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• Individual effect of acid blocking AEM and monovalent selective CEM in selective ED was studied. • The recovered acid concentration increased by using acid blocking AEM, but limited by high Cu2+ flux. • Monovalent selective CEM further improved the acid concentration by breaking the H+ transfer balance. • Acid concentration was increased with electric current and dilute volume in SED. • H+ concentration difference plays crucial role in improving the current efficiency of SED. Electrodialysis (ED) could concentrate salt solutions, but the leakage of H+ ions across the anion-exchange membrane (AEM) obstructed their application in waste acid recovery. Selective electrodialysis (SED) with acid blocking AEM and monovalent selective cation-exchange membrane (CEM) has the ability of reclaiming acid with high concentration efficiently. This study investigated the individual effect of the two selective ion-exchange membranes by comparing the acid reclamation performance of configurations with standard AEM and CEM (A-C), acid blocking AEM and standard CEM (SA-C) and acid blocking AEM and monovalent selective CEM (SA-SC) for etching solution treatment after diffusion dialysis. Substituting acid blocking AEMs for the standard ones could significantly increase the recovered acid concentration. An acid concentration plateau was reached quickly, but Cu2+ ions transfer through the CEMs continuously due to the low H+/Cu2+ ratio in the dilute of SA-C configuration. The monovalent selective CEM obstructed the migration of Cu2+ through the CEM and broke the balance of H+ migration into and out of the dilute through CEM and selective AEM individually. The configuration of SA-SC has the highest current efficiency and the configuration of A-C has the lowest. The utilization of selective membranes increased the purity of the recovered acid, and decreased the specific energy consumption simultaneously. The acid concentration could be further improved by higher current or enlarged dilute volume in SA-SC configuration. During the ED process, H+ concentration difference between the concentrate and the dilute plays a crucial role on the current efficiency for acid recovery. [ABSTRACT FROM AUTHOR]

Composites of nano silver on magnetic carbon (Ag-Fe 3 O 4 /C) were facilely prepared by in-situ reduction of Tollen's reagent. The prepared sample was characterized and compared with a control sample obtained from AgNO 3 . The results showed that the Ag-Fe 3 O 4 /C sample obtained from Tollen's reagent as the silver source had better degree of crystallinity, smaller size and more Ag loading amount than that of the control sample. The reason of these advantages was discussed base on the in-situ loading mechanism. Then the prepared sample and the control sample were used in the reduction of Rhodamine B, the prepared sample also showed better performance in the catalytic application. It was suggested that using Tollen's reagent as the silver source could improve the economics of the Ag nanocomposites on their preparation and further application. [ABSTRACT FROM AUTHOR]

In an electrodialysis with filtration membrane (EDFM) separation process, a pair of restriction membranes is used to prevent leakage of molecules into the electrode solution. Driven by the electrical potential gradient, ions transport across these membranes in different directions, resulting in concentration changes in the feed and permeate compartments respectively. However, the effects of these restriction membranes have not been systemically studied to date. In the present work, the performance of a non-charged polyacrylamide (PAm) membrane and two ion-exchange membranes were compared. PAm restriction membranes were found to give the most stable operation, with only slight concentration and pH changes in the feed and permeate compartments. The configurations with either cation or anion exchange membranes showed more significant changes in electrolyte concentration in opposing directions but the same pH trend, as the current density increased. The configuration with cation exchange membranes as restriction membranes resulted in the highest protein recovery, while the use of anion exchange membranes would appear as the best choice for separation of a protein with net positive charge. The results of this work provide important insights for the design and operation of EDFM processes and a better understanding of the transport phenomena that occur during the separation of bioactive compounds. [ABSTRACT FROM AUTHOR]

