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

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.

scholarly journals Zeolite Synthesis from Brazilian Coal Fly Ash for Removal of Zn2+ and Cd2+ from Water

2011 ◽  
Vol 356-360 ◽  
pp. 1900-1908 ◽  
Author(s):  
Juliana De Carvalho Izidoro ◽  
Denise Alves Fungaro ◽  
Shao Bin Wang
Keyword(s):  
Fly Ash ◽  
Specific Surface ◽  
Surface Area ◽  
Specific Surface Area ◽  
Metal Ion ◽  
Raw Materials ◽  
Coal Fly Ash ◽  
Mineralogical Composition ◽  
Batch Process ◽  
Metal Ion Removal

A Brazilian fly ash sample (CM1) was used to synthesize zeolites by hydrothermal treatment. Products and raw materials were characterized in terms of real density (Helium Pycnometry), specific surface area (BET method), morphological analysis (SEM), chemical composition (XRF) and mineralogical composition (XRD). The zeolites (ZM1) from fly ash were used for metal ion removal from water. Results indicated that hydroxy-sodalite zeolite could be synthesized from fly ash sample. The zeolite presented higher specific surface area and lower SiO2/Al2O3ratio than the ash precursor. The adsorption showed that cadmium is more preferentially adsorbed on ZM1 than zinc. The adsorption equilibrium time for both Zn2+and Cd2+was 20 hours in a batch process. The adsorption isotherms were better fitted by the Langmuir model and the highest percentages of removal using ZM1 were obtained at pH 6 and 5 and doses of 15 and 18 g L-1for Zn2+and Cd2+, respectively. Thermodynamic studies indicated that adsorption of Zn2+and Cd2+by ZM1 was a spontaneous, endothermic process and presented an increase of disorder at the interface solid/solution.

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

Desalination ◽  
2007 ◽  
Vol 211 (1-3) ◽  
pp. 128-137 ◽  
Author(s):  
G Tziotzios ◽  
Ch.N. Economou ◽  
G. Lyberatos ◽  
D.V. Vayenas
Keyword(s):  
Specific Surface ◽  
Surface Area ◽  
Specific Surface Area ◽  
Operating Mode ◽  
Packed Bed ◽  
Phenol Removal ◽  
Packed Bed Reactors

Performance of anaerobic packed-bed system with different media characteristics

1996 ◽  
Vol 34 (5-6) ◽  
pp. 453-459 ◽  
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.

scholarly journals Carbon dioxide captured by multi-walled carbon nanotube and activated charcoal: A comparative study

2013 ◽  
Vol 19 (1) ◽  
pp. 153-164 ◽  
Author(s):  
Soodabeh Khalili ◽  
Asghar Ghoreyshi ◽  
Mohsen Jahanshahi
Keyword(s):  
Carbon Nanotube ◽  
Specific Surface ◽  
Surface Area ◽  
Specific Surface Area ◽  
Co2 Capture ◽  
Activated Charcoal ◽  
Isotherm Models ◽  
Co2 Uptake ◽  
Practical Applications ◽  
Multi Walled Carbon Nanotube

this study, the equilibrium adsorption of CO2 on activated charcoal (AC) and multi-walled carbon nanotube (MWCNT) were investigated. Experiments were performed at temperature range of 298-318 K and pressures up to 40 bars. The obtained results indicated that the equilibrium uptakes of CO2 by both adsorbents increased with increasing pressure and decreasing temperature. In spite of lower specific surface area, the maximum amount of CO2 uptake achieved by MWCNT at 298K and 40 bars were twice of CO2 capture by AC (15 mmol.g-1 compared to 7.93 mmol.g-1). The higher CO2 captured by MWCNT can be attributed to its higher pore volume and specific structure of MWCN T such as hollowness and light mass which had greater influence than specific surface area. The experimental data were analyzed by means of Freundlich and Langmuir adsorption isotherm models. Following a simple acidic treatment procedure increased marginally CO2 capture by MWCNT over entire range of pressure, while for AC this effect appeared at higher pressures. Small values of isosteric heat of adsorption were evaluated based on Clausius-Clapeyron equation showed the physical nature of adsorption mechanism. The high amount of CO2 capture by MWCNT renders it as a promising carrier for practical applications such as gas separation.

scholarly journals Metal Foams as Novel Catalyst Support in Environmental Processes

Catalysts ◽  
2019 ◽  
Vol 9 (7) ◽  
pp. 587 ◽  
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.

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

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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