High-Throughput Microfiltration Membranes with Natural Biofouling Reducer Agent for Food Processing

High performance filtration membranes from electrospun poly (3-hydroxybutyrate)-based fiber membranes for fine particulate protection

PM2.5 (particulate matter with a size of <2.5 μm) pollution has become a critical issue owing to its adverse health effects, including bronchitis, pneumonopathy, and cardiovascular diseases. Globally, around 8.9 million premature casualties related to exposure to PM2.5 were reported. Face masks are the only option that may restrict exposure to PM2.5. In this study, a PM2.5 dust filter was developed via the electrospinning technique using the poly (3-hydroxybutyrate) (PHB) biopolymer. Smooth and continuous fibers without beads were formed. The PHB membrane was further characterized, and the effects of the polymer solution concentration, applied voltage, and needle-to-collector distance were analyzed via the design of experiments technique, with three factors and three levels. The concentration of the polymer solution had the most significant effect on the fiber size and the porosity. The fiber diameter increased with increasing concentration, but decreases the porosity. The sample with a fiber diameter of ∼600 nm exhibited a higher PM2.5 filtration efficiency than the samples with a diameter of 900 nm, according to an ASTM F2299-based test. The PHB fiber mats fabricated at a concentration of 10%w/v, applied voltage of 15 kV, and needle tip-to-collector distance of 20 cm exhibited a high filtration efficiency of 95% and a pressure drop of <5 mmH2O/cm2. The tensile strength of the developed membranes ranged from 2.4 to 5.01 MPa, higher than those of the mask filters available in the market. Therefore, the prepared electrospun PHB fiber mats have great potential for the manufacture of PM2.5 filtration membranes.

Strategies to Enhance the Membrane-Based Processing Performance for Fruit Juice Production: A Review

Fruit juice is an essential food product that has received significant acceptance among consumers. Harmonized concentration, preservation of nutritional constituents, and heat-responsive sensorial of fruit juices are demanding topics in food processing. Membrane separation is a promising technology to concentrate juice at minimal pressure and temperatures with excellent potential application in food industries from an economical, stable, and standard operation view. Microfiltration (MF) and ultrafiltration (UF) have also interested fruit industries owing to the increasing demand for reduced pressure-driven membranes. UF and MF membranes are widely applied in concentrating, clarifying, and purifying various edible products. However, the rising challenge in membrane technology is the fouling propensity which undermines the membrane's performance and lifespan. This review succinctly provides a clear and innovative view of the various controlling factors that could undermine the membrane performance during fruit juice clarification and concentration regarding its selectivity and permeance. In this article, various strategies for mitigating fouling anomalies during fruit juice processing using membranes, along with research opportunities, have been discussed. This concise review is anticipated to inspire a new research platform for developing an integrated approach for the next-generation membrane processes for efficient fruit juice clarification.

A critical review on diverse technologies for advanced wastewater treatment during SARS-CoV-2 pandemic: What do we know?

Advanced wastewater treatment technologies are effective methods and currently attract growing attention, especially in arid and semi-arid areas, for reusing water, reducing water pollution, and explicitly declining, inactivating, or removing SARS-CoV-2. Overall, removing organic matter and micropollutants prior to wastewater reuse is critical, considering that water reclamation can help provide a crop irrigation system and domestic purified water. Advanced wastewater treatment processes are highly recommended for contaminants such as monovalent ions from an abiotic source and SARS-CoV-2 from an abiotic source. This work introduces the fundamental knowledge of various methods in advanced water treatment, including membranes, filtration, Ultraviolet (UV) irradiation, ozonation, chlorination, advanced oxidation processes, activated carbon (AC), and algae. Following that, an analysis of each process for organic matter removal and mitigation or prevention of SARS-CoV-2 contamination is discussed. Next, a comprehensive overview of recent advances and breakthroughs is provided for each technology. Finally, the advantages and disadvantages of each method are discussed.

Cacao Pod Husk Extract Phenolic Nanopowder-Impregnated Cellulose Acetate Matrix for Biofouling Control in Membranes

The ultrafiltration membrane process is widely used for fruit juice clarification, yet the occurring of fouling promotes a decline in process efficiency. To reduce the fouling potential in the membrane application in food processing, the use of natural phenolic compounds extracted from cocoa pod husk is investigated. The cocoa pod husk extract (CPHE) was prepared in phenolic nanoparticles form and added into the polymer solution at varying concentrations of 0.5 wt%, 0.75 wt%, and 1.0 wt%, respectively. The composite membrane was made of a cellulose acetate polymer using DMF (dimethylformamide) and DMAc (dimethylacetamide) solvents. The highest permeability of 2.34 L m⁻² h⁻¹ bar⁻¹ was achieved by 1.0 wt% CPHE/CA prepared with the DMAc solvent. CPHE was found to reduce the amount of Escherichia coli attached to the membranes by 90.5% and 70.8% for membranes prepared with DMF and DMAc, respectively. It is concluded that CPHE can be used to control biofouling in the membrane for food applications.

