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1
Chen, Kuei-Hsiang, You-Ren Lai, Nguyen The Duc Hanh, Steven S. S. Wang und Yu-Kaung Chang. „Breakthrough Curve Modeling and Analysis for Lysozyme Adsorption by Tris(hydroxymethyl)aminomethane Affinity Nanofiber Membrane“. Membranes 13, Nr. 9 (28.08.2023): 761. http://dx.doi.org/10.3390/membranes13090761.
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In this study, a polyacrylonitrile nanofiber membrane was first hydrolyzed and then functionalized with tris(hydroxymethyl)aminomethane (P-Tris), then used as an affinity nanofiber membrane for lysozyme adsorption in membrane chromatography. The dynamic adsorption behavior of lysozyme was investigated in a flow system under various operating parameters, including adsorption pHs, initial feed lysozyme concentration, loading flow rate, and the number of stacked membrane layers. Four different kinetic models, pseudo-first-order, pseudo-second-order, Elovich, and intraparticle diffusion kinetic models, were applied to experimental data from breakthrough curves of lysozyme. The results showed that the dynamic adsorption results were fitted well with the pseudo-second-order kinetic model. The breakthrough curve experimental results show significant differences in the breakthrough time, the dynamic binding capacity, the length of the mass transfer zone, and the utilization rate of the membrane bed under different operating parameters. Four dynamic adsorption models (i.e., Bohart–Adams, Thomas, Yoon–Nelson, and BDST models) were used to analyze the breakthrough curve characteristics of the dynamic adsorption experiments. Among them, the Yoon–Nelson model was the best model to fit the breakthrough curve. However, some of the theoretical results based on the Thomas and Bohart–Adams model analyses of the breakthrough curve fit well with the experimental data, with an error percentage of <5%. The Bohart–Adams model has the largest difference from the experimental results; hence it is not suitable for breakthrough curve analysis. These results significantly impact dynamic kinetics studies and breakthrough curve characteristic analysis in membrane bed chromatography.
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Rajeshkannan, R., M. Rajasimman und N. Rajamohan. „Packed bed column studies for the removal of dyes using novel sorbent“. Chemical Industry and Chemical Engineering Quarterly 19, Nr. 4 (2013): 461–70. http://dx.doi.org/10.2298/ciceq120407081r.
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A continuous fixed bed study was carried out by using tamarind seed as a sorbent for the removal of malachite green (MG) and acid blue 9(AB9) from aqueous solution. The effect of factors, such as flow rate and bed depth was studied. Data confirmed that the breakthrough curves were dependent on flow rate and bed depth. Thomas, Adams-Bohart, and Yoon-Nelson models were applied to experimental data to predict the breakthrough curves using non-linear regression and to determine the characteristic parameters of the packed bed column. Bed depth/service time analysis (BDST) model was used to express the effect of bed depth on breakthrough curves. The results showed that Thomas model was found suitable for the normal description of breakthrough curve at the experimental condition, while Adams-Bohart and Yoon-Nelson model were able to explain only the initial part of dynamic behaviour of the tamarind seed column. The data were in good agreement with BDST model. It was concluded that the tamarind seed can be effectively used as a sorbent for the removal of dyes.
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Nedoma, Marek, Marek Staf und Jan Hrdlička. „Experimental and simulation study of CO2 breakthrough curves in a fixed-bed adsorption process“. Acta Polytechnica 62, Nr. 3 (30.06.2022): 370–85. http://dx.doi.org/10.14311/ap.2022.62.0370.
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This paper focuses on the laboratory experiments of low-temperature adsorption of CO2 at elevated pressure and on the validation of our mathematical model with the data obtained. The numerical approach uses fitting of adsorption isotherm parameters and sensitivity analysis of parameters influencing the breakthrough curve shape and onset time. We first evaluate the results of breakthrough experiments for zeolite 13X. Then, we use the results obtained to design a dynamic mathematical model to predict the breakthrough curve profile. Experimental results show that zeolite 13X possesses high adsorption capacities (over 10 % of its weight at adsorption temperatures of 293 K and below), as expected. The mathematical simulation was accurate at predicting the breakthrough onset time; however, this prediction accuracy declined with the outlet CO2 concentration exceeding 75 %, which is discussed. The sensitivity analysis indicated that the choice of different estimates of mass transport and bed porosity, as well as the choice of numerical scheme, can lead to a more accurate prediction, but the same set of parameters is not suitable for all process conditions.
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Kamble, Manisha G., Milind D. Nagrale, Ankit A. Kamdi, Sunil K. Deokar und Sachin A. Mandavgane. „Packed column dynamic studies and breakthrough curve analysis for adsorption of paraquat herbicide onto agroindustrial ashes“. DESALINATION AND WATER TREATMENT 83 (2017): 86–97. http://dx.doi.org/10.5004/dwt.2017.21043.
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Kumpanenko, I. V., N. A. Ivanova, M. V. Dyubanov, O. V. Shapovalova, A. A. Solov’yanov und A. V. Roshchin. „Analysis of Breakthrough Curves of Dynamic Adsorptive Removal of Pollutants from Water“. Russian Journal of Physical Chemistry B 13, Nr. 2 (März 2019): 328–38. http://dx.doi.org/10.1134/s1990793119020040.
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Appiah-Brempong, Miriam, Helen Michelle Korkor Essandoh, Nana Yaw Asiedu und Francis Yao Momade. „Bone Char Adsorption of COD and Colour from Tannery Wastewater: Breakthrough Curve Analysis and Fixed Bed Dynamic Modelling“. Advances in Civil Engineering 2024 (20.02.2024): 1–14. http://dx.doi.org/10.1155/2024/6651094.
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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.
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Tejada-Tovar, Candelaria, Angel Villabona-Ortíz und Ángel Darío González-Delgado. „Dynamic Removal of Nickel (II) on Elaeis guineensis Waste Bed: Study of the Breakage Curve and Simulation“. International Journal of Environmental Research and Public Health 19, Nr. 24 (12.12.2022): 16668. http://dx.doi.org/10.3390/ijerph192416668.
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This research focused on the use of residual fiber from oil palm (Elaeis guineensis) for Ni (II) adsorption in a packed bed column. An analysis was conducted on the effect and statistical incidence of changes in temperature, adsorbent particle size, and bed height on the adsorption process. The results showed that particle size and bed height significantly affect the adsorption of Ni (II) ions, reaching adsorption efficiencies between 87.24 and 99.86%. A maximum adsorption capacity of 13.48 mg/g was obtained in the bed with a break time of 180 min. The Ni (II) adsorption in the dynamic system was evaluated by the analysis of the breakage curve with different theoretical models: Yoon–Nelson, dose–response, and Adams–Bohart; the dose–response model was the most appropriate to describe the behavior of the packed bed with an R2 of 84.56%. The breakthrough curve obtained from Aspen Adsorption® appropriately describes the experimental data with an R2 of 0.999. These results indicate that the evaluated bioadsorbent can be recommended for the elimination of Ni (II) in aqueous solutions in a dynamic system, and the simulation of the process can be a tool for the scalability of the process.
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Dolatyari, Leila, Mohammad Reza Yaftian und Sadegh Rostamnia. „Fixed-bed column dynamic studies and breakthrough curve analysis of Eu(III) ion adsorption onto chemically modified SBA-15 silica materials“. Separation Science and Technology 52, Nr. 3 (28.11.2016): 393–403. http://dx.doi.org/10.1080/01496395.2016.1250781.
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Bahrun, Mohd Hardyianto Vai, Awang Bono, Nur Kamaliyah Dzilrazman und Zykamilia Kamin. „Recovery of Minor Palm Oil Compounds Using Packed Bed Adsorption Column“. Jurnal Bahan Alam Terbarukan 9, Nr. 1 (20.06.2020): 21–29. http://dx.doi.org/10.15294/jbat.v9i1.23461.
