Bed Column Research Articles

Scale-bridging And Modelling Study of Graphene Shell Composite Adsorption for Dye Removal in Water Treatment

Continuous fixed-bed adsorption is a cost-effective water-treatment method for dye removal. This research examined parameters such as bed heights (5, 7, and 9cm), initial methylene blue (MB) concentrations (10, 15, and 20mg/L), and feed flow rates (8, 10, 12 and mL/min) on fixed-bed adsorption performance. Our findings showed that the performance was improved under longer exhaustion times not only with increasing column bed heights, but also with decreasing initial MB concentrations and feed flow rates. Of note, the Thomas and Yoon-Nelson models accurately described MB adsorption in a fixed-bed column, with R2 values from 0.7525 to 0.9833. Response surface methodology via central composite design optimized column bed heights and feed flow rates on the duration required to achieve 50% of column breakthrough. The coefficient of determination (R2) and analysis of variance demonstrated the significance of the Two Factor Interaction (2FI) model in fitting the actual values. The optimum conditions were determined to be as follows: a bed height of 5cm; a feed flow rate of 8mL/min; and a duration of 54.74min to achieve 50% of column breakthrough. Lastly, a confirmatory test further verified the precision of the proposed optimum conditions with an error of only 0.02%.

Continuous removal of thorium from aqueous solution using functionalized graphene oxide: study of adsorption kinetics in batch system and fixed bed column

This article investigated the kinetic studies of thorium adsorption from an aqueous solution with graphene oxide functionalized with aminomethyl phosphonic acid (AMPA) as an adsorbent. First, the AMPA-GO adsorbent was characterized using TEM, XRD, and FTIR methods. Experiments were performed in two batch and continuous modes. In batch mode, adsorption kinetics were studied in different pH (1–4), temperature (298–328 K), initial concentration (50–500 mg L−1), and dosages (0.1–2 g L−1). The results showed that thorium adsorption kinetic follows pseudo-first-order kinetic model and that the adsorption reaction is endothermic. The maximum experimental adsorption capacity of thorium ions was observed 138.84 mg g−1 at a pH of 3, adsorbent dosage of 0.5 g L−1, and a temperature of 328 K. The results showed that AMPA-GO adsorbent can be used seven times with an acceptable change in adsorption capacity. In continuous conditions, the effect of feed flow rate (2–8 mL min−1), initial concentration (50–500 mg L−1), and column bed height (2–8 cm) was investigated. The continuous data was analyzed using the Thomas, Yoon-Nelson, and Bohart-Adams models. The experimental data of the column were well matched with the Thomas, and Yoon-Nelson models. The research results showed that the use of functionalized graphene oxide adsorbents has a great ability to remove thorium from aqueous solutions.

Assessment of molecularly imprinted polymers for selective removal of diclofenac from wastewater by laboratory and pilot-scale adsorption tests

This study investigated the potential of Molecularly Imprinted Polymers (MIPs) to integrate schemes for wastewater reuse and to serve as effective adsorbent for the removal of a target emerging contaminant (i.e., diclofenac – DCF), after or within pilot scale anaerobic biological treatments. Batch tests were performed to evaluate the effect on DCF removal during anaerobic biological processes by enriching activated sludge of an Upflow Anaerobic Sludge Blanket (UASB) reactor (TSS =19.6 g/L), and an Anaerobic Membrane Bioreactor (AnMBR) (TSS = 120 mg/L) reactors with MIPs (3 mg/L). Therefore, tertiary treatments were investigated by columns adsorption tests that were performed first at lab scale using DCF (15 mg/L) solution in deionized water, and then in-site by treating the anaerobic permeate effluent from the AnMBR at pilot scale level (DCF 500 μg/L). Clogging or blockage of the column bed was not observed during these field tests, where the saturation process of MIPs was slower compared to laboratory tests that used deionized water. In addition, the empirical Thomas Model, Yoon-Nelson Model, Dose-Response Model and Adam Bohart Model showed very good fittings with the experimental data obtained during experiments performed with both synthetic water and anaerobic effluents showing their suitability for the description of breakthrough curves. Finally, it was observed that after regeneration the MIPs can be efficiently reused since adsorption capacity is sufficiently preserved.

