scholarly journals Sulfate Radicals-Based Technology as a Promising Strategy for Wastewater

Water ◽  
2019 ◽  
Vol 11 (8) ◽  
pp. 1695 ◽  
Author(s):  
María Arellano ◽  
Marta Pazos ◽  
María Ángeles Sanromán
Keyword(s):  
Organic Contaminants ◽  
Fixed Bed ◽  
Fixed Bed Reactor ◽  
Continuous Treatment ◽  
Sulfate Radicals ◽  
System A ◽  
Lissamine Green ◽  
Cationic Resin ◽  
Homogenous Catalyst ◽  
Complex Organic

This study was focused on the generation of sulfate radicals and their applicability as powerful oxidants for degrading complex organic compounds with the final objective of operating in flow systems. To this end, the removal of two compounds from the pharmaceutical industry was assessed, lissamine green and prednisolone. Initially, sulfate radicals were generated by the activation of persulfate with iron as homogenous catalyst, and the key parameters involved in the process, as catalyst concentration and oxidant dosage, were evaluated. Furthermore, with the aim of preventing the secondary contamination due to metal leaching and to be operate in a continuous mode, a heterogeneous catalyst was developed. For it, the iron was fixed on a cationic resin as Amberlite IR120 Na+ form. It was demonstrated that the removal of both pollutants increases with greater catalyst dosages, achieving a decay of 85% within 25 min with 30 g·L−1 of catalyst. Moreover, the reuse capability of the catalyst was tested, illustrating that it is rough enough for its reuse. Conversely, in order to develop a continuous treatment in flow system, a fixed bed reactor was constructed and its feasibility was proven. Different experiments with residence times from 10 min to 60 min were performed, obtaining a removal level of ≈95% and 90% for prednisolone and lissamine green, respectively, at residence time of 60 min. In conclusion, the potential of sulfate radicals-based technology for degrading organic contaminants has been demonstrated.

Catalytic Wet Peroxide Oxidation Process for the Continuous Treatment of Polluted Effluents on a Pilot Plant Scale

2008 ◽  
Vol 11 (1) ◽  
Author(s):  
Fernando Martínez ◽  
M Isabel Pariente ◽  
Juan Antonio Melero ◽  
Juan Ángel Botas
Keyword(s):  
Pilot Plant ◽  
Fixed Bed ◽  
Pilot Scale ◽  
Fixed Bed Reactor ◽  
Continuous Treatment ◽  
Continuous Stirred Tank Reactor ◽  
Peroxide Oxidation ◽  
Wet Peroxide Oxidation ◽  
Pilot Plant Scale ◽  
Catalytic Wet Peroxide Oxidation

AbstractCatalytic Wet Peroxide Oxidation (CWPO) for the continuous treatment of a phenolic aqueous solution has been studied on a pilot scale process. The pilot plant has been designed by integration of a catalytic fixed bed reactor (FBR) with a continuous stirred tank reactor (CSTR). The CSTR is used as reservoir for the continuous delivering of a recirculation stream through the catalytic bed. The main part of phenol mineralization takes place by catalytic oxidation in the FBR. The mesoporous SBA-15 silica-supported iron oxide (Fe

Assessment of Fe2O3/SiO2 catalysts for the continuous treatment of phenol aqueous solutions in a fixed bed reactor

2010 ◽  
Vol 149 (3-4) ◽  
pp. 334-340 ◽  
Author(s):  
J.A. Botas ◽  
J.A. Melero ◽  
F. Martínez ◽  
M.I. Pariente
Keyword(s):  
Aqueous Solutions ◽  
Fixed Bed ◽  
Fixed Bed Reactor ◽  
Continuous Treatment

The mathematical theory of a countercurrent catalytic reactor

1982 ◽  
Vol 383 (1784) ◽  
pp. 147-189 ◽  
Keyword(s):  
Steady State ◽  
Fixed Bed ◽  
Chemical Species ◽  
Fixed Bed Reactor ◽  
Catalytic Reactor ◽  
Adsorption Model ◽  
Transient Model ◽  
System A ◽  
Internal Shock ◽  
State Behaviour

