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•The recovery of valuable products from acid whey is proposed.•Simultaneous demineralization and deacidification of lactose by NF is demonstrated.•Better removal of lactic acid and ...electrolytes is obtained operating at low fluxes.•The integrated NF+DF process allows to obtain a lactose purity of 93.6%•The integrated NF+DF process can achieve lactic acid/lactose ratio of 0.018 g/g.
The flowsheet of an overall process to recover valuable products from raw acid whey is proposed. It considers typical pretreatments, an ultrafiltration step to remove proteins, a decalcification step to remove calcium and magnesium by precipitation, and a nanofiltration/diafiltration step for demineralization and deacidification of lactose. The performance of each step is evaluated and the characteristics of the main streams are estimated. The feasibility of lactose recovery after the decalcification step by nanofiltration is demonstrated by using a spiral wound module. Membrane characterization was performed at pH 4 and 50 °C, with an artificial solution containing lactose, lactic acid and sodium chloride, prepared to mimic the clarified supernatant from the decalcification unit. The feasibility of the simultaneous concentration and deacidification of lactose is finally validated by processing a real solution. With the real solution, the maximum removal of lactic acid, close to 87%, is obtained by operating with a nanofiltration (NF) step (at a concentration factor of 3.5) followed by a NF step operated in diafiltration mode (DF) at constant volume (at a dilution factor of 1.8). A lactic acid/lactose ratio of 0.018 g/g is achieved, with an overall lactose purity and yield of 93.6% and 98.2%, respectively, when operating at low pressure values (up to 12–14 bar). A preliminary process simulation is finally performed to identify the premises for process optimization of the NF+DF configuration. The success of the integrated NF+DF process is contingent upon the correct balance between the choice of the membrane and the operating conditions, which ensure lactose rejections exceeding 98.5% and lactic acid rejections falling below 20–30%, while maintaining transmembrane fluxes between 8 and 15 dm3/(hm2).
The diafiltration-nanofiltration-reverse osmosis (DiaNF-RO) is an innovative process that aims to achieve ion fractionation of divalent/monovalent ions, i.e., Mg/Na (SF1Mg-Na), an important step ...towards resource recovery, while producing clean water in seawater desalination at a reasonable specific energy consumption (SEC). Firstly, the novelty of DiaNF-RO process is compared with the RO-DiaNF process where ion fractionation is performed at the pretreatment stage (i.e., seawater) in the former and post-treatment stage (i.e., SWRO brine) in the latter. DiaNF-RO outperforms RO-DiaNF in many aspects, including higher Mg recovery, higher SF1Mg-Na, lower scaling risk, and more efficient cost utilization, which emphasizes the benefits of initiating ion fractionation at low salinity in brine management. Secondly, the process practicality is reiterated by showing how desirable performance is achievable at low number of stages with some modifications. One possible adjustment is to improve NF membrane performance in the priority order of higher water permeability, lower Na rejection, and higher Mg rejection, which enables the 2DiaNF-RO to achieve the desirable SF1Mg-Na of 13.7 at 5.71 kWh/m3. Another possible adjustment is to integrate the 2nd RO stage for more product water recovery to achieve a competitive net SEC (4.01 kWh/m3). These results further solidify the industrial implementation possibility of the DiaNF-RO process.
Comparison between DiaNF-RO and RO-DiaNF, and enhancement of the 2DiaNF-RO process with improved NF membrane performance or 2nd RO integration. Display omitted
•Pre-treatment is more preferred than post-treatment for Mg/Na fractionation.•Pre-treatment has better cost utilization for ion fractionation.•Higher NF permeability triples the Mg/Na fractionation.•2nd RO stage integration reduces energy by 30 % at lower water cost.•Desirable 2DiaNF-RO performance emphasizes process practicality.