Fabrication of melamine formaldehyde/graphene oxide composite for efficient static and dynamic adsorption of lead ions from aqueous medium.

The present work discusses the synthesis, characterization, and environmental applications of graphene oxide (GO), melamine formaldehyde resin (MF), and melamine formaldehyde/graphene oxide composite (MGO) for the efficient removal of Pb2+ from aqueous medium via batch and column procedures. TGA, XRD, TEM, zeta potential, nitrogen adsorption/desorption, ATR-FTIR, and other characterization techniques revealed that MGO is characterized by a greater surface area (609 m2/g), total pore volume (1.0106 cm3/g), pHPZC (6.5), and the presence of various surface chemical functional groups. The synthesized solid adsorbents were used in both static and dynamic adsorption processes to remove Pb2+, with varying application parameters such as pH, starting concentration, adsorbent dosage, and shaking time in the case of static adsorption method. While through the column adsorption process the effects of column bed height, flow rate, and starting Pb2+ were taken into consideration. Results of the batch adsorption demonstrated that MGO had the highest Langmuir adsorption capacity (201.5 mg/g), and the adsorption fit the nonlinear Langmuir adsorption model and Elovich kinetic models. The adsorption of Pb2+ onto all prepared solid materials is endothermic, spontaneous, and physical in nature, as demonstrated by thermodynamic studies. Column adsorption of Pb2+ well fitted by Thomas and Yoon Nelson nonlinear adsorption models. MGO showed a maximum column adsorption capacity of 168 mg/g when applying 4 cm, 15 mL/min, and 150 mg/L as bed height, flow rate, and initial Pb2+, respectively. With only a 12.6% reduction in its adsorption capacity, column regeneration showed that MGO exhibited a high degree of reusability even after five cycles of adsorption/desorption studies.

Bone Char Adsorption of COD and Colour from Tannery Wastewater: Breakthrough Curve Analysis and Fixed Bed Dynamic Modelling

This study delves into the simultaneous adsorption of chemical oxygen demand (COD) and colour from tannery wastewater using bone char through a fixed bed column. The bone char, which was derived from cattle skulls, was characterised using the Fourier transform infrared spectroscopy, Braeuer–Emmett–Teller surface area analysis, and the scanning electron microscope/energy-dispersive X-ray spectroscopy. The effects of different process conditions, specifically, packed bed height (5, 10, and 15 cm) and flow rate (2, 5, and 8 mL/min), on the adsorption efficiency of the fixed bed column were assessed through breakthrough curve analysis. The results revealed that the efficiency of the column bed enhanced with increasing bed height and declined with increasing wastewater flow rate. The optimal operating conditions for COD and colour removal onto the bone char occurred at 15 cm bed height and 2 mL/min flow rate. The adsorption capacities at these conditions were 227.4 mg/g and 53.03 Pt-Co/g for COD and colour, respectively. The kinetics associated with the fixed bed adsorption of COD and colour onto bone char were elucidated through the fitting of the Thomas, Adams–Bohart, and Yoon–Nelson models to the experimental data. Among the three models, the Yoon–Nelson model gave the best prediction of the experimental data. Maximum adsorption efficiencies of 80.65% and 84% were attained for COD and colour removal, respectively, proving that bone char is a promising and ecologically friendly alternative adsorbent for the treatment of tannery wastewater.

NFeS Embedded into Cryogels for High-Efficiency Removal of Cr(VI): From Mechanism to for Treatment of Industrial Wastewater.

Most studies have focused on complex strategies for materials preparation instead of industrial wastewater treatment due to emergency treatment requirements for metal pollution. This study evaluated sodium polyacrylate (PSA) as a carbon skeleton and FeS as a functional material to synthesize PSA-nFeS material. The characteristics and interactions of PSA-nFeS composites treated with hexavalent chromium were analyzed by means of various techniques, such as scanning electron microscopy-energy dispersive X-ray spectrometry (SEM-EDS), X-ray photoelectron spectroscopy (XPS), Fourier transform infrared spectrometry (FTIR), and atomic absorption spectroscopy (AAS). Adsorption-coupled reduction was observed to be the predominant mechanism of Cr(VI) removal. The feasibility of PSA-nFeS composites in reducing toxicity and removing of Cr(VI) from real effluents was investigated through column studies and material properties evaluation. The continuous column studies were conducted using tannery effluents to optimize feed flow rates, initial feed Cr(VI) concentration, and column bed height. The results revealed that PSA-nFeS composites are ideal for filling materials in portable filtration devices due to their lightweight and compact size.