Ion-exchange membranes have beenwidely used in the separationof ionic mixtures or as a barrier in some types of chemical powersource because of their selectivity to cations and anions. In thisarticle, a novel single-ion selective ion-exchange membrane was fabricatedto selectively separate copper ion from aqueous media. Polyethylenemine(PEI) was deposited onto a commercial cation-exchange membrane throughan electric-field-enhanced procedure, and was subsequently modifiedwith an ion imprinting technique. The effects of different parameterssuch as current density and feed composition on the deposition ofPEI were studied. The copper ion imprinted membrane (Cu-IIM) showedlower resistance than the nonimprinted membrane (NIM) indicating theformation of a specific transportation path for the ions. The differenceof binding isotherms for copper ion and zinc ion confirmed that theCu-IIM had specificity to recognize copper ions. The permselectivityof the Cu-IIM was tested on an electrodialysis setup. The imprintingfactor calculated from the separation factors of the imprinted andnonimprinted membrane was 1.99, demonstrating that the imprintingprocess enhanced the permselectivity of the membrane. The transportmechanism of ions in the Cu-IIM was also studied and analyzed. [ABSTRACT FROM AUTHOR]

A novel copper ion-selective membrane was prepared bypressure-drivendepositing poly(ethyleneimine) (PEI) onto the surface of a polyacrylonitrile(PAN) ultrafiltration (UF) membrane and was subsequently modifiedwith molecular imprinting technique. Examination by infrared spectroscopyand scanning electron microscopy (SEM) confirmed PEI was successfullyintroduced onto the surface of a hydrolyzed PAN UF membrane. The increaseof the pH of copper ion solution was beneficial to the template ionadsorption on the PEI deposited PAN (PEI-PAN) membrane. In ion imprinting,with the cross-linking time prolonged, the adsorption selectivityof the ion imprinted membrane (IIM) increased. The results of bindingexperiment fitted well with the Langmuir model and showed that theCu2+imprinted membrane has the ability of specificityand recognition toward the imprinted copper ion. The imprinting factorcalculated from the separation factor was 2.25, indicating that thesurface imprinting process facilitated the perm-selectivity of themembrane. [ABSTRACT FROM AUTHOR]

It has been still expected to explore a green and low-cost raw material for fabricating high performance loose nanofiltration (LNF) membrane with high permeance and dye/salt selectivity. In this report, aminated mesoporous hollow silica (AHS) nanospheres are first synthesized. Then, a lignin-based LNF membrane is fabricated employing aminated lignin as raw material, trimesoyl chloride as a crosslinker, and AHS nanospheres as nano additives by interfacial polymerization. It shows excellent pure water permeance, high dye rejection, and salt permeation. After being modified with L-arginine, the PWP (49.9 LMH bar−1) and salt permeation are further improved. Simultaneously, the dye rejections are kept at a high level. The AHS nanospheres provided abundant water/salt diffusion channels for the lignin-based separation layer. The hollow structure of the nanospheres decreases the diffusion resistance of the water and salt. Moreover, the membrane shows satisfactory structural and separation performance stability during immersion in acid and/or alkaline solutions. After being treated with 5500 ppm h chlorination strength, it still exhibits excellent BBR/NaCl selectivity accompanied by a small permeance increase. Furthermore, the membrane shows excellent fouling resistances, satisfactory bactericidal (92.5 %) and bacterial anti-adhesion properties. The membrane shows excellent performance stability in a long-term (80 h) dye/salt separation process. [Display omitted] • A lignin-based membrane is fabricated by using TMC to crosslink aminated lignin. • The membrane has high permeability, satisfactory dye rejection and salt permeation. • Introducing silica hollow nanospheres can improve membrane permeance and selectivity. • The membrane has good resistance to acid, alkaline, active chlorine, and fouling. • L-arginine modification improves the antibacterial property of the membrane. [ABSTRACT FROM AUTHOR]

Four different impregnation methods, namely ultrasonic co-impregnation, ultrasonic stepwise impregnation, co-impregnation and stepwise impregnation, were used to prepare Cu/B/Ca/Al2O3 catalyst. The effects of ultrasonic-assisted impregnation on the physicochemical properties, morphology and hydrogenation performance of sec-butyl acetate were investigated, and the difference between ultrasonic co-impregnation and ultrasonic stepwise impregnation was further explored. The catalysts were characterized by inductively coupled plasma atomic emission spectrometry, X-ray diffraction, scanning electron microscopy, Transmission electron microscope and N2 physical adsorption-desorption. The results indicate that ultrasonic-assisted treatment can reduce the agglomeration of copper particles, and that the active components are uniformly dispersed on the surface of the catalyst, expanding the specific surface area and, thus, increasing the conversion of sec-butyl acetate from 79.6% to 99.8%, and the selectivity of sec-butanol from 63.5% to 70.2%. In addition, the reaction pressure is reduced from 8 MPa to 5 MPa compared to the conventional impregnation.Ultrasonic co-impregnation is more advantageous than ultrasonic stepwise impregnation, since it can shorten the catalyst preparation cycle, avoid loss of B2O3 and CaO components during the secondary impregnation, expand the effective contact area between Ca and Cu species, increase the electron transfer rate from Ca to Cu, avoid the increase of Cu+/Cu and finally ensure the hydrogenation activity of the catalyst. The catalyst has the highest reactivity at an ultrasonic power of 80 W and within the duration of 0.75h. However, continued increase in ultrasonic power and time leads to catalyst deactivation. A long term test for catalyst stability which lasted for 200h had been run at 226 °C, 5 MPa H2, space velocity = 0.5h−1. [ABSTRACT FROM AUTHOR]