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Carotene and tocopherol are valuable products that exist as minor compounds in palm oil and mostly extracted out during many stages of palm oil processing. Hence, most of it ended up in wastewater or palm oil mill effluent (POME). Fortunately, adsorption is potentially one of the most efficient method as compared to the others. In fact, it is widely studied in laboratory scale, in order to obtain equilibrium data for the steady state system. However, industrial practices are mostly operated in unsteady state in a continuous manner. Consequently, this study is executed to design a recovery process of one of the minor compounds in palm oil mill effluent (POME), which is carotene, using silica gel. It aims to predict the dynamic adsorption of recovery of minor compounds from palm oil mill effluent based on available equilibrium data, investigate the effects of dynamic and physical properties of the system towards the process by analyzing the breakthrough curve and study the feasibility of the scale up process by performing a sensitivity analysis on the system. Then, a base simulation was prepared by using available equilibrium data. Operating and design parameters such as, bed height, inlet flowrate and concentration were manipulated. Consistent with previous packed column studies, increase flow and concentration will reduce the time required for the column to achieve saturation, while increase bed height effects were vice versa. Finally, the last objective to achieve was to study the practicality of the packed bed column and perform a sensitivity on assumptions and predictions such as predicted mass transfer coefficient and isotherm model. It is proven that the selection of isotherm model and prediction in coefficient did not pose a large impact to the breakthrough curve and the average time required for the column of 1.5 m tall and 0.8 in diameter, to reach breakthrough time is 1.7 days. Hence, it can be concluded that adsorption technology using silica gel as its adsorbent can be applied is recovering minor compounds in palm oil mills.
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Hanami, Zarah Arwieny, und Puji Lestari. „Characterization and Application of Mangosteen Peel Activated Carbon for Ammonia Gas Removal“. Environment and Natural Resources Journal 19, Nr. 4 (10.06.2021): 320–29. http://dx.doi.org/10.32526/ennrj/19/2020298.
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Mangosteen peel can be used as an activated carbon precursor because of its high lignin content and hardness. In this study, mangosteen peel activated carbon (MP-AC) was prepared by a physical activation method using CO2 at 850°C. The Brunauer-Emmett-Teller (BET) analysis was used to assess the optimal activation time to identify the largest surface area. The properties of MP-AC were characterized by the SEM-EDS and FTIR analyses. The results showed that MP-AC obtained from the 120-minute activation time had the largest BET specific surface area of 588.41 m2/g and was selected as an adsorbent in the dynamic adsorption of ammonia gas. The values of moisture content, ash content, and iodine number of MP-AC were 6.07%, 9.8%, and 1153.69 mg/g, respectively. Breakthrough curve indicated that with lower inlet concentration and higher adsorbent mass, longer breakthrough time is reached. Equilibrium data was best fitted to the Langmuir isotherm, while the pseudo-first order kinetic model favorably described the adsorption kinetics. The results revealed a potential to utilize MP-AC as an adsorbent for ammonia gas removal with average NH3 adsorption capacity of 0.41 mg/g.
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Wang, Yiqi, Yueying Wen, Cong Mao, Hongji Sang, Yan Wu, Huibo Li und Yuezhou Wei. „Development of chromatographic process for the dynamic separation of 90Sr from high level liquid waste through breakthrough curve simulation and thermal analysis“. Separation and Purification Technology 282 (Februar 2022): 120103. http://dx.doi.org/10.1016/j.seppur.2021.120103.
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Bai, Shuqin, Jiaxin Li, Wei Ding, Shuxuan Chen und Ru Ya. „Removal of boron by a modified resin in fixed bed column: Breakthrough curve analysis using dynamic adsorption models and artificial neural network model“. Chemosphere 296 (Juni 2022): 134021. http://dx.doi.org/10.1016/j.chemosphere.2022.134021.
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Aziz, Abdul Shukor Abdul, Latifah Abd Manaf, Hasfalina Che Man und Nadavala Siva Kumar. „Column dynamic studies and breakthrough curve analysis for Cd(II) and Cu(II) ions adsorption onto palm oil boiler mill fly ash (POFA)“. Environmental Science and Pollution Research 21, Nr. 13 (23.03.2014): 7996–8005. http://dx.doi.org/10.1007/s11356-014-2739-5.
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Recepoğlu, Yaşar K., Nalan Kabay, Idil Yılmaz Ipek, Müşerref Arda, Mithat Yüksel, Kazuharu Yoshizuka und Syouhei Nishihama. „Packed bed column dynamic study for boron removal from geothermal brine by a chelating fiber and breakthrough curve analysis by using mathematical models“. Desalination 437 (Juli 2018): 1–6. http://dx.doi.org/10.1016/j.desal.2018.02.022.
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Pancl, Jan. „Dynamic sorption of Cr3+ on strongly acidic cation exchangers and separation of Cr(VI), Cr3+ and cations interfering with the spectrophotometric determination of chromium“. Collection of Czechoslovak Chemical Communications 50, Nr. 12 (1985): 2840–52. http://dx.doi.org/10.1135/cccc19852840.
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The dynamic sorption of Cr3+ on two strongly acidic cation exchangers, viz. the microreticular Ionenaustauscher I and the macroreticular Amberlyst 15, is studied by measuring the breakthrough curves for the hexaquochromium(III) ions, products of their partial hydrolysis, and mixtures of Cr3+ with Co2+, Cr2+, and Ni2+ ions, hence, ions interfering with the spectrophotometric determination of chromium. Analysis of the breakthrough curves made it possible to find the experimental conditions for the quantitative separation of Cr(VI) from Cr3+ and for the separation of chromium from the interfering cations. A procedure for the determination of Cr(VI), Cr3+ and total chromium in the presence of the interfering ions is based on the oxidation of Cr3+ with hydrogen peroxide, reduction of Cr(VI) with hydroxylammonium chloride, separation of Cr(VI) on a strongly acidic cation exchanger, and spectrophotometric determination of Cr3+ with DCTA.
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Chowdhury, Z. Z., S. M. Zain, A. K. Rashid, R. F. Rafique und K. Khalid. „Breakthrough Curve Analysis for Column Dynamics Sorption of Mn(II) Ions from Wastewater by UsingMangostana garciniaPeel-Based Granular-Activated Carbon“. Journal of Chemistry 2013 (2013): 1–8. http://dx.doi.org/10.1155/2013/959761.
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The potential of granular-activated carbon (GAC) derived from agrowaste of Mangostene (Mangostana garcinia) fruit peel was investigated in batch and fixed bed system as a replacement of current expensive methods for treating wastewater contaminated by manganese, Mn(II) cations. Batch equilibrium data was analyzed by Langmuir, Freundlich, and Temkin isotherm models at different temperatures. The effect of inlet metal ion concentration (50 mg/L, 70 mg/L, and 100 mg/L), feed flow rate (1 mL/min and 3 mL/min), and activated carbon bed height (4.5 cm and 3 cm) on the breakthrough characteristics of the fixed bed sorption system were determined. The adsorption data were fitted with well-established column models, namely, Thomas, Yoon-Nelson, and Adams-Bohart. The results were best-fitted with Thomas and Yoon-Nelson models rather than Adams-Bohart model for all conditions. The column had been regenerated and reused consecutively for five cycles. The results demonstrated that the prepared activated carbon was suitable for removal of Mn(II) ions from wastewater using batch as well as fixed bed sorption system.
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Yu, Hang, Jiarui Shi, Jin Qian, Shi Wang und Sheng Li. „Single dendritic neural classification with an effective spherical search-based whale learning algorithm“. Mathematical Biosciences and Engineering 20, Nr. 4 (2023): 7594–632. http://dx.doi.org/10.3934/mbe.2023328.
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<abstract><p>McCulloch-Pitts neuron-based neural networks have been the mainstream deep learning methods, achieving breakthrough in various real-world applications. However, McCulloch-Pitts neuron is also under longtime criticism of being overly simplistic. To alleviate this issue, the dendritic neuron model (DNM), which employs non-linear information processing capabilities of dendrites, has been widely used for prediction and classification tasks. In this study, we innovatively propose a hybrid approach to co-evolve DNM in contrast to back propagation (BP) techniques, which are sensitive to initial circumstances and readily fall into local minima. The whale optimization algorithm is improved by spherical search learning to perform co-evolution through dynamic hybridizing. Eleven classification datasets were selected from the well-known UCI Machine Learning Repository. Its efficiency in our model was verified by statistical analysis of convergence speed and Wilcoxon sign-rank tests, with receiver operating characteristic curves and the calculation of area under the curve. In terms of classification accuracy, the proposed co-evolution method beats 10 existing cutting-edge non-BP methods and BP, suggesting that well-learned DNMs are computationally significantly more potent than conventional McCulloch-Pitts types and can be employed as the building blocks for the next-generation deep learning methods.</p></abstract>
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He, Xiaodong, Jiamei Zhu, Hongmin Wang, Min Zhou und Shuangquan Zhang. „Surface Functionalization of Activated Carbon with Phosphonium Ionic Liquid for CO2 Adsorption“. Coatings 9, Nr. 9 (18.09.2019): 590. http://dx.doi.org/10.3390/coatings9090590.
