Packed Bed Column Research Articles

Green Clay Materials Applied in Packed Bed Columns for the Hexavalent Chromium Adsorption from Aqueous Solutions

Green Clay Materials Applied in Packed Bed Columns for the Hexavalent Chromium Adsorption from Aqueous Solutions

Improved packed bed column bioreactor to produce fungal conidia for biological control

Improved packed bed column bioreactor to produce fungal conidia for biological control

Selective separation and recovery of rare-earth elements (REEs) from acidic solutions and coal fly ash leachate by novel TODGA-Impregnated organosilica media

Rare-earth elements (REEs) are essential in a wide range of applications including magnets and satellite technology, with demand driven by geopolitical factors. While multiple techniques exist for REE recovery including solvent extraction and selective precipitation, solid–liquid extraction offers key advantages in selectivity, scalability, and recyclability. N, N, N′, N′-tetraoctyl diglycolamide (TODGA) is a tridentate ligand widely used in solvent extraction, but the incorporation in a solid support to separate individual lanthanides from acid solutions remains largely unexplored. A novel TODGA-organosilica sorbent material was developed and tested to evaluate recovery of 17 elements (REEs and thorium) in terms of selectivity, kinetics, and equilibrium isotherms in 0.01 to 15.9 M nitric acid. Characterization of the new sorbent was performed before and after sorption using FTIR, XPS, and SSA techniques to help elucidate sorption mechanisms and limiting variables. REE adsorption increased from 1.26 mg g−1 to 10 mg g−1 with nitric acid concentrations of 0.01 M and 15.9 M, respectively. TODGA-organosilica exhibits high selectivity towards heavy REEs (Dy to Lu), with minimal sorption of lighter REEs (Ce to Gd). Batch adsorption experiments confirm pseudo-second-order kinetics and a Langmuir adsorption isotherm with TODGA binding to REEs in a 3:1 complex. A packed bed column study confirmed the high selectivity of TODGA-impregnated organosilica towards heavy REEs and a proof-of concept experiment with coal fly ash leachate shows high selectivity for REEs over Al, Fe, and Ca present in several orders of magnitude higher concentrations. Fractionation was observed where loading cycle effluent contained 84 % light REEs while strip cycle effluent contained 80 % heavy REEs. More than 90 % of loaded REEs were successfully stripped with water as the stripping agent.

Numerical modelling and simulation of methane enrichment: a systematic review on pressure swing adsorption technology

ABSTRACT Enriching methane from sources such as natural gas, biogas, and coalbed methane is a valuable gas separation endeavor, given methane as a cleaner and more sustainable fuel resource. Pressure swing adsorption (PSA) is widely regarded as a mature technology for this purpose. The essence of the mathematical model is to capture the fundamental aspects of the problem, enabling an accurate description of the system. This review summarizes recent trends in the mathematical modelling of PSA for methane enrichment. It provides a comprehensive compilation of numerical modelling and simulation studies, with a critical emphasis on methane enrichment applications. A rigorous mathematical model describing the adsorption phenomenology in a packed bed column is presented, incorporating mass, momentum, and energy balances, which serve as the fundamental framework for the cyclic adsorption process. Key analyses and performance metrics of PSA systems are detailed through examples from the literature. A case study based on a single column is presented to exemplify the mathematical modelling pathway and serve as a basis for model validation. The paper concludes by highlighting instructive avenues for future research directions and development in this area.

