advanced oxidation processes (AOPs) (Cecconet et al, 2020; O'Connor et al, 2018).…”

Section: Introductionmentioning

confidence: 99%

l‐cysteine‐modified Fe₃O₄ nanoparticles as a novel heterogeneous catalyst for persulfate activation on BTEX removal

Sun

Lyu

2021

Water Environment Research

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l‐cysteine‐modified Fe3O4 nanoparticles (l‐cys@nFe3O4) were synthesized successfully and used as catalyst to activate persulfate (PS) for benzene, toluene, ethylbenzene, and xylenes (BTEX) degradation. The composite was fully characterized, and the l‐cys@nFe3O4 had more protrusions and l‐cys was combined on the surface of nFe3O4. The removals of BTEX were 78.2%, 85.1%, 85.3%, 81.2%, respectively, in PS/l‐cys@nFe3O4 system, while only 52.7% 57.8%, 60.8%, and 56.3% of BTEX removals reached under the same condition for nFe3O4 chelated with l‐cys in 48 h. Four successive cycles of BTEX degradation were completed in PS/l‐cys@nFe3O4 system. The synergistic mechanisms of BTEX degradation in PS/l‐cys@nFe3O4 system were investigated by electron paramagnetic resonance (EPR), benzoic acid (BA) probe and X‐ray photoelectron spectroscopy (XPS) tests. SFe bond in l‐cys‐Fe complexes promoted the electron transfer between nFe3O4 core and the solution, iron and iron at the interface, thereby promoting the Fe3+/Fe2+ cycle and the catalytic capacity of nFe3O4. The optimal pH of PS/l‐cys@nFe3O4 system was 3, while HCO3− and Cl− exhibited negative influences on BTEX degradation. Only 14.2%, 15.5%, 15.9%, and 15.6% BTEX had been removed in the presence of 0.12‐M PS and 8.0 g/L l‐cys@nFe3O4 under the actual groundwater condition. However, expanding the dosage of PS and l‐cys@nFe3O4 was an effective strategy to overcome the adverse effect. Practitioner Points L‐cys@nFe3O4 were synthesized successfully and used as catalyst to activate PS for BTEX degradation. Four successive cycles of BTEX degradation were completed in PS/L‐cys@nFe3O4 system. lS―Fe bond in L‐cys@nFe3O4 promoted the electron transfer between PS and nFe3O4 core.

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The performance of nCaO₂ for BTEX removal: Hydroxyl radical generation pattern and the influences of co‐existing environmental pollutants

Cited by 7 publications

References 41 publications

Degradation of BTEX in groundwater by nano-CaO2 particles activated with L-cysteine chelated Fe(III): enhancing or inhibiting hydroxyl radical generation

Degradation of BTEX in groundwater by nano-CaO2 particles activated with L-cysteine chelated Fe(III): enhancing or inhibiting hydroxyl radical generation

Sorptive removal versus catalytic degradation of aqueous BTEX: a comprehensive review from the perspective of life-cycle assessment

l‐cysteine‐modified Fe₃O₄ nanoparticles as a novel heterogeneous catalyst for persulfate activation on BTEX removal

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The performance of nCaO2 for BTEX removal: Hydroxyl radical generation pattern and the influences of co‐existing environmental pollutants

Cited by 7 publications

References 41 publications

Degradation of BTEX in groundwater by nano-CaO2 particles activated with L-cysteine chelated Fe(III): enhancing or inhibiting hydroxyl radical generation

Degradation of BTEX in groundwater by nano-CaO2 particles activated with L-cysteine chelated Fe(III): enhancing or inhibiting hydroxyl radical generation

Sorptive removal versus catalytic degradation of aqueous BTEX: a comprehensive review from the perspective of life-cycle assessment

l‐cysteine‐modified Fe3O4 nanoparticles as a novel heterogeneous catalyst for persulfate activation on BTEX removal

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The performance of nCaO₂ for BTEX removal: Hydroxyl radical generation pattern and the influences of co‐existing environmental pollutants

l‐cysteine‐modified Fe₃O₄ nanoparticles as a novel heterogeneous catalyst for persulfate activation on BTEX removal