A simulation study of CO<sub>2</sub> gas adsorption with bottom ash adsorbent from palm oil mill waste using computational fluid dynamic (CFD)

<abstract> <p>Biogas is a cost-effective, efficient, environmentally friendly, and renewable alternative energy source. While biogas contains CH<sub>4</sub>, it also contains impurities in the form of 27–45% CO<sub>2</sub> gas. Therefore, it is necessary to purify biogas by removing CO<sub>2</sub> gas as it can reduce the calorific value of CH<sub>4</sub>, the main component of biogas. The process of methane purification can be achieved through adsorption. Bottom ash, derived from palm oil mill waste, shows great potential for methane purification by effectively adsorbing CO<sub>2</sub>. This research simulated the methane purification process using the computational fluid dynamics (CFD) method with the student version of the ANSYS R20 software. The study utilized an adsorbent made from bottom ash obtained from palm oil mill waste. The main objective was to investigate the performance of bottom ash as an adsorbent for removing CO<sub>2</sub> gas in a continuous gas flow within an adsorption column. The study involved varying the column bed height (4 cm, 8 cm, 12 cm) and gas flow rate (10 L/min, 15 L/min, 20 L/min). The results showed that the highest efficiency in removing CO<sub>2</sub> gas was 84.53% with a bed height of 12 cm and a flow rate of 10 L/min, while the lowest efficiency was 47.87% with a bed height of 4 cm and a flow rate of 20 L/min. Furthermore, the highest adsorption capacity for CO<sub>2</sub> gas was 1.64 mg/g with a bed height of 12 cm and a flow rate of 10 L/min, while the lowest capacity was 0.93 mg/g with a bed height of 4 cm and a flow rate of 20 L/min. The linearization of adsorption isotherm data indicated that the CO<sub>2</sub> gas adsorption process using bottom ash adsorbent followed the Langmuir model.</p> </abstract>

Breakthrough curve analysis of phosphorylated hazelnut shell waste in column operation for continuous harvesting of lithium from water

In batch-scale operations, biosorption employing phosphorylated hazelnut shell waste (FHS) revealed excellent lithium removal and recovery efficiency. Scaling up and implementing packed bed column systems necessitates further design and performance optimization. Lithium biosorption via FHS was investigated utilizing a continuous-flow packed-bed column operated under various flow rates and bed heights to remove Li to ultra-low levels and recover it. The Li biosorption capacity of the FHS column was unaffected by the bed height, however, when the flow rate was increased, the capacity of the FHS column decreased. The breakthrough time, exhaustion time, and uptake capacity of the column bed increased with increasing column bed height, whereas they decreased with increasing influent flow rate. At flow rates of 0.25, 0.5, and 1.0 mL/min, bed volumes (BVs, mL solution/mL biosorbent) at the breakthrough point were found to be 477, 369, and 347, respectively, with the required BVs for total saturation point of 941, 911, and 829, while the total capacity was calculated as 22.29, 20.07, and 17.69 mg Li/g sorbent. In the 1.0, 1.5, and 2.0 cm height columns filled with FHS, the breakthrough times were 282, 366, and 433 min, respectively, whereas the periods required for saturation were 781, 897, and 1033 min. The three conventional breakthrough models of the Thomas, Yoon-Nelson, and Modified Dose-Response (MDR) were used to properly estimate the whole breakthrough behavior of the FHS column and the characteristic model parameters. Li's extremely favorable separation utilizing FHS was evidenced by the steep S-shape of the breakthrough curves for both parameters flow rate and bed height. The reusability of FHS was demonstrated by operating the packed bed column in multi-cycle mode, with no appreciable loss in column performance.

