Beer dealcoholization by forward osmosis diafiltration

Membrane separation processes used for beer dealcoholization have as main advantage the operation at mild temperatures when compared to traditional thermal technologies. Such alternatives to thermal treatment preserve the organoleptic quality of the foods that are being processed. This work assesses the use of forward osmosis to dealcoholize a commercial beer containing 5 vol% of alcohol. In this process, water and ethanol are removed from the beer simultaneously, and diafiltration is used to rehydrate the beer, reducing its alcohol content. We assess this study by characterizing the chemical profile of the beer before and after the FO diafiltration process. It was possible to obtain a low alcohol beer containing 0.5 vol%, but physical-chemical properties were impaired. The turbidity and salinity increased by 44% and 70%, respectively, while color decreased 7%. We also noticed the loss of flavor compounds. Results indicate that forward osmosis can be an alternative to reduce the ethanol content of aqueous solutions such as beverages and fermentation broths.     

Isotope and ion selectivity in reverse osmosis desalination: geochemical tracers for man-made freshwater

A systematic measurement of ions and 2H/1H, 7Li/6Li, 11B/10B, 18O/ 16O, and 87Sr/86Sr isotopes in feed-waters, permeates, and brines from commercial reverse osmosis (RO) desalination plants in Israel (Ashkelon, Eilat, and Nitzana) and Cyprus (Larnaca) reveals distinctive geochemical and isotopic fingerprints of fresh water generated from desalination of seawater (SWRO) and brackish water (BWRO). The degree of isotope fractionation during the passage of water and solutes through the RO membranes depends on the medium (solvent-water vs. solutes), chemical speciation of the solutes, their charge, and their mass difference. O, H, and Sr isotopes are not fractionated during the RO process. 7Li is preferentially rejected in low pH RO, and B isotope fractionation depends on the pH conditions. Under low pH conditions, B isotopes are not significantly fractionated, whereas at high pH, RO permeates are enriched by 20 per thousand in 11B due to selective rejection of borate ion and preferential permeation of 11B-enriched boric acid through the membrane. The specific geochemical and isotopic fingerprints of SWRO provide a unique tool for tracing "man-made" fresh water as an emerging recharge component of natural water resources.     

Emerging forward osmosis and membrane distillation for liquid food concentration: A review

As emerging membrane technologies, forward osmosis (FO) and membrane distillation (MD), which work with novel driving forces, show great potential for liquid food concentration, owing to their low fouling propensity and great driving force. In the last decades, they have attracted the attention of food industry scientists in global scope. However, discussions of the FO and MD in liquid food concentration advancement, membrane fouling, and economic assessment have been scant. This review aims to provide an up-to-date knowledge about liquid food concentration by FO and MD. First, we introduce the principle and applications of FO and MD in liquid food concentration, and highlight the effect of process on liquid food composition, membrane fouling mechanism, and strategies for fouling mitigation. Besides, economic assessment of FO and MD processes is reviewed. Moreover, the challenges as well as future prospects of FO and MD applied in liquid food concentration are proposed and discussed. Comparing with conventional membrane-based or thermal-based technologies, FO and MD show outstanding advantages in high concentration rate, good concentrate quality, low fouling propensity, and low cost. Future efforts for liquid food concentration by FO and MD include (1) development of novel FO draw solution (DS); (2) understanding the effects of liquid food complex compositions on membrane fouling in FO and MD concentration process; and (3) fabrication of novel membranes and innovation of membrane module and process configuration for liquid food processing.     

利用模拟苹果汁体系探究正渗透浓缩技术

浓缩苹果汁不仅能够解决苹果的堆积腐败、贮存问题,还是生产饮料的重要基础配料,可应用于果酒酿制、化妆品及药品添加剂。为了更好地探究正渗透体系中苹果汁糖组分对浓缩性能和反向渗透扩散(reverse solute flux, RSF)的影响,实验对模拟苹果汁体系进行了研究。首先通过改变膜操作模式对模拟体系进行研究,再探究功能性汲取液对模拟苹果汁体系的浓缩能力,分别测定水通量、反向溶质扩散以及浓缩倍数等。结果表明,压力延迟渗透模式的水通量较高,反向渗透较少,比正渗透模式更有利于正渗透浓缩苹果汁;相较于传统的氯化钠汲取液,柠檬酸钠汲取液汲水能力更强,RSF更小,可大大提高果汁浓缩效率。     

Development of the microbial electrolysis desalination and chemical-production cell for desalination as well as acid and alkali productions