Enzymatic CO2 Capture in intensified packed-bed column bioreactors: A techno-economic assessment

To reduce the impact of industrial carbon dioxide (CO2) emissions on climate change, energy-efficient and cost-effective carbon capture technologies are needed. With this in mind, our research group has proposed an intensified enzyme-mediated CO2 capture process in packed-bed column bioreactors with carbonic anhydrase (CA) immobilized on the packing surface and on magnetic nanoparticles (MNPs). This study, in continuation of our efforts to amend these processes, aims to showcase a techno-economic assessment (TEA) of this promising technology in an industrial-scale context and to emphasize the inherent benefits of intensification. The TEA results suggest that this enzyme-mediated technology has the potential to reduce capture costs, chiefly due to the possibility of utilizing an alternative solvent that requires less energy to regenerate, while also being non-corrosive and non-toxic. The capture process consumes 39.8% less energy than the benchmark process utilizing a MEA-based solution. Immobilizing the enzyme on MNPs has tangible benefits, such as enhancing mass transfer and reducing the equipment footprint, which improves flexibility and contributes to the viability of the industrial process. The intensified enzyme-mediated CO2 capture process achieves a 28.6% reduction in capture cost compared to the benchmark technology. Sensitivity analyses were conducted to highlight the impact of key parameters on the overall cost-effectiveness of the technology, providing beneficial insights for further improvement. The results indicate that it is crucial to maximize enzyme lifespan and minimize energy consumption. The liquid flow rate and buffer concentration are additional constraints that should be thoughtfully considered to ensure the feasibility of this process.

Best of Both Worlds: Adsorptive Ultrafiltration Nanocellulose‐Hypercrosslinked Polymer Hybrid Membranes for Metal Ion Removal

Efficient water treatment ideally combines ion exchange for the removal of hardness elements and toxic trace metals as well as ultrafiltration for the removal of particulate matter. Although promising for adsorption, many high‐surface‐area polymer materials cannot be easily processed into freestanding membranes or packed bed columns, due to poor solution processability and high back pressures, respectively. The preparation of hybrid membranes comprising sulfonated hypercrosslinked polymers entrapped in nanocellulose papers is described. The hybrid membranes are effective for simultaneous ultrafiltration and ion exchange. Increasing the polymer loading of the hybrid membrane produces synergy by increasing the permeance of the membranes while enhancing the ion adsorption capacity to values exceeding those of bulk hypercrosslinked polymers. The maximum ion adsorption capacity for copper is determined to be ≈100 mg g−1 outperforming that of pure polymer (71 mg g−1) and commercially available ion exchange resins. Competitive adsorption is tested in samples containing water hardness elements and trace toxic metal ions showing high ion‐exchange capacities. Even when fully loaded with water hardness elements, Ba2+ and Sr2+ are still removed from solution.

Carbon Dioxide Removal Using Blended Amine Solution in a Randomly Packed Bed Column

Many researchers are currently investigating carbon dioxide capture and storage since it is suppressing the global warming phenomenon. Aqueous carbon dioxide chemical absorption is the most effective method. The present study incorporates the applicability and performance of blended alkanol amine solutions monoethanolamine (MEA) with diethylenetriamine (DETA) as a chemical blended absorbent investigated in a pilot scale column packed randomly with Rashing rings. The effect of operating conditions on absorption performance was examined. The performance investigation is given in terms of the overall mass transfer coefficient and carbon dioxide capture efficiency (ƞ). Typically, DETA: MEA with a mass ratio of 1:1 and total mass concentration of 30 % wt. could provide the highest KGav with a value of 0.1572 (kmol/(m3*Kpa*hr)) and ƞ with a value of 98.79 %. While at the same condition in terms of liquid and gas rate, with DETA: MEA in the blending mass ratio 0.25:1, the KGav and ƞ values equal to: 0.1198 (kmol/(m3*Kpa*hr)) and 96.37%, respectively. Based on these findings, it is reasonable to assume that diethylenetriamine, a solution of alkanol amines, would serve as an efficient blending absorbent for carbon dioxide removal.