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Immobilization of phosphonium ionic liquid (IL) onto activated carbon (AC) was synthesized via grafting and impregnated methods, and the modified materials were analyzed via Fourier-transform infrared spectroscopy (FTIR), X-ray diffraction, thermal gravity analysis, scanning electron microscope, pore structure and CO2/N2 adsorption selectivity. The effect of the gas flow rate (100–500 mL/min) and adsorption pressure (0.2–0.6 MPa) on the dynamic adsorption behavior of mixture gas containing 15 vol.% CO2 and 85 vol.% N2 was explained using a breakthrough method. By analyzing the breakthrough curves, the adsorption capacity was determined. The results show that surface functionalization of activated carbon with phosphonium ionic liquid is conducive to improving CO2/N2 selectivity, especially ionic liquid-impregnated film. The different adsorption behaviors of impregnated and grafted adsorbents are observed under various conditions. The grafted AC had better CO2 adsorption and mass transfer due to a lower blockage of pores by ionic liquid.
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Seghier, Abdelkarim, Ahmed Boucherdoud, Soraya Seghier, Meriem Bendjelloul, Mohammed Hadjel, El Hadj Elandaloussi, Noureddine Benderdouche und Benaouda Bestani. „Dynamic behavior of a fixed-bed adsorption column for acid red removal using natural Algerian cactos“. STUDIES IN ENGINEERING AND EXACT SCIENCES 5, Nr. 2 (19.09.2024): e8035. http://dx.doi.org/10.54021/seesv5n2-229.
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In this work, the ability of Natural Algerian Cactus (NAC) to adsorb Acid Red (AR) from aqueous solution was investigated in a fixed-bed column. Scanning Electron Microscopy (SEM) was employed to examine the surface of the biosorbent, Fourier Transform Infrared Spectroscopy (FTIR) was utilized to analyze the chemical composition of NAC, and Brunauer-Emmett-Teller (BET) analysis was conducted to determine the surface area of NAC. We examined the effects of flow rate and influent concentration of AR on the efficiency of the fixed bed. Additionally, we analyzed the sorption of AR using the Thomas and Yoon-Nelson models at various dye concentrations and flow rates to predict breakthrough curves and determine the characteristic parameters of the fixed bed sorption column. The applied models were found to describe the NAC column biosorption process. The obtained results show that the natural Algerian cactus is an efficient Acid Red biosorbent from its aqueous solutions. A sorption capacity of 39.51 mg/g was recorded for the highest concentration (100 mg/l) at a flow rate of 0.8 mL/min while for the highest flow rate (2 mL/min), the sorption capacity attained 30.27 mg/g for a concentration of 50 mg/l. However, the longest breakthrough time was noted for the lowest concentration and flow rate respectively (tb=21h and te=38h for 50mg/l and 0.8 mL/min).
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Amiri, Mohammad Javad, Maryam Khozaei und Antonio Gil. „Modification of the Thomas model for predicting unsymmetrical breakthrough curves using an adaptive neural-based fuzzy inference system“. Journal of Water and Health 17, Nr. 1 (02.01.2019): 25–36. http://dx.doi.org/10.2166/wh.2019.210.
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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.
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Solgi, Mostafa, Bernd G. K. Steiger und Lee D. Wilson. „A Fixed-Bed Column with an Agro-Waste Biomass Composite for Controlled Separation of Sulfate from Aqueous Media“. Separations 10, Nr. 4 (17.04.2023): 262. http://dx.doi.org/10.3390/separations10040262.
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An agro-waste composite with a pelletized form was prepared and characterized via IR and 13C solids NMR spectroscopy. Thermal gravimetry analysis (TGA) was used to study the weight loss profiles, while SEM images provided insight on the biocomposite morphology, along with characterization of the sulfate adsorption properties under equilibrium and dynamic conditions. The sulfate monolayer adsorption capacity (qe = 23 mg/g) of the prepared agro-waste pellets was estimated from the adsorption isotherm results by employing the Langmuir model, and comparable fitting results were obtained by the Freundlich model. The dynamic adsorption properties were investigated via adsorption studies with a fixed bed column at pH 5.2. The effects of various parameters, including flow rate, bed height and initial concentrations of sulfate, were evaluated to estimate the optimal conditions for the separation of sulfate. The experimental data of the breakthrough curves were analyzed using the Thomas and Yoon–Nelson models, which provided satisfactory best-fits for the fixed bed kinetic adsorption results. The predicted adsorption capacities for all samples according to the Thomas model concur with the experimental values. The optimum conditions reported herein afford the highest dynamic adsorption capacity (30 mg/g) as follows: 1100 mg/L initial sulfate concentration, 30 cm bed height and 5 mL/min flow rate. The breakthrough time was measured to be 550 min. This study contributes to a strategy for controlled separation of sulfate using a sustainable biocomposite material that is suitable for fixed-bed column point-of-use water treatment systems.
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Huang, Renquan, und Jing Tian. „Dynamic Scenario Analysis of Science and Technology Innovation to Support Chinese Cities in Achieving the “Double Carbon” Goal: A Case Study of Xi’an City“. International Journal of Environmental Research and Public Health 19, Nr. 22 (15.11.2022): 15039. http://dx.doi.org/10.3390/ijerph192215039.
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Since the Chinese government proclaimed the “double carbon” goal in 2020, carbon emissions reduction has become an important task for the Chinese government. Cities generate more than 60% of carbon emissions. There are many challenges in achieving the “double carbon” goal for the cities of China. Science and technology innovation (STI) provides a feasible path, and the mechanism of STI influencing carbon emissions is analyzed. The STI factors, economic factors, energy factors, and population factors are studied based on the generalized Divisia index method. According to the decomposing results, science and technology innovation investment is the most important increasing factor in carbon emissions, and technology innovation investment efficiency is the most important decreasing factor, respectively. Three scenarios are set up and simulated with Monte Carlo technology evaluating the city of Xi’an in China. Under the baseline development scenario, it cannot achieve the carbon peak goal, and the uncertainty of carbon emissions increases. Under the green development scenario, it will peak in 2051, with a 95% confidence interval of 6668.47–7756.90 × 104 tons. Under the technology breakthrough scenario, the lower and median boundaries of carbon emissions peak at 4703.94 × 104 tons and 4852.39 × 104 tons in 2026, and the upper boundary peaks at 5042.15 × 104 tons in 2030. According to the Environmental Kuznets Curve theory, it will peak between 2028 and 2029 with a GDP per capita of CNY 153,223.85. However, it will fail to achieve the carbon neutrality goal by 2060, and should rely on the national carbon trading market of China to achieve the goal with a trading volume of 2524.61–3007.01 × 104 tons.
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Voronkova, Valentyna, Vitalina Nikitenko, Nataliia Kapitaneko, Regina Andriukaitiene und Roman Oleksenko. „Cybercrime as the Newest Phenomenon of Information and Communication Society and the Means of Its Prevention“. Newsletter on the Results of Scholarly Work in Sociology, Criminology, Philosophy and Political Science 1, Nr. 2 (13.05.2020): 48–57. http://dx.doi.org/10.61439/ztuh3582.
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The purpose of the research is to analyze cybercrime as the most recent phenomenon of the information society, induced by the technological breakthrough of the Fourth Industrial Revolution, which brought risks and challenges to all mankind. Objective of the study is the theoretical analysis of a rather complex and dangerous phenomenon of cybercrime, the occurrence of which is caused by a dynamic process of criminal use of disruptive technologies in selfish purposes of criminals for the enrichment and unlawful use. Cybercriminals are regularly updating techniques and tools to apply the latest technology to their illegal activities. Today, criminals are developing their clandestine mobile radio telecommunications systems in all countries and are demonstrating the highest level of technical expertise to improve them and in doing so outperform the defenders of law and order. Nowadays cybercriminals are practicing hacking into hundreds of millions of dollars’ worth of accounts, and they are far ahead of the curve. Thus, today we must realize the threatening scale of both organized cybercrime and terrorist organizations, to which governments have fallen out of favor as they turn on the people. The control of cybercrime in the information space acts as an object of research. The subject of the study includes ways to overcome the challenges and threats spread in cyberspace.
