Ppm NaCl Research Articles

Oil and Flower Production in Rosa damascena trigintipetala Dieck under Salinity Stress in Taif Region, Saudi Arabia

The flower industry depends on oil and fragrance, which is addressed in the current work. Different concentrations of NaCl (0, 250, 500, 1000, and 1500 ppm) were applied to Taif rose plants (Rosa damascena var. trigintipetala Dieck) to evaluate their effects on growth and essential oil content. Results clearly indicated the highest survival percentage (98.3%) was seen in untreated plants compared to plants under salinity stress. Moreover, increasing the NaCl levels induced an adverse effect on the growth parameters of Taif rose plants, while some essential oil contents were increased to the maximum degree of their tolerance to salinity stress. The extracted essential oils were analyzed using GC/MS. The essential oils of Taif rose plants treated with 500 ppm NaCl recorded the highest values of citronellol, geraniol and phenylethyl alcohol contents (16.56, 8.67 and 9.87%), respectively. NaCl at 250 ppm produced the highest values of heneicosane (13.12%), and then decreased to the lowest value (7.79%) with the increase of NaCl to 1500 NaCl, compared to the control and other NaCl levels. The current results could highlight the impact of salinity stress on Rosa damascena Miller var. trigintipetala Dieck for better economic and industrial applications.

Enhanced capacitive deionization performance of activated carbon derived from coconut shell electrodes with low content carbon nanotubes–graphene synergistic hybrid additive

With increasing desalination demand worldwide, electrode materials for capacitive deionization (CDI) have attracted extensive attention recently. To compete with Reverse Osmosis, the performance of CDI electrode still needs to be further enhanced. In this work, graphene (Gr)/carbon nanotubes (CNTs) conducting hybrid was dispersed at as low as 1 wt% in coconut shell derived activated carbon (AC) to fabricate cost effective and high performance electrode for brackish water CDI desalination. The fabricated AC/Gr/CNTs electrodes show an excellent performance with the capacitance of 60 F/g (at 5 mV/s), the salt adsorption capacity of 9.58 mg/g and salt adsorption rate of 1.51 mg/g min at 1.0 V in 200 ppm NaCl solution. It should be highlighted that owing to the synergistic effect, the role of hybrid additive (1 wt%) was demonstrated to be more effective than that of single one, from a technical as well as from an economical viewpoint. To our best knowledge, this is the first study reporting the application of ultra-low content AC/CNTs hybrid in AC based CDI electrodes.

Development of a novel temperature-resistant and salt-resistant double-cationic surfactant with “super thick hydration layer” for clean fracturing fluid

In recent years, cationic surfactants have received extensive attention in cleaning fracturing fluid thickeners due to various unique properties. At the same time, the development of temperature-resistant and salt-resistant clean fracturing fluid is the key to deep well oil and gas resource development. In this study, the rigid-soft combined strategy is adopted for molecular structure designs. N,N-dimethylcyclohexylamine and epichlorohydrin are used as the initial reactants; after the ring-opening reaction occurs, they are quaternized with erucamide propyl dimethyl ammonium to synthesize a novel double-cation viscoelastic surfactant, SY–JS. With double-cationic charges on the head group, water molecules are selectively adsorbed around the cation lattice to increase the hydration layer, and thus, salt tolerance is improved. Cyclohexane with a rigid structure improves temperature resistance. The ultra-long unsaturated hydrophobic tail imparts excellent heat tolerance and dissolubility to the designed viscoelastic surfactant. The clean fracturing fluid prepared by 3 wt% SY–JS with 130,000 ppm NaCl or KCl performs well under a shear rate of 170 s−1 at 140 °C, and the apparent viscosity remains above 30 mPa s−1 after 120 min.. Additionally, the results show that single-tail surfactants exhibit excellent performance at approximately 140 °C. Afterward, the brine produced from Rumaila and Jiyuan oil fields is used to prepare brine-based clean fracturing fluids, and evaluations, including proppant suspension, gel breaking, and permeability damage, were conducted. The results show that the brine-based clean fracturing fluid completely meets the requirements of hydraulic fracturing industrial application.