The steady-state behaviour of a countercurrent catalytic reactor has been analysed mathematically for a reversible reaction─adsorption system A ⇌ A* ⇌ B* ⇌ B occurring, in the first instance, under the ideal chromatographic conditions in which negligible axial dispersion and instantaneous local adsorption equilibrium are assumed. The system is considered to be one-dimensional and isothermal. The internal discontinuity of the steady-state model was analysed in connection with the transient model, while the boundary behaviour was investigated in relation to the non-equilibrium-adsorption model. Two of the most influential parameters on the system behaviour were found to be the relative adsorptivity of the two chemical species A and B, and the relative carrying capacity of the two moving streams. It has been shown by heuristic examples how the chemical reaction process and the adsorption process interact to break the local thermodynamic equilibrium limitation by the formation of a stationary shock front inside the reactor. The physical meaning of this internal shock appears to be that it is the interface between two different regions; on one side the process is controlled by the reaction rate, and on the other side by the adsorption rate. The effect of non-ideality has also been investigated, and the performance characteristics have been discussed in comparison with those of the conventional fixed-bed reactor.

Catalytic wet peroxidation of phenol in a fixed bed reactor

2007 ◽  
Vol 55 (12) ◽  
pp. 75-81 ◽  
Author(s):  
F. Martínez ◽  
M.I. Pariente ◽  
J.A. Melero ◽  
J.A. Botas ◽  
E. Gómez
Keyword(s):  
Phenol Degradation ◽  
Fixed Bed ◽  
Methyl Cellulose ◽  
Packed Bed ◽  
Packed Bed Reactor ◽  
Fixed Bed Reactor ◽  
Continuous Treatment ◽  
Catalyst Stability ◽  
Solid Catalyst ◽  
Relevant Role

Iron-containing mesostructured materials (Fe-SBA-15) are suitable for continuous treatment of phenolic aqueous solutions by means of catalytic wet peroxide oxidation (CWPO) in a packed-bed reactor. These materials were successfully extruded, crushed and sieved with a particle size ranging from 1 to 1.6 mm using mineral clay and methyl cellulose as binders. Non-significant changes have been found in the textural and structural properties of the extruded material in comparison to the parent powder Fe-SBA-15 material. Activity of extruded catalyst in terms of phenol degradation and TOC reduction has been monitored in a continuous mode. The increase of residence time enhances significantly the TOC degradation. The catalyst stability, taking into account the loss of iron species from the catalyst into the aqueous solution, has also been examined. The catalytic results of Fe-SBA-15 material in comparison to a homogeneous catalytic test prove the relevant role of the solid catalyst in the oxidation process.

Continuous Treatment of Phenol over an Fe2O3/γ-Al2O3 Catalyst in a Fixed-Bed Reactor

2015 ◽  
Vol 226 (4) ◽  
Author(s):  
Minghui Lu ◽  
Yue Yao ◽  
Lulu Gao ◽  
Dongmei Mo ◽  
Fang Lin ◽  
...  
Keyword(s):  
Fixed Bed ◽  
Fixed Bed Reactor ◽  
Continuous Treatment ◽  
Al2o3 Catalyst

Role of filter media in an anaerobic fixed-bed reactor

1995 ◽  
Vol 31 (9) ◽  
pp. 137-144 ◽  
Author(s):  
T. Miyahara ◽  
M. Takano ◽  
T. Noike
Keyword(s):  
Anaerobic Bacteria ◽  
Fixed Bed ◽  
Methanogenic Bacteria ◽  
The Other ◽  
Fixed Bed Reactor ◽  
Filter Media ◽  
Fixed Bed Reactors ◽  
Attached Bacteria ◽  
The Relationship

The relationship between the filter media and the behaviour of anaerobic bacteria was studied using anaerobic fixed-bed reactors. At an HRT of 48 hours, the number of suspended acidogenic bacteria was higher than those attached to the filter media. On the other hand, the number of attached methanogenic bacteria was more than ten times as higher than that of suspended ones. The numbers of suspended and deposited acidogenic and methanogenic bacteria in the reactor operated at an HRT of 3 hours were almost the same as those in the reactor operated at an HRT of 48 hours. Accumulation of attached bacteria was promoted by decreasing the HRT of the reactor. The number of acidogenic bacteria in the reactor packed sparsely with the filter media was higher than that in the closely packed reactor. The number of methanogenic bacteria in the sparsely packed reactor was lower than that in the closely packed reactor.

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