Engineering Multinanochannel Polymer-Intercalated Graphene Oxide Membrane for Strict Volatile Sieving in Membrane Distillation.

Graphene oxide (GO) membranes enabled by subnanosized diffusion channels are promising to separate small species in membrane distillation (MD). However, the challenge of effectively excluding small volatiles in MD persists due to the severe swelling and subsequent increase in GO interlamination spacing upon direct contact with the hot feed. To address this issue, we implemented a design in which a polymer is confined between the GO interlaminations, creating predominantly 2D nanochannels centered around 0.57 nm with an average membrane pore size of 0.30 nm. Compared to the virginal GO membrane, the polymer-intercalated GO membrane exhibits superior antiswelling performance, particularly at a high feed temperature of 60 °C. Remarkably, the modified membrane exhibited a high flux of approximately 52 L m-2 h-1 and rejection rates of about 100% for small ions and 98% for volatile phenol, with a temperature difference of 40 °C. Molecular dynamics simulations suggest that the sieving mechanisms for ions and volatiles are facilitated by the narrowed nanochannels within the polymer network situated between the 2D nanochannels of GO interlaminations. Concurrently, the unrestricted permeation of water molecules through the multinanochannel GO membrane encourages high-flux desalination of complex hypersaline wastewater.

Hypercrosslinked Hydrogel Composite Membranes Targeted for Removal of Volatile Organic Compounds via Selective Solution-Diffusion in Membrane Distillation.

Membrane distillation (MD) has attracted considerable interest in hypersaline wastewater treatment. However, its practicability is severely impeded by the ineffective interception of volatile organic compounds (VOCs), which seriously affects the product water quality. Herein, a hypercrosslinked alginate (Alg)/aluminum (Al) hydrogel composite membrane is facilely fabricated via Alg pregel formation and ionic crosslinking for efficient VOC interception. The obtained MD membrane shows a sufficient phenol rejection of 99.52% at the phenol concentration of 100 ppm, which is the highest rejection among the reported MD membranes. Moreover, the hydrogel composite membrane maintains a high phenol interception (>99%), regardless of the feed temperature, initial phenol concentration, and operating time. Diffusion experiments and molecular dynamics simulation verify that the selective diffusion is the dominant mechanism for VOCs-water separation. Phenol experiences a higher energy barrier to pass through the dense hydrogel layer compared to water molecules as the stronger interaction between phenol-Alg compared with water-Alg. Benefited from the dense and hydratable Alg/Al hydrogel layer, the composite membrane also exhibits robust resistance to wetting and fouling during long-term operation. The superior VOCs removal efficiency and excellent durability endow the hydrogel composite membrane with a promising application for treating complex wastewater containing both volatile and nonvolatile contaminants.

Industrial Distillation Fractions of Garlic Essential Oil, Design, Synthesis, and Antifungal Activity Evaluation of Aliphatic Substituted Trisulfide Derivatives.

Garlic oil has a wide range of biological activities, and its broad-spectrum activity against phytopathogenic fungi still has the potential to be explored. In this study, enzymatic treatment of garlic resulted in an increase of approximately 50 % in the yield of essential oil, a feasible GC-MS analytical program for garlic oil was provided. Vacuum fractionation of the volatile oil and determination of its inhibitory activity against 10 fungi demonstrated that garlic oil has good antifungal activity. The antifungal activity levels were ranked as diallyl trisulfide (S-3)>diallyl disulfide (S-2)>diallyl monosulfide (S-1), with an EC50 value of S-3 against Botrytis cinerea reached 8.16 mg/L. Following the structural modification of compound S-3, a series of derivatives, including compounds S-4~7, were synthesized and screened for their antifungal activity. The findings unequivocally demonstrated that the compound dimethyl trisulfide (S-4) exhibited exceptional antifungal activity. The EC50 of S-4 against Sclerotinia sclerotiorum reached 6.83 mg/L. SEM, In vivo experiments, and changes in mycelial nucleic acids, soluble proteins and soluble sugar leakage further confirmed its antifungal activity. The study indicated that the trisulfide bond structure was the key to good antifungal activity, which can be developed into a new type of green plant-derived fungicide for plant protection.

The Flow Rate of the Condenser Cooling Water in the Distillation Process Increases the Quality and Quantity of Patchouli Oil.