By combining the microbial electrolysis cell and the microbial desalination cell, the microbial electrolysis desalination cell (MEDC) becomes a novel device to desalinate salty water. However, several factors, such as sharp pH decrease and Cl(-) accumulation in the anode chamber, limit the MEDC development. In this study, a microbial electrolysis desalination and chemical-production cell (MEDCC) was developed with four chambers using a bipolar membrane. Results showed that the pH in the anode chamber of the MEDCC always remained near 7.0, which greatly enhanced the microbial activities in the cell. With applied voltages of 0.3-1.0 V, 62%-97% of Coulombic efficiencies were achieved from the MEDCC, which were 1.5-2.0 times of those from the MEDC. With 10 mL of 10 g/L NaCl in the desalination chamber, desalination rates of the MEDCC reached 46%-86% within 18 h. Another unique feature of the MEDCC was the simultaneous production of HCl and NaOH in the cell. With 1.0 V applied voltage, the pH values at 18 h in the acid-production chamber and cathode chamber were 0.68 and 12.9, respectively. With the MEDCC, the problem with large pH changes in the anode chamber was resolved, and products of the acid and alkali were obtained.     

Synthesis and characterization of novel forward osmosis membranes based on layer-by-layer assembly

Forward osmosis (FO) has received considerable interest for water- and energy-related applications in recent years. FO does not require an applied pressure and is believed to have a low fouling tendency. However, a major challenge in FO is the lack of high performance FO membranes. In the current work, novel nanofiltration (NF)-like FO membranes with good magnesium chloride retention were synthesized using layer-by-layer (LbL) assembly. The membrane substrate was tailored (high porosity, finger-like pores, thin cross-section, and high hydrophilicity) to achieve a small structural parameter of 0.5 mm. Increasing the number of polyelectrolyte layers improved the selectivity of the LbL membranes while reducing their water permeability. The more selective membrane 6#LbL (with 6 polyelectrolyte layers) had much lower reverse solute transport compared to 3#LbL and 1#LbL. Meanwhile, the FO water flux was found to be strongly affected by both membrane water permeability and solute reverse transport. Severe solute reverse transport was observed for the active-layer-facing-draw-solution membrane orientation, likely due to the suppression of Donnan exclusion as a result of the high ionic strength of the draw solution. In contrast, the active-layer-facing-feed-solution orientation showed remarkable FO performance (15, 20, and 28 L/m2.h at 0.1, 0.5, and 1.0 M MgCl?, respectively, for membrane 3#LbL using distilled water as feed solution), superior to other NF-like FO membranes reported in the literature. To the best of the knowledge of the authors, this is the first work on the synthesis and characterization of LbL based FO membranes.     

Integrating forward osmosis into microbial fuel cells for wastewater treatment, water extraction and bioelectricity generation

A novel osmotic microbial fuel cell (OsMFC) was developed by using a forward osmosis (FO) membrane as a separator. The performance of the OsMFC was examined with either NaCl solution or artificial seawater as a catholyte (draw solution). A conventional MFC with a cation exchange membrane was also operated in parallel for comparison. It was found that the OsMFC produced more electricity than the MFC in both batch operation (NaCl solution) and continuous operation (seawater), likely due to better proton transport with water flux through the FO membrane. Water flux from the anode into the cathode was clearly observed with the OsMFC but not in the MFC. The solute concentration of the catholyte affected both electricity generation and water flux. These results provide a proof of concept that an OsMFC can simultaneously accomplish wastewater treatment, water extraction (from the wastewater), and electricity generation. The potential applications of the OsMFC are proposed for either water reuse (linking to reverse osmosis for reconcentration of draw solution) or seawater desalination (connecting with microbial desalination cells for further wastewater treatment and desalination).     

Membrane concentration of liquid foods by forward osmosis: Process and quality view

The industrial thermal processing of foods may have a severe impact on the sensorial and nutritional properties of the final product. Membrane technologies have been extensively studied as alternative processes. Forward osmosis (FO) is a promising membrane technology to be used in food industries. The only driving force of the process is the osmotic pressure difference between the two solutions that flow in counter-current mode on opposite sides of a permeable membrane. Thus, the main advantages of FO, compared to both thermal and conventional membrane processing, include low hydraulic pressure, low treatment temperature, low fouling tendency, high solids content processing capability and easy scale-up. A detailed, up-to-date summary of potential FO applications for concentrating liquid foods is presented in this review article. The effect of the main process parameters on the filtration performance and their impact on the sensorial and nutritional factors of the final product are described and discussed for a broad spectrum of foods.     