Alleviation of the necessity for supernatant prefiltering in the protein a recovery of Monoclonal antibodies from Chinese hamster ovary cell cultures

Protein A (ProA) chromatography is a mainstay in the analytical and preparative scale isolation/purification of monoclonal antibodies (mAbs). One area of interest is continuous processing or continuous chromatography, where ProA chromatography is used in the large-scale purification of mAbs. However, filtration is required prior to all ProA isolations to remove large particulates in cell culture supernatant, consisting of a mixture of cell debris, host cell contaminants, media components, etc. Currently, in-line filters are used to remove particles in the supernatant, requiring replacement over time due to fouling; regardless of the scale. Here we demonstrate the ProA isolation of unfiltered Chinese hamster ovary (CHO) cell media using capillary-channel polymer (C-CP) fiber stationary phases modified with S. aureus Protein A (rSPA). The base polymer of the analytical scale C-CP columns costs ∼$5 per 30 cm column, and when modified with ProA, the base cost is ∼$25 per 30 cm column, a cost-effective option in comparison to analytical-scale commercial columns. To directly sample unfiltered media, a 5 cm gap was created at the head of the C-CP column, where the large particulates are trapped, while molecular solutes flow through the capillary channels without sacrifice in analytical performance, mAb loading capacity, or backpressure increases. The binding capacity of the gap ProA C-CP column was ∼ 2 mg mL−1 of IgG per bed volume. The same analytical column could be operated after processing a total of ∼ 56 column bed volumes of supernatant (>25 analytical cycles) without the need for caustic clean-in-place processing.

High-efficient removal of tungsten from hafnium by TOA/XAD-7 extraction resin from HCl-HF media

ABSTRACT For removal of the natural isobar 182W interference prior to ultra-trace 182Hf determination by accelerator mass spectrometry, an extraction chromatographic method for separation of Hf from W has been developed by using a newly synthesized tri-n-octylamine (TOA)/XAD-7 resin as the stationary phase and HCl-HF media as the mobile phase. Based on the TOA liquid-liquid extraction studies in HF and HCl-HF solutions at wide concentration range, a maximum separation factor of 8.6 × 103 for W/Hf was obtained in 8 M HCl-0.05 M HF solution. Subsequently, the macroporous organic polymer-based TOA/XAD-7 resin was prepared by vacuum impregnation technique and its morphology, chemical structure and composition were characterized by SEM, EDS, FT-IR, TG-DSC, and EA. The results showed the self-assembly TOA/XAD-7 resin uptakes about 50% of extractant and keeps intact binding characteristic for metal ions. Hence, this resin was employed to investigate the column chromatographic behavior of Hf and W with variable parameters of sample loading and column bed dimensions. As a result, a high yield of more than 99% for Hf and high decontamination factor of 3.2 × 105 for W were achieved under the optimal column condition. The strategy developed provides a simple and efficient alternative to sample preparation for 182Hf measurement.

Adsorption of Acid Yellow 23 Dye on Organobentonite/Alginate Hydrogel Beads in a Fixed-Bed Column

This research evaluates the use of organoclay/alginate hydrogels in removing Acid Yellow 23 in a fixed-bed column and contributes to the application of these composites in the context of the adsorption of anionic dyes that are present in wastewater. An organobentonite (OBent) was synthesized and encapsulated in an alginate matrix, using Ca2+ ions as a crosslinking agent. Experiments in fixed-bed columns showed that breakthrough and exhaustion times were longer with increasing bed height, which decreased with increases in flow rate and initial dye concentration. The Thomas, Yoon–Nelson, and Adams–Bohart models were well fitted to the experimental data for the breakthrough curves with high Adj. R2 correlation coefficients and low values of χ2. The theoretical adsorption capacity of the organobentonite/alginate hydrogel calculated from the Thomas model was 0.50 ± 0.01 mg/g (equivalent to 30.97 mg/g OBent), and this was obtained by using a 15 cm (10.10 g) bed height, 1 mL/min flow rate, and a 45 mg/L input dye concentration. The bed was regenerated with a 0.5 M NaOH solution, and the reuse of the saturated column bed was studied for two adsorption–desorption cycles. The results obtained in this study suggest the potential use of an organoclay/alginate hydrogel for the adsorption of pollutants in continuous systems.