Nanofiltration (NF) membranes have been used previously for the recovery of dyes, salts, and water from textile wastewaters with high salinity. However, commercially available NF membranes have a ...high rejection for divalent salts (i.e., Na2SO4), substantially reducing the salt recovery and membrane flux when treating textile wastewater containing Na2SO4. In this study, a tight ultrafiltration membrane (UH004, Microdyn-Nadir) was proposed to fractionate the dye and Na2SO4 in the textile wastewater. The UH004 membrane with a molecular weight cutoff of 4700Da provided complete passage of monovalent salts, with little rejection of Na2SO4. This significantly increases the filtrate flux that can be achieved with high-salinity wastewater since osmotic pressure and concentration polarization effects are minimized. Furthermore, the retention behavior of four different dyes was evaluated to determine the efficiency of this membrane process. This tight ultrafiltration membrane offered the high retention for direct dyes (i.e., direct red 80, direct red 23, and Congo red) and reactive blue 2. For instance, the UH004 membrane yielded >98.9% rejection for all of the dyes at a pressure of 4bar even in the presence of 60gL−1 Na2SO4. Subsequently, an ultrafiltration-diafiltration process was designed to separate a dye/Na2SO4 aqueous mixture with 98% desalination efficiency and greater than 97% dye recovery after 5 diavolumes. These results clearly demonstrate that tight ultrafiltration membranes can be a stand-alone alternative to NF membranes for the effective fractionation of dye and Na2SO4 in the direct treatment of high-salinity textile wastewater.
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•Tight UF membrane can be an alternative to NF membrane to fractionate the dye/Na2SO4 mixture.•No obvious effect is observed on dye rejection of tight UF membrane after the addition of Na2SO4.•5-diavolume diafiltration by tight UF membrane removes 98% of Na2SO4 from the feed.•Over 97% dye recovery is obtained after diafiltration by UF membrane due to high dye rejection.
•Successful technical proof of concept regarding continuous antibody processing.•Fully automated and closed pilot plant and 100% single-use equipment.•Continuously operated platform process.•Pilot ...plant’s bulk drug substance fulfills specification limits.
To maintain or strengthen their market position, biopharmaceutical producers have to adapt their production facilities to a drastically changed market environment. Contrary to currently used large scale batch-wise operated production facilities, where stainless steel equipment is widely applied, small scale and flexible production processes are desired. Consequently, the concept of the “biofacility of the future” has been developed, which combines the attributes fast, flexible, small, inexpensive and sustainable. Four design principles build the facility’s basis and are presented within this work: continuous processing, 100% single-use equipment, closed processing and adopting the ballroom concept. However, no publication presents a completely continuously operated platform process for the production of monoclonal antibodies up to now. Therefore, this work establishes the proof of concept regarding continuous antibody manufacturing. A pilot plant for the production of monoclonal antibodies has been built 100% in single-use equipment. It was operated fully continuous and automated in the upstream and the downstream part. The concepts that allow continuously operating the pilot plant are presented within this work, i.e., continuously operated filtration, continuously operated viral inactivation, continuously operated chromatography and a continuously operated formulation. Analytics showed that the produced product was within specification limits of industrial bulk drug substances.
In this work, a diafiltration-based process was investigated for the recovery of pectic oligosaccharides produced by subcritical water hydrolysis from onion skin waste. Four tubular ceramic membranes ...from 100 to 1 kDa were selected based on the molecular weight of the different galacturonic acid species present in the onion skin hydrolysate. All these membranes showed high selectivity towards pectic oligosaccharides, with low retention for free galacturonic acid, monosaccharides, organic acids, and other impurities. The 50 and 100 kDa membranes completely retained pectic oligosaccharides with a molecular weight exceeding 80 kDa, accounting for approximately 30 % of the initial pectic oligosaccharides in the hydrolysate. However, the purification rate was significantly slower using the 50 kDa membrane due to the increased cake layer resistance. Furthermore, it was examined a fractionation/purification cascade involving sequential diafiltration stages using 100, 10, and 1 kDa membranes at 25 °C, TMP = 1 bar, and a crossflow velocity of 1.5 m s−1. Approximately 87 % of the initial pectic oligosaccharides were successfully recovered and purified in the retentates, highlighting their potential for diverse applications due to their narrow molecular weight distribution, while phenolic compounds and other valuable low molecular weight molecules were recovered in the final permeate.