Indonesia is an important essential oil-exporting country globally, where 40 types of essential oils have been traded on the international market and are products of Indonesia. However, the quality and quantity of patchouli oil produced in Indonesia are still low. Most essential oil processing units use simple or traditional technology and generally have limited production capacity. This study aimed to obtain the optimum water flow rate in a condenser system for patchouli oil production in Maluku, Indonesia. Patchouli oil extraction from fresh patchouli leaves and twigs was carried out by increasing the condenser water discharge rate. Patchouli oil extraction with a condenser cooling water discharge treatment of 1.74 L/min and drying time for 5 days produced the highest patchouli oil yield of 1.4%. The greater the condenser water discharge rate, the better the yield and accumulation of patchouli oil recovery obtained. In addition, based on the results of the analysis of the composition of patchouli oil compounds with GCMS, it can be seen that 13 compounds can be detected in patchouli oil. The three main components of patchouli oil in all condenser cooling water treatments were alpha-guaiene, delta-guaiene, and patchouli alcohol. Considering the results of all parameters mentioned above, the treatment of the condenser cooling water discharge of 1.74 L/min and drying time for 5 days increases the quality and quantity of patchouli oil.

Experimental investigation on the hybrid system of mechanical vapor recompression and hollow fiber vacuum membrane distillation applied for wastewater treatment.

In order to achieve zero discharge and resource utilization of industrial high salt wastewater, a hybrid system of mechanical vapor recompression (MVR) and hollow fiber vacuum membrane distillation (HFVMD) was constructed, and several experiments of air tightness, single working condition and multiple working conditions were carried out with ammonium chloride solution as feed, then thermal economic performance were evaluated via a single factor analysis method. The obtained results showed that the system had excellent airtightness to ensure normal evaporation experiment, and high separation efficiency of 99.9% and lower evaporation energy consumption to achieve high efficient separation by combining the advantages of the hydrophobic membrane evaporation and latent heat recovery in view of MVR and HFVMD technologies. Furthermore, increasing feed temperature and feed flow rate increased evaporation rate and decreased evaporation energy consumption, while increasing feed concentration decreased evaporation rate and increased evaporation energy consumption. Finally, the single factor analysis indicated that total investment cost, annual operation cost and annual evaporation capacity were the main factors while environmental cost and equipment service life were the secondary factors which affected the specific evaporation cost. The above research provides theoretical and experimental bases for the development of the proposed system in the future.

The Valorisation of Melissa officinalis Distillation By-Products for the Production of Polyphenol-Rich Formulations.

Lemon balm (Melissa officinalis) is an aromatic and medicinal plant, rich in bioactive ingredients and with superior antioxidant activity. The essential oil of this plant is an expensive product, so the use of the by-products of the essential oil industry is particularly useful. The aim of this research was to process Melissa officinalis distillation by-products to develop a series of polyphenol-rich formulations. In the present research, lemon balm was distilled in a laboratory-scale distiller, and the recovered by-product was used for further successive extractions with acetone and water, using a fixed-bed semi-batch extractor. Acetone extract exhibited relatively poor results as far as yield, phenolic composition and antiradical activity are concerned. However, the aqueous extract presented high yield in both total phenolic content (i.e., 111 mg gallic acid equivalents (GAE)/g, on a dry herb basis (dw)), and anti-radical capacity (205 mg trolox equivalents (TE)/g dw). On a dried extract basis, the results were also impressive, with total phenols reaching 322 mg GAE/g dry extract and antiradical capacity at 593 mg TE/g dry extract. The phenolic components of the extract were identified and quantified by HPLC-DAD. Rosmarinic acid was the major component and amounted to 73.5 mg/g dry extract, while the total identified compounds were quantified at 165.9 mg/g dry extract. Finally, formulations with two different wall materials (gum arabic-maltodextrin and maltodextrin) and two different drying methods (spray-drying and freeze-drying) were applied and evaluated to assess their performance, yield, efficiency and shelf-life of total phenolic content and rosmarinic acid concentration. From the present investigation, it is concluded that after one year of storage, rosmarinic acid does not decrease significantly, while total phenolic content shows a similar decrease for all powders. According to the yield and efficiency of microencapsulation, maltodextrin alone was chosen as the wall material and freeze-drying as the preferred drying method.