Studying the effects of Aspergillus niger (MF431834) dead biomass on water defluoridation in batch and bed column: Adsorption kinetics, characterization, genotoxicity studies

Fluoride pollution in water caused by biological and anthropogenic activities has been recorded as a significant global issue, posing severe risks to the ecosystem. The present study focuses on the isolated fungus Aspergillus niger (MF431834)-dead biomass served as novel adsorbents for defluorination. The dead fungal mycelium of A. niger was used to study the biosorption of fluoride from an aqueous medium while varying the pH, fluoride concentrations, bio-sorbent concentrations, temperatures, contact periods, and coexisting ions. After the batch experimentation, the maximum fluoride adsorption capacity of 93.85 % was achieved by 0.2 g dosage, a 50-min equilibrium time was predicted as a contact time, considerable fluoride adsorption was observed at 15 mg/L of initial fluoride concentration, the maximum fluoride adsorption of 92 % was achieved by pH 2.0, and NaOH was the best desorption agent. The biosorption of fluoride ion well pseudo-second-order (R20.99) compared to pseudo-first-order and the biosorption equilibrium data were more suited by the Langmuir isotherm than the Freund isotherm model. Thermodynamic parameters such as ΔG°, ΔS°, and ΔH° the biosorption of fluoride ions by endothermic nature. Energy Dispersive Spectroscopy (SEM-EDX) and Fourier transform infrared (FTIR) spectroscopy examine the biosorption of fluoride by fungal bio-sorbent. Fluoride removal was also significantly attained in the column study with bio-sorbent. The findings demonstrated that A. cepa subjected to untreated polluted fluoride water exhibited chromosome abnormalities, including disorganized, disturbed metaphase, chromosomal displacement in anaphase, aberrant telophase, spindle disturbances, and binucleate cells. The highest chromosomal aberrations and mitotic inhibition were found in roots exposed to contaminated fluoride water. The novelty of this research can be used as a biomarker to identify the genotoxic effects of fluoride water contamination on biota. Hence, the native fungus A. niger exhibits as an effective adsorbent for fluoride elimination, being valuable in the theory and practical management of environmental pollution.

Application of artificial neural network and dynamic adsorption models to predict humic substances extraction from municipal solid waste leachate

Sustainable municipal solid waste leachate (MSWL) management requires a paradigm shift from removing contaminants to effectively recovering resources and decreasing contaminants simultaneously. In this study, two types of humic substances, fulvic acid (FA) and humic acid (HA) were extracted from MSWL. HA was extracted using HCl and NaOH solution, followed by FA using a column bed under diversified operations such as flow rate, input concentration, and bed height. Also, this work aims to evaluate efficiency of Artificial Neural Network (ANN) and Dynamic adsorption models in predicting FA. With the flow rate of 0.3 mL/min, bed height of 15.5 cm, and input concentration of 4.27 g/mL, the maximum capacity of FA was obtained at 23.03 mg/g. FTIR analysis in HA and FA revealed several oxygen-containing functional groups including carboxylic, phenolic, aliphatic, and ketone. The high correlation coefficient value (R2) and a lower mean squared error value (MSE) were obtained using the ANN, indicating the superior ability of ANN to predict adsorption capacity compared to traditional modeling.

Fixed bed mycofilter column optimization and performance evaluation through the removal of a food coloring agent from an aqueous solution

Mycofiltration via continuous fixed bed adsorption, helped to assess the effect of flow rate, pH, column bed height and myceliation on the sorption capacity of a mycofilter. The mycofilter (thatching straw and Pleurotus ostreatus) was cultured and loaded into polypropylene columns (2.5 × 12 cm) to bed heights of 2 and 4 cm. A food color solution was passed through at different pH (2 and 7.5) and flow rates (0.25 ml/min and 2 ml/min). The filtrate was collected and measured at time intervals. Under constant flow rate and solution pH, the 4 cm bed adsorbed 8 times the inlet amount of food color compared to 1.6 times only for the 2 cm bed. More food color was adsorbed with the higher flow rate (10 times the inlet concentration). Adsorption was only observed in the solution with pH = 2. The control filter (without mycelia) adsorbed 3-fold less than the mycofilter. The experimental data best fitted into the Thomas model (compared to the Yoon-Nelson model) which showed that an increase in bed height caused an increase in adsorption capacity (qTH), and that an increase in flow rate resulted in an increase in Thomas rate constant (KTH). FTIR analyses of the mycofilter revealed amide, hydroxyl, and chitin groups possibly involved in adsorption processes. Our fixed bed mycofilter optimally removed food color from aqueous solutions, in high bed height and flow rate, and low pH conditions.