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Ronka, Sylwia. „Removal of triazine-based herbicides on specific polymeric sorbent: fixed bed column studies“. Pure and Applied Chemistry 88, Nr. 12 (01.12.2016): 1179–89. http://dx.doi.org/10.1515/pac-2016-0905.
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AbstractThe porous material containing carboxyl groups was investigated in fixed bed system for the triazine-based herbicides removal from aqueous solution. In order to obtain adsorbent capable of generating specific interactions with triazines, the poly(divinylbenzene) was synthesized in radical suspension polymerization and then was modified with maleic anhydride in Diels-Alder reaction with subsequent base hydrolysis. The introduction of carboxyl groups into polymer structure resulted in obtaining specific interactions, such as hydrogen bonds between modified poly(divinylbenzene) and triazines, therefore the selectivity and the high adsorption capacity towards terbuthylazine, propazine, atrazine and simazine was observed. The total and usable adsorptive capacities, the breakthrough and exhaustion times, the coefficients of sphericity of isoplanes, the heights of adsorption fronts and the mass exchange moving rates were calculated based on the analysis of the breakthrough curves. Results show that the best sorption parameters in dynamic conditions were achieved for terbuthylazine and propazine. For them the highest values of adsorptive capacities, the smallest heights of mass transfer fronts and their slow movement along the bed height were obtained. The use of ethanol for herbicides elution provided a high recovery degree of adsorbed substances. Reusability of investigated polymer bed was studied in three adsorption/desorption cycles.
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puii, Lalchhing, Seung-Mok Lee und Diwakar Tiwari. „Synthesis and Characterization of Chitosan templated Mesoporous Silica: Efficient use of Mesoporous Silica in the removal of Cu(II) from Aqueous Solutions“. Science & Technology Journal 4, Nr. 2 (01.07.2016): 105–12. http://dx.doi.org/10.22232/stj.2016.04.02.04.
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A mesoporous silica was synthesized by annealing (3-Aminopropyl) triethoxysilane grafted chitosan at 800˚C. The mesoporous silica was characterized by the XRD (X-ray diffraction) analysis. The BET specific surface area and pore size of silica was found to be 178.42 m2/g and 4.13 nm. The mesoporous silica was then employed for the efficient remediation of aqueous solutions contaminated with Cu(II) under batch and column reactor operations. The mesoporous silica showed extremely high per cent removal of Cu(II) at wide pH range i.e., pH ~2.0 to 7.0. Relatively a fast uptake of Cu(II) was occurred and high percentage removal was obtained at initial concentrations studied from 1.0 to 15.0 mg/L. The equilibrium state sorption data were utilized for the Langmuir and Freundlich adsorption isotherm studies. Moreover, the effect of an increase in background electrolyte concentrations from 0.0001 to 0.1 mol/L NaNO3 was assessed for the uptake of Cu(II) by mesoporous silica. The equilibrium sorption was achieved within 240 min of contact and the kinetic data is best fitted to the pseudo-second-order and fractal like pseudo-second-order kinetic models. In addition, the mesoporous silica was used for dynamic studies under column reactor operations. The breakthrough curve was then used for the non-linear fitting of the Thomas equation and the loading capacity of the column for Cu(II) was estimated.
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Sakhnevych, Aleksandr, Raffaele Maglione und Francesco Timpone. „A Non-Destructive Methodology for the Viscoelastic Characterization of Polymers: Toward the Identification of the Time–Temperature Superposition Shift Law“. Sensors 23, Nr. 22 (16.11.2023): 9213. http://dx.doi.org/10.3390/s23229213.
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Polymers find widespread applications in various industries, such as civil engineering, aerospace, and industrial machinery, contributing to vibration control, dampening, and insulation. To accurately design products that are able to predict their dynamic behavior in the virtual environment, it is essential to understand and reproduce their viscoelastic properties via material physical modeling. While Dynamic Mechanical Analysis (DMA) has traditionally been used, innovative non-destructive techniques are emerging for characterizing components and monitoring their performance without deconstructing them. In this context, the Time–Temperature Superposition Principle (TTSP) represents a powerful empirical procedure to extend a polymer’s viscoelastic behavior across a wider frequency range. This study focuses on replicating an indentation test on viscoelastic materials using the non-destructive Viscoelasticity Evaluation System evolved (VESevo) tool. The primary objective is to derive a unique temperature–frequency relationship, referred to as a “shift law”, using characteristic curves from this non-invasive approach. Encouragingly, modifying the device setup enabled us to replicate, virtually, three tests under identical initial conditions but with varying indentation frequencies. This highlights the tool’s ability to conduct material testing across a range of frequencies. These findings set the stage for our upcoming experiment campaign, aiming to create an innovative shift algorithm from at least three distinct master curves at specific frequencies, offering a significant breakthrough in non-destructive polymer characterization with broad industrial potential.
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Banks, Eddie W., Margaret A. Shanafield, Saskia Noorduijn, James McCallum, Jörg Lewandowski und Okke Batelaan. „Active heat pulse sensing of 3-D-flow fields in streambeds“. Hydrology and Earth System Sciences 22, Nr. 3 (20.03.2018): 1917–29. http://dx.doi.org/10.5194/hess-22-1917-2018.
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Abstract. Profiles of temperature time series are commonly used to determine hyporheic flow patterns and hydraulic dynamics in the streambed sediments. Although hyporheic flows are 3-D, past research has focused on determining the magnitude of the vertical flow component and how this varies spatially. This study used a portable 56-sensor, 3-D temperature array with three heat pulse sources to measure the flow direction and magnitude up to 200 mm below the water–sediment interface. Short, 1 min heat pulses were injected at one of the three heat sources and the temperature response was monitored over a period of 30 min. Breakthrough curves from each of the sensors were analysed using a heat transport equation. Parameter estimation and uncertainty analysis was undertaken using the differential evolution adaptive metropolis (DREAM) algorithm, an adaption of the Markov chain Monte Carlo method, to estimate the flux and its orientation. Measurements were conducted in the field and in a sand tank under an extensive range of controlled hydraulic conditions to validate the method. The use of short-duration heat pulses provided a rapid, accurate assessment technique for determining dynamic and multi-directional flow patterns in the hyporheic zone and is a basis for improved understanding of biogeochemical processes at the water–streambed interface.
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Gabrin, V. A., T. E. Nikiforova, V. A. Kozlov und P. B. Razgovorov. „Concentration of heavy metal ions from aqueous media under dynamic conditions using a composite sorbent based on chitosan and silica“. Fine Chemical Technologies 19, Nr. 3 (05.07.2024): 183–91. http://dx.doi.org/10.32362/2410-6593-2024-19-3-183-191.
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Objectives. The study set out to investigate the sorption, toxicological, and regeneration properties of a composite sorbent based on chitosan hydrogel and unsuspended silicon dioxide (chitosan–colloidal silica), which manifest themselves under dynamic conditions of purification of aqueous solutions, as a means of removing heavy metal ions.Methods. The total dynamic exchange capacity of a chitosan–colloidal silica composite sorbent was evaluated under dynamic sorption conditions by passing solutions containing Zn(II), Cd(II), Cu(II), and Cr(III) ions having a concentration of 240–251 mg/L through a fixed sorption bed. The method for determining acute toxicity using daphnia (Daphnia magna Straus) is based on the direct calculation of the mortality of daphnia exposed to toxic substances contained in the test aqueous extract in comparison with a reference culture in samples that do not contain toxic substances. The regeneration ability of the sorbent was assessed by counting the number of sorption–desorption cycles using 0.1 M NaOH and 0.1 M NaHCO3 eluents, as well as aqueous solutions of H2O2 (1 and 3%).Results. The effectiveness of the chitosan–colloidal silica composite sorbent in the process of dynamic purification of aqueous media to remove Cu(II), Zn(II), Cd(II), and Cr(III) ions was established. After determining the times of ion breakthrough and saturation of the developed sorbent, its dynamic exchange capacity was calculated by processing the kinetic curves of sorption of heavy metal ions under dynamic conditions. The results of regeneration of the sorbent were presented in the context of the possibility of its reuse. It is shown that the sorbent can withstand up to five sorption–desorption cycles while maintaining a level copper cation extraction above 90%.Conclusions. Analysis of the kinetic curves demonstrated that the driving force behind the removal of heavy metals from aqueous media by means of the obtained sorbent is the external diffusion mass transfer of ions from the mobile phase of the solution. Biotesting of samples showed that the developed chitosan-based sorbent does not have acute toxicity.