Separation techniques for manufacturing fruit spirits: From traditional distillation to advanced pervaporation process.

Separation process is one of the key processes in the production of fruit spirits, including the traditional distillation method and the new pervaporation membrane method. The separation process significantly determines the constituents and proportions of compounds in the fruit spirit, which has a significant impact on the spirit quality and consumer acceptance. Therefore, it is important and complex to reveal the changing rules of chemical substances and the principles behind them during the separation process of fruit spirits. This review summarized the traditional separation methods commonly used in fruit spirits, covering the types, principles, and corresponding equipment of distillation methods, focused on the enrichment or removal of aroma compounds and harmful factors in fruit spirits by distillation methods, and tried to explain the mechanism behind it. It also proposed a new separation technology for the production of fruit spirits, pervaporation membrane technology, summarized its working principle, operation, working parameters, and application in the production of fruit spirits, and outlined the impact of the separation method on the production of fruit spirits based on existing research, focusing on the separation of flavor compounds, sensory qualities, and hazard factors in fruit spirits, along with a preliminary comparison with distillation. Finally, according to the current researches of the separation methods and the development requirement of the separation process of fruit spirits, the prospect of corresponding research is put forward, in order to propose new ideas and development directions for the research in this field.

Membrane distillation of wastewater: comparison of model and real organics.

Fouling behaviour in membrane distillation (MD) processes plays a crucial role in determining their widespread acceptability. Most studies have primarily focused on model organic foulants, such as humic acid (HA) and sodium alginate (SA). This study investigates the fouling of a polytetrafluoroethylene membrane in a direct contact MD (DCMD) using model organics (i.e., HA and SA) and real wastewater. The results indicated that the flux decline (5-60%) was only observed during the initial phase of the operation with model organic foulants. In contrast, real wastewater caused a gradual decline in flux throughout the experiment in both the concentrate (40%) and continuous (90%) modes. The study also found significant differences in the fouling layer morphology, composition, and hydrophobicity between the model organic foulants and real wastewater. Fourier transform infrared spectroscopy findings demonstrated that the fouling layer formed by real wastewater varied significantly from model organics, which primarily comprised of protein-like and polysaccharide-like functional groups. Finally, liquid chromatography-organic carbon detection revealed that the fouling layer of the MD membrane with real wastewater was composed of 40.7% hydrophobic and 59.3% hydrophilic organics. This study suggests that model organics may not accurately reflect real wastewater fouling.

A novel electro-Fenton hybrid system for enhancing the interception of volatile organic compounds in membrane distillation desalination.

Membrane distillation (MD) is a promising alternative desalination technology, but the hydrophobic membrane cannot intercept volatile organic compounds (VOCs), resulting in aggravation in the quality of permeate. In term of this, electro-Fenton (EF) was coupled with sweeping gas membrane distillation (SGMD) in a more efficient way to construct an advanced oxidation barrier at the gas-liquid interface, so that the VOCs could be trapped in this layer to guarantee the water quality of the distillate. During the so-called EF-MD process, an interfacial interception barrier containing hydroxyl radical formed on the hydrophobic membrane surface. It contributed to the high phenol rejection of 90.2% with the permeate phenol concentration lower than 1.50 mg/L. Effective interceptions can be achieved in a wide temperature range, even though the permeate flux of phenol was also intensified. The EF-MD system was robust to high salinity and could electrochemically regenerate ferrous ions, which endowed the long-term stability of the system. This novel EF-MD configuration proposed a valuable strategy to intercept VOCs in MD and will broaden the application of MD in hypersaline wastewater treatment.

Interpretable pairwise distillations for generative protein sequence models.

Many different types of generative models for protein sequences have been proposed in literature. Their uses include the prediction of mutational effects, protein design and the prediction of structural properties. Neural network (NN) architectures have shown great performances, commonly attributed to the capacity to extract non-trivial higher-order interactions from the data. In this work, we analyze two different NN models and assess how close they are to simple pairwise distributions, which have been used in the past for similar problems. We present an approach for extracting pairwise models from more complex ones using an energy-based modeling framework. We show that for the tested models the extracted pairwise models can replicate the energies of the original models and are also close in performance in tasks like mutational effect prediction. In addition, we show that even simpler, factorized models often come close in performance to the original models.