Facile Approaches of Polymeric Face Masks Reuse and Reinforcements for Micro-Aerosol Droplets and Viruses Filtration: A Review

Since the widespread of severe acute respiratory syndrome of coronavirus 2 (SARS-CoV-2) disease, the utilization of face masks has become omnipresent all over the world. Face masks are believed to contribute to an adequate protection against respiratory infections spread through micro-droplets among the infected person to non-infected others. However, due to the very high demands of face masks, especially the N95-type mask typically worn by medical workers, the public faces a shortage of face masks. Many papers have been published recently that focus on developing new and facile techniques to reuse and reinforce commercially available face masks. For instance, the N95 mask uses a polymer-based (membrane) filter inside, and the filter membrane can be replaced if needed. Another polymer sputtering technique by using a simple cotton candy machine could provide a cheap and robust solution for face mask fabrication. This review discuss the novel approaches of face mask reuse and reinforcement specifically by using membrane-based technology. Tuning the polymeric properties of face masks to enhance filterability and virus inactivity is crucial for future investigation.

Filtration Performances of Different Polysaccharides in Microfiltration Process

Membrane technology has been widely applied for water treatment, while membrane fouling still remains a big challenge. The polysaccharides in extracellular polymeric substances (EPS) have been known as a significant type of foulant due to their high fouling propensity. However, polysaccharides have many varieties which definitely behave differently in membrane filtration. Therefore, in this study, different polysaccharides alginate sodium and xanthan gum were chosen to study their effects on membrane fouling in a wide concentration range. The results demonstrated that the filtration behaviors of alginate sodium and xanthan gum were completely different, which was due to their different molecular structures. Alginate had a small molecular weight and it was easy for alginate to penetrate membrane pores resulting in pore blocking. A series of concentrations of alginate including 5 mg/L, 10 mg/L, 20 mg/L, 30 mg/L, 40 mg/L, and 50 mg/L were examined and it was found that the permeate flux decline highly depended on the level of alginate in the feed water. While for the filtration of xanthan gum, the same concentration of xanthan gum led to more serious fouling than that observed in alginate, which might be due to its large molecule. In addition, calcium chloride was added in the solutions of both alginate and xanthan gum to examine the influence of a divalent cation on polysaccharide fouling. A “unimodal” peak can be observed in the fouling propensity caused by Ca2+ and alginate with increasing the concentration of alginate. Such a phenomenon was not found in the fouling of xanthan gum and Ca2+ led to more serious fouling for all concentrations of xanthan gum. In light of this, this study gave new insights into the fouling propensities of different polysaccharides.

Special Issue on “Membrane Materials, Performance and Processes”

This Special Issue on “Membrane Materials, Performance and Processes” of Processes provides a collection of interdisciplinary work representative of the current development in the fields ofmembrane science and technology [...]

Unravelling the Potency of Activated Carbon Powder Derived from Cultivated Marine Microalgae as a Promising Filler in Mixed Matrix Membranes

Activated carbon-filled mixed matrix membranes were commonly used to enhance the separation performance of liquid or gas separation processes. Activated carbon is traditionally derived from agricultural crops such as coconut shells or wood biomass. Marine microalgae however have a great potential to produce powdered activated carbon. In this study, marine microalgae Chlorella vulgaris have been evaluated for their carbon content, and the 16.09% carbon content has potential to be employed as a raw material in manufacturing activated carbon powder. Dry microalgae were carbonized at a temperature of 500 °C for 30 min, at a constant increment rate of temperature of 10 °C per minute to produce microalgae charcoal. Chemically-based activation treatments using H3PO4 and ZnCl2 with concentrations of 10%, 30%, and 50%, respectively, assisted by microwave irradiation, have been used to prepare activated carbon. The properties of activated carbon powder were analyzed including yields, ash content, volatile substances, pure activated carbon content, absorption of iodine solution, surface area, and imaging of activated carbon using SEM-EDX. The best treatment characteristics were obtained using H3PO4 at a concentration of 50% with characteristics of 19.47% yield, 11.19% ash content, 31.92% volatile content, 56.89% pure activated carbon, 325.17 mg g−1 iodine absorption, and 109.273 m2 g−1 surface area based on the Brunauer–Emmett–Teller (BET) method, as well as a 5.5-nm average pore diameter. The SEM-EDX imaging results showed the formation of micropores on the surface of activated carbon, with carbon content reaching 72.31%; however, impurities could decrease the surface area and reduce the absorption performance of microalgae activated carbon.