Highlights • Phenol was removed from model solution using an electromembrane process. • Energy consumption for phenol removal was affected by the competing anions. • Increased phenol concentration in feed water led to lower energy consumption. Abstract The discharge of phenol-containing wastewater has become a crucial and health threatening environmental issue. In this paper, an electro-electrodialysis (EED) process was investigated to remove phenol molecules in the form of phenoxide ions, and simultaneously desalt the laboratory-prepared salty wastewater. The influence of applied voltage, sodium sulfate and phenol concentrations on the separation performance and energy consumption of the EED process was studied. More than 90% of the phenol could be removed, illustrating the feasibility of the EED process. The specific energy consumption for phenol removal was primarily influenced by the concentration and characteristics of the competitive anions, such as sulfate and hydroxide ions in the feed solution. An increase of phenol concentration reduced the specific energy consumption, while a higher salt concentration resulted in higher energy consumption. The EED process is more energy-efficient for treating wastewater with low salt concentrations and high phenol concentrations. These results can significantly enhance the application potential of this emerging separation process. [ABSTRACT FROM AUTHOR]

Abstract Novel antifouling blend polyethersulfoune (PES) membranes were prepared via phase inversion assisted by a direct current (DC) electric field with the addition of extremely low concentration of graphene oxide (GO). The GO particles were observed migrating toward the anode and better distributed in the casting solution with a DC electric field exerted. The effect of the applied DC electric field intensity on the properties of blend membranes was systematically investigated. The enrichment of GO on the membrane surface assisted by the electric field was confirmed by the enhanced hydrophilicity and negative charge density, and the XPS results. The blend PES membrane prepared under an electric field of 5000 V cm−1 exhibits not only a high water flux (289.63 L m − 2 h − 1 ), which is more than double of the pristine PES membrane (137.67 L m − 2 h − 1 ), but also an improved methyl red rejection. The membrane fouling performance was studied with bovine serum albumin (BSA) as model protein. The PES/GO membranes prepared under a 5000 V cm−1 electric field showed an obviously increased flux recovery ratio (FRR) and a decreased irreversible fouling ratio (R ir) value, compared to ones without using an electric field. The membrane fabrication assisted by an electric field opens a new way to enhance hydrophilicity, charge density, separation performance and antifouling ability of mixed matrix membranes. Highlights • PES/GO membranes are fabricated assisted by DC electric field with extremely low concentration of GO addition. • Enrichment of GO on membrane surface is confirmed by contact angle, zeta potential and XPS result. • Electric field assisted blend membranes show enhanced water flux and methyl red rejection. • Antifouling ability is obviously improved with 5000 V cm−1 DC electric field exerted. [ABSTRACT FROM AUTHOR]