Adsorption linked fungal degradation process for complete removal of Lanasyn olive dye using chemically valorized sugarcane bagasse

Textile dye effluents have been reported for many deleterious effects; therefore, it is essential to remove before releasing into waterbodies. A two-step agro-waste-based technology for the remediation of a textile dye Lanasyn olive was developed in this study. The first step involved the chemical modification of agro-waste sugarcane bagasse (SCB) with a natural acid (alginic acid). The modified SCB was used for the column bed preparation and adsorptive removal of the dye. In the second step, SCB used for dye removal was decolorized through a fungus Pleurotus sp. to produce a dye-free SCB with a potential for application as manure. To evaluate the efficacy of the column device, parameters like removal percentage, and adsorption capacity were determined. There was 90% removal of dye in aqueous dye solution and 83% removal in dye spiked textile industry effluent. To comprehend the column properties, three non-equilibrium models—Thomas, Yoon-Nelson, and Adams-Bohart—were used. Among the models applied, Adams-Bohart fitted well with the obtained data. Dye bioremediation efficiency by Pleurotus sp. was assessed by studying the deviation in absorption maxima, dye decolorization on the agar plate, Fourier-transform infrared spectroscopy (FTIR). The fungus-treated SCB showed no signs of residual toxicity towards alga Chlorella vulgaris. The carbon, hydrogen, nitrogen, sulfur (CHNS) profile examination of spent SCB revealed significantly improved nitrogen content after the treatment (from 0.35% to 0.69%). The prototype of the column, chemical valorization of SCB, and degradation of dye-adsorbed SCB through Pleurotus sp. provides a green solution for the safe disposal of textile dye through a novel agro waste-based treatment process.

Landfill leachate treatment by activated carbon (AC) from banana pseudo-stem, iron oxide nanocomposite (IOAC), and iron oxide nanoparticles (IONPs)

This study investigated the efficiency of activated carbons (ACs) produced from banana pseudo-stem, iron oxide nanocomposite (IOAC), and iron oxide nanoparticles (IONPs) for chemical oxygen demand (COD, mg/L), dissolved organic carbon (DOC, mg/g), and color (mg/g) removal from landfill leachate. A continuous-flow bed column study was conducted to ascertain behavioral pattern of the adsorbents during adsorption experiments (variables: bed column height, flow rate, and influent concentration). Kinetics (pseudo-first (PFO) and pseudo-second (PSO) orders) and isotherms (Langmuir, Freundlich, and Temkin) models were used to describe adsorption trends of pollutants. An artificial neural network (ANN) was used to model the adsorption process. Risk assessment analysis on the treated effluent was determined based on risk quotients (RQ) from COD standards for sewage and effluents. The bed column study showed that percentage removal of COD, DOC, and color increased with increasing the bed height while empty bed contact time (EBCT) increased from 1.6 to 4.7 min as the column bed height increased from 7.5 to 12.5 cm respectively. The adsorption kinetics for all treatments were well-fitted with the PSO kinetic model suggesting that the removal rate of COD, DOC, and color is dependent on the availability of the sorption sites. The adsorption process was observed to have good linearity in the three isotherm models with an overall R2 > 0.90. The values from tqt for each dataset of AC, IOAC, and IONPs fit the Levenberg–Marquardt (LM) training algorithm with best validation performance, lowest mean square error (MSE) of 0.19789 at epoch 8 and highest coefficient of determination (R2) of 0.9922. The IONPs treatment showed the lowest RQ (0.5732–0.4723) from all dosages of adsorbents indicating medium risk to aquatic organisms.

