Osmotic Membrane Research Articles

Numerical modeling of an integrated OMBR-NF hybrid system for simultaneous wastewater reclamation and brine management

The osmotic membrane bioreactor (OMBR) is an energy-efficient wastewater purification technique that integrates a membrane bioreactor (MBR), a forward osmosis (FO) membrane, and a draw solution. The main objective of this study was to develop a hybrid model that combines an OMBR with nanofiltration (NF) for simultaneous wastewater reclamation and brine management. In this model, reverse osmosis (RO) reject brine and wastewater were used as draw and feed solutions, respectively. The results from the model suggested that a stable pure water flux of 2.10 dm/d can be obtained with a water salinity of 352.62 mg/L at an effective osmotic pressure of 11.42 bar. To further investigate the model, sensitivity analysis of five main system inputs of the hybrid OMBR-NF system was carried out. The results showed that the water flux can be improved by enhancing the mass diffusion coefficient on the draw solution side (Kd) and the salt concentration of the final draw solution (Xdi). In addition, the water flux can be improved by reducing the internal concentration polarization (ICP) effect. For instance, the water flux increased from around 1.90 to 2.33 dm/d when KICP was decreased from 0.56 to 0.36 d/dm. Lastly, it was found that Xdi was the main influence on the permeate water quality; increasing it from 20,000 to 70,000 mg/L caused the water salinity to increase from 100 to 352 mg/L. Overall, this novel hybrid system can be used to achieve better water quality and reduce environmental pollution from highly concentrated brines.

Sustainable fertilizer-drawn forward osmosis for the vegetable industry in reducing liquor from vegetable waste

ABSTRACT Forward osmosis has been widely used due to its advantages such as low energy consumption and low membrane fouling. Conventional treatment of vegetable industry wastes leaving the liquor an additional puzzle. The objective of this study is to evaluate the feasibility of reducing energy consumption by using forward osmotic membrane technology to concentrate vegetable liquor. In this research, the suitable draw solutes’ condition was investigated, results showed 1 M ammonium sulphate could reach 7.21 LMH water flux and it was chosen as the draw solution for concentrating vegetable liquor, then the long-term FO performance was compared with theoretical water flux showing that the difference of water flux decrease is caused by the organic matter. Further identification of the major foulant via a control variable method using simulated vegetable liquor leads to anthocyanins as the major foulant. This novel application of the fertilizer drawn FO process provided an environmentally friendly solution to the vegetable industry, which would potentially transform an industry into a sustainable cyclic economy.

An osmotic computing infrastructure for urban pollution monitoring

SummaryUrban pollution control systems suffer from the presence of fixed stations in a greater number than mobile monitoring devices. Data gathered from such stations provide detailed and reliable information, thanks to equipment quality and effective measuring protocols, but these sampled data are gathered from very limited areas and through discontinuous monitoring campaigns. Fortunately, the spread of technologies for mobility has fostered the development of new approaches like mobile crowdsensing (MCS), increasing the chances of using mobile devices, even personal ones, as suitable sensors for the urban monitoring scenario. Nevertheless, one of the open challenges is the management of integrated heterogeneous data flows, differing in terms of typology, technical specifications (eg, transmission protocols), and semantics. The osmotic computing paradigm aims at creating an abstract level between mobile devices/Internet‐of‐Things devices and a cloud platform, which enables opportunistic filtering and the addition of metadata for improving the data processing flow. This work focuses on the design and development of a middleware that integrates data coming from mobile and Internet‐of‐Things devices specifically deployed in urban contexts using the osmotic computing paradigm. Moreover, a component of the osmotic membrane has been developed for security management.

Comparison of hybrid ultrafiltration-osmotic membrane bioreactor and conventional membrane bioreactor for oil refinery effluent treatment

Although membrane bioreactors (MBR) has become the preferred choice for oil refinery reclamation, the osmotic membrane bioreactor (OMBR) has gained interest in the last years because of the low membrane fouling propensity and the high rejection capacity to both inorganic and organic contaminants. However, progress of OMBR is hindered by the salinity build-up in the bioreactor. This study evaluated the hybrid ultrafiltration-osmotic membrane bioreactors (UF-OMBR) performance in the treatment of oil refinery effluent and compare its performance with conventional MBR focusing the mixed liquor characteristics, the membrane fouling and the overall performance. The results indicated that the salinity build-up in the biological reactor was successfully prevented by integrating ultrafiltration to OMBR. Dissolved organic carbon (DOC) removal efficiencies for the UF and FO in the UF-OMBR were 81 ± 15 and 99.6 ± 0.5%, respectively, while for UF in the conventional MBR was 66 ± 8%. The high removal efficiency for UF in UF-OMBR compared to UF in conventional MBR can be attributed to the longer retention time of recalcitrant organic compounds. This could occur due to the high rejection of FO membrane which is not attenuated by UF permeate as efficiently as it was observed for salinity. However, this organic matter build-up in the biological reactor contributed to the greater UF membrane fouling in UF-OMBR compared to in conventional MBR. Low fouling tendency was observed for FO membrane. Overall, the UF-OMBR process was able of simultaneously producing two streams (UF and FO permeate) with different opportunities for water reclamation.