• Monovalent selective AEMs were prepared by electrodeposition of PDA and Fe-PAA. • The electrostatic repulsion between PDA and PAA was reduce byorientation of PDA. • Fe3+ promoted the stability of PDA layer by oxidation and complexation. • The elution of Fe3+ released electronegative groups in PAA. Monovalent selective anion exchange membranes were efficiently prepared by two-steps electrodeposition. Firstly, a polydopamine (PDA) interlayer was formed onto the surface of a commercial anion exchange membrane (AEM), followed by the deposition of a top layer of Fe3+ complexed polyacrylic acid (Fe-PAA). The PDA interlayer formation was investigated by reversing the polarity of the electric field applied. In particular, modified membrane prepared with PDA layer facing the cathode (labeled as FC-PDA-M) exhibited lower negative charge surface density compared to the membrane prepared with DA solution close to the anode (labeled as FA-PDA-M). This effect resulted in an increased deposition of PAA, due to the diminished electrostatic repulsion, when a solution of Fe3+ complexed polyacrylic acid with a Fe/PAA ratio of 1/4 was electrodeposited on the PDA layer. After eluting the Fe3+ with EDTA, the two manufacture membranes, labeled as FC-PDA/(Fe)PAA-M and FA-PDA/(Fe)PAA-M, were characterized. The former exhibited a higher Cl−/SO 4 2− permselectivity than the latter, although the latter demonstrated better performance compared to both the pristine AEM and a PAA-PDA-M obtained without applying any current during the deposition process. The effect the Fe3+ addition and varied the Fe/PAA ratio was also investigated. The membranes obtained using the Fe/PAA ratio of 1/4 exhibited best separation performance. Finally, the stability of this membrane was assessed by conducting ten consecutive electrodialysis (ED) experiments, revealing consistent Cl−/SO 4 2− permselectivity values within the 5–6 range. [ABSTRACT FROM AUTHOR]

Exploring green, renewable, and low-cost raw materials has great significance on developing high-performance loose nanofiltration (LNF) membranes using a scalable fabrication approach. Lignin is the second most abundant biomacromolecule in the botanic field. In this report, a lignin-based LNF membrane is successfully fabricated using alkaline lignin and sodium ligninsulfonate as raw materials and dopamine (DA) as a surface modifier by a brush assisted layer-by-layer assembly. The driving forces for the assembly are hydrogen bonds between hydrophilic groups and π-π stacking in phenyl groups. The experimental results show that the membrane possesses ultrahigh pure water permeability (65.2 LMH bar−1), and high dye rejections (100% for brilliant blue R (BBR), 96.1% for congo red (CR)) and salt permeations (85.1% for NaCl, 96.7% for MgCl 2), exhibiting satisfactory dye/salt separation performance. The separation process is dominated by the synergistic action of the size exclusion and Donna repulsion between charged dye clusters and the membrane surface. The separation selectivity of the membrane can keep stable accompanied by a small permeate-flux fluctuation during immersed in HCl solution for 7 days. The membrane also shows low flux decline and excellent flux recoverability during a three-cycle CR fouling process. Moreover, the separation capability and permeate flux only show small fluctuations under 5500 ppm·h chlorination strength (pH = 5). The DA surface modification can significantly enhance the membrane permeability, fouling and chlorine resistances. The membrane possesses satisfactory performance stability on a long-term running process for the CR/NaCl separation. [Display omitted] • A loose NF membrane is fabricated using low-cost lignin-based raw materials. • The membrane has high water permeance due to suitable pore size and hydrophilic surface. • The membrane exhibits high dye rejection, salt permeation, and dye/salt selectivity. • The membrane shows good acid, chlorine, and dye fouling resistances, and stability. • Dopamine modification improves the water permeance, chlorine and fouling resistances. [ABSTRACT FROM AUTHOR]

This paper introduces a superstructure-based simultaneous optimum design and operation of seawater reverse osmosis (RO) system with boron removal under time-variant constraints. Three operational strategies are utilized to improve operability of the system under boron restrictions, including changing the activated number of pressure vessels, permeates split ratio, and pH values. Moreover, exergo-environmental and exergo-econoenvironmental analysis models are integrated. The economic efficiency, energy utilization, and environmental impact could be optimized in both design and operation phases. The effect of water tank area, membrane type, and boron concentration on water production are investigated with constant feed conditions. Choosing proper water tank volume and type of membrane could not only reduce cost but also better operation conditions, such as improving the efficiency of pumps and reducing feed pH of RO pass 2. When both the eco-costs/value ratio and emergy rate of product are added as a penalty, the annual operation cost (a reduction of 5.50 %), emergy rate (a reduction of 7.02 %) and eco-costs/value ratio (a reduction of 7.48 %) of the product could be reduced with only a small amount of water cost increment (about 2.66 %). Improving the efficiency of pumps would be an effective method to improve overall performance of the RO plant. [Display omitted] • Optimal design and operation of RO networks with boron removal are considered. • Economic, thermodynamic, and environmental analysis are integrated in model. • Economic efficiency, energy utilization, and environmental impact are optimized. • Improving efficiency of pumps could improve emergy performance of the RO plant. • Operational cost, emergy rate and eco-costs/value ratio are effectively reduced. [ABSTRACT FROM AUTHOR]