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Brion-Roby, Roxanne, Jonathan Gagnon, Jean-Sébastien Deschênes und Bruno Chabot. „Development and treatment procedure of arsenic-contaminated water using a new and green chitosan sorbent: kinetic, isotherm, thermodynamic and dynamic studies“. Pure and Applied Chemistry 90, Nr. 1 (26.01.2018): 63–77. http://dx.doi.org/10.1515/pac-2017-0305.
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AbstractArsenic is classified as one of the most toxic elements for humans by the World Health Organization (WHO). With the tightening drinking water regulation to 10 μg L−1 by the WHO, it is necessary to find efficient sorbent materials for arsenic. In this work, the removal of arsenic(V) from water is achieved with an insoluble chitosan sorbent in the protonated form obtained by a simple heating process. Kinetic studies show a very fast sorption (less than 10 min). The Langmuir isotherm model is best describing experimental data with a capacity of 42 mg g−1 at pH 8. The sorption process is based on anion exchange (chemisorption) determined from the Dubinin-Radushkevich model. The sorption efficiency of the chitosan sorbent is 97% at low concentrations (e.g. 100 μg L−1). Thermodynamic analysis reveals that the sorption process is exothermic and is controlled by enthalpic factors. Breakthrough curves (BTC) were acquired in real-time by instrumental chromatography and was better described by the Thomas model. BTC from column sorption and desorption with a salt solution suggest that this sorbent is relevant for large scale applications. With this new renewable product, it will be possible to treat arsenic contaminated water at low cost and with little waste (concentration factor of 1500).
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Rusu, Lăcrămioara, Cristina-Gabriela Grigoraș, Andrei-Ionuț Simion, Elena-Mirela Suceveanu, Andreea V. Dediu Botezatu und Maria Harja. „Biosorptive Removal of Ethacridine Lactate from Aqueous Solutions by Saccharomyces pastorianus Residual Biomass/Calcium Alginate Composite Beads: Fixed-Bed Column Study“. Materials 15, Nr. 13 (02.07.2022): 4657. http://dx.doi.org/10.3390/ma15134657.
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In this study, ethacridine lactate removal from aqueous solution using a biosorbent material based on residual microbial biomass and natural polymers in fixed-bed continuous column was investigated. Composite beads of Saccharomyces pastorianus residual biomass and calcium alginate were obtained by immobilization technique. The prepared biosorbent was characterized by Fourier transformed infrared spectroscopy, scanning electron microscopy, and analysis of point of zero charge value. Then, laboratory-scale experiments by fixed-bed column biosorption were conducted in continuous system. To this purpose, the column bed high (5 cm; 7.5 cm), initial pollutant concentration (20 mg/L; 40 mg/L), and solution flow through the column (0.6 mL/min; 1.5 mL/min) were considered the main parameters. Recorded breakthrough curves suggest that lower flow rates, greater bed heights, and a lower concentration of ethacridine lactate led to an increased biosorption of the target compound. The biosorption dynamic was investigated by nonlinear regression analysis using the Adams–Bohart, Yoon–Nelson, Clark, and Yan mathematical models. Conclusively, our research highlights, firstly, that the obtained biosorbent material has the required properties for retaining the ethacridine lactate from aqueous solution in continuous system. Secondly, it emphasizes that the modeling approach reveals an acceptable fitting with the experimental data for the Yoon–Nelson, Clark, and Yan models.
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Kosakian, Aslan, Fei Wei, Jeremy (Jie) Zhou, Seongyeop Jung, Jonathan Sharman und Marc Secanell. „Fuel-Cell Performance and Stability during Liquid-Water Removal Cycles“. ECS Meeting Abstracts MA2023-02, Nr. 37 (22.12.2023): 1719. http://dx.doi.org/10.1149/ma2023-02371719mtgabs.
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Water management is crucial for achieving high-performance proton-exchange-membrane fuel cells (PEMFCs), as it helps keep the electrolyte hydrated while avoiding performance degradation and cell shutdown due to liquid-water accumulation. According to ex-situ measurements [1-3], accumulation of liquid water in gas-diffusion layers (GDLs) of PEMFCs is a transient process that can be accompanied with oscillations in capillary pressure and saturation. To understand how liquid-water accumulation and drainage impact PEMFC performance hysteresis and stability, a transient cell-level model that accounts for electrode structure and composition and is computationally efficient is needed. A number of volume-averaged models that describe the electrode structure through pore-size distribution have been developed in the past [4-7], but they are steady-state and thus cannot predict dynamic PEMFC performance. Existing transient models have also not been used to analyze cyclic liquid-water accumulation [8-10]. In this work, a transient two-phase 2D PEMFC model is developed in the open-source fuel-cell modeling software OpenFCST [11] and applied to analyze PEMFC performance hysteresis and stability during liquid-water accumulation and drainage cycles. The model accounts for the electrode structure through a mixed-wettability pore-size-distribution framework and incorporates a novel dynamic boundary condition to describe the experimentally observed cyclic liquid-water accumulation. Results of the numerical simulations are compared to transient current-density and resistance data at two polarization scan rates and during voltage steps measured with an in-house single-channel cell at multiple operating conditions. This work demonstrates how high breakthrough pressure and rapid liquid-water removal from GDLs may cause highly unstable fuel-cell operation with strong hysteresis and oscillations in the polarization curve (such as those in the figure below) that closely resemble experimental reports [12]. Numerical simulations also reveal the existence of a scan rate that maximizes polarization hysteresis due to a match between the time scale of GDL flooding and of a complete voltage sweep. Fast-scan polarization sweeps are shown most suitable for detecting catalyst-layer flooding that depends on its wettability and occurs within single seconds in contrast to GDL flooding that takes hundreds of seconds. Overall, this work brings more attention to the transient analysis of fuel-cell performance under wet conditions. Figure: Polarization-curve oscillations caused by cyclic liquid-water removal from the cathode GDL. Similar fluctuations have been experimentally observed in [12]. Transient graphs show the dynamics of current density and cathode GDL saturation. Operating conditions are 60 °C, 90% RH, 1.5 atm; scan rate is 0.5 mV/s. References J. T. Gostick et al., J. Electrochem. Soc. 157.4 (2010) C. Quesnel et al., J. Phys. Chem. C 119.40 (2015) D. Ziegler, B.Sc. thesis, Hochschule Mannheim / University of Alberta (2020) A. Z. Weber et al., J. Electrochem. Soc. 151.10 (2004) M. Eikerling, J. Electrochem. Soc. 153.3 (2006) V. Mulone and K. Karan, Int. J. Hydrog. Energy 38.1 (2013) Zhou et al., J. Electrochem. Soc. 164.6 (2017) R. J. Balliet and J. Newman, J. Electrochem. Soc. 158.8 (2011) I. V. Zenyuk et al., J. Electrochem. Soc. 163.7 (2016) A. Goshtasbi et al., J. Electrochem. Soc. 166.7 (2019) M. Secanell et al. ECS Transactions 64.3 (2014) C. Ziegler and D. Gerteisen, J. Power Sources 188.1 (2009) Figure 1
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Hinokiyama, Kazushige, Konosuke Nishida, Masahiro Osako und Nobuo Muto. „Dynamic adsorption characteristics (breakthrough curve) of methyl mercaptan“. International Journal of Environmental Studies 43, Nr. 1 (Mai 1993): 65–77. http://dx.doi.org/10.1080/00207239308710813.