Energy generation and storage by salinity gradient power: A model-based assessment

Abstract Three energy storage systems based on mixing and desalination of solutions with different salt concentrations are presented, namely, reverse electrodialysis, pressure retarded osmosis and capacitive Donnan potential, coupled to their corresponding desalination technologies: electrodialysis, reverse osmosis and membrane capacitive deionisation. Conceptual mathematical models are used to assess power densities and efficiency, and to address the influence on the performance of factors such as temperature and residence time. The maximum power densities for electrodialysis, osmotic and capacitive energy storage systems are calculated as 4.69, 4.83 and 0.503 W m−2, respectively, at 25 °C and residence time of 20 s, corresponding to an average fluid velocity of 5 mm/s. In order to achieve competitive economic energy (in the EU) with this power density, the membrane price needs to be lower than 2.9, 3.0 and 0.31$ m−2, for each of the technologies. Utilisation of waste heat to increase the temperature to 60 °C increases the power density to 8.54, 6.04 and 0.708 W m−2, which allows for 25% higher osmotic membrane price (3.7$ m−2), and over 80% and 40% higher price (5.2 and 0.43$ m−2) for the ionic exchange membrane used in the electrodialytic and capacitive energy storage system respectively, while still having economic energy production. Advantages and disadvantages of the proposed energy storage systems are discussed, along with the cost evaluation for each technology.

Performance of a forward osmotic membrane bioreactor for anaerobic digestion of waste sludge with increasing solid concentration

A forward osmotic membrane bioreactor for sludge anaerobic digestion (ad-OMBR) could realize high-solid digestion via drawing moisture out by forward osmosis (FO). Methane production and microbial community evolution were monitored in an ad-OMBR as the total solids (TS) content was gradually increased. With magnesium chloride (MgCl2) and cellulose triacetate (CTA) membrane as a draw solution and FO membrane, respectively, the ad-OMBR exhibited better performance than the conventional digester, with higher solid content, organic degradation and methane content in biogas. The conductivity of the ad-OMBR did not increase, potentially because of the formation of struvite crystals aided by the reverse-fluxed Mg2+ ions. Microbial diversity increased along with the increase in solid content based on the Shannon index, while the most operational taxonomic units were obtained in the 8% TS sludge Although phylum Firmicutes decreased when the TS content was raised to 11%, the relative abundance of Proteobacteria, Chloroflexi, Actinobacteria, and Bacteroidetes, which could also degrade organic matter, increased with increasing TS in ad-OMBR. FO membrane fouling in ad-OMBR was highly reversible.

Epidemiological, biological and clinical update on exercise-induced hemolysis.

Exercise-induced hemolysis can be conventionally defined as rupture and destruction of erythrocytes during physical exercise. The currently available epidemiologic information attests that a substantial degree of exercise-induced hemolysis is commonplace after short-, medium-, long- and ultra-long distance running, as reflected by significant decrease of serum or plasma haptoglobin and significant increase of plasma concentration (or overall blood content) of free hemoglobin. This paraphysiological intravascular hemolysis is typically mild (average variations of hemolysis biomarkers are usually comprised between 1.2- and 1.8-fold), almost self-limiting (completely resolving within 24-48 hours), with severity depending on athlete population, analytical technique used for detecting intravascular hemolysis, as well as on number, frequency and intensity of ground contacts, but not on running technique. Additional lines of evidence support the notion that both osmotic fragility and membrane structure of erythrocytes are considerably modified during endurance exercise. This fact goes hand in hand with findings that erythrocyte lifespan in runners is approximately 40% shorter than in sedentary controls. Direct mechanical injury caused by forceful ground contacts, repeated muscle contractile activity or vasoconstriction in internal organs are three potential sources of exercise-induced hemolysis, whilst metabolic abnormalities developing while exercising (e.g., hyperthermia, dehydration, hypotonic shock, hypoxia, lactic acidosis, shear stress, oxidative damage, proteolysis, increased concentration of catecholamines and lysolecithin) may actively contribute to trigger, accelerate or amplify this phenomenon. Although no systematic evidence is available, it seems also reasonable to hypothesize that patients bearing erythrocyte disorders may be particularly vulnerable to developing exercise-induced hemolysis.