A cross talk based critical analysis of solvent free microwave extraction to accentuate it as the new normal for extraction of essential oil: an attempt to overhaul the science of distillation through a comprehensive tutelage.

Microwave-assisted extraction (MAE) is a sustainable non-contact heating source and has been extensively researched for extraction of plant bioactives. There are various derivatives or modules available for MAE and solvent free microwave extraction (SFME) is one of them where by operational aspects of MAE have been maneuvered to make it compatible for extraction of essential oil (EO). This article makes an attempt to overhaul the science of distillation by revisiting SFME and trying to learn through a comprehensive tutelage comprising of 20 years of published literature in Web of Science so that a shrewd decision can be obtained through a cross talk based critical analysis on the science SFME. A total of 312 articles within the time frame of 2001-2020 were extracted from WOS and critically analyzed. Considering the various uncertainties involved with SFME the articles establishes some global working standards and tries to explore the dynamic relationship between plant part/genus and microwave power, microwave power and time, microwave power and extracted volatile principles, prioritizes plant family selection and also presents a research blueprint of SFME. A techno-commercial feasibility study has been presented for smooth industrial transition of SFME. The tutelage presented decodes the publication trends and SFME blueprint.

Interlayered Interface of a Thin Film Composite Janus Membrane for Sieving Volatile Substances in Membrane Distillation.

Hypersaline wastewater treatment using membrane distillation (MD) has gained significant attention due to its ability to completely reject nonvolatile substances. However, a critical limitation of current MD membranes is their inability to intercept volatile substances owing to their large membrane pores. Additionally, the strong interaction between volatile substances and MD membranes underwater tends to cause membrane wetting. To overcome these challenges, we developed a dual-layer thin film composite (TFC) Janus membrane through electrospinning and sequential interfacial polymerization of a polyamide (PA) layer and cross-linking a polyvinyl alcohol/polyacrylic acid (PP) layer. The resulting Janus membrane exhibited high flux (>27 L m-2 h-1), salt rejection of ∼100%, phenol rejection of ∼90%, and excellent resistance to wetting and fouling. The interlayered interface between the PA and PP layer allowed the sieve of volatile substances by limiting their dissolution-diffusion, with the increasing hydrogen bond network formation preventing their transport. In contrast, small water molecules with powerful dynamics were permeable through the TFC membrane. Both experimental and molecular dynamics simulation results elucidated the sieving mechanism. Our findings demonstrate that this type of TFC Janus membrane can serve as a novel strategy to design next-generation MD membranes against volatile and non-volatile contaminants, which can have significant implications in the treatment of complex hypersaline wastewater.

Membrane Design Criteria and Practical Viability of Pressure-Driven Distillation.

Pressure-driven distillation (PD) is a novel desalination technology based on hydraulic pressure driving force and vapor transport across a hydrophobic porous membrane. In theory, PD offers near-perfect rejection for nonvolatile solutes, chlorine resistance, and the ability to decouple water and solute transport. Despite its advantages, pore wetting and the development of a reverse transmembrane temperature difference are potential critical concerns in PD, with the former compromising the salt rejection and the latter reducing or even eliminating the driving force for vapor transport. We herein present an analysis to evaluate the practical viability and membrane design principles of PD with a focus on the dependence of flux and salt rejection (SR) on membrane properties. By modeling the mass transfer in a PD process under different conditions, we arrive at two important conclusions. First, a practically detrimental reverse transmembrane temperature difference does not develop in PD under all relevant circumstances and is thus not a practical concern. Second, for a PD process to achieve an acceptable SR, the membrane pores should be at the nanometer scale with a highly uniform pore size distribution. This analysis demonstrates the practical viability of PD and provides the principles for designing robust and high-performance PD membranes.

Simultaneous Desalination and Glyphosate Degradation by a Novel Electro-Fenton Membrane Distillation Process.

The industrial effluent from glyphosate production has high salinity and refractory organic contaminants. The removal of organics and the recycling of inorganic salts from this kind of water are challenging issues. In this study, electro-Fenton (EF) and membrane distillation (MD) were coupled in a single reactor utilizing a membrane-based electrode (Mem-GDE) with the ability to bidirectionally transfer vapor and oxygen and electrochemically synthesize H2O2. The operating thermal conditions for MD significantly promoted Fenton reactions and, thus, the removal of glyphosate. During operation, Fe species deposited on the Mem-GDE and enhanced its catalytic activity and adsorptive capacity, which markedly increased the apparent reaction rate constant of glyphosate by 6 times. This novel EF-MD process simultaneously removed organics and concentrated the inorganics, which is very meaningful for decreasing the costs for subsequent crystallization and achieving high-quality crystal salts. This study provides an efficient method for the treatment of organic-inorganic hybrid wastewater.

