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In dieser Arbeit wurde eine Mixed-Matrix-Kompositmembran zur selektiven Abtrennung höherer Kohlenwasserstoffe entwickelt. Eine detaillierte Untersuchung der Trennleistung unter variierenden Betriebsbedingungen wurde anhand von Einzelgasen und Gasmischungen durchgeführt, um die optimalen Betriebsbedingungen zu identifizieren und die Trennleistung hinsichtlich eines industriellen Einsatzes zu bewerten., In this work a thin film mixed matrix membrane material for the selective separation of higher hydrocarbons is developed. A detailed study of the separation performance under varying single and mixed-gas operating conditions is performed to identify the optimal range of application and evaluate the performance with respect to an industrial application., Bundesministerium für Bildung und Forschung (BMBF)

Forward osmosis (FO) is an emerging process to dewater whey streams energy efficiently. The driving force for the process is the concentration gradient between the feed (FS) and the concentrated draw (DS) solution. Here we investigate not only the effect of the DS concentration on the performance, but also that of the FS is varied to maintain equal driving force at different absolute concentrations. Experiments with clean water as feed reveal a flux increase at higher osmotic pressure. When high product purities and thus low reverse salt fluxes are required, operation at lower DS concentrations is preferred. Whey as FS induces severe initial flux decline due to instantaneous protein fouling of the membrane. This is mostly due to reversible fouling, and to a smaller extent to irreversible fouling. Concentration factors in the range of 1.2–1.3 are obtained. When 0.5 M NaCl is added to whey as FS, clearly lower fluxes are obtained due to more severe concentration polarization. Multiple runs over longer times show though that irreversible fouling is fully suppressed due to salting in/out effects and flux decline is the result of reversible fouling only.

Forward osmosis (FO) is an emerging process to dewater whey streams energy efficiently. The driving force for the process is the concentration gradient between the feed (FS) and the concentrated draw (DS) solution. Here we investigate not only the effect of the DS concentration on the performance, but also that of the FS is varied to maintain equal driving force at different absolute concentrations. Experiments with clean water as feed reveal a flux increase at higher osmotic pressure. When high product purities and thus low reverse salt fluxes are required, operation at lower DS concentrations is preferred. Whey as FS induces severe initial flux decline due to instantaneous protein fouling of the membrane. This is mostly due to reversible fouling, and to a smaller extent to irreversible fouling. Concentration factors in the range of 1.2–1.3 are obtained. When 0.5 M NaCl is added to whey as FS, clearly lower fluxes are obtained due to more severe concentration polarization. Multiple runs over longer times show though that irreversible fouling is fully suppressed due to salting in/out effects and flux decline is the result of reversible fouling only.

For osmotically driven membrane processes, including forward osmosis (FO) and pressure retarded osmosis (PRO), water permeate was selectively induced across a semi-permeable polymeric membrane by the osmotic pressure generated from the salinity gradient. Although both FO and PRO processes are mainly driven by the osmotic pressure difference increased by the more concentrated draw solution on the permeate site of the membrane, membrane orientations for the processes are mainly confirmed as the active layer facing the feed solution (AL-FS) for FO, and the active layer facing the draw solution (AL-DS) for PRO, respectively. Although the AL-FS orientation for FO is beneficial for controlling membrane fouling on the dense active layer, diluted internal concentration polarisation (ICP) inside a FO membrane would be a major obstacle to maintaining the osmotic driving force under FO operation. These processes have been widely used for a variety of water treatments and hybrid systems as a low-energy process. However, the processes still have some critical challenges for membrane development, which are related to the following aspects: water permeability, reverse solute diffusion, concentration polarisation, membrane fouling and membrane stability. Although many earlier studies developed various kinds of polymeric membranes at laboratory scale to produce outstanding performances for overcoming existing challenges in FO and PRO processes, most of them never produced their own scaled-up membrane modules for commercial applications. This study, therefore, initially targeted novel nanocomposite membrane development for FO and PRO processes using the dual-blade casting technique and two hydrophilic nanomaterials (graphene oxide and halloysite nanotubes). Subsequently, we selected the best strategy in our activities, and the selected one was further investigated for its commercial viability.

For osmotically driven membrane processes, including forward osmosis (FO) and pressure retarded osmosis (PRO), water permeate was selectively induced across a semi-permeable polymeric membrane by the osmotic pressure generated from the salinity gradient. Although both FO and PRO processes are mainly driven by the osmotic pressure difference increased by the more concentrated draw solution on the permeate site of the membrane, membrane orientations for the processes are mainly confirmed as the active layer facing the feed solution (AL-FS) for FO, and the active layer facing the draw solution (AL-DS) for PRO, respectively. Although the AL-FS orientation for FO is beneficial for controlling membrane fouling on the dense active layer, diluted internal concentration polarisation (ICP) inside a FO membrane would be a major obstacle to maintaining the osmotic driving force under FO operation. These processes have been widely used for a variety of water treatments and hybrid systems as a low-energy process. However, the processes still have some critical challenges for membrane development, which are related to the following aspects: water permeability, reverse solute diffusion, concentration polarisation, membrane fouling and membrane stability. Although many earlier studies developed various kinds of polymeric membranes at laboratory scale to produce outstanding performances for overcoming existing challenges in FO and PRO processes, most of them never produced their own scaled-up membrane modules for commercial applications. This study, therefore, initially targeted novel nanocomposite membrane development for FO and PRO processes using the dual-blade casting technique and two hydrophilic nanomaterials (graphene oxide and halloysite nanotubes). Subsequently, we selected the best strategy in our activities, and the selected one was further investigated for its commercial viability.