Hydrodynamics, mass and heat transfer study for emerging heterogeneous Fenton process in multiphase fluidized-bed reactor system for wastewater treatment — A review

Sharma, Manisha; Mohapatra, Titikshya; Ghosh, Prabir

doi:10.1016/j.cherd.2021.04.019

Cited by 16 publications

(3 citation statements)

References 49 publications

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“…To confirm the model's reliability, an additional laboratory experiment was conducted using optimum conditions found by the DOE results at reaction times of 5 min, 30 min, 90 min, 24 h, 48 h, and 72 h. After the process was scaled up to 2 L, the efficiency of Cr (III), Cr (VI), and COD removal was 20% lower than the data determined in the model (Figure 2). This limitation was due to the mass transfer of substances required in the Fenton reaction (nZVI and H 2 O 2 ), making it difficult to maintain adequate agitation [46]. In a previous work, Vilardi et al [22] achieved a COD removal efficiency of 75.5%.…”

Section: Validation Of the Doe Resultsmentioning

confidence: 99%

Removal of Cr and Organic Matter from Real Tannery Wastewater via Fenton-like Process Using Commercial Nano-Scale Zero-Valent Iron

Vasquez,

Franco,

Vasquez

et al. 2024

Water

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The tannery wastewater from the tanning stage (TWT) comprises organic and Cr pollutants, which can adversely affect aquatic life and have carcinogenic effects. In this study, we investigated the performance of a Fenton-like process using commercial Nano-scale zero-valent iron (nZVI) for the simultaneous removal of Cr and organic matter from real TWT. We used an experimental design to select the principal operating parameters. A Plackett–Burman design identified variables for Cr-total and COD removal, followed by a central composite design (CC-D) to determine optimal variable levels. Finally, the response surface methodology (RSM) was used to find the optimum concentration of individual variables influencing Cr-total removal. Additionally, the effect of the leather-related, co-existing substances that influenced the efficiency of the process and the possibility of recycling nZVI were explored. The inclusion of nZVI was significantly more effective at removing both Cr-total and COD (97.3% ± 5.7% and 73.9% ± 9.1%, respectively), whereas the traditional Fenton process achieved lower removal rates (55.6% ± 10.0% for Cr-total and 34.8% ± 10.9% for COD). The optimal conditions for the Fenton-like process were nZVI/H2O2 = 1.05 w/w, and pH = 2.93. We obtained the best results during the first 5 min of the reaction, which increased after 48 h of agitation and subsequent neutralization. According to the results of four consecutive cycles, nZVI exhibited high reusability (97%) without compromising its adsorption potency. XPS analysis confirmed Cr removal through the adsorption mechanism on the nZVI surface. Hence, a Fenton-like process based on nZVI can be used as a promising alternative for treating organic and Cr wastewater.

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Section: Validation Of the Doe Resultsmentioning

confidence: 99%

Removal of Cr and Organic Matter from Real Tannery Wastewater via Fenton-like Process Using Commercial Nano-Scale Zero-Valent Iron

Vasquez,

Franco,

Vasquez

et al. 2024

Water

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“…The Fenton reaction can be considered an AOP, where it is based on a mixture of ferrous ion (Fe 2+ ) (usually in a liquid state) with hydrogen peroxide (H 2 O 2 ) [37], which, under the right reaction conditions, results in the formation of hydroxyl radicals [38] with high oxidative potential capable of degrading a wide range of contaminants (Figure 1) [39].…”

Section: Fenton Reactionmentioning

confidence: 99%

From Fenton and ORR 2e−-Type Catalysts to Bifunctional Electrodes for Environmental Remediation Using the Electro-Fenton Process