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Reynel-Ávila, Hilda Elizabeth, Ismael Alejandro Aguayo-Villarreal, Lizbeth Liliana Diaz-Muñoz, Jaime Moreno-Pérez, Francisco Javier Sánchez-Ruiz, Cintia Karina Rojas-Mayorga, Didilia Ileana Mendoza-Castillo und Adrián Bonilla-Petriciolet. „A Review of the Modeling of Adsorption of Organic and Inorganic Pollutants from Water Using Artificial Neural Networks“. Adsorption Science & Technology 2022 (27.02.2022): 1–51. http://dx.doi.org/10.1155/2022/9384871.
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The application of artificial neural networks on adsorption modeling has significantly increased during the last decades. These artificial intelligence models have been utilized to correlate and predict kinetics, isotherms, and breakthrough curves of a wide spectrum of adsorbents and adsorbates in the context of water purification. Artificial neural networks allow to overcome some drawbacks of traditional adsorption models especially in terms of providing better predictions at different operating conditions. However, these surrogate models have been applied mainly in adsorption systems with only one pollutant thus indicating the importance of extending their application for the prediction and simulation of adsorption systems with several adsorbates (i.e., multicomponent adsorption). This review analyzes and describes the data modeling of adsorption of organic and inorganic pollutants from water with artificial neural networks. The main developments and contributions on this topic have been discussed considering the results of a detailed search and interpretation of more than 250 papers published on Web of Science ® database. Therefore, a general overview of the training methods, input and output data, and numerical performance of artificial neural networks and related models utilized for adsorption data simulation is provided in this document. Some remarks for the reliable application and implementation of artificial neural networks on the adsorption modeling are also discussed. Overall, the studies on adsorption modeling with artificial neural networks have focused mainly on the analysis of batch processes (87%) in comparison to dynamic systems (13%) like packed bed columns. Multicomponent adsorption has not been extensively analyzed with artificial neural network models where this literature review indicated that 87% of references published on this topic covered adsorption systems with only one adsorbate. Results reported in several studies indicated that this artificial intelligence tool has a significant potential to develop reliable models for multicomponent adsorption systems where antagonistic, synergistic, and noninteraction adsorption behaviors can occur simultaneously. The development of reliable artificial neural networks for the modeling of multicomponent adsorption in batch and dynamic systems is fundamental to improve the process engineering in water treatment and purification.
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Sorokin, Alexey, Alexander Bolotov, Mikhail Varfolomeev, Ilgiz Minkhanov, Azat Gimazov, Evgeny Sergeyev und Angelica Balionis. „Feasibility of Gas Injection Efficiency for Low-Permeability Sandstone Reservoir in Western Siberia: Experiments and Numerical Simulation“. Energies 14, Nr. 22 (18.11.2021): 7718. http://dx.doi.org/10.3390/en14227718.
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Gas injection is one of the prospective methods in the development of unconventional oil reserves. Before implementation in the field, it is necessary to justify the effectiveness of using gas agents in specific object conditions. Experiments of oil displacement on physical models with subsequent numerical modeling can provide the information necessary to justify the feasibility of using gas injection in specific reservoir conditions. This work is devoted to a series of experiments determining the minimum miscibility pressure (MMP) on a slim tube model and the analysis of oil displacement dynamics for various gas compositions, as well as numerical modeling. Displacement experiments were carried out using a recombined oil sample from one of the fields in Western Siberia. The MMP was determined by the classical method of inflection point on the displacement efficiency versus injection pressure curve, which was 34.6 MPa for associated petroleum gas (APG) and 49.9 MPa for methane. The dysnamics of oil displacement for different gas compositions at the same injection pressure showed that APG and carbon dioxide (CO2) are the most effective in the conditions of the studied field. The influence of the gas composition on the gas breakthrough point was also shown. It is revealed that the change in the concentration of the displacing agent in the outgoing separation gas helps define in more detail the process of displacement and the processes implemented in this case for various displacing gas agents. Similarly, it is shown that the displacing efficiency of a gas agent in a miscibility injection mode is affected by the configuration of wells when it is necessary to achieve MMP in reservoir conditions. For the immiscible gas injection mode, no influence of the well configuration was observed.
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Li, Haibo, Zhonghua Tang und Dongjin Xiang. „Study on Numerical Simulation of Reactive-Transport of Groundwater Pollutants Caused by Acid Leaching of Uranium: A Case Study in Bayan-Uul Area, Northern China“. Water 16, Nr. 3 (04.02.2024): 500. http://dx.doi.org/10.3390/w16030500.
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Acid in situ leaching (ISL) is a common approach to the recovery of uranium in the subsurface. In acid ISL, there are numerous of chemical reactions among the injected sulfuric acid, groundwater, and porous media containing ore layers. A substantial amount of radioactive elements including U, Ra, Rn, as well as conventional elements like K, Na, and Ca, and trace elements such as As, Cd, and Pb, are released into the groundwater. Thus, in acid ISL, understanding the transport and reactions of these substances and managing pollution control is crucial. In this study, a three-dimensional reactive transport modeling (RTM) using TOUGHREACT was built to investigate the dynamic reactive migration process of UO22+, H+, and SO42− at a typical uranium mine of Bayan-Uul. The model considering the partial penetration through wellbore in confined aquifer and complex chemical reactions among main minerals like uranium, K-feldspar, calcite, dolomite, anhydrite, gypsum, iron minerals, clay minerals, and other secondary minerals. The results show that after mining for one year, from the injection well to the extraction well, the spatial distribution of uranium volume fraction does not consistently increase or decrease, but it decreases initially and then increases. After mining for one year, the concentration front of UO22+ is about 20 m outside the mining area, the high concentration zone is mainly inside the mining area. The concentration front of H+ is no more than 50 m. SO42− is the index with the highest concentration among the three indexes, the concentration front of SO42− is no more than 100 m. The concentration breakthrough curve of the observation well 10 m from the mining area indicates that the concentrations of the three indicators began to significantly rise approximately after mining 0.05 years, reached the maximum value after mining 0.08 to 0.1 years, and then stabilized. The parameter sensitivity of absolute permeability and specific surface area of minerals shows that the concentration of H+ and SO42− is positively correlated with absolute permeability. The concentration of H+ is negatively correlated with the specific surface area of calcite, anhydrite, K-feldspar, gypsum, hematite, and dolomite. The concentration of SO42− is positively correlated with the specific surface area of K-feldspar and Hematite, and negatively correlated with the specific surface area of calcite, anhydrite, gypsum, and dolomite. The influence analysis of pumping ratio and non-uniform injection ratio shows that the non-uniform injection scheme has a more significant impact on pollution control. The water table, streamline, capture envelope, and the concentration breakthrough curve of five schemes with different pumping ratios and non-uniform injection ratio were obtained. The water table characteristics of five schemes shown that increase in the pumping ratio and the non-uniform injection ratio, the water table convex near the outer injection well is weakened and the groundwater depression cone near the pumping well is strengthened. This characteristic of water table exerts a notable retarding influence on the migration of pollutants from the mining area to the outside. For the scheme with a pumping ratio is 0 (the total pumping flow rate is equal to the total injection flow rate) and a non-uniform injection ratio is 0 (the flow rate of inner injection well Q1,Q2,Q3 is equal to the flow rate of outer injection well Q4,Q5,Q6), the streamline characteristics shown that a segment of the streamline of is diverging from inner region to the outer region. For other schemes, the streamline exhibits a convergent feature. It is indicated that by increasing the pumping ratio and non-uniform injection ratio, a closure flow field can be established, confining the groundwater pollutants resulting from mining within the capture envelope. Hence, the best scheme for preventing pollution migration is the scheme with a pumping ratio is 0 (the total pumping flow rate is equal to the total injection flow rate) and a non-uniform injection ratio is 0.1 (the flow rate of inner injection well Q1,Q2,Q3 is 10% more than the flow rate of outer injection well Q4,Q5,Q6). In this scheme, the optimal stable concentration of UO22+, H+, and SO42− at the observation well obtained by RTM is lower than other schemes, and the values are 0.00316 mol/kg, 2.792 (pH), and 0.0952 mol/kg. The inner well injection rate is 194.09 m3/d, the outer well injection rate is 158.89 m3/d, and the pumping rate is 264.00 m3/d. Numerical simulation analysis suggests that a scheme with a larger non-uniform injection ratio is more conducive to the formation of a strong hydraulic capture zone, thereby controlling the migration of pollutants in the acid ISL. A reasonable suggestion is to adopt non-uniform injection mining mode in acid ISL.