• Monovalent selective CEMs were fabricated through a 30-min PDA-PEI deposition induced by Fe3+. • Fe3+ were exchanged to the CEM substrates before PDA-PEI deposition. • Fe3+ accelerated the polymerization of DA through oxidation and chelation. • Varying the Fe3+ concentration could manipulate the characteristics and performance of membranes. • Fe3+ enhanced the stability of the PDA-PEI deposited membranes. Selective monovalent cation transport is crucial for the concentration of target ion(s) using electro-membrane processes prior to precipitation. Co-deposition of biomimetic adhesive polydopamine (PDA) and the positively charged polyethyleneimine (PEI) has emerged as an effective approach for building monovalent perm-selectivity functional coatings for cation exchange membranes (CEMs). Here we report a facile strategy to fabricate monovalent selective cation exchange membranes through quick co-deposition of PDA-PEI induced by ferric (Fe3+) ions. With CEM substrate ion exchanged with Fe3+ ions, the polymerization of DA on the membrane surface was accelerated. The mechanism of the promoting effect of Fe3+ ions on the PDA-PEI co-deposition was explored by UV spectroscopy, SEM, AFM, zeta potential and area resistance measurements. In this approach, the characteristics of the membrane surface were easily manipulated by varying the Fe3+ concentration. The selective CEM fabricated through 0.0001 M FeCl 3 pretreatment and only 30-min PDA-PEI deposition showed remarkably enhanced Na+/Mg2+ selectivity of 8.3, low electrical resistance and excellent stability. This study provides a simple and scalable technique for time-saving and environmentally friendly construction of PDA based coating for membrane modifications. [ABSTRACT FROM AUTHOR]

This study aims to fabricate monovalent cations selective membranes through Layer-by-Layer (LbL) assembly with ion-imprinting introduced. Nickel ions (Ni2+) were introduced into the polycation of polyethyleneimine (PEI) as template and then modified the ultrafiltration membrane through LbL assembly followed by glutaraldehyde (GA) crosslinking and reduction. After eluting the template, ion-imprinting channels with specific size were formed in the modified layer. These channels enhanced the water flux with the selectivity for Na+/Mg2+ improved 2.25 times simultaneously compared to the non-imprinted membrane. Besides, the membrane preparation conditions were optimized and the optimum selectivity of 4.16 was achieved. We analyzed the mechanism of improving separation performance via ion-imprinting technology and believed that this environmental-friendly method provides a new road to fabricate monovalent selective membrane for seawater softening and lithium extraction from magnesium-rich brine. • Monovalent cations selective membranes were prepared by combining LbL and ion-imprinting. • Ni2+ was coordinated with PEI as template ions and induced to LbL self-assembly. • The ion-imprinting formed channels improved the water flux and monovalent selectivity simultaneously. [ABSTRACT FROM AUTHOR]