et al. 2023

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Currently, the presence of emerging contaminants in water sources has raised concerns worldwide due to low rates of mineralization, and in some cases, zero levels of degradation through conventional treatment methods. For these reasons, researchers in the field are focused on the use of advanced oxidation processes (AOPs) as a powerful tool for the degradation of persistent pollutants. These AOPs are based mainly on the in-situ production of hydroxyl radicals (OH•) generated from an oxidizing agent (H2O2 or O2) in the presence of a catalyst. Among the most studied AOPs, the Fenton reaction stands out due to its operational simplicity and good levels of degradation for a wide range of emerging contaminants. However, it has some limitations such as the storage and handling of H2O2. Therefore, the use of the electro-Fenton (EF) process has been proposed in which H2O2 is generated in situ by the action of the oxygen reduction reaction (ORR). However, it is important to mention that the ORR is given by two routes, by two or four electrons, which results in the products of H2O2 and H2O, respectively. For this reason, current efforts seek to increase the selectivity of ORR catalysts toward the 2e− route and thus improve the performance of the EF process. This work reviews catalysts for the Fenton reaction, ORR 2e− catalysts, and presents a short review of some proposed catalysts with bifunctional activity for ORR 2e− and Fenton processes. Finally, the most important factors for electro-Fenton dual catalysts to obtain high catalytic activity in both Fenton and ORR 2e− processes are summarized.

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“…Zhang et al [18] explored the uneven flow phenomenon in a high-efficiency clarifier based on CFD, and it was shown that the uneven distribution of water flow would be suppressed by lengthening the baffles and adding 45 • baffles in the high-efficiency clarifier. In summary, CFD has become an efficient and cost-effective tool for the design and optimization of water treatment equipment [19][20][21][22].…”

Section: Introductionmentioning

confidence: 99%

Three-Dimensional Numerical Analysis and Operational Optimization of High-Efficiency Sedimentation Tank

Ye,

Kang,

Wang

et al. 2023

Water

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The high-efficiency sedimentation tank has a wide range of application prospects in industrial wastewater treatment due to its small footprint, strong resistance to shock loads, and high efficiency. However, the complex flow field distribution inside significantly affects the treatment performance of the high-efficiency tank. In this study, a three-dimensional geometric model of the high-efficiency sedimentation tank was constructed based on an engineering prototype. The corresponding solid–liquid two-phase, whole-process computational fluid dynamics (CFD) model for the high-efficiency sedimentation tank was established using the realizable k-ε turbulent model and the multiple reference frame (MRF) method. The internal structures of the flocculation zone, plug-flow zone, and clarification zone were optimized, and then the influence of operational process conditions on the flocculation treatment performance was investigated. The results indicate that, for the given engineering model, the average turbulent kinetic energy k in the flocculation zone exhibits a trend that initially increases and then decreases with the increase in the diameter and height of the draft tube. The optimal hydraulic conditions for the flocculation zone are achieved when the diameter of the draft tube is 2.5 m and the height is 3.5 m. The average turbulent kinetic energy dissipation rate in the plug-flow/clarification zone tends to decrease first and then increase as the height of the water tunnel and water-retaining weir increases. The optimal hydraulic conditions for the plug-flow and clarification zones are achieved when the height of the water tunnel is 1.0 m and the height of the water-retaining weir is 1.6 m. Under optimal operating conditions (dosage of dense media particles: 40 mg/L, stirring rate: 30 rpm, and inlet velocity: 0.72 m/s), satisfactory overall hydraulic conditions can be achieved throughout the entire high-efficiency sedimentation tank. Comparisons between a high-efficiency settling tank and a conventional clarifier for the treatment of circulating water sewage in a practical implementation reveals that the ballasted high-efficiency settling tank has advantages in terms of high hydraulic loading, high removal efficiency of hardness, small footprint, and low doses of flocculant. This research will provide reference values for the design and operation optimization of high-efficiency sedimentation tanks.

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Hydrodynamics, mass and heat transfer study for emerging heterogeneous Fenton process in multiphase fluidized-bed reactor system for wastewater treatment — A review

Cited by 16 publications

References 49 publications

Removal of Cr and Organic Matter from Real Tannery Wastewater via Fenton-like Process Using Commercial Nano-Scale Zero-Valent Iron

Removal of Cr and Organic Matter from Real Tannery Wastewater via Fenton-like Process Using Commercial Nano-Scale Zero-Valent Iron

From Fenton and ORR 2e−-Type Catalysts to Bifunctional Electrodes for Environmental Remediation Using the Electro-Fenton Process

Three-Dimensional Numerical Analysis and Operational Optimization of High-Efficiency Sedimentation Tank

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