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Liang, Qihui, Xinxi Fu, Ping Wang, Xinxian Li und Peiyuan Zheng. „Dynamic Adsorption Characteristics of Phosphorus Using MBCQ“. Water 14, Nr. 3 (08.02.2022): 508. http://dx.doi.org/10.3390/w14030508.
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Biochar is a new type of adsorption material with excellent performance, but it has some problems, such as light texture, poor sedimentation, and difficult recovery, which limits its practical application. In this study, biochar microspheres (MBCQ) were prepared by the sol–gel method using powdery biochar from Hydrocotyle vulgaris as raw material and sodium alginate as a granular carrier. Experiments were performed to investigate the dynamic adsorption characteristics of phosphorus by MBCQ in the adsorption column and the influences of particle size, initial phosphorus concentration, flow rate, and column height on the breakthrough curve. The results showed that the static adsorption properties of different particles varied and that 3-millimeter particles were optimal. The breakthrough time positively correlated with column height and negatively correlated with initial phosphorus concentration, flow rate, and particle size. Flow velocity significantly impacted breakthrough time and length of mass transfer. The bed depth/service time model accurately predicted the relationship between breakthrough times and column heights. When ct/c0 = 0.6, the average relative deviation between predicted and measured values was the lowest. The Thomas model described the MBCQ adsorption process of Ph (R2 > 0.95), which indicated that diffusion in MBCQ adsorption was not a rate-limiting step.
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Fahrner, Robert L., und Gregory S. Blank. „Real‐time monitoring of recombinant antibody breakthrough during Protein A affinity chromatography“. Biotechnology and Applied Biochemistry 29, Nr. 2 (April 1999): 109–12. http://dx.doi.org/10.1111/j.1470-8744.1999.tb00539.x.
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An on‐line assay was developed to monitor antibody breakthrough in real time during Protein A affinity chromatography of recombinant antibodies. When loading cell culture fluid on to a Protein A affinity column, antibody breakthrough cannot be measured by UV absorbance because of the flow‐through of UV‐absorbing impurities. An assay using perfusion chromatography media with immobilized Protein A is a rapid, antibody‐specific assay. It directly samples preparative column effluent, allowing real‐time measurement of antibody breakthrough during loading of Protein A affinity chromatography. Breakthrough curves were generated for three column media at five flow rates, showing the effects of diffusion on the shape of the breakthrough curve. The breakthrough curves were used to measure dynamic capacity.
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Shavelzon, Evgeny, und Yaniv Edery. „Shannon entropy of transport self-organization due to dissolution–precipitation reaction at varying Peclet numbers in initially homogeneous porous media“. Hydrology and Earth System Sciences 28, Nr. 8 (22.04.2024): 1803–26. http://dx.doi.org/10.5194/hess-28-1803-2024.
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Abstract. Dissolution and precipitation processes in reactive transport in porous media are ubiquitous in a multitude of contexts within the field of Earth sciences. In particular, the dynamic interaction between the reactive dissolution and precipitation processes and the solute transport is of interest as it is capable of giving rise to the emergence of preferential flow paths in the porous host matrix. It has been shown that the emergence of preferential flow paths can be considered to be a manifestation of transport self-organization in porous media as these create spatial gradients that distance the system from the state of perfect mixing and allow for a faster and more efficient fluid transport through the host matrix. To investigate the dynamic feedback between the transport and the reactive processes in the field and its influence on the emergence of transport self-organization, we consider a two-dimensional Darcy-scale formulation of a reactive-transport setup, where the precipitation and dissolution of the host matrix are driven by the injection of an acid compound, establishing local equilibrium with the resident fluid and an initially homogeneous porous matrix, composed of a calcite mineral. The coupled reactive process is simulated in a series of computational analyses employing the Lagrangian particle-tracking (LPT) approach, capable of capturing the subtleties of the multiple-scale heterogeneity phenomena. We employ the Shannon entropy to quantify the emergence of self-organization in the field, which we define as a relative reduction in entropy compared to its maximum value. Scalability of the parameters, which characterize the evolution of the reactive process, with the Peclet number in an initially homogeneous field is derived using a simple one-dimensional ADRE model with a linear adsorption reaction term and is then confirmed through numerical simulations, with the global reaction rate, the mean value, and the variance of the hydraulic-conductivity distribution in the field all exhibiting dependency on the reciprocal of the Peclet number. Our findings show that transport self-organization in an initially homogeneous field increases with time, along with the emergence of the field heterogeneity due to the interaction between the transport and reactive processes. By studying the influence of the Peclet number on the reactive process, we arrive at a conclusion that self-organization is more pronounced in diffusion-dominated flows, characterized by small Peclet values. The self-organization of the breakthrough curve exhibits the opposite tendencies, which are observed from the perspective of a thermodynamic analogy. The hydraulic power, required to maintain the driving head pressure difference between the inlet and outlet of the field, was shown to increase with the increasing variance, as well as with the increasing mean value of the hydraulic-conductivity distribution in the field, using a simple analytic model. This was confirmed by numerical experiments. This increase in power, supplied to the flow in the field, results in an increase in the level of transport self-organization. Employing a thermodynamic framework to investigate the dynamic reaction–transport interaction in porous media may prove to be beneficial whenever the need exists to establish relations between the intensification of the preferential flow path phenomenon, represented by a decline in the Shannon entropy of the transport, with the amount of reaction that occurred in the porous medium and the change in its heterogeneity.
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Knox, James C., Armin D. Ebner, M. Douglas LeVan, Robert F. Coker und James A. Ritter. „Limitations of Breakthrough Curve Analysis in Fixed-Bed Adsorption“. Industrial & Engineering Chemistry Research 55, Nr. 16 (09.04.2016): 4734–48. http://dx.doi.org/10.1021/acs.iecr.6b00516.
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Wang, Haijun, und Junzhen Feng. „Influences of dynamic capability on breakthrough innovation“. Chinese Management Studies 14, Nr. 3 (09.12.2019): 565–86. http://dx.doi.org/10.1108/cms-03-2019-0099.
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Purpose The purpose of this paper is to focus on the influences of dynamic capability on breakthrough innovation and explores the essential mechanisms related to such influence. The impact of breakthrough innovation on organizational performance is also examined in conjunction with the manufacturing industry samples in China. Design/methodology/approach This paper follows an empirical design. Data are collected from a survey administered to manufacturing samples in China. Regression analysis is used to test the hypothesis. Findings Results show that the positive impact of breakthrough innovation on organization performance is verified. Technological breakthrough innovation affects both the organization’s financial performance and growth performance in a linear and positive way, while market breakthrough innovation affects organization performance positively with marginal increments. Research limitations/implications This paper uses data of manufacturing industry of China, hence, an extended survey in depth and width is worthy of future investigation. In addition, more unique predisposing factors on breakthrough innovation should be considered in the context of China. Practical implications The research enriches the understanding of how the dynamic capability affects the enterprise’s breakthrough innovation, which helps entrepreneurs understand how to strategize to build dynamic capability during breakthrough innovation decisions and implementations. Originality/value Dynamic capability is uniquely viewed as a multi-dimensional concept from a perspective of modularity, while breakthrough innovation is composed of two constructs. It not only enriches the understanding of how dynamic capability affects breakthrough innovation but also discovers the non-linear impact of breakthrough innovation on enterprise’s organizational performance in the context of China’s manufacturing industry.
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He, Zhao Ju, Yan Qin Lu, Li Zhu und Feng Mei Qiao. „Phosphorus Dynamic Adsorption from Wastewater by Iron-Oxide-Coated-Zeolite“. Applied Mechanics and Materials 522-524 (Februar 2014): 660–64. http://dx.doi.org/10.4028/www.scientific.net/amm.522-524.660.
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In this paper, Iron-Oxide-Coated-Zeolite has been prepared by using natural zeolite and ferric nitrate. The absorbing effect of IOCZ on phosphorus is also investigated, including the filler height, the flow rate and initial phosphorus concentration on breakthrough curve were studied. The results show that IOCZ as an adsorbent can effectively remove the phosphorus from the wastewater. When the filler height and the initial phosphorus concentration increased, the adsorption effect increased and the breakthrough time reduced. The best filler height is 30cm. The higher the initial phosphorus concentration is, the less the processing water is. Column experiment was used for advanced treatment and it can process substantial wastewater, and then makes the effluent phosphorus concentration meet the national emission standards. When the regenerated solution was trickled into the solution about 5min, almost all of the phosphorus separated from the IOCZ.
