Starting from the classical Kedem–Katchalsky model for filtration through membranes, we derive an... more Starting from the classical Kedem–Katchalsky model for filtration through membranes, we derive an equation to compute the permeate flux and the rejection of diprotic amino acid compounds. We discuss the influence of the pH, the viscosity and the feed concentration of the solution on the transport parameters which characterize the membrane, and we improve the basic equation by accounting for these dependencies. We propose two possible strategies to estimate the transport parameters from experimental data. Finally, we compare our simulation results with experiments of tight ultrafiltration (UF) and nanofiltration (NF).
ABSTRACT A simple numerical technique is presented for batch membrane filtration design. The unde... more ABSTRACT A simple numerical technique is presented for batch membrane filtration design. The underlying model accounts for variable solute rejection coefficients, and it has a modular structure which permits to easily describe the batch process involving different arrangements of the three typical basic steps: pre-concentration, dilution mode and final concentration. The experimental design required to set up the model is discussed, together with the necessary sampling procedure. In order to validate the technique, multi-step nanofiltration experiments were carried out using a binary test solution containing organic and inorganic substances. The objective of the process is to remove the electrolyte from the solution and concentrate the organic component. The predictions for the multi-step process performances were found to be in good agreement with the experimental results. Finally, optimum-search techniques for the overall multi-step process are discussed, considering economical aspects and technological demands. The presented optimization procedure can be useful to find the optimum pre-concentration and dilution factors for a membrane plant with a defined module configuration and membrane area.
A mathematical frame for modeling batch and semi-batch membrane filtration processes is provided.... more A mathematical frame for modeling batch and semi-batch membrane filtration processes is provided. The approach followed in this work uses the feed concentrations as a basis for the calculations, rather than the concentration factor. A practical computational algorithm is proposed. Our method hands separately the design equations describing the engineering aspects of batch and semi-batch systems and the models of
Abstract Different ways of operating a photocatalytic membrane reactor have been investigated and... more Abstract Different ways of operating a photocatalytic membrane reactor have been investigated and discussed. Studies have pointed out that the application of pressure-driven membranes with the selective separation characteristics from reverse osmosis, nanofiltration (NF), ultrafiltration (UF), and microfiltration (MF) has contributed strongly to the further development of the photocatalytic reaction systems. In all those processes, membranes serve as mechanical barriers for photocatalytic particles or molecular barriers for selective separation or transport of dissolved reaction components. Immobilizing fine photocatalytic particles down to nanometer sizes, MF or UF membranes can be applied and technical configurations and cost are already well known in this area. NF membranes are used mostly for more sophisticated separation tasks. System examples and cost aspects of such membrane-coupled photocatalytic reactor systems will be described and discussed herein, which will prove the usefulness and economics of those concepts.
Spent sulfite liquor derived from sulfite pulping is considered as carbon source for bio-based pl... more Spent sulfite liquor derived from sulfite pulping is considered as carbon source for bio-based platform chemicals. The spent sulfite liquor containing sugars, hydroxylic acids, furan derivatives and cooking chemicals is currently predominantly combusted to generate energy and to recover the pulping chemicals. In order to improve the economic performance of the whole pulping process a partial material use of the spent sulfite liquor is desirable. The lignosulfonates can be separated by ultrafiltration and be used as concrete plasticizer or as source for phenolic-based hydrogels or performance materials. The carbohydrates and other wood degradation products can be used as energy and carbon source in a fermentation process. In order to improve the fermentation process, the amount of inhibitory compounds, such as furan derivatives and short-chain organic acids needs to be reduced. Intermolecular interactions between different molecules influence the detoxification process by means of na...
This research focused on the performance evaluation of a new fruit juice concentration concept na... more This research focused on the performance evaluation of a new fruit juice concentration concept named JEVA, which is featured by the connection of moisture condensation with moderate warming of the juice in a circulation loop. The warming temperatures were between 30°C and 45°C and the process was carried out at ambient pressure. The evaluation is based on analysis of the changes in physicochemical and aroma characteristics (pH, acidity, total solids content, vitamin content and microbiological and aroma analysis) of concentrated passion fruit and guava juice in comparison with those of fresh fruit juices. Fresh fruits were enzyme treated, filtrated and concentrated by a JEVA based pilot-scale equipment system. The concentrated juices were then reconstituted and characterized.