Concentration of grape juice: Combined forward osmosis/evaporation versus conventional evaporation

The present study aimed to evaluate the process of forward osmosis (FO) for the concentration of grape juice using NaCl as the osmotic solution facing the thermal evaporation process, commonly used in industry. A combined experiment (FO + evaporation) was also performed to evaluate the potential of FO as a pre-concentration process. FO experiments were performed according to the Box-Behnken design. Some degree of concentration of the grape juice was obtained in all FO experimental runs, and it was observed a strong influence of the parameters studied on the fluxes. In the evaporation experiments, the quality of the final product was affected concerning the content of phenolic compounds, which have undergone significant degradation by heat. In the combined process, grape juice concentration to up to 65.7°Brix could be achieved showing greater retention of quality factors and bioactive compounds, highlighting the advantage of FO and its potential as a pre-concentration step.     

Performance of forward (direct) osmosis process: membrane structure and transport phenomenon

The performance of a forward (direct) osmosis (FO) process was investigated using a laboratory-scale unit to elucidate the effect of membrane structure and orientation on waterflux. Two types of RO membrane and a FO membrane were tested using ammonium bicarbonate, glucose, and fructose as the draw solution to extract water from a saline feed solution. The FO membrane was able to achieve higher water flux than the RO membranes under the same experimental conditions while maintaining high salt rejection of greater than 97%. Increasing operating temperature increased the water flux in FO process. To investigate the effect of membrane orientation on water flux, the FO membrane was tested normally (dense selective layer facing draw solution) and reversely (dense selective layer facing feed solution). Explanations on transport phenomenon in FO process were proposed which explain the observation that the FO membrane, when used in the normal orientation, performed better due to lesser internal concentration polarization. This study suggests that an ideal FO membrane should consist of a thin dense selective layer without any loose fabric support layer.     

Boric acid permeation in forward osmosis membrane processes: modeling, experiments, and implications

Forward osmosis (FO) is attracting increasing interest for its potential applications in desalination. In FO, permeation of contaminants from feed solution into draw solution through the semipermeable membrane can take place simultaneously with water diffusion. Understanding the contaminants transport through and rejection by FO membrane has significant technical implications in the way to separate clean water from the diluted draw solution. In this study, a model was developed to predict boron flux in FO operation. A strong agreement between modeling results and experimental data indicates that the model developed in this study can accurately predict the boron transport through FO membranes. Furthermore, the model can guide the fabrication of improved FO membranes with decreased boron permeability and structural parameter to minimize boron flux. Both theoretical model and experimental results demonstrated that when membrane active layer was facing draw solution, boron flux was substantially greater compared to the other membrane orientation due to more severe internal concentration polarization. In this investigation, for the first time, rejection of contaminants was defined in FO processes. This is critical to compare the membrane performance between different membranes and experimental conditions.     

High performance thin-film composite forward osmosis hollow fiber membranes with macrovoid-free and highly porous structure for sustainable water production

The development of high-performance and well-constructed thin-film composite (TFC) hollow fiber membranes for forward osmosis (FO) applications is presented in this study. The newly developed membranes consist of a functional selective polyamide layer formed by highly reproducible interfacial polymerization on a polyethersulfone (PES) hollow fiber support. Using dual-layer coextrusion technology to design and effectively control the phase inversion during membrane formation, the support was designed to possess desirable macrovoid-free and fully sponge-like morphology. Such morphology not only provides excellent membrane strength, but it has been proven to minimize internal concentration polarization in a FO process, thus leading to the water flux enhancement. The fabricated membranes exhibited relatively high water fluxes of 32-34 LMH and up to 57-65 LMH against a pure water feed using 2 M NaCl as the draw solution tested under the FO and pressure retarded osmosis (PRO) modes, respectively, while consistently maintaining relatively low salt leakages below 13 gMH for all cases. With model seawater solution as the feed, the membranes could display a high water flux up to 15-18 LMH, which is comparable to the best value reported for seawater desalination applications.     

Effect of high or low molecular weight of components of feed on transmembrane flux during forward osmosis

The possible mechanism of water transport from feed to osmotic agent side during forward osmosis in situation when feed contains high or low molecular weight compounds and their combination has been presented. The orientation of membrane was found to influence the transmembrane flux. When the feed contains mixture of low and high molecular weight compounds mode I (feed towards the support layer) was found to result in lower flux values as compared to Mode II (feed towards active layer) due to significant external concentration polarization. Forward osmosis resulted in the concentration of betalains content in beetroot juice and anthocyanin content in grape juice from 50.92 mg/L to 2.91 g/L (57.1 fold) and from 104.85 mg/L to 715.6 mg/L (6.8 fold), respectively. Total soluble solids in case of beetroot, grape and pineapple juice were found to increase from 2.3 to 52 °Brix, from 8.0 to 54.6 °Brix from 4.4 to 54 °Brix, respectively.     