Displacement chromatography of gadolinium isotopes with strong cation exchange resin using 1,2-cyclohexanedinitrilotetraacetic acid (CDTA)

Adsorptive separation of Gd3+ ions was evaluated using DOWEX-50×8 ion exchange resin. It has shown a maximum adsorption capacity of 228.50 mg/g at optimum pH 5 and room temperature. Separation of Gd isotopes was investigated using packed bed columns of the resin in displacement chromatographic techniques where 1,2-cyclohexanedinitrilotetraacetic acid was used as displacer in the mobile phase. Isotopic analysis data by using MC‒ICP‒MS confirmed that the front end of the Gd adsorption band exhibited enrichment of the heavier isotope (160Gd), while the lighter isotopes (157Gd and 155Gd) were concentrated at the rear end of the stationary phase.

Optimization using central composite design for continuous absorption of CO2 gas with green sodium silicate in a packed bed column

If absolutely nothing is taken to reduce carbon dioxide (CO2) emissions, atmospheric concentrations of carbon dioxide will rise to 550 parts per million by 2050, which will have disastrous effects on the world's climate and food production. An apparatus has been designed and setup to convert CO2 into a useful and vital product which was silica. The effect of different experimental factors on the compositions by weight percent of SiO2 and Na2CO3 were studied including the CO2 gas flow rate (1.037, 1.648 and 2.26 L/min), initial concentration of sodium silicate (Na2SiO3) solution (5, 7.5 and 10 %wt) and the packing size (15.95, 20.175, and 24.4 mm). An optimization process was performed using the Design Expert software program to achieve the optimum experimental conditions at which the maximum weight percent of SiO2 (main product), the minimum weight percent of (Na2CO3) (side product) and the minimum reaction time were determined. From the optimization process, the maximum weight percent of SiO2 (25.63 %), the minimum weight percent of (Na2CO3) (9.62 %) and the minimum reaction time (7.59 min) were achieved at the following optimum experimental conditions of CO2 gas flow rate = 1.648 L/min, packing size = 24.4 mm and initial concentration of sodium silicate solution = 10 %wt.

Continuous production of aromatic esters from Chinese liquor yellow water by immobilized lipase in a packed-bed column bioreactor

Yellow water is a kind of Chinese liquor-making wastewater, and contains rich organic components such as alcohols and organic acids, if not treated, it can cause environmental pollution. Herein, continuous aromatic ester production from Chinese liquor yellow water by a packed-bedcolumnbioreactor withimmobilized lipase was achieved. Inspired by interface activation of lipase, lipase from Aspergillus oryzae (AOL) was immobilized on LX-1000HA resin with silicone DC1–2577 modification (SH-LX-1000HA) and oleic acid modification (LX-1000HA-NH2-OA), respectively. Benefiting from the hydrophobic properties of the surface, the resultant AOL@SH LX-1000HA and AOL@LX-1000HA-NH2-OA were 2.3-times and 1.5-times higher activity than that of free AOL, reached 240 U/g and 156 U/g respectively. Meanwhile, the AOL@SH LX-1000HA and AOL@LX-1000HA-NH2-OA exhibited higher thermal stability, storage stability, and recyclability than free lipase. Furthermore, the aromatic ester production from yellow water by an packed-bedcolumnbioreactor increased from 1.293 g/L to 3.976 g/L. This efficient continuous bioprocess presents great industrial potential for high value utilization from Chinese liquor yellow water.

Congo red removal from aqueous solution by a consortium of Aspergillus sp. immobilized on activated carbon in a packed bed column: modelling of the breakthrough curves

Congo red removal from aqueous solution by a consortium of <i>Aspergillus</i> sp. immobilized on activated carbon in a packed bed column: modelling of the breakthrough curves

Adsorption of an antiseptic in a functionalized fixed-bed: Analysis of breakthrough scenarios and validation of simplistic models defending a novel proposition