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•Onion skin waste hydrolysates were complex multicomponent mixtures.•Different galacturonic acid species below 150 kDa were identified.•MWCO size impacted the retention of galacturonic acid species but not impurities.•Diafiltration models accurately predicted purification and fractionation rates.•87 % recovery of pectic oligosaccharides was reached by diafiltration cascades.
Graphene-based materials have been used for fabricating organic solvent nanofiltration membranes due to their excellent mechanical properties and chemical stability in organic solvents. However, ...graphene membranes exhibit low organic solvent permeation properties due to the large molecular size of the organic solvent molecules and their strong interactions with the graphene surface. Herein, a nanoporous graphene membrane was fabricated to enhance organic solvent permeation. Nanopores were generated on the basal plane of graphene by rapid thermal annealing of graphene oxide. The size of the nanopores was also tuned from micropores to nanopores by adjusting the activation temperatures. The optimized nanoporous graphene membrane showed ultrafast isopropyl alcohol permeance up to 295 Lm−2h−1bar−1 and a sharp molecular weight cut-off of 616 Da. The membrane showed excellent stability and diafiltration performance under cross-flow filtration with a separation factor of around 1000 for dye molecules mixed in isopropyl alcohol.
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•Nanopores were easily generated by rapid thermal annealing of graphene oxide.•The pore structure can be controlled by adjusting the thermal activation temperatures.•Mixed organic molecules can be precisely separated by both dead-end or cross-flow filtration.
Use of tight ultrafiltration (UF) membranes has created a new pathway in fractionation of dye/salt mixtures from textile wastewater for sustainable resource recovery. Unexpectedly, a consistently ...high rejection for the dyes with smaller sizes related to the pore sizes of tight UF membranes is yielded. The potential mechanism involved in this puzzle remains unclear. In this study, seven tailored UF membranes with molecular weight cut-offs (MWCOs) from 6050 to 17530 Da were applied to separate dye/salt mixtures. These UF membranes allowed a complete transfer for NaCl and Na2SO4, due to large pore sizes. Additionally, these UF membranes had acceptably high rejections for direct and reactive dyes, due to the aggregation of dyes as clusters for enhanced sizes and low diffusivity. Specifically, the membrane with an MWCO of 7310 Da showed a complete rejection for reactive blue 2 and direct dyes. An integrated UF-diafiltration process was subsequently designed for fractionation of reactive blue 2/Na2SO4 mixture, achieving 99.84% desalination efficiency and 97.47% dye recovery. Furthermore, reactive blue 2 can be concentrated from 2.01 to 31.80 g·L–1. These results indicate that UF membranes even with porous structures are promising for effective fractionation of dyes and salts in sustainable textile wastewater treatment.
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•Loose NF membrane is successfully applied in dye purification for digital ink-jet printing.•Loose NF membrane yields a high rejection (>97.2%) for 2 reactive dyes and 4 cationic ...dyes.•Integrated diafiltration process by loose NF membrane removes 99.3% of NaCl with 5 diavolumes.
In digital printing, a high salt content in dye solutions is detrimental, which calls for effective strategy for dye/salt fractionation. In this study, a loose nanofiltration (NF) membrane Sepro 2A was employed to desalinate diverse dye species (2 reactive dyes and 4 cationic dyes). This membrane, with a molecular weight cutoff of 490 Da, showed consistently high rejections to all the reactive and cationic dyes (>97.7%). Operational conditions such as dye concentrations and applied pressures have limited effects on the rejection of the membrane. An integrated NF-diafiltration process, involving a pre-concentration and a diafiltration step, was specifically designed for the fractionation of dye/NaCl mixtures. This loose NF membrane showed >99.7% rejection to reactive dyes (reactive blue 2 and reactive orange 16) and ca. 99.3% salt removal with ca. 2.0% dye loss after 5.0 diavolumes. However, the NF membrane experienced a 15.9% loss to methylene blue due to the lower rejection to this model cationic dye (97.2%). The current study provides important insights into dye/salt fractionation by loose NF membranes for digital ink-jet printing.