Related U.S. Application Data JP 62-244494 (1987) (Abstract). 62 Division of Ser. No. 709,865, Ju... more Related U.S. Application Data JP 62-244494 (1987) (Abstract). 62 Division of Ser. No. 709,865, Jun. 3, 1991, Pat. No. JP 87-289299 (1987) (Abstract). 5,308,492, which is a division of Ser. No. 346,767, May Primary Examiner-Thomas Wyse 3, 1989, Pat. No. 5,039,416. Attorney, Agent, or Firm-Robert S. Honor; Richard E. 51) Int, C. ................................................ CO2F 3/00 Vila; Diane E. Furman 52 U.S. Cl. .................................... 210/631; 210/759; 26/6.26/908 (57) ABSTRACT 58) Field of Search ........ 210/631, 638, 639, 650-652, The invention relates to a process for treating industrial 210/663, 668, 669, 670, 694,759, 763, 908,909 waste water which comprises either: (a) pre-treating the 56) References Cited waste water with at least two different pre-treatments selected from adsorption, membrane filtration and oxi U.S. PATENT DOCUMENTS dation and then, biologically purifying the waste water 3,472,765 10/1969 Budd et al. .......................... 210/651 or...
The invention relates to a process for the preparation of brine for the production of alkali hali... more The invention relates to a process for the preparation of brine for the production of alkali halide (s), which is characterized in that (a) divalent cations are separated from the brine by one or more precipitation steps, (b) the brine pretreated according to (a) Single or multi-stage evaporation is subjected to (c) the mother liquor occurring in (b) being separated into retentate and permeate by nanofiltration, (d) the retentate being used as a precipitation agent in (a). Furthermore, the present invention relates to alkali halide (e), which are obtained from a process with the aforementioned process steps (a) to (d).
The field of membrane distillation (MD) is currently enjoying a great deal of interest and its po... more The field of membrane distillation (MD) is currently enjoying a great deal of interest and its possible fields of application are being explored. However, penetration of liquid feed in membrane pores (wetting phenomenon) has caused in the lack of overall attention in the MD processes. Even though commercial polymeric membranes (e.g., polyvinylidene fluoride (PVDF), polypropylene (PP), and polytetrafluoroethylene) show intrinsic hydrophobicity, the pore wetting may still take place for treatment of solutions with surface tensions lower than water. Depositing nanoparticles (nPs) on membrane surface to form a microstructure on top of macrostructure (physical property rather than a chemical property of surface) as it is in natural superhydrophobic surfaces such as lotus leaf can increase water repelling effect of membranes.In this paper, membrane pore wetting behavior is investigated by depositing/grafting SiO2 nanoparticles on the surface of commercially available polypropylene membran...
The reuse of steeping lye is crucial for the sustainable production of viscose fibers. Steeping l... more The reuse of steeping lye is crucial for the sustainable production of viscose fibers. Steeping lye contains hemicellulose and many alkaline degradation products, such as organic acids, so that its purification can be evaluated in terms of total organic carbon removal. When considering purification by membrane filtration, intermolecular interactions between hemicellulose and organic acids can strongly affect their retention efficiency. Herein, we give more insights into the ultrafiltration and nanofiltration of steeping lye and corresponding model solutions. Furthermore, we studied the impact of total organic carbon concentration, hemicellulose concentration and sodium hydroxide concentration on the membrane performance. Hydrogen bonds between hemicellulose and certain types of hydroxy acids increased the retention of the latter. In contrast, charge based repulsion forces led to a decreased retention of a certain type of hydroxy acids. It can be clearly shown that taking intermolecu...
