Papers by Keyword: Breakthrough Curve

Abstract: Continuous fixed-bed column studies were performed using nanocomposite beads made up of chitosan, polyethyleneimine, and graphene oxide as adsorbents for the removal of methyl orange (MO) in water. The effects of different operating parameters such as initial MO concentration (5, 10, and 15 ppm), bed height (10, 17.5, and 25 cm), and flow rate (27, 43, and 58 mL/min) were investigated using an upward-flow fixed-bed column set-up. The breakthrough curves generated were fitted with Adams-Bohart, Thomas, Yoon-Nelson, and Yan et al. models. The results showed that Yan et al. model agreed best with the breakthrough curves having an R² as high as 0.9917. Lastly, design parameters for a large-scale adsorption column were determined via scale-up approach using the parameters obtained from column runs.

Abstract: In this work, experimental data of CO₂ capture by adsorption was determined gravimetrically, at 30 °C and pressures up to 40 bar, and in a fixed bed unit at 20 bar, using NaY as adsorbent. Langmuir, Sips and Tóth isotherm models were used to correlate the equilibrium data. Sips and Tóth models were best fitted allowing estimate the maximum CO₂ adsorbed amount. The breakthrough curve was modeled using Linear Driving Force (LDF) and Thomas models. The LDF model represented better the CO₂ breakthrough curve than Thomas model. The mass transfer resistance in NaY micropores can be assumed as the limiting step for CO₂ adsorption in fixed bed, since the intraparticle mass transfer coefficient of LDF model was smaller than the experimental overall volumetric mass transfer coefficient, although external film resistance is not negligible.

Abstract: A column sorption study was carried out by using four resins (D113, D001, LS-1000, LS-5000) for the adsorption of alkaline-earth metal ions from aqueous solutions. The breakthrough curve was obtained as a function of feed flow rate, and the total and breakthrough capacity values of the resins were calculated. Four kinetic models: Adams-Bohart, Wolborska and Thomas models were applied to experimental data to predict the breakthrough curves of Na-form resins and to determine the characteristic parameters of the column useful for process design. All models were found suitable for describing the whole or a definite part of the dynamic behavior of the column with respect to flow rate and inlet ion concentration. The results obtained would be helpful for the understanding of the competitive adsorption processes and the recovery or removal of one or more alkaline-earth metal ions from aqueous solutions.

Abstract: The technologies of ion exchange resin for ultra pure hydrogen peroxide production are more and more focused.The aim of this research was to select suitable parmeters for effective removal of P ion impurities from the experimetal aqueous hydrogen peroxide solution to produce ultra-pure hydrogen peroxide. Dynamic experiments for the different operation conditions, i.e., initial concentrations, flow rates, ratios of height to diameter were carried out. The concentrations of P anion of the effluent samples from the anion exchange resin column were determined by ICPS-7510.The breakthrough curves of P ion were measured and analyzed. The results showed that P ion could be reduced effectively from the experimetal aqueous hydrogen peroxide solution with the fitting conditions of ion exchange resin column, It provided the basis for determining of the suitable operating conditions of ion exchange column of commercial plant.

Abstract: Groundwater in fractured media plays an important role in drinking water supply, and the understanding of its principle mechanisms is essential for securing the groundwater exploring and utilization. In this paper, a novel conceptual fracture model was presented on the basis of the reality of channeling flow in natural fractures and laboratory experiments were conducted for the purpose of getting a better understanding of the step-like breakthrough curve (BTC). Experimental results were fitted with convective dispersive equation (CDE) and compared with those of the finite element method (FEM) models. Results showed that the traditional one-dimensional CDE was invalid in the fitting of a step-like BTC and needed to be improved.

Abstract: A continuous dynamic adsorption in a fixed-bed column was studied by canna edulis ker residue (CEKR) as an adsorbent for the removal of Cr (VI) ions from aqueous solution. The dynamic adsorption process was simulated by some mathematic models, to determine the characteristic parameters of the column. The results indicated that CEKR could effectively absorb Cr (VI) ions from aqueous solution. Breakthrough time reaching saturation increased significantly with the increase of the temperature, while the bed depth increased and the pH value decreased. In comparison, the initial metal concentration is able to slightly affect the adsorption. Some mathematical models could calculate the rate constants, correlation coefficients, the equilibrium adsorption and kinetic parameters, however, they were not suitable for the description the dynamic adsorption of Cr (VI) ions in the fixed-bed column.

Abstract: The technologies of ion exchange resin for ultra pure hydrogen peroxide production are more and more focused. The aim of this research was to determine suitable parameters for effective removal of Na+ impurities from aqueous hydrogen peroxide solution to produce ultra pure hydrogen peroxide. Dynamic experiments for the different operation conditions, i.e., initial concentration, flow rate, ratio of height to diameter were carried out. The concentrations of Na+ of the effluents from the ion exchange resin column were determined by ICPS-7510.The breakthrough curves of Na+ were measured and analyzed. The results shown that Na+ could be reduced effectively from the experimental aqueous hydrogen peroxide solution with the fitting conditions of ion exchange resin column, which provided the basis for determining of the suitable operating conditions of ion exchange column of a pilot plant.

Abstract: In this study, a commercial activated carbon was assessed as adsorbent for post-combustion CO₂ capture. The breakthrough adsorption experiments were conducted in a fixed-bed column with simulated flue gas of 12% CO₂. The effects of feed flow rate and adsorption pressure on breakthrough time and CO₂ adsorption capacity were evaluated. The column efficiency was introduced to estimate the percentage of the utilization of the bed adsorbent capacity. At a higher flow rate, the breakthrough time, breakthrough capacity and column efficiency decreased. Conversely, increasing adsorption pressure was favorable to CO₂ adsorption by the increase in breakthrough time, CO₂ adsorption capacity and the column efficiency. During the experiments, temperature changes were detected at three positions inside the column to track the movement of breakthrough front.

Abstract: The performance of expanding rice husk (ERH) fixed bed column in removing Zn (II) from aqueous solution were studied in this work. Different column design parameters like bed height, flow rate and initial concentration were calculated. It was found that ERH was found to be an effective adsorbent for removal of Zn (II); and when conducted with Zn (II) concentration 12.8 mg L^-1 and flow rate 10 ml min^-1 with different bed depths such as 3, 6 and 9 cm, the equilibrium uptake was decreased from 5.181 to 4.33 mg g^-1; the equilibrium uptake also decreased from 4.51 to 3.807 mg g^-1 with increasing of flow rate from 5 to 15 ml min^-1 and increased from 4.447 to 5.752 mg g^-1 when initial concentration increased from 12.8 to 35 mg L^-1. The dynamics of adsorption process was modeled by bed depth service time (BDST), and indicating the validity of BDST model when applied to the continuous column studies.

Abstract: Fixed-bed column studies for the removal of Ag(Ⅰ) and Cr(Ⅲ) from individual aqueous solutions using puffed rice husk were investigated in this work. The experiments were conducted to study the effect of important column parameters such as bed height, feed flow rate and feed initial concentration of solution. It was found that increasing bed depth yielded longer service time while increase in influent concentration and flow rate resulted in faster breakthrough. Bed Depth Service Time (BDST) model was applied to analyze the experimental data and the model parameters were evaluated. Good agreement of the experimental breakthrough curves with the model predictions was observed.