In this report, yolk-shell (YS) organic-inorganic hybrid nanospheres (YSHNs) with radially ordered mesopores were synthesized by a co-assembly strategy using 1,2-bis(triethoxysilyl)ethane and tetraethoxysilane as precursors, and cetyltrimethylammonium bromide as a soft template. Then, Silver nanoparticles (AgNPs) were uniformly embedded in the hollow cavities of the YSHNs. The semi-aromatic polyamide (SAP) based nanocomposite membrane was fabricated using 1,3,5-cyclohexane tricarbonyl chloride as an organic phase, meta -phenylene diamine as an aqueous phase, and the mesoporous YS hybrid nanospheres as nanoadditives by an interfacial polymerization approach. The results show that the YS nanospheres were successfully incorporated into the polyamide (PA) separation layer, and the membrane becomes very hydrophilic. The membrane incorporated with the aminated YS mesoporous nanospheres exhibits ultrahigh pure water permeability (PWP, 9.34 L m−2 h−1 bar−1) and comparable NaCl rejection (96.1%), which is dramatically higher than the membrane with common mesoporous nanospheres. It is because that the hollow cavity of the YS nanosphere further decreases the membrane resistance, and the aminated spherical surface improves the interfacial compatibility between the PA matrix and the YS nanospheres. Furthermore, the flexible YS hybrid structure and the mesoporous core could play an important buffering for avoiding the shell fracture under a high operation pressure. The chlorine resistance of the YS-nanosphere incorporated membrane is significantly improved compared to the pristine SAP membrane in a strong chlorination strength (5500 ppm h, pH = 5). The confined AgNPs in the YS mesostructure endow the membrane with a sustainable antibiofouling property. Moreover, the polylysine modification improves the membrane fouling resistance and performance stability. [Display omitted] • Yolk-shell mesoporous hybrid nanospheres are added into the semi-aromatic membrane. • The nanocomposite membrane has ultrahigh permeability with comparable salt rejection. • AgNPs are confined in the cavities of the yolk-shell nanospheres to avoid leaching. • The nanocomposite membrane shows good chemical and bacterial fouling resistances. • The membrane exhibits good performance stability in continuous running. [ABSTRACT FROM AUTHOR]

[Display omitted] • Pre-treatments enhanced cell disruption in Nannochloropsis slurries. • Neutral lipid yield was directly dependent on the degree of cell disruption. • Mechanical disruption was more effective for neutral lipid recovery. • Protein yield was determined by both cell disruption and linkage hydrolysis. • Chemical disruption was able to extract both structural and soluble proteins. Novel cell-disruption combinations (autolytic incubation and hypotonic osmotic shock combined with HPH or pH12) were used to investigate the fundamental mass transfer of lipids and proteins from Nannochloropsis slurries (140 mg biomass/g slurry). Since neutral lipids exist as cytosolic globules, their mass transfer was directly dependent on disintegration of cell walls. Complete recovery was obtained with complete physical disruption. HPH combinations exerted more physical disruption and led to higher yields than pH12. In contrast, proteins exist as both cytosolic water-soluble fractions and cell-wall/membrane structural fractions and have a complex extraction behaviour. Mass transfer of cytosolic proteins was dependent on cell-wall disintegration, while that of structural proteins was governed by cell-wall disintegration and severance of protein linkage from the wall/membrane. HPH combinations exerted only physical disruption and were limited to releasing soluble proteins. pH12 combinations hydrolysed chemical linkages in addition to exerting physical disruption, releasing both soluble and structural proteins. [ABSTRACT FROM AUTHOR]

• The environmentally friendly EED process is used to acidify K 2 Tar to H 2 Tar. • The conversion ratio from K 2 Tar into H 2 Tar reached 99% in three-chamber process. • The competitive migration of H+ and K+ limited the conversion ratio in the two-chamber EED. • The two-chamber EED process shows lower specific energy consumption. • Water splitting occurred on the CEM in the latter stage of three-chamber process. Acidification is an essential step in organic acid production. In this work, an environmentally friendly electro-electrodialysis (EED) process was carried out to transform potassium tartrate (K 2 Tar) to tartaric acid (H 2 Tar) without additional waste salt generation. The characteristics of ions migration in the two-chamber EED and three-chamber EED processes were investigated, and the conversion ratio of tartaric acid and specific energy consumption of the two configurations were also compared. The competitive migration of K+ ions and H+ ions through cation exchange membrane was the key factor affecting the extent of acidification in the two-chamber EED process, while the selective transport of tartrate ions (Tar2−) and H+ ions through the anion exchange membrane influenced the three-chamber EED process significantly. The three-chamber process generated pure H 2 Tar solution with higher concentration than the two-chamber process and reached a conversion ratio of 99% after 120 min's operation running at 7 mA/cm2. Owing to the lower resistance of the two-chamber membrane stack, the specific energy consumption in the two-chamber EED process was lower than that of three-chamber EED process. This work provides important knowledge for assessing the application of EED in the production of tartaric acid (H 2 Tar) from potassium tartrate (K 2 Tar) and a better understanding of the transport phenomena in the system with ionic organic compounds. [ABSTRACT FROM AUTHOR]