Osmotic membrane distillation for retention of antioxidant potential in Nagpur mandarin (Citrus reticulata Blanco) fruit juice concentrate

AbstractConsumers desire for processed fruit juices which are of higher quality, nutritionally rich, and convenient to prepare and store. Membranes have found many applications throughout the food processing industry. The present study describes the potential use of osmotic distillation process for concentrating Nagpur mandarin (Citrus reticulata Blanco) juice for the first time and to study its impact on ascorbic acid content and antioxidant activity assessed by ABTS, DPPH, FRAP, and TPC assays. The flux and concentration factor was also determined to evaluate the performance of the OD process. The juice clarified by the ultrafiltration technique having a TSS of 9.0°Brix was concentrated up to 60.4°Brix. The ascorbic acid content (15.5 mg/100 mL) and antioxidant activity by ABTS (9.69 mmolL−1 Trolox), DPPH (2.77 mmolL−1 Trolox), FRAP (1.33 mmolL−1 Trolox), and TPC content (13 mg GAE L−1) was retained, thus suggesting the use of membrane technology for concentrating fruit juice providing an alternative to the traditionally employed thermal evaporation processes.Practical applicationsThis work offers an alternative to the thermal evaporation method for concentrating Nagpur mandarin juice with less energy consumption, low equipment cost, and less damage to the product and retention of antioxidant compounds, for example, ascorbic acid, which plays an important role in human health. The Nagpur mandarin juice was transformed to concentrate with the osmotic membrane distillation (OD) technique. The concentrate so produced is significantly potential to the food processing industry with retained nutritional qualities, and is suitable for many purposes due to its reduced weight and volume, less handling and storage costs and reduced in water activity with enhancement of product stability. Production of Nagpur mandarin juice concentrate also broadens its potential applications in food industry and its good quality renders it easily acceptable to consumers.

Defect-free outer-selective hollow fiber thin-film composite membranes for forward osmosis applications

This study presents the successful fabrication of a novel defect-free outer-selective hollow fiber (OSHF) thin-film composite (TFC) membrane for forward osmosis (FO) applications. Thin and porous FO membrane substrates made of polyether sulfone (PES) with a dense and smooth outer surface were initially fabricated at different air-gap distances. A modified vacuum-assisted interfacial polymerization (VAIP) technique was then successfully utilised for coating polyamide (PA) layer on the hollow fiber (HF) membrane substrate to prepare OSHF TFC membranes. Experimental results showed that the molecular weight cut-off (MWCO) of the surface of the membrane substrate should be less than 88 kDa with smooth surface roughness to obtain a defect-free PA layer via VAIP. The FO test results showed that the newly developed OSHF TFC membranes achieved water flux of 30.2 L m−2 h−1 and a specific reverse solute flux of 0.13 g L−1 using 1 M NaCl and DI water as draw and feed solution, respectively. This is a significant improvement on commercial FO membranes. Moreover, this OSHF TFC FO membrane demonstrated higher fouling resistance and better cleaning efficiency against alginate-silica fouling. This membrane also has a strong potential for scale-up for use in larger applications. It also has strong promise for various FO applications such as osmotic membrane bioreactor (OMBR) and fertilizer-drawn OMBR processes.

Innovative upflow anaerobic sludge osmotic membrane bioreactor for wastewater treatment

A novel upflow anaerobic sludge–forward osmotic membrane bioreactor was developed for simultaneous wastewater treatment, membrane fouling reduction, and nutrient recovery. An upflow anaerobic sludge blanket (UASB) reactor was incorporated into the system, suspending the anaerobic sludge at the bottom of the reactor. A forward osmosis membrane replaced the traditional three-phase separator of the UASB technology. The removals of chemical oxygen demand, PO43−, and NH4+ were all more than 95% with low membrane fouling in this system. Halotolerant Fusibacter, which can ferment organics to acetate, was increased rapidly from 0.1% to 5% in this saline environment. Acetoclastic Methanosaeta was the most dominant prokaryotes and responsible for majority of methane production. Reduction of membrane fouling in this system was verified by the fluorescence excitation-emission matrix spectrophotometry. Furthermore, phosphorus recovery and salinity build-up mitigation were achieved using periodic microfiltration to recover 57–105 mg/L phosphorus from pH 9 to 12.