Membrane Distillation-Crystallization for Sustainable Carbon Utilization and Storage.

Anthropogenic greenhouse gas emissions from power plants can be limited using postcombustion carbon dioxide capture by amine-based solvents. However, sustainable strategies for the simultaneous utilization and storage of carbon dioxide are limited. In this study, membrane distillation-crystallization is used to facilitate the controllable production of carbonate minerals directly from carbon dioxide-loaded amine solutions and waste materials such as fly ash residues and waste brines from desalination. To identify the most suitable conditions for carbon mineralization, we vary the membrane type, operating conditions, and system configuration. Feed solutions with 30 wt % monoethanolamine are loaded with 5-15% CO2 and heated to 40-50 °C before being dosed with 0.18 M Ca2+ and Mg2+. Membranes with lower surface energy and greater roughness are found to more rapidly promote mineralization due to up to 20% greater vapor flux. Lower operating temperature improves membrane wetting tolerance by 96.2% but simultaneously reduces crystal growth rate by 48.3%. Sweeping gas membrane distillation demonstrates a 71.6% reduction in the mineralization rate and a marginal improvement (37.5%) on membrane wetting tolerance. Mineral identity and growth characteristics are presented, and the analysis is extended to explore the potential improvements for carbon mineralization as well as the feasibility of future implementation.

Multistage Surface-Heated Vacuum Membrane Distillation Process Enables High Water Recovery and Excellent Heat Utilization: A Modeling Study.

Surface-heated membrane distillation (MD) enhances the energy efficiency of desalination by mitigating temperature polarization (TP). However, systematic investigations of larger scale, multistage, surface-heated MD system with high water recovery and heat recycling are limited. Here, we explore the design and performance of a multistage surface-heated vacuum MD (SHVMD) with heat recovery through a comprehensive finite difference model. In this process, the latent heat of condensation is recovered through an internal heat exchanger (HX) using the retentate from one stage as the condensing fluid for the next stage and an external HX using the feed as the condensing fluid. Model results show that surface heating enhances the performance compared to conventional vacuum MD (VMD). Specifically, in a six-stage SHVMD process, 54.44% water recovery and a gained output ratio (GOR) of 3.28 are achieved with a surface heat density of 2000 W m-2, whereas a similar six-stage VMD process only reaches 18.19% water recovery and a GOR of 2.15. Mass and energy balances suggest that by mitigating TP, surface heating increases the latent heat trapped in vapor. The internal and external HXs capture and reuse the additional heat, which enhances the GOR values. We show for SHVMD that the hybrid internal/external heat recovery design can have GOR value 1.44 times higher than that of systems with only internal or external heat recovery. Furthermore, by only increasing six stages to eight stages, a GOR value as high as 4.35 is achieved. The results further show that surface heating can reduce the energy consumption of MD for brine concentration. The multistage SHVMD technology exhibits a promising potential for the management of brine from industrial plants.

Hierarchically Structured Nanoparticle-Free Omniphobic Membrane for High-Performance Membrane Distillation.

The functional loss of membranes caused by pore wetting, mineral scaling, or structural instability is a critical challenge in membrane distillation (MD), which primarily hinders its practical applications. Herein, we propose a novel and facile strategy to fabricate omniphobic membranes with exceptionally robust MD performance. Specifically, a substrate with a hierarchical re-entrant architecture was constructed via spray-water-assisted non-solvent-induced phase separation (SWNIPS), followed by a direct fluorinated surface decoration via "thiol-ene" click chemistry. Deionized (DI) water contact angle measurements revealed an ultrahigh surface water contact angle (166.8 ± 1.8°) and an ultralow sliding angle (3.6 ± 1.1°) of the resultant membrane. Destructive abrasion cycle and ultrasonication tests confirmed its structural robustness. Moreover, the membrane possessed excellent wetting resistance, as evidenced by the prevention of membrane pore penetration by all low-surface-tension testing liquids, allowing stable long-term MD operation to treat brine wastewater with a surfactant content of 0.6 mM. In a desalination experiment using shale gas wastewater, the omniphobic membrane exhibited robust MD performance, achieving a high water recovery ratio of ∼60% without apparent changes in water flux and permeate conductivity over the entire membrane process. Overall, our study paves the way for a nanoparticle-free methodology for the scalable fabrication of high-performance MD membranes with surface omniphobicity and structural robustness in hypersaline wastewater treatment.