Optimization of interfacial polymerization to fabricate thin-film composite hollow fiber membranes in modules for brackish water reverse osmosis

The development of commercial-scale thin-film composite (TFC) hollow fiber membranes and modules for reverse osmosis (RO) has been lagging behind spiral wound TFC flat-sheet membranes and modules for many years. The delay arises from the challenges of synthesizing a defect-free polyamide selective layer on hollow fibers in modules. In order to solve this problem, a novel interfacial polymerization method is presented in this work to fabricate 1-inch TFC hollow fiber membrane modules for RO applications. By circulating the m-phenylenediamine (MPD) solution on the lumen side under a positive pressure and circulating the trimesoyl chloride (TMC) solution at the atmosphere pressure, a strong, uniform and defect-free polyamide selective layer is formed on the inner surface of hollow fiber membranes in modules. Under pressure, not only MPD monomers are evenly distributed on the inner surface of each hollow fiber substrate in modules, but also sufficient MPD monomers can retain in the substrate pores for further reaction with TMC monomers. The best RO performance obtained by this newly developed TFC hollow fiber membrane module has a water permeability of 4.49 L m−2 h−1 bar−1 and a NaCl rejection of ~99%, using a feed solution of 1000 ppm NaCl under a transmembrane pressure of 20 bar. The novel interfacial polymerization method may provide useful insights to fabricate TFC hollow fiber membrane modules for desalination of brackish water.

A positively charged loose nanofiltration membrane fabricated through complexing of alginate and polyethyleneimine with metal ions on the polyamideimide support for dye desalination

Abstract Nowadays, loose nanofiltration (NF) membranes are preferred for dye desalination to achieve high dye/salt selectivity and enable filtration at low operating pressure. However, current fabrication techniques require rigorous reaction conditions and long preparation times. Herein, we used the chelating ability of the polyethyleneimine (PEI) and alginate with the metal ions to fabricate loose NF membranes via a facile approach. The positively charged polyamide imide (PAI)/PEI support was used to build the assembly. Direct attachment of Zn or Fe ions to the PEI chains did not result in a stable complex in the presence of a high salt concentration (1000 ppm NaCl). On the other hand, alginate coated on the support allowed building permanent assemblies after crosslinked with Fe3+ and Zn2+ transition metal ions. The PAI/PEI-Alg-Fe3+ membrane exhibited the highest permeability, excellent antifouling behaviour upon exposure to synthetic textile wastewater, and maintained long-term stability under static and dynamic conditions. Also, the same membrane rejected dyes and coloured substances in real wastewater sample during 72 h continuous filtration. With alginate metal complex formation on a suitable support, a scalable loose NF membrane was manufactured, demonstrating improved throughput value compared to current NF membranes.

Thin-film nanocomposite membranes incorporated with defective ZIF-8 nanoparticles for brackish water and seawater desalination

In this work, a series of defective ZIF-8 (dZIF-8) nanoparticles with tuneable inner defects have been synthesized and successfully incorporated into the polyamide-based thin-film nanocomposite (TFN) membranes for brackish water and seawater desalination. This is the first attempt to use dZIF-8 nanoparticles as nanofillers in TFN membranes. Additional inner porosity of dZIF-8 nanoparticles endows the membranes with additional pathways for water molecules. Thus, the newly developed TFN membranes have higher separation performance for brackish water reverse osmosis (BWRO) desalination than the normal ZIF-8-incorporated TFN membranes. In addition, the influences of dZIF-8 loading on membrane properties and separation performance have been investigated. At a loading of 0.15 wt% dZIF-8 nanoparticles in the oil phase, the TFN membrane shows a water permeance of 2.61 L m-2 h-1 bar-1 (LMH bar-1) and a salt rejection of 98.6% for brackish water desalination at 20 bar. This water permeance is 52% higher than the pristine thin-film composite (TFC) membrane while the salt rejection is well maintained. Moreover, a steady water flux above 38 LMH is obtained when using seawater of 32000 ppm NaCl as the feed at 50 bar.

