scholarly journals Modification of the Thomas model for predicting unsymmetrical breakthrough curves using an adaptive neural-based fuzzy inference system

2019 ◽  
Vol 17 (1) ◽  
pp. 25-36 ◽  
Author(s):  
Mohammad Javad Amiri ◽  
Maryam Khozaei ◽  
Antonio Gil
Keyword(s):  
Hybrid Model ◽  
Fuzzy Inference ◽  
Fixed Bed ◽  
Breakthrough Curves ◽  
Dynamic Adsorption ◽  
Thomas Model ◽  
Fixed Bed Column ◽  
Column System ◽  
Bone Ash ◽  
Model Complex

Abstract The Thomas equation is a popular model that has been widely used to predict breakthrough curves (BTCs) when describing the dynamic adsorption of different pollutants in a fixed-bed column system. However, BTCs commonly exhibit unsymmetrical patterns that cannot be predicted using empirical equations such as the Thomas model. Fortunately, adaptive neural-based fuzzy inference systems (ANFISs) can be used to model complex patterns found in adsorption processes in a fixed-bed column system. Consequently, a new hybrid model merging Thomas and an ANFIS was introduced to estimate the performance of BTCs, which were obtained for Cd(II) ion adsorption on ostrich bone ash-supported nanoscale zero-valent iron (nZVI). The results obtained showed that the fair performance of the Thomas model (NRMSE = 27.6% and Ef = 64.6%) improved to excellent (NRMSE = 3.8% and Ef = 93.8%) due to the unique strength of ANFISs in nonlinear modeling. The sensitivity analysis indicated that the initial solution pH was a more significant input variable influencing the hybrid model than the other operational factors. This approach proves the potential of this hybrid method to predict BTCs for the dynamic adsorption of Cd(II) ions by ostrich bone ash-supported nZVI particles. This article has been made Open Access thanks to the generous support of a global network of libraries as part of the Knowledge Unlatched Select initiative.

scholarly journals Sorption of Ag+ and Cu2+ by Vermiculite in a Fixed-Bed Column: Design, Process Optimization and Dynamics Investigations

2018 ◽  
Vol 8 (11) ◽  
pp. 2221 ◽  
Author(s):  
Olga Długosz ◽  
Marcin Banach
Keyword(s):  
Flow Rate ◽  
Continuous Process ◽  
Fixed Bed ◽  
Copper Ion ◽  
Cost Effective ◽  
Breakthrough Curves ◽  
Fixed Bed Column ◽  
Column System ◽  
Total Percentage ◽  
Bed Height

Vermiculite has been used for the removal of Cu 2 + and Ag + from aqueous solutions in a fixed-bed column system. The effects of initial silver and copper ion concentrations, flow rate, and bed height of the adsorbent in a fixed-bed column system were investigated. Statistical analysis confirmed that breakthrough curves depended on all three factors. The highest inlet metal cation concentration (5000 mg/dm3), the lowest bed height (3 cm) and the lowest flow rate (2 and 3 cm3/min for Ag + and Cu 2 + , respectively) were optimal for the adsorption process. The maximum total percentage of metal ions removed was 60.4% and 68.7% for Ag+ and Cu2+, respectively. Adsorption data were fitted with four fixed-bed adsorption models, namely Clark, Bohart–Adams, Yoon–Nelson and Thomas models, to predict breakthrough curves and to determine the characteristic column parameters. The adsorbent was characterized by SEM, FTIR, EDS and BET techniques. The results showed that vermiculite could be applied as a cost-effective sorbent for the removal of Cu 2 + and Ag + from wastewater in a continuous process.