Recent advances in nanomaterial-modified polyamide thin-film composite membranes for forward osmosis processes

Polyamide thin-film composite (PA TFC) membranes have attained much attention for forward osmosis (FO) applications in separation processes, water and wastewater treatment due to their superior intrinsic properties, such as high salt rejection and water permeability compared to the first-generation cellulose-based FO membranes. Nonetheless, several problems like fouling and trade-off between membrane selectivity and water permeability have hindered the progress of conventional PA TFC FO membranes for real applications. To overcome these issues, nanomaterials or chemical additives have been integrated into the TFC membranes. Nanomaterial-modified membranes have demonstrated significant improvement in their anti-fouling properties and FO performance. In addition, the PA TFC membranes can be designed for specific applications like heavy metal removal and osmotic membrane bioreactor by using nanomaterials to modify their physicochemical properties (porosity, surface charge, hydrophilicity, membrane structure and mechanical strength). This review provides a comprehensive summary of the progress of nanocomposite PA TFC membrane since its first development for FO in the year 2012. The nanomaterial-incorporated TFC membranes are classified into four categories based on the location of nanomaterial in/on the membranes: embedded inside the PA active layer, incorporated within the substrate, coated on the PA layer surface, or deposited as an interlayer between the substrate and the PA active layer. The key challenges still being confronted and the future research directions for nanocomposite PA TFC FO are also discussed.

Fabrication and characterization of zeolitic imidazolate framework-embedded cellulose acetate membranes for osmotically driven membrane process

Zeolitic imidazolate framework-302 (ZIF-302)-embedded cellulose acetate (CA) membranes for osmotic driven membrane process (ODMPs) were fabricated using the phase inversion method. We investigated the effects of different fractions of ZIF-302 in the CA membrane to understand their influence on ODMPs performance. Osmotic water transport was evaluated using different draw solution concentrations to investigate the effects of ZIF-302 contents on the performance parameters. CA/ZIF-302 membranes showed fouling resistance to sodium alginate by a decreased water flux decline and increased recovery ratio in the pressure retarded osmosis (PRO) mode. Results show that the hydrothermally stable ZIF-302-embedded CA/ZIF-302 composite membrane is expected to be durable in water and alginate-fouling conditions.

An insight into the mechanism of antifungal activity of biogenic nanoparticles than their chemical counterparts

Herein, we describe the enhanced antifungal activity of silver nanoparticles biosynthesized by cell free filtrate of Trichoderma viride (MTCC 5661) in comparison to chemically synthesized silver nanoparticles (CSNP) of similar shape and size. Biosynthesized silver nanoparticles (BSNP) enhanced the reduction in dry weight by 20 and 48.8% of fungal pathogens Fusarium oxysporum and Alternaria brassicicola respectively in comparison to their chemical counterparts (CSNP). Nitroblue tetrazolium and Propidium iodide staining demonstrated the higher generation of superoxide radicals lead to higher death in BSNP treated fungus in comparison to CSNP. Scanning electron microscopy of A. brassicicola revealed the osmotic imbalance and membrane disintegrity to be major cause for fungal cell death after treatment with BSNP. To gain an insight into the mechanistic aspect of enhanced fungal cell death after treatment of BSNP in comparison to CSNP, stress responses and real time PCR analysis was carried out with A. brassicicola. It revealed that generation of ROS, downregulation of antioxidant machinery and oxidative enzymes, disruption of osmotic balance and cellular integrity, and loss of virulence are the mechanisms employed by BSNP which establishes them as superior antifungal agent than their chemical counterparts. With increasing drug resistance and ubiquitous presence of fungal pathogens in plant kingdom, BSNP bears the candidature for new generation of antifungal agent.

Nutrient removal in an algal membrane photobioreactor: effects of wastewater composition and light/dark cycle.

Graesiella emersonii was cultivated in an osmotic membrane photobioreactor (OMPBR) for nutrients removal from synthetic wastewater in continuous mode. At 1.5days of hydraulic retention time and under continuous illumination, the microalgae removed nitrogen (N) completely at influent NH4+-N concentrations of 4-16mg/L, with removal rates of 3.03-12.1mg/L-day. Phosphorus (P) removal in the OMPBR was through biological assimilation as well as membrane rejection, but PO43--P assimilation by microalgae could be improved at higher NH4+-N concentrations. Microalgae biomass composition was affected by N/P ratio in wastewater, and a higher N/P ratio resulted in higher P accumulation in the biomass. The OMPBR accumulated about 0.35g/L biomass after 12days of operation under continuous illumination. However, OMPBR operation under 12h light/12h dark cycle lowered biomass productivity by 60%, which resulted in 20% decrease in NH4+-N removal and nearly threefold increase in PO43--P accumulation in the OMPBR. Prolonged dark phase also affected carbohydrate accumulation in biomass, although its effects on lipid and protein accumulation were negligible. The microalgae also exhibited high tendency to aggregate and settle, which could be attributed to reduction in cell surface charge and enrichment of soluble algal products in the OMPBR. Due to a relatively shorter operating period, membrane biofouling and salt accumulation did not influence the permeate flux significantly. These results improve the understanding of the effects of N/P ratio and light/dark cycle on biomass accumulation and nutrients removal in the OMPBR.

