scholarly journals Removal of Cu(II) by Fixed-Bed Columns Using Alg-Ch and Alg-ChS Hydrogel Beads: Effect of Operating Conditions on the Mass Transfer Zone

Polymers ◽  
2020 ◽  
Vol 12 (10) ◽  
pp. 2345
Author(s):  
Ilse Paulina Verduzco-Navarro ◽  
Nely Rios-Donato ◽  
Carlos Federico Jasso-Gastinel ◽  
Álvaro de Jesús Martínez-Gómez ◽  
Eduardo Mendizábal
Keyword(s):  
Mass Transfer ◽  
Flow Rate ◽  
Linear Regression Analysis ◽  
Fixed Bed ◽  
Operating Conditions ◽  
Column Height ◽  
Thomas Model ◽  
Hydrogel Beads ◽  
Mass Transfer Zone ◽  
Transfer Zone

The removal of Cu(II) ions from aqueous solutions at a pH of 5.0 was carried out using fixed-bed columns packed with alginate-chitosan (Alg-Ch) or alginate-chitosan sulfate (Alg-ChS) hydrogel beads. The effect of the initial Cu(II) concentration, flow rate, pH, and height of the column on the amount of Cu removed by the column at the breakpoint and at the exhaustion point is reported. The pH of the solution at the column’s exit was initially higher than that at the entrance, and then decreased slowly. This pH increase was attributed to proton transfer from the aqueous solution to the amino and COO− groups of the hydrogel. The effect of operating conditions on the mass transfer zone (MTZ) and the length of the unused bed (HLUB) is reported. At the lower flow rate and lower Cu(II) concentration used, the MTZ was completely developed and the column operated efficiently; by increasing column height, the MTZ has a better opportunity to develop fully. Experimental data were fitted to the fixed-bed Thomas model using a non-linear regression analysis and a good correspondence between experimental and Thomas model curves was observed.

scholarly journals CO2 sorption from a mixture of N2/CO2 using an activated carbon and silica gel: equilibrium, breakthrough and mass transfer zone

2020 ◽  
Keyword(s):  
Mass Transfer ◽  
Partial Pressure ◽  
Flow Rate ◽  
Feed Rate ◽  
Fixed Bed ◽  
Feed Flow Rate ◽  
Utilization Factor ◽  
Mass Transfer Zone ◽  
Maximal Capacity ◽  
Transfer Zone

<p>The temperature, feed rate, length of mass transfer zone, utilization factor and partial pressure are the parameters considered for fixed bed sorption of CO2 from N2/CO2 mixture. The breakthrough time relies strongly on the temperature and feed rate. The prolonged breakthrough and saturation times have been realized for AC. The response curves of AC are vastly steep signifying the maximal utilization of bed capacity at the breakpoint. In general, the length of MTZ increases with raised temperature and feed flow rate. The capacity utilization factor reduces with raised temperature and feed flow rate. A utilization factor of 0.919 was determined for AC. The maximal capacity for CO2 reduces significantly with an increased temperature. The maximal capacities of 32.99 gm CO2/Kg was determined at a temperature of 298 K for AC. The capacity improves considerably with CO2 partial pressure and AC exhibited higher adsorption capacity compared to SG. The capacity improves considerably with increased feed rates and maximal capacity of 39.14 g CO2/Kg adsorbent was determined for AC at the feed rate of 8.33 x10-3 m3/sec. Owing to higher sorption capacity and utilization factor, the AC may be used for economical separation of CO2 from N2/CO2 mixture</p>

scholarly journals Dynamic Adsorption of Sulfamethoxazole from Aqueous Solution by Lignite Activated Coke

Materials ◽  
2020 ◽  
Vol 13 (7) ◽  
pp. 1785 ◽  
Author(s):  
Haiyan Li ◽  
Juan He ◽  
Kaiyu Chen ◽  
Zhou Shi ◽  
Mengnan Li ◽  
...  
Keyword(s):  
Mass Transfer ◽  
Flow Rate ◽  
Column Height ◽  
Dynamic Adsorption ◽  
Zone Length ◽  
Initial Concentration ◽  
Column Adsorption ◽  
Activated Coke ◽  
Mass Transfer Zone ◽  
Transfer Zone