BackgroundChlorhexidine gluconate (CHG) and cetrimide, which are widely used in various pharmaceutical compositions, are considered potentially hazardous compounds. This combination was largely used during and after Covid 19 pandemic for sanitization. Removal of these two compounds from pharmaceutical waste-water with commercial and functionalized activated carbon in a packed bed column is reported. MethodsEffects of changes in bed height, flow rate, and initial concentration on the performance of the packed bed are analyzed using Yoon-Nelson, BDST and Thomas models for commercial scale-up operation. The effects of primary design parameters like bed depth and operating parameters like inflow rate and inlet concentration of influent wastewater are studied on the extent of removal of cetrimide and chlorhexidine gluconate. Granular activated carbon (GAC) is functionalized using HF and NH4OH. The extent of enhanced adsorption using the functionalized GAC is demonstrated using breakthrough curves. Significant findingsK. H. Chu's iconic proposition is validated. Breakthrough time (BT) increases with bed heights and it is less in the case of cetrimide as compared to chlorhexidine gluconate. This shows that cetrimide wins in the competition and occupies the pores much faster than CHG.Mostly, BT-CHG (GAC) < BT-CHG (FAC-HF) < BT-CHG (FAC-NH3) and BT-cetrimide (GAC) < BT-cetrimide (FAC-NH3) < BT-cetrimide (FAC-HF) for a particular bed height.BT−CHG(FAC−HF)BT−cetrimide(FAC−HF)<BT−CHG(FAC−NH3)BT−cetrimide(FAC−NH3)<BT−CHG(GAC)BT−cetrimide(GAC)

Point Source Capture of Methane Using Ionic Liquids in Packed Bed Absorbers/Strippers: Experimental and Modelling

Fugitive methane emissions from the mining industry, particularly so-called ventilation air methane (VAM) emissions, are considered among the largest sources of greenhouse gas (GHG) emissions. VAM emissions not only contribute to the global warming but also pose a significant hazard to mining safety due to the risk of accidental fires and explosions. This research presents a novel approach that investigates the capture of CH4 in a controlled environment using 1-butyl-3-methylimidazolium bis (trifluoromethylsulfonyl) imide [BMIM][TF2N] ionic liquid (IL), which is an environmentally friendly solvent. The experimental and modelling results confirm that CH4 absorption in [BMIM][TF2N], in a packed column, can be a promising technique for capturing CH4 from point sources, particularly the outlet streams of ventilation shafts in underground coal mines, which typically accounts for &lt;1% v/v of the flow. This study assessed the effectiveness of CH4 removal in a packed bed column by testing various factors such as absorption temperature, liquid and gas flow rates, flow pattern, packing size, desorption temperature, and desorption pressure. According to the optimisation results, the following parameters can be used to achieve a CH4 removal efficiency of 23.8%: a gas flow rate of 0.1 L/min, a liquid flow rate of 0.5 L/min, a packing diameter of 6 mm, and absorption and desorption temperatures of 303 K and 403.15 K, respectively. Additionally, the experimental results indicated that ILs could concentrate CH4 in the simulated VAM stream by approximately 4 fold. It is important to note that the efficiency of CH4 removal was determined to be 3.5-fold higher compared to that of N2. Consequently, even though the VAM stream primarily contains N2, the IL used in the same stream shows a notably superior capacity for removing CH4 compared to N2. Furthermore, CH4 absorption with [BMIM][TF2N] is based on physical interactions, leading to reduced energy requirements for regeneration. These findings validate the method’s effectiveness in mitigating CH4 emissions within the mining sector and enabling the concentration of VAM through a secure and energy-efficient procedure.

The relative performance of gelatin hydrogels doped with nanostructured transition-metal ferrites for chromium (VI) removal: Packed bed column studies and insights into reduction mechanisms