Membrane distillation (MD) has shown promise for concentrating a wide variety of brines, but the ... more Membrane distillation (MD) has shown promise for concentrating a wide variety of brines, but the knowledge is limited on how different brines impact salt scaling, flux decline, and subsequent wetting. Furthermore, past studies have lacked critical details and analysis to enable a physical understanding, including the length of experiments, the inclusion of salt kinetics, impact of antiscalants, and variability between feed-water types. To address this gap, we examined the system performance, water recovery, scale formation, and saturation index of a lab-scale vacuum membrane distillation (VMD) in long-running test runs approaching 200 h. The tests provided a comparison of a variety of relevant feed solutions, including a synthetic seawater reverse osmosis brine with a salinity of 8.0 g/L, tap water, and NaCl, and included an antiscalant. Saturation modeling indicated that calcite and aragonite were the main foulants contributing to permeate flux reduction. The longer operation times...
Abstract Sulfite spent liquor, a side stream of the pulping process, is an abundantly available s... more Abstract Sulfite spent liquor, a side stream of the pulping process, is an abundantly available source for bio-based platform chemicals. Lignosulfonates can be separated from the other organic components and pulping chemicals by ultrafiltration. The ultrafiltration permeate can either be used directly in a fermentation process or may be further treated by nanofiltration to reduce the fermentation inhibitor concentration. FilmTec NF270 was used to study different intermolecular interactions in the ultrafiltration permeate at various pH values and lignosulfonate concentrations. Intermolecular interactions between lignosulfonates and inhibitor components decrease membrane selectivity. Several furan derivatives interact via hydrogen bonds with the hydroxyl groups of the lignosulfonates. The oxygen of the aldehyde group or the ring oxygen atom with two lone pairs were found to form hydrogen bonds and thereby affect the retention. By comparison, the hydrogen bonds of the alcohol group did not noticeably affect the retention. Magnesium as counter ion of the lignosulfonate interacts with acetate and formate ions, thereby increasing their retention. Substitution of magnesium with sodium prevents a lignosulfonate ion interaction. The investigated interactions of lignosulfonates in sulfite spent liquor may help to improve the applicability of nanofiltration processes for the detoxification of lignocellulose-derived fermentation feed. Furthermore, insights can be used for other separation methods as well because they are not specified for membrane separation processes.
Nanofiltration is considered to be an appropriate separation technique in the production of bio-b... more Nanofiltration is considered to be an appropriate separation technique in the production of bio-based materials. For the utilization of process streams from the viscose-fiber production, understanding the separation behavior of organic compounds in highly alkaline solutions is necessary. Experiments with succinic acid in sodium hydroxide (NaOH) solutions with varying concentrations up to 5 mol L−1 were performed with the NP030 membrane from Microdyn Nadir. Furthermore, experiments with aqueous disodium succinate and solutions of sodium sulfate in sodium hydroxide were carried out. The influence of concentration ratios and temperature was studied. The Spiegler and Kedem model as well as the Pusch model were applied to fit the experimental data. Additionally, scanning electron microscopy (SEM) and infrared (ATR–IR) measurements were performed to validate the chemical and thermomechanical stability of the membrane. The succinic acid retention varies with its degree of dissociation. In ...
Membrane distillation (MD) is a rapidly emerging water treatment technology; however, membrane po... more Membrane distillation (MD) is a rapidly emerging water treatment technology; however, membrane pore wetting is a primary barrier to widespread industrial use of MD. The primary causes of membrane wetting are exceedance of liquid entry pressure and membrane fouling. Developments in membrane design and the use of pretreatment have provided significant advancement toward wetting prevention in membrane distillation, but further progress is needed. In this study, a broad review is carried out on wetting incidence in membrane distillation processes. Based on this perspective, the study describes the wetting mechanisms, wetting causes, and wetting detection methods, as well as hydrophobicity measurements of MD membranes. This review discusses current understanding and areas for future investigation on the influence of operating conditions, MD configuration, and membrane non-wettability characteristics on wetting phenomena. Additionally, the review highlights mathematical wetting models and...