Electrodialysis has been considered to be a competitive technology in the treatment and reclamation of organic saline wastewater. As a kind of typical compounds in industrial wastewater, the mass transfer property of organic electrolyte were important to the operation of the treatment process and product quality. The benzoic acid/sodium benzoate and citric acid/sodium citrate in the electrodialysis process and diffusion process were investigated in this paper. The effects of cations (Na+, K+, Mg2+, Ca2+) and anions (Cl- and SO 4 2-) were discussed. The mass transfer of organic acids and their salts through the ion exchange membrane has two forms: electromigration and diffusion, both of which were affected by the degree of ionization, molecular size and molecular structure. The contribution of electromigration was found to be predominant over that of diffusion as a current is applied. The influence of inorganic ions mainly includes dehydration of organic matter and water content of the membrane. These opposite effects play different roles in the mass transfer of organic acids and their salts through the ion exchange membrane with and without current. It was also shown that the existence of organic acids and their salts had little effect on the mass transfer properties of inorganic salts. Image 1 • The transfer of weak organic acids & salts were affected by ionization, molecular size and structure. • The transfer of weak organic acids & salts is contributed by the neutral molecules and acid ions. • The hydration capacity of inorganic ions is the critical parameter affecting the organic transfer. • The transfer of salt and water were affected little by the organics. [ABSTRACT FROM AUTHOR]

• AEMs with super-hydrophilic surface were prepared with TiO 2 coating assisted by PDA and PSS. • Electric resistance of the modified AEMs was marginally increased after 100-min fouling. • The foulants on the modified AEMs were removed rapidly through simply water rinsing. The fabrication of reliable anion exchange membranes (AEMs) with superior antifouling abilities is critical in applications of electrodialysis (ED) technology. Surface modification with hydrophilic nanoparticles to improve antifouling of the membrane is an effective method. In this study, the effect of hydrophilicity of the AEMs surface on their antifouling properties was studied in detail. Commercial AEMs were modified with super-hydrophilic titanium dioxide (TiO 2) coating assisted by polydopamine (PDA) and poly (sodium 4-styrene sulfonate) (PSS). Owing to the strong adhesion of PDA, a stable TiO 2 layer was constructed on the membrane surfaces and endowed them super-hydrophilic properties. These modified AEMs exhibited slightly increased membrane area resistance compared to the pristine membrane, while after 100-min fouling experiments with sodium dodecyl benzene sulfonate (SDBS) the resistance of the 0.75 g/L-DA modified membrane increased only marginally relative to 48 % of the pristine membrane. The feasibility of rapid cleaning during ED separation operated with SDBS as the foulant without ultraviolet (UV) irradiation was also investigated. Ascribed to the super-hydrophilicity of the TiO 2 modified surface, the modified AEMs showed good fouling reversibility through simply water rinsing. [ABSTRACT FROM AUTHOR]

• Lipid-rich Nannochloropsis slurries were repeatedly washed with fresh water. • Hypotonic osmotic shock damaged cell membranes but did not rupture cell walls. • Freshwater washing was applied as a pretreatment to other cell disruption methods. • Osmotic shock doubled the lipid yield of high-pressure homogenisation and hexane. • Osmotic shock led to a multiple-fold rise in the protein yield of NaOH hydrolysis. This study reports the use of hypotonic osmotic shock as a treatment step to enhance the recoveries of biofuel-convertible lipids and proteins from lipid-rich saltwater Nannochloropsis gaditana (N. gaditana) slurries (biomass content = ~140 mg biomass / g slurry, total lipid content = ~600 mg lipid /g biomass). The osmotic shock was induced through repeated washing of microalgal slurries with multiple batches of fresh water. Subjecting the slurries to 2 stages of freshwater washing resulted in a measurable damage to cell membranes (the uptake of membrane permeability marker increased by 6 folds), a partial loss of cell viability (only 64% of available cells were recoverable), and a minor release of free protein (~2 wt% of available protein) from the biomass into the interstitial space of the slurries. Hypotonic osmotic shock was revealed to be ineffective in rupturing N. gaditana slurries (only 13 ± 9% of available cells were ruptured after 2-stage washing) and, as such, had a limited prospect as a stand-alone cell disruption technology for the saltwater strain. The washing treatment, however, was found to be able to weaken the structural integrity of N. gaditana slurries and enhance the performance of subsequent mechanical or chemical cell disruption technologies when installed as a preparatory step. Applying the washing treatment prior to high-pressure homogenisation (HPH) and low-solvent-to-biomass ratio hexane extraction (hexane : slurry = 1:1 w/w) for the recovery of biofuel-convertible lipids increased the extent of cell rupture from 28 ± 8 to 46 ± 19% of available cells and more than doubled neutral lipid yield from 25.1 ± 2.0 to 64.6 ± 4.9 wt% of available neutral lipid. Initial analysis revealed that the washing treatment had a minimal energy cost (~6% of the total energy expenditure of downstream processing) and that its integration into HPH + hexane lipid recovery led to a 2.5 fold increase in the energy output of the biomass. Partnering the washing treatment with NaOH hydrolysis increased protein yield from 6.7 ± 2.4 to 31.9 ± 10.7 wt% of available protein. [ABSTRACT FROM AUTHOR]