The Complex Fine-Tuning of K⁺ Fluxes in Plants in Relation to Osmotic and Ionic Abiotic Stresses.

As the main cation in plant cells, potassium plays an essential role in adaptive responses, especially through its involvement in osmotic pressure and membrane potential adjustments. K+ homeostasis must, therefore, be finely controlled. As a result of different abiotic stresses, especially those resulting from global warming, K+ fluxes and plant distribution of this ion are disturbed. The hormone abscisic acid (ABA) is a key player in responses to these climate stresses. It triggers signaling cascades that ultimately lead to modulation of the activities of K+ channels and transporters. After a brief overview of transcriptional changes induced by abiotic stresses, this review deals with the post-translational molecular mechanisms in different plant organs, in Arabidopsis and species of agronomical interest, triggering changes in K+ uptake from the soil, K+ transport and accumulation throughout the plant, and stomatal regulation. These modifications involve phosphorylation/dephosphorylation mechanisms, modifications of targeting, and interactions with regulatory partner proteins. Interestingly, many signaling pathways are common to K+ and Cl−/NO3− counter-ion transport systems. These cross-talks are also addressed.

Osmotic Squeezing and Membrane Tension Drive Vesicle Evolution during Exocytosis

Osmotic Squeezing and Membrane Tension Drive Vesicle Evolution during Exocytosis

A novel thin film composite hollow fiber osmotic membrane with one-step prepared dual-layer substrate for sludge thickening

Forward osmosis (FO) membranes have received attention as an energy-efficient and low-cost technique in stream concentrating processes. In this work, a novel double-skinned hollow fiber thin film composite (TFC) FO membrane has been successfully fabricated, which consists of a one-step prepared dual layer substrate and a thin inner selective layer formed via interfacial polymerization. The substrate consists of a relatively dense ultrafiltration (UF) outer layer and a porous UF inner layer, both of which were constructed from polyethersulfone (PES) as the substrate material by using dual-layer co-extrusion technique. Compared to the commercial and reported double-skinned FO membranes, the FO membrane developed in this work exhibited a higher permeate flux with humic acid solution as feed. Furthermore, the double-skinned FO membrane was applied in concentrating activated sludge using 0.5 M NaCl as draw solution, and a permeate flux at 5.4 L/m2h was achieved after 5 h operation, which was higher than or comparable to those of the reported FO membranes. Membrane autopsies and foulant analysis suggested that the dense UF skin layer helped to reject greater-sized organic foulants (> 300 Da). This study shed light on the important fabrication features and promising application of the double-skinned hollow fiber TFC FO membrane in sludge concentration.

Concentration of skim milk using a hybrid system of osmotic distillation and membrane distillation

Concentration of skim milk using a hybrid system of osmotic distillation and membrane distillation

Mitigation of solute buildup by using a biodegradable and reusable polyelectrolyte as a draw solute in an osmotic membrane bioreactor

Biodegradable draw solutes can help alleviate the accumulation of draw solutes in an osmotic membrane bioreactor through biodegradation, and thus achieve better water recovery and contaminant removal.

Smart Experience in Fashion Design: A Speculative Analysis of Smart Material Systems Applications

During the last decade, smart materials and systems have increasingly impacted several niches, including ‘one-off/limited edition experimental fashion’. As the traditional boundaries between what is art and what was not supposed to be art are now turning into osmotic membranes, we will speculatively focus on how ‘smart material systems’ are highly contributing to outline a new creative landscape full of interesting and compelling issues. Introducing three different sub-niches of experimental fashion—multi-sensory dresses, empathic dresses, and bio-smart dresses—this article outlines the emergence of a new smart design scenario. Then, we critically discuss some of the implications of the developing research in terms of design thinking and design aesthetics. This paper aims to contribute to the topic of next design scenario, demonstrating how design research is increasingly affecting the extension of human perception, emotions, and the concept of ‘almost-living’ entities, projecting towards the redefinition of relationships with materials and objects.