Starting from the classical Kedem–Katchalsky model for filtration through membranes, we derive an... more Starting from the classical Kedem–Katchalsky model for filtration through membranes, we derive an equation to compute the permeate flux and the rejection of diprotic amino acid compounds. We discuss the influence of the pH, the viscosity and the feed concentration of the solution on the transport parameters which characterize the membrane, and we improve the basic equation by accounting for these dependencies. We propose two possible strategies to estimate the transport parameters from experimental data. Finally, we compare our simulation results with experiments of tight ultrafiltration (UF) and nanofiltration (NF).
ABSTRACT A simple numerical technique is presented for batch membrane filtration design. The unde... more ABSTRACT A simple numerical technique is presented for batch membrane filtration design. The underlying model accounts for variable solute rejection coefficients, and it has a modular structure which permits to easily describe the batch process involving different arrangements of the three typical basic steps: pre-concentration, dilution mode and final concentration. The experimental design required to set up the model is discussed, together with the necessary sampling procedure. In order to validate the technique, multi-step nanofiltration experiments were carried out using a binary test solution containing organic and inorganic substances. The objective of the process is to remove the electrolyte from the solution and concentrate the organic component. The predictions for the multi-step process performances were found to be in good agreement with the experimental results. Finally, optimum-search techniques for the overall multi-step process are discussed, considering economical aspects and technological demands. The presented optimization procedure can be useful to find the optimum pre-concentration and dilution factors for a membrane plant with a defined module configuration and membrane area.
A mathematical frame for modeling batch and semi-batch membrane filtration processes is provided.... more A mathematical frame for modeling batch and semi-batch membrane filtration processes is provided. The approach followed in this work uses the feed concentrations as a basis for the calculations, rather than the concentration factor. A practical computational algorithm is proposed. Our method hands separately the design equations describing the engineering aspects of batch and semi-batch systems and the models of
Abstract Different ways of operating a photocatalytic membrane reactor have been investigated and... more Abstract Different ways of operating a photocatalytic membrane reactor have been investigated and discussed. Studies have pointed out that the application of pressure-driven membranes with the selective separation characteristics from reverse osmosis, nanofiltration (NF), ultrafiltration (UF), and microfiltration (MF) has contributed strongly to the further development of the photocatalytic reaction systems. In all those processes, membranes serve as mechanical barriers for photocatalytic particles or molecular barriers for selective separation or transport of dissolved reaction components. Immobilizing fine photocatalytic particles down to nanometer sizes, MF or UF membranes can be applied and technical configurations and cost are already well known in this area. NF membranes are used mostly for more sophisticated separation tasks. System examples and cost aspects of such membrane-coupled photocatalytic reactor systems will be described and discussed herein, which will prove the usefulness and economics of those concepts.
Spent sulfite liquor derived from sulfite pulping is considered as carbon source for bio-based pl... more Spent sulfite liquor derived from sulfite pulping is considered as carbon source for bio-based platform chemicals. The spent sulfite liquor containing sugars, hydroxylic acids, furan derivatives and cooking chemicals is currently predominantly combusted to generate energy and to recover the pulping chemicals. In order to improve the economic performance of the whole pulping process a partial material use of the spent sulfite liquor is desirable. The lignosulfonates can be separated by ultrafiltration and be used as concrete plasticizer or as source for phenolic-based hydrogels or performance materials. The carbohydrates and other wood degradation products can be used as energy and carbon source in a fermentation process. In order to improve the fermentation process, the amount of inhibitory compounds, such as furan derivatives and short-chain organic acids needs to be reduced. Intermolecular interactions between different molecules influence the detoxification process by means of na...
This research focused on the performance evaluation of a new fruit juice concentration concept na... more This research focused on the performance evaluation of a new fruit juice concentration concept named JEVA, which is featured by the connection of moisture condensation with moderate warming of the juice in a circulation loop. The warming temperatures were between 30°C and 45°C and the process was carried out at ambient pressure. The evaluation is based on analysis of the changes in physicochemical and aroma characteristics (pH, acidity, total solids content, vitamin content and microbiological and aroma analysis) of concentrated passion fruit and guava juice in comparison with those of fresh fruit juices. Fresh fruits were enzyme treated, filtrated and concentrated by a JEVA based pilot-scale equipment system. The concentrated juices were then reconstituted and characterized.