Removal of the natural hormone estrone from aqueous solutions using nanofiltration and reverse osmosis

The ability of a variety of nanofiltration and reverse osmosis membranes to retain the natural hormone estrone are examined here as a function of solution conditions. While size exclusion dominates retention with the tighter membranes, both size exclusion and adsorptive effects appear to be instrumental in maintaining high retention on nanofiltration membranes that otherwise exhibit relatively low ion retentions. These adsorptive effects may be driven by hydrogen bonding between estrone and the membrane. Electrostatic attraction appears to aid retention with an apparent slight decrease in retention at high NaCl concentrations. Deprotonation of estrone leads to a significant decrease in retention, most likely as a result of the effect of strong electrostatic repulsive forces decreasing the proximity of the negatively charged estrone to the negatively charged membrane surface and thus lowering the potential for adsorptive retention. This deprotonation effect is absent for tight RO membranes. The results reported here indicate that while open nanofiltration membranes may be effective in retaining estrone under some conditions, the extent of retention may be very susceptible to maintenance of adsorptive capacity at the membrane surface and depend on solution chemistry.     

Use of a liter-scale microbial desalination cell as a platform to study bioelectrochemical desalination with salt solution or artificial seawater

Bioelectrochemical desalination is potentially advantageous because of bioenergy production and integrated wastewater treatment and desalination. In this work, the performance and energy benefits of a liter-scale upflow microbial desalination cell (UMDC) were evaluated. The UMDC desalinated both salt solution (NaCl) and artificial seawater, and the removal rate of total dissolved solid (TDS) increased with an increased hydraulic retention time, although TDS reduction in artificial seawater was lower than that in salt solution. Our analysis suggested that electricity generation was a predominant factor in removing TDS (more than 70%), and that other factors, like water osmosis and unknown processes, also contributed to TDS reduction. It was more favorable given the high energy efficiency, when treating salt solution, to operate the UMDC under the condition of high power output compared with that of high current generation because of the amount of energy production; while high current generation was more desired with seawater desalination because of lower salinity in the effluent. Under the condition of the high power output and the assumption of the UMDC as a predesalination in connection with a reversal osmosis (RO) system, the UMDC could produce electrical energy that might potentially account for 58.1% (salt solution) and 16.5% (artificial seawater) of the energy required by the downstream RO system. Our results demonstrated the great potential of bioelectrochemical desalination.     

用于梳理机和并条机的自动频谱图分析

梳理机和并条机上的棉条生产受到许多机器元件的影响,其中由带轮传动的主罗拉的运作情况会对棉条的质量产生较大的影响。     

混合的两性聚丙烯酰胺用作高效助留剂

纸浆中细小纤维和无机盐所占比例的增加降低了助留剂的使用效果,而高速纸机运行中需要高效而又不会破坏纸张匀度的助留剂：本实验合成了富阴离子和富阳离子单元的两性聚丙烯酰胺,并把两者混合作为助留剂进行实验。文中分析了絮凝过程中的应力变化和每种PAM及混合后溶液的性质,结果表明,这种混合系统可有效地产生絮凝,并提高助剂的作用。同时,文中探讨了该系统可能的絮凝机理     

以梦为马,砥砺前行

<正>我们都在努力奔跑,我们都是追梦人!习近平2019春节励志金句激发国人强烈共鸣,也激发出食品行业工作者前所未有的干事创业热情。人民对美好生活的向往,就是我们的奋斗目标。十八大以来,以习近平为核心的党中央,把人民身体健康作为全面建成小康社会的重要内涵,从维护全民健康和实现国家长远发展出发,身体力行、率先垂范,正在铺设一条以人民为中心的健康之路。我们都是追梦人,要坚决落实安全责任。民以食为天,食以安为先。能不能在食品     

Pulsed forward flushes as a novel method for cleaning spent grains-loaded filter cloth

This paper presents a novel method to remove spent grains efficiently from filter cloths via pulsed forward flushes. In breweries, mash filters separate liquid wort from solid spent grains, a by-product. These mash filters use woven fabrics made from synthetic materials as filter media. However, rough filter surfaces often hinder the cleaning process. Concerning modern hygienic design principles, filter cloths are only designed for efficient filtration performances, in which cleanability is not considered. Hence, in combination with strongly adhesive spent grains, brewers often reject mash filters. The paper illustrates an experimental parameter variation and a comparison of pulsed with continuous cleaning in respect to their cleaning performance. The results showed that the proposed method is suitable, reaching up to 30% higher cleaning degrees than conventional methods. Furthermore, the technique required up to 50% fewer cleaning fluids and shorter cleaning times, indicating economic and ecological advantages.