Investigating Changes in the Physical and Chemical Effects of Tartarazine Dye Remove on Industrial Wastewater by Electrocoagulation Method

This study has been accomplished to investigate the efficiency of electrocoagulation (EC) in aqua and determine operative condition and the effect of elements (Iron, Aluminum as an electrode), as well as, different connections in the amount of removing the tartrazine color of aqua using DC sources in an electrochemical cell, including anode and cathode the effect of each of varieties like the density of electricity circulation, time of the electrolyze distance between two electrodes, the density of electrolytic and pH which can have the most effect on color destroy. For solution 500 ppm NaCl +50 ppm tartrazine, COD (the amount O2 in chemical activity) almost equals 40 ppm in pH about 6, the density of electricity flow was about 125 Am-2 and distance between two electrodes was 2 cm in 8 min from electrolyzing almost 100% color and 90% COD were canceled in next stage. We compared the efficiency of EC cells, including monopole electrodes in parallel connection and series with EC cells including polarize electrode along with one simple cell of EC. The result of this experiment demonstrated that EC cells including monopole electrode with series connection with sacrifices electrode of aluminum and cathode, anode iron had more efficiency and when using EC simple cells, including an ironic anode and cathodic aluminum. We could see better results rather than EC simple cells including ironic anode cathode.

Fabrication of high-performance pervaporation membrane for sulfuric acid recovery via interfacial polymerization

Industrial acid wastewater is one of the top hazardous wastes to environment. Acid-resistant nanofiltration membrane has been applied in acid wastewater reclamation but is limited to the high osmotic pressure for treating concentrated acid solution. On the other hand, pervaporation (PV) technology has been industrialized for dehydration from organic solvents. It has the potential to extract water from concentrated acid solutions. Nevertheless, PV membrane must have excellent acid resistance besides good ion rejection. Here, we prepared a series of thin-film composite PV membranes based on polysulfonamide (PSA)/polyethersulfone (PES). The PSA selective layer was formed by interfacial polymerization (IP) between a polyethyleneimine (PEI)/m-phenylenediamine (MPD) mixed aqueous solution and a hexane solution of m-phenylenedisulfonyl chloride (BDSC). By optimizing the preparation conditions, the PSA/PES membrane exhibited a water flux of 51.1 ± 2.3 kg m−2 h−1 with a NaCl rejection of 99.60% when desalinating a 35000 ppm NaCl solution at 75 °C. After soaking in 20 wt% H2SO4 solution for one month, the desalination performance of the membrane was maintained. Furthermore, the membrane showed a water flux of 47.5 ± 1 kg m−2 h−1 and a rejection to H2SO4 over 99.9% when separated a 10 wt% H2SO4 solution at 75 °C for at least 20 h. All these results demonstrate that the thin film composite PV membrane is very suitable for treating concentrated acid wastewater.

The Effect of Biofertilizer and Salinity Stress on Amaranthus tricolor L. Growth and Total Leaf Chlorophyll Content

Amaranth is one of the most consumed vegetables in Indonesia. Meanwhile, the productions of plants are affected by productivity and environmental factors such as abiotic stresses. One of these is salinity, which affects plant growth and becomes an issue in the agricultural sector. Moreover, biofertilizer contains microbial elements that are necessary for plant growth and play an important role in the nutrient cycle of the soil. Therefore, this study aims to analyze the effect of biofertilizer combined with NaCl on Amaranthus tricolor L. growth. The biofertilizer doses used were 10 L/ha, 20 L /ha, and 30 L /ha, each combined with manure fertilizer and 2500 ppm, 5000 ppm, 7500 ppm, and 10.000 ppm of NaCl. The parameters were measured using quantitative methods while a UV-vis spectrophotometer was used for the chlorophyll content. Meanwhile, the results were analyzed using the one-way ANOVA method at a 95% of confidence level. This analysis showed that the highest amaranth growth was found in 0 l/ ha of biofertilizer combined with 7500 ppm Na Cl treatment, a number of leaves in 10 l/ha biofertilizer, and 2500 ppm NaCl, and chlorophyll content in 30 l/ha biofertilizer. Based on the results, biofertilizer had an insignificant effect on plant growth while fertilizer had, while the most appropriate biofertilizer dose for chlorophyll content was 30 l/ha.

