Effect of the specific surface area and operating mode on biological phenol removal using packed bed reactors

Gel derived TiO2-SiO2 and N-TiO2-SiO2 mixed oxides are synthesized and employed for phenol removal under UVA light and natural sunlight in this study. Both SiO2 and N are interestingly found to improve the specific surface area of resulting catalysts as compared to bare TiO2. Meanwhile, only N is observed to significantly shift the light absorption of derived catalyst to visible range. Optimization between specific surface area and crystallinity is found to give rise to the superior photoactivity of TiO2-SiO2 catalyst in comparison with TiO2 counterpart. Under natural sunlight in Hochiminh City in September, N-TiO2-SiO2 presents the outstanding photoactivity towards phenol removal with the efficiency up to 90% as compared to those of 62% and 60% for bare TiO2-SiO2 and bare TiO2, respectively.

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Performance of anaerobic packed-bed system with different media characteristics

Water Science & Technology ◽

10.2166/wst.1996.0582 ◽

1996 ◽

Vol 34 (5-6) ◽

pp. 453-459 ◽

Cited By ~ 2

Author(s):

Joo-Hwa Tay ◽

S. Jeyaseelan ◽

Kuan-Yeow Show

Keyword(s):

Specific Surface ◽

Pore Size ◽

Surface Area ◽

Removal Efficiency ◽

Specific Surface Area ◽

Oxygen Demand ◽

Specific Area ◽

Packed Bed ◽

Cod Removal ◽

Cod Removal Efficiency

The effects of media specific surface area, porosity, and pore size on the performance of upflow anaerobic packed-bed reactors (APBRs) were examined in the laboratory. The results showed that, the APBR containing media of the lowest surface area but the largest pore size and porosity, demonstrated the highest chemical oxygen demand (COD) removal efficiencies of 90% and 73% at loading rates of 8 and 16 g COD/L.day, respectively. An increase of over 40% in specific area in an APBR had not improved the removal efficiency, instead it produced 16% lower in COD removal efficiency at loading rate of 16 g COD/L.d. A study on the effects of effluent recycle indicates that the APBR having the largest pore size and porosity benefited from the recirculation. The reactor exhibited an increase in overall COD removal efficiency of 8% and a substantial decrease in effluent COD concentration of 30%. The results suggest that media pore size and porosity play a more significant role than media specific surface area in the performance of upflow APBRs.

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Batch and packed bed techniques for adsorptive aqueous phase removal of selected phenoxyacetic acid herbicide using sugar industry waste ash

International Journal of Chemical Reactor Engineering ◽

10.1515/ijcre-2020-0084 ◽

2020 ◽

Vol 18 (12) ◽

Author(s):

Sunil K. Deokar ◽

Pooja G. Theng ◽

Sachin A. Mandavgane

Keyword(s):

Kinetic Model ◽

Specific Surface ◽

Surface Area ◽

Specific Surface Area ◽

Sugar Industry ◽

Batch Process ◽

Packed Bed ◽

Breakthrough Curves ◽

Isotherm Models ◽

Phenoxyacetic Acid

AbstractBatch and packed bed adsorption of 4-chloro-2-methylphenoxyacetic acid (MCPA) herbicide was performed using bagasse fly ash (BFA) as an adsorbent. In batch process, characteristics of adsorbent, and the influence of adsorbent dosage, initial herbicide concentration, time, pH, particle size of adsorbent and temperature on adsorption were studied. Results disclose higher removal of MCPA on bigger particles of BFA owing to higher specific surface area because of greater carbon and lesser silica percentage in bigger particles. Application of isotherm models in present study indicates the best fitting of Langmuir and Temkin isotherms whereas the kinetic models suggest the suitability of pseudo second order and Elovich models. Thermodynamic study specifies the temperature preferred adsorption process. In packed bed technique, the effect of influent concentration, flow rate and bed height were investigated. The deactivation kinetic model which was previously considered only for studies in gas-solid adsorption is applied in this study to solid-liquid adsorption along with conventional packed bed models. In packed bed study, Bohart-Adams and Wolborska models are appropriate to explain the experimental data upto 60% saturation of the column. The deactivation kinetic model is found the best to elucidate the nature of breakthrough curves till the complete saturation of column. Batch capacity and packed bed capacity per m2 specific surface area of BFA is found about two and three times greater than the previously used adsorbents for MCPA respectively.

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Metal Foams as Novel Catalyst Support in Environmental Processes

Catalysts ◽

10.3390/catal9070587 ◽

2019 ◽

Vol 9 (7) ◽

pp. 587 ◽

Cited By ~ 5

Author(s):

Anna Gancarczyk ◽

Katarzyna Sindera ◽

Marzena Iwaniszyn ◽

Marcin Piątek ◽

Wojciech Macek ◽

...