Nanocomposite Hydrogel Engineered Janus Membrane for Membrane Distillation with Robust Fouling, Wetting, and Scaling Resistance.

Membrane distillation (MD) is considered to be rather promising for high-salinity wastewater reclamation. However, its practical viability is seriously challenged by membrane wetting, fouling, and scaling issues arising from the complex components of hypersaline wastewater. It remains extremely difficult to overcome all three challenges at the same time. Herein, a nanocomposite hydrogel engineered Janus membrane has been facilely constructed for desired wetting/fouling/scaling-free properties, where a cellulose nanocrystal (CNC) composite hydrogel layer is formed in situ atop a microporous hydrophobic polytetrafluoroethylene (PTFE) substrate intermediated by an adhesive layer. By the synergies of the elevated membrane liquid entry pressure, inhibited surfactant diffusion, and highly hydratable surface imparted by the hydrogel/CNC (HC) layer, the resultant HC-PTFE membrane exhibits robust resistance to surfactant-induced wetting and oil fouling during 120 h of MD operation. Meanwhile, owing to the dense and hydroxyl-abundant surface, it is capable of mitigating gypsum scaling and scaling-induced wetting, resulting in a high normalized flux and low distillate conductivity at a concentration factor of 5.2. Importantly, the HC-PTFE membrane enables direct desalination of real hypersaline wastewater containing broad-spectrum foulants with stable vapor flux and robust salt rejection (99.90%) during long-term operation, demonstrating its great potential for wastewater management in industrial scenarios.

Challenges and advancements in membrane distillation crystallization for industrial applications.

Membrane distillation crystallization (MDC) is an emerging hybrid thermal membrane technology that synergizes membrane distillation (MD) and crystallization, which can achieve both freshwater and minerals recovery from high concentrated solutions. Due to the outstanding hydrophobic nature of the membranes, MDC has been widely used in numerous fields such as seawater desalination, valuable minerals recovery, industrial wastewater treatment and pharmaceutical applications, where the separation of dissolved solids is required. Despite the fact that MDC has shown great promise in producing both high-purity crystals and freshwater, most studies on MDC remain limited to laboratory scale, and industrializing MDC processes is currently impractical. This paper summarizes the current state of MDC research, focusing on the mechanisms of MDC, the controls for membrane distillation (MD), and the controls for crystallization. Additionally, this paper categorizes the obstacles hindering the industrialization of MDC into various aspects, including energy consumption, membrane wetting, flux reduction, crystal yield and purity, and crystallizer design. Furthermore, this study also indicates the direction for future development of the industrialization of MDC.

Fatty acid, triglyceride, and kinetic properties of milk fat fractions made by the combination of dry fractionation and short-path molecular distillation.

In this study, we aimed to detect the physicochemical properties of distilled products (residue and distillate) obtained from anhydrous milk fat (AMF) and its dry fractionation products (liquid and solid fractions at 25°C [25 L and 25 S]). The results showed that the saturated fatty acids and low- and medium molecular-weight triglycerides were easily accumulated in the distillate, and the percentage of unsaturated fatty acid and high molecular-weight triglycerides in the residue were higher, and these components in 25 S and 25 L were influenced more significantly than those in the AMF. In addition, the distillate had larger melting ranges in comparison with the distilled substrate, while the melting ranges of residue was smaller. The triglycerides were presented as the mixture crystal forms (α, ß', and ß crystal) in 25 S, AMF, and their distilling products, and it was transformed gradually to a single form as the increasing of distilling temperature. Moreover, the accumulated pattern of triglycerides was double chain length in 25 S, AMF, and their distilling products. These results provide a new approach to obtain the milk fat fractions with different properties, and the findings of this study enrich the theoretical basis of milk fat separation in practical production.