Partially hydrolyzed polyacrylamide apparent viscosity in porous media enhancement by silica dioxide nanoparticles under high temperature and high salinity

ABSTRACT Polymer flooding effectiveness is hindered by high temperature and high salinity due to polymer degradation. Researchers proposed the addition of nanoparticle to improve polymer stability to withstand reservoir conditions. Therefore, extensive rheological study and flooding test of partially hydrolyzed polyacrylamide (HPAM) solutions with silica dioxide nanoparticles (SiO2 NPs) were carried out under high temperature and high salinity conditions. Shear viscosity of HPAM-SiO2 NPs in rheological study was measured using rheometer while apparent viscosity in porous media was calculated from flooding test and modelled using a numerical model. Apparent viscosity includes shear viscosity and elongational viscosity. Shear viscosity was estimated from Carreau-Yasuda model and elongational viscosity was correlated with Deborah number via relaxation time. At T=80°C the shear viscosity and apparent viscosity in porous media of HPAM-SiO2 NPs are 50% and 64% higher than HPAM. The results further shows that HPAM-SiO2 NPs’ shear viscosity and apparent viscosity in porous media at 60,000 ppm of NaCl are 39% and 53% higher than HPAM, respectively. Nevertheless, enhanced apparent viscosity of HPAM-SiO2 NPs was owed to the formation of stable and dense interwoven HPAM molecules induced from the hydrogen bonds and alkoxysilane (Si-O-Si) crosslinks between SiO2 NPs and HPAM. This study suggested that the addition of SiO2 NPs could significantly improves the HPAM apparent viscosity in porous media under high temperature and high salinity producing ideal mobility control agent.

Potentiality of Different Seed Priming Agents to Mitigate Cold Stress of Winter Rice Seedling

Seed priming has proved to be an effective pre-germination seed invigoration technique for different crops to improve seed and seedling performance under different abiotic stresses. In Bangladesh, winter rice is very often exposed to cold waves just after sowing in the nursery bed resulting in poor seed germination and seedling emergence, yellowish and thin seedlings production, and a very low survival rate. Seed priming may mitigate the cold stress during seed germination and seedling emergence and helps in the quality seedling production of winter rice. To evaluate the efficacy of different seed priming techniques in increasing seedling emergence, growth, vigor and survivability of winter rice cultivars under cold stress, a pot experiment was conducted at the Department of Agronomy, Bangladesh Agricultural University during December 2018 to January 2019. The experiment comprised two factors, (A) Winter rice variety namely, i) BRRI dhan29 and ii) BRRI dhan36; (B) Seed priming agent namely i) Control (no priming), ii) 20000 ppm NaCl, iii) 30000 ppm NaCl, iv) 20000 ppm KCl, v) 30000 ppm KCl, vi) 20000 ppm CaCl2, vii) 30000 ppm CaCl2, viii) 50 ppm CuSO4, ix) 75 ppm CuSO4, x) 10000 ppm ZnSO4, xi) 15000 ppm ZnSO4, xii) 2 ppm Na2MoO4, xiii) 3 ppm Na2MoO4, xiv) 100 ppm PEG (Polyethylene glycol 4000) and xv) 150 ppm PEG. Seeds were sown on two different dates viz., 1st December and 1st January so that seedlings are exposed to cold stress at different stages. The experiment was laid out in a completely randomized design (CRD) with three replications. Results indicated that (in most of the cases) seed priming has a positive impact on seedling emergence rate (%), root length, shoot length, root shoot ratio, root dry weight, shoot dry weight, seedling dry weight and survival rate (%). Among the priming agents, KCl and CaCl2 performed best; while priming with NaCl and PEG showed no advantages over no priming for both the sowing dates. In general, BRRI dhan36 performed better than BRRI dhan29 in terms of seedling growth because of its higher tolerance to cold stress. But, both the varieties performed similarly in terms of emergence rate and survival rate. Thus, priming is an effective tool to increase seed germination, better seedling growth, and higher seedling survivability of winter rice under cold stress, and KCl (20000 ppm) or CaCl2 (20000 ppm) can be considered as a viable priming agent.