The article comprehends investigations using gelatin hydrogels reinforced with cobalt and nickel ferrites to remove chromium ions. The synthesized ferrite nanoparticles are mesoporous with high surface areas of 132.059 m2/g and 141.792 m2/g. The deposition of chromium ions on the dissected surfaces is more evident from the morphological studies. Supporting evidence from thermal studies showed how the nanofiller encapsulation increased hydrogels' thermal stability. The bed capacity in the packed bed column is 32.48 mg/g and 31.81 mg/g for cobalt ferrite and nickel ferrite nanoparticles entrapped hydrogels, respectively. X-ray Photoelectron spectroscopy findings indicated that the presence of characteristic peaks at 578.68 eV and 591.16 eV is assigned to hexavalent chromium, and the peaks observed at 575.56 and 583.71 eV correspond to the trivalent state of chromium. The electron transfer from the iron centre to chromium (VI) favoured the reduction of chromium (VI) to less toxic chromium (III)

Estimating the percentage effects of Bemacid red dye adsorption dynamic parameters using a full factorial design approach

Abstract In this study, we investigate the removal of Bemacid red dye using brewery waste in a packed bed column. We examined the effects of bed height, inlet flow, and inlet dye concentration on the column dynamics of adsorption. To assess the favorable column dynamics, we analyzed the breakthrough curves (BTCs). We also used the Clark, Thomas, Bed Depth Service Time (BDST), and Adams-Bohart models to determine the kinetic constants of the adsorption column from the obtained results of the dynamic studies curve of the BTCs. Analysis of the BTC studies revealed that both the BTCs time and worn-out time values increased with an increase in bed height and inlet Bemacid red dye dosage but decreased with an increase in the inlet flow rate. The results further showed that Thomas’ model was the most suitable for describing the entire BTCs (R2 &amp;gt; 0.93). Using a full factorial design to estimate the percentage effects of cited dynamic parameters, we found that these parameters accounted for 98% of the adsorption capacity. This methodology for estimation provides crucial information on the effects of parameters and the extent to which the adsorption capacity depends on the studied parameters.

Continuous precision separation of gold using a metal–organic framework/polymer composite

Critical metals of environmental and economic relevance can be found within complex mixtures, such as mine tailings, electronic waste and wastewater, at trace amounts. Specifically, gold is a critical metal that carries desired redox active properties in various applications, including modern electronics, medicine and chemical catalysis. Here we report the structuring of sub-micron Fe-BTC/PpPDA crystallites into larger 250 μm or 500 μm granules for continuous packed bed experiments for the precision separation of gold. The Structured Fe-BTC/PpPDA is highly crystalline and porous with a BET surface area of 750 m2 g−1. Further, the hybrid nanocomposite material maintains its selectivity for gold ions over common inorganic interferents. The structuring approach reported prevents excessive pressure drop and ensures stability over time and operation in a packed bed column. Further, we demonstrate that the Structured Fe-BTC/PpPDA can concentrate at least 42 wt% of gold under a dynamic continuous flow operation. These findings highlight the potential of Structured Fe-BTC/PpPDA for practical applications in industry, particularly in the selective capture of gold from complex mixtures.

Removal of phenol from wastewater using Luffa cylindrica fibers in a packed bed column: Optimization, isotherm and kinetic studies

This research entails a comparison of the effectiveness of unmodified Luffa cylindrica fiber in a fully packed bed (RLCF) and NaOH-modified Luffa cylindrica fiber in another fully packed bed (MLCF) in the context of phenol removal from wastewater. Experimental data obtained through batch adsorption experiments were utilized to determine the most suitable model. It was observed that as the initial concentration of phenol increased from 100 to 500 mg/l, the maximum percentage removal increased from 63.5 to 83.1% for RLCF-PB and from 89.9 to 99.5% for MLCF-PB. The correlation coefficient (R2) was calculated for the Langmuir, Freundlich, Temkin, Harkin-Jura, Halsey, and Flory-Huggins models for both materials. The analysis revealed that the pseudo-second-order model was the most suitable, followed by the Elovich model, with the pseudo-first-order model being the least suitable. The Weber-Morris diffusion model suggested that pore diffusion was the rate-determining step, and diffusion at the border layer was determined to be endothermic, feasible, heterogeneous, and spontaneous. In summary, this study indicates that MLCF-PB is a promising material for the efficient removal of phenol from aqueous solutions.