Related U.S. Application Data JP 62-244494 (1987) (Abstract). 62 Division of Ser. No. 709,865, Ju... more Related U.S. Application Data JP 62-244494 (1987) (Abstract). 62 Division of Ser. No. 709,865, Jun. 3, 1991, Pat. No. JP 87-289299 (1987) (Abstract). 5,308,492, which is a division of Ser. No. 346,767, May Primary Examiner-Thomas Wyse 3, 1989, Pat. No. 5,039,416. Attorney, Agent, or Firm-Robert S. Honor; Richard E. 51) Int, C. ................................................ CO2F 3/00 Vila; Diane E. Furman 52 U.S. Cl. .................................... 210/631; 210/759; 26/6.26/908 (57) ABSTRACT 58) Field of Search ........ 210/631, 638, 639, 650-652, The invention relates to a process for treating industrial 210/663, 668, 669, 670, 694,759, 763, 908,909 waste water which comprises either: (a) pre-treating the 56) References Cited waste water with at least two different pre-treatments selected from adsorption, membrane filtration and oxi U.S. PATENT DOCUMENTS dation and then, biologically purifying the waste water 3,472,765 10/1969 Budd et al. .......................... 210/651 or...
The invention relates to a process for the preparation of brine for the production of alkali hali... more The invention relates to a process for the preparation of brine for the production of alkali halide (s), which is characterized in that (a) divalent cations are separated from the brine by one or more precipitation steps, (b) the brine pretreated according to (a) Single or multi-stage evaporation is subjected to (c) the mother liquor occurring in (b) being separated into retentate and permeate by nanofiltration, (d) the retentate being used as a precipitation agent in (a). Furthermore, the present invention relates to alkali halide (e), which are obtained from a process with the aforementioned process steps (a) to (d).
The field of membrane distillation (MD) is currently enjoying a great deal of interest and its po... more The field of membrane distillation (MD) is currently enjoying a great deal of interest and its possible fields of application are being explored. However, penetration of liquid feed in membrane pores (wetting phenomenon) has caused in the lack of overall attention in the MD processes. Even though commercial polymeric membranes (e.g., polyvinylidene fluoride (PVDF), polypropylene (PP), and polytetrafluoroethylene) show intrinsic hydrophobicity, the pore wetting may still take place for treatment of solutions with surface tensions lower than water. Depositing nanoparticles (nPs) on membrane surface to form a microstructure on top of macrostructure (physical property rather than a chemical property of surface) as it is in natural superhydrophobic surfaces such as lotus leaf can increase water repelling effect of membranes.In this paper, membrane pore wetting behavior is investigated by depositing/grafting SiO2 nanoparticles on the surface of commercially available polypropylene membran...
The reuse of steeping lye is crucial for the sustainable production of viscose fibers. Steeping l... more The reuse of steeping lye is crucial for the sustainable production of viscose fibers. Steeping lye contains hemicellulose and many alkaline degradation products, such as organic acids, so that its purification can be evaluated in terms of total organic carbon removal. When considering purification by membrane filtration, intermolecular interactions between hemicellulose and organic acids can strongly affect their retention efficiency. Herein, we give more insights into the ultrafiltration and nanofiltration of steeping lye and corresponding model solutions. Furthermore, we studied the impact of total organic carbon concentration, hemicellulose concentration and sodium hydroxide concentration on the membrane performance. Hydrogen bonds between hemicellulose and certain types of hydroxy acids increased the retention of the latter. In contrast, charge based repulsion forces led to a decreased retention of a certain type of hydroxy acids. It can be clearly shown that taking intermolecu...