Tolerance of 20 heirloom rice varieties at seedling stage salinity stressed and their growth in lowland coastal area

Coastal area of Bengkulu Province is home of many heirloom rice varieties and play an important role in contributing rice production in the province. However, as the climate change proceeds, a progressive sea water inundation has increased soil salinity mainly in low-lying areas and jeopardizing the sustainability of rice production in coastal regions. The use of salt-tolerant varieties, therefore, would be a sensible solution to alleviate the adverse effect of soil salinity in respect of maintaining the crop production in the coastal areas. The objective of this study was to examine the salinity tolerance of 20 heirloom rice varieties collected from a coastal area of Bengkulu Province. Prior to the screening process, lethal concentration 90 (LC90) was determined by assaying the seedlings of ‘Kuning Tinggi’ in a series of nutrient solution containing a different concentration of NaCl (0, 2000, 4000, 6000, 8000 and 10000 ppm). Using a regression analysis, LC90 was detected at a concentration of 3910 ppm. The screening was performed by exposing the varieties in the nutrient solution culture containing 4000 ppm NaCl and growing them on the tidal swamp. Under nutrient culture evaluation, the symptom of NaCl toxicity was scored and converted to salinity tolerance index. ‘Humbur’, ‘Kuning Tinggi’ and ‘Padang Bakung’ exhibited medium tolerant, while ‘Beram’, ‘Imperata’ and ‘Kuning’ exhibited very sensitive. Further evaluation of the tidal swamp for vegetative and generative performances signified that ‘Humbur’ and ‘Kuning Tinggi’ had medium tolerant to salinity stress

Selective Capacitive Removal of Pb2+ from Wastewater over Redox-Active Electrodes.

Water pollution has become an environmental hazard. Diverse metal cations exist in wastewater; lead is the most common heavy metal pollutant among them. Selective removal of highly toxic and ultradiluted lead ions from wastewater is a major challenge for water purification. Here, selective capacitive removal (SCR) of lead ions from wastewater over redox-active molybdenum dioxide/carbon (MoO2/C) electrodes was developed by an environment-friendly asymmetric capacitive deionization (CDI) method. The MoO2/C spheres act as cathodes of an asymmetric CDI device and effectively reduce the concentration of Pb2+ from 50 ppm to <0.21 ppb. Moreover, the SCR efficiency of lead ions over redox-active MoO2/C electrodes is >99% in mixtures of 100 ppm Pb(NO3)2 and 100 ppm NaCl solutions. In addition, the electrodes exhibit high regeneration performance in mixtures of NaCl and Pb(NO3)2 and high SCR efficiency for lead ions from mixtures of heavy metal ions. The tetrahedral structure of the [MoO4] lattice is shown to be more favorable for the intercalation of lead ions. In situ Raman spectroscopy further shows that the transition of the crystal interface between [MoO6] and [MoO4] cluster lattice could be electrochemically controlled during SCR. Therefore, this study provides a new direction for the SCR of lead ions from wastewater.

Highly permeable thin film composite hollow fiber membranes for brackish water desalination by incorporating amino functionalized carbon quantum dots and hypochlorite treatment

A novel strategy has been demonstrated to synergistically improve the separation performance of thin film composite (TFC) hollow fiber membranes for brackish water reverse osmosis (BWRO) desalination. It consists of two steps. Firstly, a series of amino functionalized carbon quantum dots (CQDs) were synthesized and incorporated into the polyamide layer of TFC membranes. The modified TFC membrane with the optimal amino functionalized CQDs has a pure water permeability (PWP) of 5.50 LMH/bar and a NaCl rejection of 98.0% against a 2000 ppm NaCl feed solution at 15 bar. Comparing with the unmodified TFC membrane, the modified TFC membrane has a 42.1% higher PWP without compromising the salt rejection. Then the modified TFC membrane was treated by a sodium hypochlorite solution at different concentrations. Chlorine was bonded to the polyamide layers, enhancing their repulsion against charged solutes and making the polyamide network less cross-linked. As a result, both PWP and NaCl rejection of the TFC membranes could be improved. After being treated with a sodium hypochlorite aqueous solution at 4000 ppm for 3h, the aforementioned modified TFC membrane displays a PWP of 10.13 LMH/bar and a NaCl rejection of 98.9% against a 2000 ppm NaCl solution at 15 bar, which demonstrates a great potential for brackish water desalination. This study may mark a milestone for the development of future BWRO membranes based on the use of amino functionalized CQDs and hypochlorite treatment.

Interactive effects of water salinity stress and chitosan foliar-spray application on vegetative and flowering growth aspects and chemical constituents of pot marigold (Calendula officinalis L.) plant.