• The corrugated tube of the semicircular surface was studied. • The axial spreading length the departure-site spacing, and flow patterns were studied. • A new correlation has been suggested to predict the column departure-site spacing. The intertube flow pattern presents droplet, droplet-column, column, column-sheet, and sheet with the increase of flow rate on the falling film flow process outside a horizontal corrugated tube. The film Reynolds number of each flow pattern transition of a horizontal corrugated tube is less than that of a horizontal smooth tube. The corrugated tube surface is more favorable to axial spreading of the liquid film compared with the smooth tube. The droplet or column departure-site spacing is smaller than in a smooth tube. As the intertube spacing of the horizontal corrugated tubes increases, the film Reynolds number of each flow pattern transition and the droplet or column departure-site spacing are increased. Based on the experimental data, a new correlation has been suggested to predict the column departure-site spacing of a horizontal corrugated tube. [ABSTRACT FROM AUTHOR]

Brine concentration is of critical importance in achieving zero liquid discharge in modern industrial processes. The effect of osmotic agent (OA) on the system performance in the treatment of different concentrations of brine using osmotic membrane distillation (OMD) was investigated. Significant improvement in water flux for concentrating the hypersaline brine was achieved compared to conventional membrane distillation processes. By altering the hydrodynamic conditions and using different combinations of feed streams and osmotic agents, a mathematical approach was applied, for the first time, to reveal the contribution of temperature and concentration polarization on flux enhancement in treating highly saline brines. This improvement was found to be caused mainly by the temperature polarization on the OA side of membrane, with less contribution from the decrease in vapor pressure of the bulk of the OA. This work illustrates that OMD is a promising process for efficient concentration of highly saline streams such as those found in the chlor-alkali industry. During the concentration of the spent brine from the electrolyte cell (NaCl concentration from 180 g/L to 310 g/L), OMD was shown to be the more cost and energy efficient compared to conventional MD processes. • The effect of osmotic agent on the performance in treatment of brine using OMD was investigated. • Water flux of OMD for concentrating hypersaline brines was significantly higher than MD. • Mathmatical models were applied to reveal the effect of temperature and concentration polarization on permeate flux. • OMD is more cost and energy efficient compared to conventional MD processes. [ABSTRACT FROM AUTHOR]

In recent decades, the advancements in layer-by-layer (LBL) assembly technology have provoked increasing interest in the preparation of multilayer polyelectrolyte membranes with excellent performance. In the current study, a novel nanofiltration (NF) membrane was prepared by pressure-driven layer-by-layer (LBL) assembly of polyethylenimine (PEI) and polyacrylicacid (PAA) on a porous substrate with chemical crosslinking. The effect of deposition pressure on separation performance of the prepared membranes was studied. The surface morphology, hydrophilicity and the charge property of the dynamically-deposited membranes were compared with those prepared by static adsorption. The characterization results showed that dynamic deposition process resulted in a smoother membrane surface with improved hydrophilicity. The mechanism of water-path formation was proposed to interpret the effect of pressure on the membrane performance. Glutaraldehyde (GA) was used as a crosslinker to reduce the number of polyelectrolyte bilayers for obtaining good separation performance. The rejections of different inorganic salts of the dynamically-deposited NF membrane were also investigated. [ABSTRACT FROM AUTHOR]