Membrane distillation (MD) has shown promise for concentrating a wide variety of brines, but the ... more Membrane distillation (MD) has shown promise for concentrating a wide variety of brines, but the knowledge is limited on how different brines impact salt scaling, flux decline, and subsequent wetting. Furthermore, past studies have lacked critical details and analysis to enable a physical understanding, including the length of experiments, the inclusion of salt kinetics, impact of antiscalants, and variability between feed-water types. To address this gap, we examined the system performance, water recovery, scale formation, and saturation index of a lab-scale vacuum membrane distillation (VMD) in long-running test runs approaching 200 h. The tests provided a comparison of a variety of relevant feed solutions, including a synthetic seawater reverse osmosis brine with a salinity of 8.0 g/L, tap water, and NaCl, and included an antiscalant. Saturation modeling indicated that calcite and aragonite were the main foulants contributing to permeate flux reduction. The longer operation times...
Abstract Sulfite spent liquor, a side stream of the pulping process, is an abundantly available s... more Abstract Sulfite spent liquor, a side stream of the pulping process, is an abundantly available source for bio-based platform chemicals. Lignosulfonates can be separated from the other organic components and pulping chemicals by ultrafiltration. The ultrafiltration permeate can either be used directly in a fermentation process or may be further treated by nanofiltration to reduce the fermentation inhibitor concentration. FilmTec NF270 was used to study different intermolecular interactions in the ultrafiltration permeate at various pH values and lignosulfonate concentrations. Intermolecular interactions between lignosulfonates and inhibitor components decrease membrane selectivity. Several furan derivatives interact via hydrogen bonds with the hydroxyl groups of the lignosulfonates. The oxygen of the aldehyde group or the ring oxygen atom with two lone pairs were found to form hydrogen bonds and thereby affect the retention. By comparison, the hydrogen bonds of the alcohol group did not noticeably affect the retention. Magnesium as counter ion of the lignosulfonate interacts with acetate and formate ions, thereby increasing their retention. Substitution of magnesium with sodium prevents a lignosulfonate ion interaction. The investigated interactions of lignosulfonates in sulfite spent liquor may help to improve the applicability of nanofiltration processes for the detoxification of lignocellulose-derived fermentation feed. Furthermore, insights can be used for other separation methods as well because they are not specified for membrane separation processes.
Nanofiltration is considered to be an appropriate separation technique in the production of bio-b... more Nanofiltration is considered to be an appropriate separation technique in the production of bio-based materials. For the utilization of process streams from the viscose-fiber production, understanding the separation behavior of organic compounds in highly alkaline solutions is necessary. Experiments with succinic acid in sodium hydroxide (NaOH) solutions with varying concentrations up to 5 mol L−1 were performed with the NP030 membrane from Microdyn Nadir. Furthermore, experiments with aqueous disodium succinate and solutions of sodium sulfate in sodium hydroxide were carried out. The influence of concentration ratios and temperature was studied. The Spiegler and Kedem model as well as the Pusch model were applied to fit the experimental data. Additionally, scanning electron microscopy (SEM) and infrared (ATR–IR) measurements were performed to validate the chemical and thermomechanical stability of the membrane. The succinic acid retention varies with its degree of dissociation. In ...
Membrane distillation (MD) is a rapidly emerging water treatment technology; however, membrane po... more Membrane distillation (MD) is a rapidly emerging water treatment technology; however, membrane pore wetting is a primary barrier to widespread industrial use of MD. The primary causes of membrane wetting are exceedance of liquid entry pressure and membrane fouling. Developments in membrane design and the use of pretreatment have provided significant advancement toward wetting prevention in membrane distillation, but further progress is needed. In this study, a broad review is carried out on wetting incidence in membrane distillation processes. Based on this perspective, the study describes the wetting mechanisms, wetting causes, and wetting detection methods, as well as hydrophobicity measurements of MD membranes. This review discusses current understanding and areas for future investigation on the influence of operating conditions, MD configuration, and membrane non-wettability characteristics on wetting phenomena. Additionally, the review highlights mathematical wetting models and...
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Papers by Wolfgang Samhaber