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>

scholarly journals Removal and Recovery of Silver by Dynamic Adsorption on Bentonite Clay Using a Fixed-Bed Column System

2015 ◽  
Vol 33 (2) ◽  
pp. 91-103 ◽  
Author(s):  
M. L. Cantuaria ◽  
E. S. Nascimento ◽  
A. F. Almeida Neto ◽  
O. A. A. dos Santos ◽  
M. G. A. Vieira
Keyword(s):  
Fixed Bed ◽  
Bentonite Clay ◽  
Dynamic Adsorption ◽  
Fixed Bed Column ◽  
Column System ◽  
Removal And Recovery

scholarly journals Treatment of wastewaters contaminated with zinc ions using natural zeolite as adsorbent in a fixed bed column

2015 ◽  
Vol 5 (4) ◽  
pp. 542-549 ◽  
Author(s):  
Waid S. Omar
Keyword(s):  
Natural Zeolite ◽  
Low Cost ◽  
Fixed Bed ◽  
Breakthrough Curves ◽  
Zinc Ions ◽  
Thomas Model ◽  
Fixed Bed Column ◽  
Nelson Model ◽  
Two Samples ◽  
High Degree

The potential of natural zeolite as a low-cost adsorbent was investigated for the removal of zinc from aqueous solution using a continuous fixed bed column. The zeolite tested was taken from the same source (Jabal Uniza in south Jordan) and subjected to crushing and sieving only, without any treatment. The two samples tested are UNZ1 (0.42–0.841 mm) and UNZ2 (0.21–0.42 mm). The Thomas model analysis of the measured breakthrough curves revealed that the adsorbent UNZ2 has a higher value of adsorption capacity to zinc ions (50.75 mg/g) than UNZ1 (33.68 mg/g). The time to 50% breakthrough was determined by the Yoon and Nelson model. It has been found that the time needed to reach 50% breakthrough is 2,006 minutes and 3,171 minutes for UNZ1 and UNZ2, respectively. This indicated that UNZ2 provides better performance with larger service time. Both UNZ1 and UNZ2 agreed to a high degree with the Thomas and Yoon and Nelson models.

scholarly journals Modified Biopolymer Adsorbents for Column Treatment of Sulfate Species in Saline Aquifers

Materials ◽  
2020 ◽  
Vol 13 (10) ◽  
pp. 2408
Author(s):  
Mostafa Solgi ◽  
Lope G. Tabil ◽  
Lee D. Wilson
Keyword(s):  
Adsorption Capacity ◽  
Fixed Bed ◽  
Breakthrough Curves ◽  
Maximum Adsorption Capacity ◽  
Adsorption Parameters ◽  
Sulfate Adsorption ◽  
Specific Flow ◽  
Fixed Bed Column ◽  
Sulfate Removal ◽  
Column System

In the present study, variable forms of pelletized chitosan adsorbents were prepared and their sulfate uptake properties in aqueous solution was studied in a fixed-bed column system. Unmodified chitosan pellets (CP), cross-linked chitosan pellets with glutaraldehyde (CL–CP), and calcium-doped forms of these pellets (Ca–CP, Ca–CL–CP) were prepared, where the removal efficiencies and breakthrough curves were studied. Dynamic adsorption experiments were conducted at pH 4.5 and 6.5 with a specific flow rate of 3 mL/min, fixed-bed height of 200 mm, and an initial sulfate concentration of 1000 mg/L. Breakthrough parameters demonstrated that Ca–CP had the best sulfate removal among the adsorbents, where the following adsorption parameters were obtained: breakthrough time (75 min), exhaust time (300 min), maximum sulfate adsorption capacity (qmax; 46.6 mg/g), and sulfate removal (57%) at pH 4.5. Two well-known kinetic adsorption models, Thomas and Yoon-Nelson, were fitted to the experimental kinetic data to characterize the breakthrough curves. The fixed-bed column experimental results were well-fitted by both models and the maximum adsorption capacity (46.9 mg/g) obtained was for the Ca–CP adsorbent. A regeneration study over four adsorption-desorption cycles suggested that Ca–CP is a promising adsorbent for sulfate removal in a fixed-bed column system.

scholarly journals Adsorption of Hg(II) and Pb(II) ions by nanoscale zero valent iron supported on ostrich bone ash in a fixed-bed column system

2017 ◽  
Vol 76 (3) ◽  
pp. 671-682 ◽  
Author(s):  
Mohammad Javad Amiri ◽  
Jahangir Abedi-koupai ◽  
Saeid Eslamian
Keyword(s):  
Metal Ions ◽  
Ph Value ◽  
Fixed Bed ◽  
Zerovalent Iron ◽  
Fixed Bed Column ◽  
Flow Rates ◽  
Nanoscale Zerovalent Iron ◽  
Column System ◽  
Bed Height ◽  
Bone Ash