In this paper, lignite activated coke was used as adsorbent for dynamic column adsorption experiments to remove sulfamethoxazole from aqueous solution. The effects of column height, flow rate, initial concentration, pH and humic acids concentration on the dynamic adsorption penetration curve and mass transfer zone length were investigated. Results showed penetration time would be prolonged significantly by increasing column height, while inhibited by the increasement of initial concentration and flow rate. Thomas and Yoon-Nelson model and the Adams-Bohart model were used to elucidate the adsorption mechanism, high coefficients of R2 > 0.95 were obtained in Thomas model for most of the adsorption entries, which revealed that the adsorption rate could probably be dominated by mass transfer at the interface. The average change rates of mass transfer zone length to the changes of each parameters, such as initial concentration, the column height, the flow rate and pH, were 0.0003, 0.6474, 0.0076, 0.0073 and 0.0191 respectively, revealed that column height may play a vital role in dynamic column adsorption efficiency. These findings suggested that lignite activated coke can effectively remove sulfamethoxazole contaminants from wastewater in practice.

scholarly journals Comparative Study of CO2 Capture by Adsorption in Sustainable Date Pits-Derived Porous Activated Carbon and Molecular Sieve

2021 ◽  
Vol 18 (16) ◽  
pp. 8497
Author(s):  
Mohd Danish ◽  
Vijay Parthasarthy ◽  
Mohammed K. Al Mesfer
Keyword(s):  
Mass Transfer ◽  
Activated Carbon ◽  
Molecular Sieve ◽  
Fixed Bed ◽  
Utilization Factor ◽  
Adsorption Performance ◽  
Mass Transfer Zone ◽  
Date Pits ◽  
Porous Activated Carbon ◽  
Transfer Zone

The rising CO2 concentration has prompted the quest of innovative tools to reduce its effect on the environment. A comparative adsorption study using sustainable low-cost date pits-derived activated carbon and molecular sieve has been carried out for CO2 separation. The adsorb ents were characterized for surface area and morphological properties. The outcomes of flow rate, temperature and initial adsorbate concentration on adsorption performance were examined. The process effectiveness was investigated by breakthrough time, adsorbate loading, efficiency, utilized bed height, mass transfer zone and utilization factor. The immensely steep adsorption response curves demonstrate acceptable utilization of adsorbent capability under breakthrough condition. The adsorbate loading 73.08 mg/g is achieved with an 0.938 column efficiency for developed porous activated carbon at 298 K. The reduced 1.20 cm length of mass transfer zone with enhanced capacity utilization factor equal 0.97 at 298 K with Cin = 5% signifies better adsorption performance for date pits-derived adsorbent. The findings recommend that produced activated carbon is greatly promising to adsorb CO2 in fixed bed column under continuous mode.

HCl Removal and Chlorine Distribution in the Mass Transfer Zone of a Fixed-Bed Reactor at High Temperature

2006 ◽  
Vol 20 (3) ◽  
pp. 959-963 ◽  
Author(s):  
Binlin Dou ◽  
Bingbing Chen ◽  
Jinsheng Gao ◽  
Xingzhong Sha
Keyword(s):  
Mass Transfer ◽  
High Temperature ◽  
Fixed Bed ◽  
Fixed Bed Reactor ◽  
Hcl Removal ◽  
Mass Transfer Zone ◽  
Transfer Zone

scholarly journals Optimization of Crystal Violet Dye Removal in Fixed Bed Column Using Eucalyptus camaldulensis as a Low-Cost Adsorbent

2021 ◽  
Vol 11 (4) ◽  
pp. 4114-4130
Keyword(s):  
Breakthrough Curve ◽  
Fixed Bed ◽  
Eucalyptus Camaldulensis ◽  
Thomas Model ◽  
Fixed Bed Column ◽  
Bed Height ◽  
Crystal Violet Dye ◽  
Best Fit ◽  
Mass Transfer Zone ◽  
Transfer Zone

Adsorption through waste adsorbents is one of the developing technologies used for treating textile wastewater. The present study explores the possible outcome of Eucalyptus camaldulensis biomass as an adsorbent for removing crystal violet dye from aqueous solutions. Eucalyptus camaldulensis biomass was used as such and used in fixed bed column mode to testify its potential at different parameters. Effect of different constraints like bed height (cm), flow rate (mlmin-1), initial dye concentration (mgL-1), and pH were studied along with breakthrough curve and exhaust time. Maximum breakthrough curve and exhaust time and utilization of mass transfer zone were observed at bed height of 20 cm. However, the promising results are obtained at higher dye concentration (50 mgL-1), lower flow rate (1 mlmin-1), and at lower pH of 5. This study reveals promising results at acidic pH. This study reflects that adsorption capacity and breakthrough curve favor lower acidic pH. The adsorption data in batch mode follow the Langmuir isotherm and best fit to pseudo-second-order reaction kinetics. The breakthrough curve and mass transfer zone are individually testified, and the breakthrough curve obeys the assumptions of the Thomas model, and R2 (0.933-0.997) values confirm the data that its best fit with the Thomas model.