A comparative study of experimental and advanced modelling analysis for adsorption of Cd (II) from aqueous solution by Melia azedarach L. charcoal powder

The present study deals with the preparation and characterization of Melia azedarach L. twigs charcoal powder (MAT-CP) followed by batch and column adsorption experiments to appraise its Cd(II) removal efficiency from aqueous solution. The characterization of charcoal was done using XRD, FTIR, FESEM, EDX and BET analysis. Batch adsorption study was conducted with varied variables including adsorbent dose, contact time, temperature, pH and agitation speed. Resultant data was suitably fitted in Langmuir isotherm model exhibiting a maximum 196.078 mg/g adsorption capacity. Kinetic studies revealed that the adsorption followed Pseudo-second order kinetic while thermodynamic analysis (enthalpy (ΔH°), entropy (ΔS°) and Gibb’s free energy (ΔG°)) revealed the interaction to be thermodynamically favorable and endothermic. Regeneration of adsorbent was also done and the reactivated MAT-CP was repeatedly used as adsorbent. In fixed-bed column investigation, variables such as flow rate, initial metal concentration and column bed height were varied to obtain breakthrough curves (BTCs). The column adsorption was optimally obtained at 2.5 mL/min flow rate, 25 mg/L of Cd(II) concentration and 5 cm bed height. Column adsorption modeling reflected higher R2 and adsorption capacity using Thomas and Nelson-Yoon models. The present study advocates the MAT-CP as an efficient adsorbent for Cd(II) removal from aqueous solution.

Synthesis, Characterization, and Adsorption Study of Magnetic Superhydrophobic Monolithic Core-Shell Polystyrene Composite for the Removal of Ethyl Naphthalene from Produced Water Using Fixed Column Bed

Synthesis, Characterization, and Adsorption Study of Magnetic Superhydrophobic Monolithic Core-Shell Polystyrene Composite for the Removal of Ethyl Naphthalene from Produced Water Using Fixed Column Bed

Simulation of interactions between dam-break flows and complex downstream beds using Flow 3D model

Dam-break flow simulations are conducted all over the world, especially in the climate change phenomena taking place, complicated and impacting humans’ lives as well as the infrastructures. This paper introduces the interactions between dam-break flows and complex beds using the Flow-3D model. The analytical solution and the physical experiment are implemented to the dam-break flow over the simple and nonrough bed case to calibrate the numerical simulation. Two complex rough beds, which are the hump bed and the solid column bed, are selected to simulate the interactions between dam-break flows and these structures. With the hump bed, the Flow 3D model accurately simulates the flow characteristics over the rough bed and the flow height overtopping the hump. With the solid column bed, the flow velocities before and after a collision are simulated correctly when compared to the experimental data.

Studying effective column lengths in liquid chromatography of large biomolecules

Based on their nature, large molecules tend to exhibit on-off elution such that only a small segment of a column bed participates in their separation. We were intrigued to investigate empirical data on this behavior and to apply a simple method to estimate the length of column bed that is needed to produce an effective separation. Models were derived by rearranging the linear solvent strength (LSS) model equations, and data sets from almost 100 different separation conditions were treated to illustrate effects for various types of solutes as separated by reversed phase (RP), ion-pair reversed phase (IP-RP), ion-exchange (IEX), hydrophobic interaction (HIC) and hydrophilic interaction (HILIC) chromatography.By empirically measuring S parameters (S is a solute dependent model parameter, it describes how sensitive is the solute retention to mobile phase composition), and calculating for an exit retention factor of 0.5, we have determined that there is little to no benefit to separating moderately sized solutes (5 – 10 kDa) with a column bed that is longer than 3 cm, particularly when a less than 20 min gradient is desired. Moreover, even shorter columns would be predicted to be adequate for 100 – 150 kDa molecules. Interpretations of this sort have become possible because there is some correlation between a solute's molecular weight and its S parameter. That is, empirical observations on retention behavior are not needed to select appropriate column lengths; molecular weight provides a sufficient approximation. With these insights, we suggest reconsidering the routine use of 5 – 15 cm long columns for >10 kDa biomolecule separations and instead propose that a new focus be placed on 1-2 cm long columns.