In this research, ostrich bone ash (OBA) was modified with nanoscale zerovalent iron (nZVI) particles and applied as a novel composite adsorbent (OBA/nZVI) for dynamic adsorption/reduction of Hg(II) and Pb(II) ions in a fixed-bed column system. Entrapment of nZVI in OBA beads barricades the particles from oxidation and aggregation. The dynamic behavior of metal ions removal by OBA/nZVI was assessed as a function of inlet flow rates, bed height, initial pollutants concentration and pH. The synthesized OBA/nZVI composite was characterized by several physicochemical techniques. Increase in pH and bed height and decrease in flow rates and initial metal concentration resulted in delay of breakthrough time. OBA breakthrough profile is sharper than the OBA/nZVI breakthrough curve for both metal ions and the breakthrough times increase in the order OBA/nZVI-Hg(II) &gt; OBA/nZVI-Pb(II) &gt; OBA-Pb(II) &gt; OBA-Hg(II). Based on the experiment results, redox reaction is expected to occur to a certain extent, as the standard reduction potentials of Hg(II) and Pb(II) are more than that of Fe(II). From a practical point of view, the OBA/nZVI could be applied as a material to remove Hg(II) and Pb(II) ions from natural surface and ground water with a pH value of 5–9.

Modeling of Fixed-Bed Column System of Hg(II) Ions on Ostrich Bone Ash/nZVI Composite by Artificial Neural Network

2017 ◽  
Vol 143 (9) ◽  
pp. 04017061 ◽  
Author(s):  
Mohammad Javad Amiri ◽  
Jahangir Abedi-koupai ◽  
Seyed Mohammad Jafar Jalali ◽  
Sayed Farhad Mousavi
Keyword(s):  
Neural Network ◽  
Artificial Neural Network ◽  
Fixed Bed ◽  
Fixed Bed Column ◽  
Column System ◽  
Bone Ash ◽  
Artificial Neural

Biochar caged zirconium ferrite nanocomposites for the adsorptive removal of Reactive Blue 19 dye in a batch and column reactors and conditions optimizaton

2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Shazia Perveen ◽  
Raziya Nadeem ◽  
Shaukat Ali ◽  
Yasir Jamil
Keyword(s):  
Experimental Data ◽  
Low Dose ◽  
Fixed Bed ◽  
Breakthrough Curves ◽  
Adsorption Efficiency ◽  
Fixed Bed Column ◽  
Flow Rates ◽  
Adsorptive Removal ◽  
Reactive Blue 19 ◽  
Pseudo Second Order

Abstract Biochar caged zirconium ferrite (BC-ZrFe2O5) nanocomposites were fabricated and their adsorption capacity for Reactive Blue 19 (RB19) dye was evaluated in a fixed-bed column and batch sorption mode. The adsorption of dye onto BC-ZrFe2O5 NCs followed pseudo-second-order kinetics (R 2 = 0.998) and among isotherms, the experimental data was best fitted to Sips model as compared to Freundlich and Langmuir isotherms models. The influence of flow-rate (3–5 mL min−1), inlet RB19 dye concentration (20–100 mg L−1) and quantity of BC-ZrFe2O5 NCs (0.5–1.5 g) on fixed-bed sorption was elucidated by Box-Behnken experimental design. The saturation times (C t /C o  = 0.95) and breakthrough (C t /C o  = 0.05) were higher at lower flow-rates and higher dose of BC-ZrFe2O5 NCs. The saturation times decreased, but breakthrough was increased with the initial RB19 dye concentration. The treated volume was higher at low sorbent dose and influent concentration. Fractional bed utilization (FBU) increased with RB19 dye concentration and flow rates at low dose of BC-ZrFe2O5 NCs. Yan model was fitted best to breakthrough curves data as compared to Bohart-Adams and Thomas models. Results revealed that BC-ZrFe2O5 nanocomposite has promising adsorption efficiency and could be used for the adsorption of dyes from textile effluents.

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