A pot experiment was conducted during the two successive seasons of 2018/2019 and 2019/2020 at west of Somosta, Beni-Suef governorate, Egypt, to explore the effect of both saline water and foliar application of chitosan treatments on growth parameters for vegetative and flowering and on some chemical constituents of Calendula officinalis L. In contrast to control plants which were irrigated with tap water, the plants were irrigated with saline water containing NaCl at concentrations of 1000, 2000, 3000, 4000 and 5000 ppm. They were treated also by chitosan as foliar spray application at 100, 200 and 400 ppm, as well as, the interaction between them were involved. The higher salinity levels (4000 and 5000 ppm NaCl) caused significant decreases in all vegetative and flowering growth measurements of pot marigold plants compared to control. Maximum reduction was observed at 5000 ppm NaCl which showed higher increase of the free proline content, sodium and chloride percentages. Meanwhile, the increase in the concentration of salt in the irrigation water resulted in a decrease in the total chlorophylls in leaves and carotene content in flowers. Foliar application of chitosan at concentrations 200 and 400 ppm alleviated the adverse effect of salinity condition thereby vegetative, flowering characters and also chemical constituents were improved. The best level of foliar application of chitosan was at 400 ppm Whereas, non-significant effects were found on the vegetative and floral parameters and some chemical components as a result of the interaction between both aspects studied in comparison with untreated treatment.

Surface morphological and quantum chemical studies of some expired drug molecules as potential corrosion inhibitors for mild steel in chloride medium

Three anti-diabetic drug based biomolecules (Acarbose, Voglibose and Miglitol) were investigated for their corrosion inhibitive effect on mild steel in 700 ppm NaCl solution. Corrosion tests were conducted using weight loss measurements, electrochemical measurements, surface morphologies, quantum chemical studies and molecular dynamics simulation techniques. The results showed increasing corrosion inhibition efficiency with increasing concentrations of all studied biomolecules. The addition of Zn ion (synergistic effect) increased the inhibition of Acarbose, Voglibose and Miglitol on mild steel to a considerable extent. The anodic mode of inhibition mechanism was proposed for the effect of examined inhibitors, as revealed by Tafel polarization technique. Adsorption process of all the investigated inhibitors on the mild steel surface obeys the Langmuir adsorption isotherm. The surface morphologies of the mild steel were studied using SEM and EDXA. The experimental results are well correlate with the quantum chemical and molecular dynamics simulation results. The trend of corrosion protection efficiency of the drug based biomolecule is Ac > Vo > Mi as observed from experimental, theoretical and simulation studies.

Development of High Corrosion Resistance Surface Treatment for Stainless Steels

Polymer electrolyte fuel cells (PEFC) is energy converter with high efficiency and operates at low temperatures of 80oC, thus it gains attention as an automotive power plant. Stainless steels, which could be used as a PEFC bipolar plate material, can be made very thin1), and has the advantage that the power density of a single cell can be improved. However, it has been reported that the proton conductivity of the electrolyte membrane decreases due to the dissolved iron and chromium ions from the polarized stainless steels due to the current fluctuation during PEFC operation2-3). In this study, the surface treatment method of stainless steels for improving the corrosion resistance was proposed and the electrochemical properties were evaluated.The anodic polarization curve of stainless steels was measured by a three-electrode system using an electrochemical measurement system (HZ-7000, Hokuto). The working electrode was SUS316L with various surface treatments. A platinum wire and a silver-silver chloride electrode were used for counter and reference electrodes. The electrolyte was 1.0 M H2SO4 (pH 3) containing 1 ppm NaCl and 3ppm NaF. and this electrolyte is defined as a PEFC simulation environment. The measurement temperature was 80oC, the potential scan range was from the immersion potential to 1.5 V vs. SSE, and the potential scan rate was 100 mV min-1.Three types of stainless steels were used for the working electrode: I. SUS316L, II. SUS316L treated by chemical conversion (CC SUS316L), and III. SUS316L anodized in electrolyte for chemical conversion (anodized SUS316L). The electrolyte for chemical conversion was a 1:1 mixture of 0.1 M Na2WO4 aqueous solution and 0.1 M Na2MoO4 aqueous solution, and the temperature of electrolyte for chemical conversion was 25oC. In the treatment II, SUS316L was immersed in the electrolyte for chemical conversion for 5 min. In the treatment III, SUS316L was polarized in a electrolyte for chemical conversion at an applied potential of 1.0 V vs. SSE for 5 min.Figure 1 displays the anodic polarization curves of SUS316L with various surface treatments in the simulated PEFC environment. The anodic polarization curve of SUS316L showed passive range from the immersion potential -0.3 V vs. SSE to 0.7 V vs. SSE and small current peak due to the formation of the passive film around 0 V vs. SSE. In the transpassive region at the potential nobler than 0.7 V vs. SSE, the current density region increased sharply. At potentials nobler than 1.3 V vs. SSE, the current density increased sharply due to electrolysis of water. The shape of the anodic polarization curve of the CC SUS316L was almost the same as that of the SUS316L, however, the polarization curve showed a small current density in the passive and transpassive regions. No passive region was observed in polarization curve of the anodized SUS316L. And compared to SUS316L and CC coating SUS316L, the immersion potential shifted to noble and the current density in the transpassive region decreased.References1) F, Barbir. “PEM Fuel Cells Theory and Practice”, Academic Press, 4 (2005), 100, 101.2) A. Pozio, R. F. Silva, M. De Francesco, L. Giorgi, Electrochim. Acta, 48 (2003), 1543-1549.3) H. Wang, J. A. Turner, J Power Sources, 183 (2008), 576-580. Figure 1