Performance of industrially implemented turbulent contact absorbers – A comparative study

The current study aims to assess the performance and industrial feasibility of using three-phase fluidized bed absorption columns for post-combustion carbon dioxide (CO2) capture. The analysis is based on a mathematical model of a scaled-up fluidized bed absorption column that has been validated using pilot plant experimental data. The focus is on evaluating the energy efficiency of the fluidized bed column in comparison to packed bed technologies, which are currently widely used. The results of the analysis are evaluated in terms of three performance indicators (i.e., absorption efficiency, carbon capture rate, and energy performance index) and compared to packed bed columns. Simulation results indicate that the best column configuration is represented by a three-stage absorber and that the system performs optimally when particle diameter and density decrease with each section. Consequently, this leads to an increase in the total fluidized bed height and carbon capture rate by up to 25%. The energy performance index is maintained below 3.6, indicating an energy-efficient operation of the system. As such, the findings of this study suggest that the use of gas-solid-liquid three-phase fluidized bed absorption columns for post-combustion CO2 capture is a promising technology for the implementation of CCUS and for achieving of climate neutrality targets.

Non-derivatizing solvent assisted waste-derived cellulose/ MOF composite porous matrix for efficient metal ion removal: comprehensive analysis of batch and continuous packed-bed column sorption studies.

The use of metal-organic frameworks (MOFs) for wastewater treatment in continuous operation is a major challenge. To address this, the present study demonstrates the eco-friendly and economic synthesis of Ca-MOF immobilized cellulose beads (Ca-MOF-CB) derived from paper waste. The synthesized Ca-MOF-CB were characterized using standard analytical techniques. Batch sorption studies were performed to check the effect of cellulose composition (wt%), Ca-MOF loading, contact time, and initial metal ion (Pb2+, Cd2+, and Cu2+) concentration. Ca-MOF-CB beads exhibited outstanding equilibrium sorption capacities for Pb2+, Cd2+, and Cu2+, with estimated values of 281.22 ± 7.8, 104.01 ± 10.58, and 114.21 ± 9.68 mg g-1, respectively. Different non-linear isotherms and kinetic models were applied which confirmed the spontaneous, endothermic reactions for the physisorption of Pb2+, Cd2+, and Cu2+. Based on the highest equilibrium sorption capacity for Pb2+ ion, in-depth parametric column studies were conducted in an indigenously developed packed-bed column set-up. The effect of packed-bed height (10 and 20 cm), inlet flow rate (5 and 10 mL min-1), and inlet Pb2+ ion concentration (200, 300, and 500 mg L-1) were studied. The breakthrough curves obtained at different operating conditions were fitted with the empirical models viz. the bed depth service time (BDST), Yoon-Nelson, Thomas, and Yan to estimate the column design parameters. In order to determine the financial implications at large-scale industrial operations, an affordable synthesis cost of 1 kg of Ca-MOF-CB was estimated. Conclusively, the present study showed the feasibility of the developed Ca-MOF-CB for the continuous removal of metal ions at an industrial scale.

Removal of fluoride from groundwater by chemically functionalized sugarcane bagasse biochar and bagasse pellets in a fixed-bed sorption system

This study aimed to investigate the design parameters for a filter intended to remove fluoride from groundwater. Water fluoridation notably influences groundwater, particularly in arid and semi-arid areas that exacerbate the challenge of availability of safe drinking water from Groundwater resources in numerous developing nations. Experiments were conducted to determine the fluoride concentrations in groundwater sources in the arid region of Maharashtra, India. Samples were collected from seven villages in three districts of Maharashtra. This study utilized chemically functionalized sugarcane bagasse biochar adsorbent (SCBB), which is low-cost and easily accessible, to remove fluoride from groundwater in a column setup. The recommended design parameters for the packed-bed column flow rate (Q) are 100 ml min−1 and bed height (d) is 30 cm.