The state-of-the-art graphene oxide (GO) has been wildly used in water purification due to its tunable nanoscale interlayer between the two-dimensional nanosheets. However, the structural instability ...and flux decline performances significantly limit the practical application of GO-based membranes. Herein, a novel GO/DTiO2-PDA-PEI (dopamine modified TiO2) composite nanofiltration membrane has been prepared via a multi-coupled strategy, combining with the self-assembly, copolymerization and surface grafting. Tuning the nanoscale interspace between the GO nanosheets, and constructing the membrane with positively charged surface and negatively charged subsurface, the loose GO/DTiO2-PDA-PEI composite nanofiltration membrane (GDP1P2-0.6 membrane with a mean pore size = 0.87 nm) show the filtration performance with water permeance as high as 41.6 L m−2 h−1 bar−1 and dye rejection around 99.9%, and the molecular selective factor (Eriochrome black T/Na2SO4) of α = 47.6. Long-term performance and stimulation have been investigated to further analyze the dye concentration and salt removing. The investigations demonstrate that the GO/DTiO2-PDA-PEI composite nanofiltration membrane enriches 14.9-fold Eriochrome black T (ET) and reduces Na2SO4 to 0.36% in the term of the concentration factor 15 and batch diafiltration factor 5.
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•A novel GO/DTiO2-PDA-PEI composite nanofiltration membrane is synthesized via a multi-coupled strategy, combining with self-assembly, copolymerization and surface grafting.•Tuning the nanoscale interspace between the GO nanosheets and constructing the membrane with positively charged surface resulted in high permeation of pure water and ions.•The GO/DTiO2-PDA-PEI composite nanofiltration membrane (GDP1P2-0.6) shows the satisfied filtration performance with effective molecular selectivity.•GO/DTiO2-PDA-PEI composite nanofiltration membrane could enrich 14.9-fold Eriochrome black T (ET) and reduce Na2SO4 to 0.36% after the diafiltration process.
•The recovery of phenolic compounds from aqueous goji berries extract was investigated.•Three tight ultrafiltration membranes with different cut-off (1, 2.5 and 3.5 kDa) were studied.•Diafiltration ...was implemented to improve the separation of phenolic compounds from sugars.•Membrane performance was evaluated in terms of productivity and selectivity towards target compounds.•All selected membranes allowed high recovery of phenolic compounds into the retentate.
Goji berries represent a valuable source of phenolic compounds with a strong antioxidant and free radical scavenging activity combined to huge quantities of small sugars. This study was aimed at evaluating the potential of three tight ultrafiltration (UF) membranes with molecular weight cut-off (MWCO) from 1.0 to 3.5 kDa in the fractionation of phenolic compounds from sugars in the aqueous extract of dried goji berries.
The aqueous extract produced in optimized conditions of water-to-solid ratio and temperature (6.66 mL/g and 65 °C, respectively) was preliminarily clarified by UF in order to remove suspended solids and colloidal particles. A membrane diafiltration (DF) process was developed in order to fractionate phenolic compounds from sugars with selected UF membranes from the clarified extract. The membrane performance was evaluated in terms of productivity and selectivity towards target compounds. All selected membranes allowed high recovery (more than 80%) of phenolic compounds into the retentate. On the other hand, the yield of carbohydrates increased in the permeate by increasing the diafiltration volume. Among the selected membranes, the 2.5 kDa membrane allowed to reduce the concentration of total carbohydrates from 26.5 up to 2.2 g glucose/L (a reduction of 91.7%) in a diafiltration/batch concentration process producing a concentrated extract enriched in phenolic compounds of interest for pharmaceutical or nutraceutical applications.