Biomimetic artificial water channel membranes for enhanced desalination.

Inspired by biological proteins, artificial water channels (AWCs) can be used to overcome the performances of traditional desalination membranes. Their rational incorporation in composite polyamide provides an example of biomimetic membranes applied under representative reverse osmosis desalination conditions with an intrinsically high water-to-salt permeability ratio. The hybrid polyamide presents larger voids and seamlessly incorporates I-quartet AWCs for highly selective transport of water. These biomimetic membranes can be easily scaled for industrial standards (>m2), provide 99.5% rejection of NaCl or 91.4% rejection of boron, with a water flux of 75 l m-2 h-1 at 65 bar and 35,000 ppm NaCl feed solution, representative of seawater desalination. This flux is more than 75% higher than that observed with current state-of-the-art membranes with equivalent solute rejection, translating into an equivalent reduction of the membrane area for the same water output and a roughly 12% reduction of the required energy for desalination.

Enhancement of ionic conductivity of aqueous solution by silanol groups over zeolite surface

The ionic conduction of zeolite powder in ion-exchanged water and various other solutions was investigated. H-BEA-92.5, which contained many silanol groups, showed the highest conductivity of 1.1 × 10−1 S cm−1 at 95 °C in a 10,000 ppm NaCl aqueous solution. After controlling the amount of surface silanol groups by calcination or dealumination, zeolites with a relatively large number of surface silanol groups showed the highest conductivity in water. The improvement of conductivity with zeolite in water was also observed for zeolite-related materials with surface silanol groups. Therefore, we conclude that surface silanol groups play an important role in increasing the conductivity of solution with zeolite in water. Furthermore, it was revealed that the mechanism of conduction was similar to the Grötthuss mechanism because of its apparent activation energy.

Ultra-low pressure cellulose-based nanofiltration membrane fabricated on layer-by-layer assembly for efficient sodium chloride removal

Cellulose is a renewable, biodegradable, biocompatible, and sustainable material. A bamboo cellulose-based nanofiltration membrane (LBL-NF-CS/BCM) was prepared with a combination of layer-by-layer assembly and spraying methods. The chemical structure, morphology, and surface charge of the resultant LBL-NF-CS/BCM composite membranes were characterized based on Thermo Gravimetric Analysis (TGA), X-ray diffraction (XRD), Scanning Electron Microscopy (SEM), Atomic Force Microscopy (AFM), and X-ray Photoelectron Spectroscopy Scanning (XPS). The nanofiltration performance of the LBL-NF-CS/BCM composite membranes was evaluated using 500 ppm NaCl solutions under 0.3 MPa pressure. It was found that the LBL-NF-CS/BCM composite membranes had a rejection rate of about 36.11 % against a 500 ppm NaCl solution under the conditions tested, and membrane flux of about 12.08 L/(m2 h) was reached. The combined layer-by-layer assembly and spraying provides a scalable and convenient process concept for nanofiltration membrane fabrication.