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Liu, Bing Tao, Ying Qi Yang und Li Zhang. „Experimental Studies on the Treatment of Aniline Wasterwater by Activated Carbon Fiber“. Advanced Materials Research 282-283 (Juli 2011): 64–67. http://dx.doi.org/10.4028/www.scientific.net/amr.282-283.64.
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Activated Carbon Fiber was use to treat aniline wastewater. Influencing factors，such as pH value ，salinity were studied and dynamic conditions of concentration and flow adsorption effects were also studied. Adsorption isotherm, dynamic curves and dynamic adsorption breakthrough curve were drawn. The results indicated that the salinity of the solution will affect the adsorption results and concentration in the same circumstances, time was 9 min, pH neutral in better conditions adsorption, adsorption capacities were determined to be 72 mg/g .Under dynamic conditions，with increasing concentration and velocity, the initial penetration point ahead．
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Sharp, R. R., A. B. Cunningham, J. Komlos und J. Billmayer. „Observation of thick biofilm accumulation and structure in porous media and corresponding hydrodynamic and mass transfer effects“. Water Science and Technology 39, Nr. 7 (01.04.1999): 195–201. http://dx.doi.org/10.2166/wst.1999.0359.
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A series of flat plate, porous media reactor studies was performed to characterize the development and structure of thick biofilms in porous media and the subsequent effects on porous media hydrodynamics and mass transport variables including average pore velocity, hydrodynamic dispersivity, and (dye tracer) breakthrough curve features. Biofilms composed of either a mucoid strain of Pseudomonas aeruginosa or a non-mucoid strain of Ps. aeruginosa were established in the reactors over a 2-3 week period. Analysis of porous media biofilms was performed using a combination of image analysis, photography, microbial vital stains, enumerations, and microscopy. Bulk fluid flow and flow channel distribution in the porous media/biofilm matrix were monitored by imaging a pulse of nigrosine dye. Hydrodynamics of the systems were determined by evaluating fluorescein dye breakthrough curves. Destructive sampling of the flat plate reactors at the end of each study provided additional information on the distribution and cell density of the porous media biofilms. Imaging results indicated the creation and closure of flow channels within the biofilm/porous media matrix for both mucoid and non-mucoid strains. Both systems exhibited accelerated tracer breakthrough and slightly increased hydrodynamic dispersivity as the biofilm matrix developed. Gray scale analysis of nigrosine pulses, along with fluorescein dye studies, suggests that biofilm development transforms the flow regime within the reactor from well defined porous media flow with a symmetric breakthrough curve to a skewed breakthrough curve with accelerated time to breakthrough.
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Długosz, Olga, und Marcin Banach. „Sorption of Ag+ and Cu2+ by Vermiculite in a Fixed-Bed Column: Design, Process Optimization and Dynamics Investigations“. Applied Sciences 8, Nr. 11 (11.11.2018): 2221. http://dx.doi.org/10.3390/app8112221.
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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.
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Kotoh, K., M. Tanaka, T. Sakamoto, Y. Nakamura, Y. Asakura, T. Uda und T. Sugiyama. „Breakthrough Curve Analysis of Pressure Swing Adsorption for Hydrogen Isotope Separation“. Fusion Science and Technology 54, Nr. 2 (August 2008): 415–18. http://dx.doi.org/10.13182/fst08-a1843.
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Amiri, Mohammad Javad, Jahangir Abedi-koupai und Saeid Eslamian. „Adsorption of Hg(II) and Pb(II) ions by nanoscale zero valent iron supported on ostrich bone ash in a fixed-bed column system“. Water Science and Technology 76, Nr. 3 (04.05.2017): 671–82. http://dx.doi.org/10.2166/wst.2017.252.
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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) > OBA/nZVI-Pb(II) > OBA-Pb(II) > 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.
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Травин, С. О., und Ю. И. Скурлатов. „Analytical Equation for Breakthrough Curves of Pollutant in the Process of Column Dynamic Adsorption“. Химическая безопасность / Chemical Safety Science 3, Nr. 2 (30.12.2019): 8–19. http://dx.doi.org/10.25514/chs.2019.2.16001.
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Проведено численное моделирование кривых выхода загрязнителя при прохождении фильтрующей колонки с адсорбентом в приближении стопки из 20 теоретических тарелок. Предложена модель, включающая стандартную S-образную зависимость в виде логистической функции от «внутреннего времени с неподвижным слоем адсорбента рассчитываемого через изотерму Лэнгмюра. Выведена в аналитическом виде общая формула для математического описания профиля выходной кривой процесса динамической сорбционной очистки в фильтрующих колонках. A numerical simulation of pollutant breakthrough curves in the course of its passing through an adsorbent-filled filter column in the approximation of a stack of 20 theoretical plates is carried out. A model is proposed based on the standard S-shaped dependence in the form of logistic function depending from an ‘internal time’ of the adsorption, calculated using the Langmuir isotherm. A general equation for mathematical description of the profile of the breakthrough curve is derived in analytical form describing the process of polluted media treatment by dynamic sorption in filter column with fixed-bed adsorbent layer.
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Lakshmanan, Shyam, und Thanapalan Murugesan. „Adsorption performance of coconut shell activated carbon for the removal of chlorate from chlor-alkali brine stream“. Water Science and Technology 74, Nr. 12 (27.09.2016): 2819–31. http://dx.doi.org/10.2166/wst.2016.455.
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Activated carbon from coconut shell was used to investigate the adsorption of chlorate from a chlor-alkali plant's brine stream. The effect of pH, flowrate, chlorate and chloride concentration on the breakthrough curves were studied in small-scale column trials. The results obtained show enhanced adsorption at low flowrates, higher chlorate concentrations, and at a pH of 10. These studies show that introducing an activated carbon adsorption column just before the saturator would remove sufficient quantities of chlorate to allow more of the chlor-alkali plant's brine stream to be reused. From column dynamic studies, the Thomas model showed close approximation when the chlorate in the effluent was higher than breakthrough concentrations and there was close correlation at high influent concentration. The qo (maximum adsorption capacity) values were close to those obtained experimentally, indicating close representation of the breakthrough curve by the Thomas model.
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Liu, Hai Ning, Hui Fang Zhang, Can Gao, Xiu Shen Ye und Zhi Jian Wu. „Adsorption Breakthrough Curves for Alkaline-Earth Metal Ions on the Resins in a Fixed-Bed Column“. Advanced Materials Research 884-885 (Januar 2014): 16–20. http://dx.doi.org/10.4028/www.scientific.net/amr.884-885.16.
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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.
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Lu, Debao, Yinfeng Xia, Nan Geng, Hui Wang, Jinlin Qian und Cundong Xu. „Estimation Parameters of Soil Solute Transport Processes by Using the Electric Resistivity Method“. Processes 10, Nr. 5 (13.05.2022): 975. http://dx.doi.org/10.3390/pr10050975.
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Preferential solute transport is a common phenomenon in soil, and it is of great significance to accurately describe the mechanism of pollutant transport and water and soil environmental governance. However, the description of preferential solutes still relies on applying solute breakthrough curves for model parameters fitting. At present, most of the solute breakthrough curves are obtained indoors, and with some limitations. Therefore, this study established a method for securing solute breakthrough curves based on the electrical resistivity method. The research results show that the change in soil concentration during the tracer infiltration process can be captured by establishing the fitting relationship between soil resistivity and solute concentration. Then the solute breakthrough curve can be found. Through a time moment analysis, the difference between the breakthrough curve parameters obtained by the traditional method and the resistivity method is slight; the average error is less than 10%. On this basis, the sensitive response of the parameters of the “mobile–immobile” model to concentration was elucidated through different concentration tracer experiments, among which β and D are more sensitive, and w is less sensitive. The suitable tracer concentration range should be 50–120 mg/L. Therefore, the established method could obtain the breakthrough curves and describe the transport of preferential solutes at the field scale.