Keyword(s):

Mass Transfer ◽

Pressure Drop ◽

Specific Surface ◽

Surface Area ◽

Specific Surface Area ◽

Mechanical Stability ◽

Packed Bed ◽

Metal Foams ◽

High Porosity ◽

Slow Kinetics

Metal foams are considered as promising catalyst carriers due to their high porosity, large specific surface area, and satisfactory thermal and mechanical stability. The study presents heat transfer and pressure drop experiments performed for seven foams of different pore densities made from diverse metals. Mass transfer characteristics are derived using the Chilton–Colburn analogy. It was found that the foams display much more intense heat/mass transfer than a monolith, comparable to packed bed. Next, the foams’ efficiencies have been compared, using 1D reactor modeling, in catalytic reactions displaying either slower (selective catalytic reduction of NOx) or faster kinetics (catalytic methane combustion). For the slow kinetics, the influence of carrier specific surface area at which catalyst can be deposited (i.e., catalyst amount) was decisive to achieve high process conversion and short reactor. For this case, monolith appears as the best choice assuming it’s the lowest pressure drop. For the fast reaction, the mass transfer becomes the limiting parameter, thus solid foams are the best solution.

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Technology Advances in Phenol Removals: Current Progress and Future Perspectives

Catalysts ◽

10.3390/catal11080998 ◽

2021 ◽

Vol 11 (8) ◽

pp. 998

Author(s):

Wibawa Hendra Saputera ◽

Amellia Setyani Putrie ◽

Ali Asghar Esmailpour ◽

Dwiwahju Sasongko ◽

Veinardi Suendo ◽

...

Keyword(s):

Specific Surface ◽

Surface Area ◽

Specific Surface Area ◽

Rational Design ◽

Catalytic Ozonation ◽

Future Research ◽

Synthesis Methods ◽

Phenol Removal ◽

Heterogeneous Catalytic ◽

Advanced Technologies

Phenol acts as a pollutant even at very low concentrations in water. It is classified as one of the main priority pollutants that need to be treated before being discharged into the environment. If phenolic-based compounds are discharged into the environment without any treatments, they pose serious health risks to humans, animals, and aquatic systems. This review emphasizes the development of advanced technologies for phenol removal. Several technologies have been developed to remove phenol to prevent environmental pollution, such as biological treatment, conventional technologies, and advanced technologies. Among these technologies, heterogeneous catalytic ozonation has received great attention as an effective, environmentally friendly, and sustainable process for the degradation of phenolic-based compounds, which can overcome some of the disadvantages of other technologies. Recently, zeolites have been widely used as one of the most promising catalysts in the heterogeneous catalytic ozonation process to degrade phenol and its derivatives because they provide a large specific surface area, high active site density, and excellent shape-selective properties as a catalyst. Rational design of zeolite-based catalysts with various synthesis methods and pre-defined physiochemical properties including framework, ratio of silica to alumina (SiO2/Al2O3), specific surface area, size, and porosity, must be considered to understand the reaction mechanism of phenol removal. Ultimately, recommendations for future research related to the application of catalytic ozonation technology using a zeolite-based catalyst for phenol removal are also described.

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Behavior of activated carbons by compound modification in high gravity for toluene adsorption

Adsorption Science & Technology ◽

10.1177/0263617417744401 ◽

2017 ◽

Vol 36 (3-4) ◽

pp. 1018-1030

Author(s):

Qiang Guo ◽

You-Zhi Liu ◽

Gui-Sheng Qi ◽

Wei-Zhou Jiao

Keyword(s):

Specific Surface ◽

Pore Size ◽

Surface Area ◽

Functional Groups ◽

Specific Surface Area ◽

Activated Carbons ◽

Packed Bed ◽

High Gravity ◽

Rotating Packed Bed ◽

Compound Modification

The rotating packed bed is a chemical apparatus that strengthens mass transfer between phases to enhance their reactivity. It can be used to modify adsorbent materials, greatly improving their chemical properties. This article studies the effect of compound modification of activated carbons in a high-gravity environment on their toluene adsorption. The compound modification includes physical (N2) and chemical modification (HNO3), and the effect of modification is compared between traditional fixed-bed and rotating packed bed modification. The physical characteristics of the activated carbons, including pore size, specific surface area, and morphology are tested by Brunauer–Emmett–Teller and scanning electron microscopy, and the surface functional groups of the activated carbons are determined by Fourier transform infrared spectroscopy and Boehm titration. The results indicate that the activated carbons modified by rotating packed bed have a larger specific surface area (871.5 m2/g) and smaller pore size (0.524 nm), and the content of acidic oxygen-containing groups is 1.5 times that of unmodified activated carbons. The adsorption capacity of the activated carbons compound-modified by rotating packed bed increases by 69% compared with the unmodified activated carbons. The adsorption by the rotating packed bed-compound-modified activated carbons obeys the Freundlich model. The modification of activated carbons by rotating packed bed greatly enhances their specific surface area, pore size, and surface content of oxygen-containing functional groups, markedly improving the adsorption performance and increasing the utilization rate.

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