Behavior of the Mass Transfer Zone in a Biosorption Column

2006 ◽  
Vol 40 (12) ◽  
pp. 3996-4003 ◽  
Author(s):  
Ghinwa Naja ◽  
Bohumil Volesky
Keyword(s):  
Mass Transfer ◽  
Mass Transfer Zone ◽  
Transfer Zone

Performance Analysis on the Internally Cooled Dehumidifier Using Two Liquid Desiccant Solutions

2012 ◽  
Author(s):  
I. P. Koronaki ◽  
R. I. Christodoulaki ◽  
V. D. Papaefthimiou ◽  
E. D. Rogdakis
Keyword(s):  
Mass Transfer ◽  
Theoretical Model ◽  
Heat And Mass Transfer ◽  
Flow Rate ◽  
Air Conditioning ◽  
Cooling Water ◽  
Operating Conditions ◽  
Inlet Temperature ◽  
Liquid Desiccant ◽  
Internally Cooled

Liquid desiccant air conditioning systems have recently been attracting attention due to their capability of handling the latent load without super-cooling and then reheating the air, as happens in a conventional compression-type air conditioning system. This paper presents the results from a study of the performance of an internally cooled liquid desiccant dehumidifier. A plate heat exchanger is proposed as the internally cooled element of the dehumidifier and water as the cooling fluid. The desiccant solution is sprayed into the internally cooled dehumidifier from the top and flows down by gravity. At the same time, fresh humid air is blown from the bottom or top, counter-flowing or co-flowing with the desiccant solution. The desiccant is in direct contact with the air, allowing for heat and mass transfer. The cooling water, flowing inside the plates of the dehumidifier, carries out the heat of the crossed air and solution. A heat and mass transfer theoretical model has been developed, based on the Runge-Kutta fixed step method, to predict the performance of the device under various operating conditions. Experimental data from previous literature have been used to validate the model. Excellent agreement has been found between experimental tests and the theoretical model, with the deviation not exceeding ±4.1% for outlet air temperature and ±4.0% for outlet humidity ratio. Following the validation of the mathematical model, the dominating effects on the absorption process have been discussed in detail. Namely, effects of flow configuration, air inlet temperature, humidity and flow rate, as well as desiccant inlet temperature, concentration and flow rate have been investigated against the dehumidification rate and the cooling efficiency. The two most commonly used liquid desiccant solutions, namely LiCl and LiBr have been also evaluated against each other. The results suggested that high dehumidification mass rate can be achieved under counter flow between air and solution, low air mass flow rates, low cooling water temperature, low desiccant temperature and LiCl as the desiccant solution.

scholarly journals Synthesis and application of CeO2/sawdust nanocomposite for removal of As (III) ions from aqueous solutions using a fixed bed column system

2016 ◽  
Vol 19 (1) ◽  
pp. 7-16 ◽  
Keyword(s):  
Aqueous Solutions ◽  
Flow Rate ◽  
Fixed Bed ◽  
Cost Effective ◽  
Sorption Process ◽  
Breakthrough Curves ◽  
Precipitation Method ◽  
Thomas Model ◽  
Influent Concentration ◽  
Column System

<p>In this study, nanocomposite of ceria sawdust (CeO<sub>2</sub>/SD) synthesized by precipitation method was utilized for removal of As (III) ions from aqueous solutions. Study of the process was done in column system. Characterization of the nano sized adsorbent particles was carried out using XRD and SEM techniques. The effects of important parameters, such as the value of initial pH, the flow rate, the influent concentration of arsenic and bed depth were studied in the column system. The Thomas model was applied for treatment of the adsorption data at different flow rate, influent concentration and bed depth. The bed-depth/service time analysis (BDST) model was also applied at different bed depth to predict the breakthrough curves. The two models were found suitable for describing the bio sorption process of the dynamic behavior of the CeO<sub>2</sub>/SD adsorbent in column investigation. Based on Thomas model, the equilibrium adsorption reached 8.28 mg g<sup>−</sup><sup>1</sup> when a As(III) polluted solution with influent concentration of As 10 mg l<sup>-1 </sup>passed through the column with a flow rate of 2 ml min<sup>−</sup><sup>1</sup>. All the results suggested the presented nanocomposite as an efficient and cost effective adsorbent for removal of As (III) ions from aqueous solutions.</p>

Sign in / Sign up

Export Citation Format

Share Document