渗透水化对饱和页岩吸水的影响

现场统计资料显示,页岩储层压裂施工后大量压裂液无法返排至地面。这些压裂液在地层中的滞留问题引发了环保及生产相关的争议。一些学者怀疑这些含有化学添加剂的漏失液会迁移到地下水层污染地下水。同时由于页岩吸水膨胀,一些学者认为漏失液会引起近井地带渗透率降低从而使油气井生产一段时间后产能骤降。但也有现场研究表明这些漏失液在焖井一段时间后会引起气井初期产气量增加。为了清楚地解释这些问题,学者们注意到了页岩中一种独特的吸水机理——渗透水化。渗透水化作用导致页岩中的渗流过程除了受注入压差的影响,还会受到孔隙中水溶液的离子浓度的影响,使得原有的达西公式不再适用于页岩地层中。本研究通过对达西公式进行修正,建立了考虑渗透水化的饱和页岩吸水的数学模型,并给出了在常见初始、边界条件下的一维模型的解析解,得到了在页岩吸水过程中,其孔隙流体压力、浓度的变化。研究发现渗透水化的存在会对水压的变化产生影响,即两种吸水方式间存在耦合关系。也就是说,渗透水化除了通过浓度差引起页岩吸水,也会通过影响水压进而影响吸水。这两种吸水过程作用方向相反且在很大程度上相互抵消,故对总吸水量影响不大。此外,在页岩吸水的初期,吸水量的增长主要由水压传递引起;而在吸水后期,吸水量的变化主要由渗透水化导致。由于浓度扩散的速度远远低于压力传递的速度,渗透水化的存在会显著延长渗流平衡时间。

大尺寸蒙脱石纳米片渗透水化剥离及调控机制

大尺寸的蒙脱石纳米片对于制备二维蒙脱石功能复合材料具有重要意义。采用原子力显微镜、透射电子显微镜和X射线衍射仪等方法研究了蒙脱石在渗透水化过程中的剥离行为,通过电导率分析和分子动力学模拟揭示了渗透水化剥离蒙脱石的机理,蒙脱石的剥片主要是在层间阳离子与外界水之间的渗透压作用下发生,进一步揭示了蒙脱石渗透水化过程中透析水量和悬浮液质量分数调控二维剥离的作用机制。结果表明:在渗透水化过程中,蒙脱石的片层厚度逐渐减小,但其片径尺寸并未遭到严重破坏,从而成功制备了大尺寸的二维蒙脱石纳米片。渗透水化制备的二维蒙脱石的厚度可达到超声剥离的效果,片径尺寸约为超声剥离的2倍以上。

Water and Heavy Metal Transport in Roadside Soils

Roads with very high traffic loads in regions where soils are low in both pH and sorption capacity might be a source of percolation water loaded with heavy metals. Looking at some "worst case" scenarios, this study focused on the input of traffic related pollutants and on Pb, Cd, Cu, Zn, Ni and Cr concentrations in the soil matrix and soil solution, respectively. The analysis also included pH and electrical conductivity and at some sites DOC. The investigations were carried out on sandy soils with more or less low pH values at four motorway sites in Germany. The average of daily traffic was about 50 000 up to 90 000 vehicles. Soil pore water was collected in two soil depths and at four distances from the road. The pH in general decreased with increasing distance from the roadside. The elevated pH near the roadside was presumably caused by deposition of dust and weathering residues of the road asphalt, as well as by infiltration of salt that was used during winter time. At these road sites, increased heavy metal concentrations in the soil matrix as well as in the soil solution were found. However, the concentrations seldom exceeded reference values of the German Soil Protection Act. The soil solution concentrations tended to increase from the road edge to 10 m distance, whereas the concentration in the soil matrix decreased. Elevated DOC concentrations corresponded with elevated Cu concentrations but did not substantially change this tendency. High soil water percolation rates were found near the roads. Thus, even low metal concentrations of percolation water could yield high metal loads in a narrow area beside the road.

Membrane Engineering for Green Process Engineering

Green process engineering, which is based on the principles of the process intensification strategy, can provide an important contribution toward achieving industrial sustainable development. Green process engineering refers to innovative equipment and process methods that are expected to bring about substan- tial improvements in chemical and any other manufacturing and processing aspects. It includes decreasing production costs, equipment size, energy consumption, and waste generation, and improving remote con- trol, information fluxes, and process flexibility. Membrane-based technology assists in the pursuit of these principles, and the potential of membrane operations has been widely recognized in the last few years. This work starts by presenting an overview of the membrane operations that are utilized in water treatment and in the production of energy and raw materials. Next, it describes the potential advantages of innovative membrane-based integrated systems. A case study on an integrated membrane system （IMS） for seawa- ter desalination coupled with raw materials production is presented. The aim of this work is to show how membrane systems can contribute to the realization of the goals of zero liquid discharge （ZLD）, total raw materials utilization, and low energy consumption.

Pervaporation Separation of Butanol-Water Mixtures Using Polydimethylsiloxane/Ceramic Composite Membrane

Pervaporation has attracted considerable interest owing to its potential application in recovering biobutanol from biomass acetone-butanol-ethanol (ABE) fermentation broth. In this study, butanol was recovered from its aqueous solution using a polydimethylsiloxane (PDMS)/ceramic composite pervaporation membrane. The effects of operating temperature, feed concentration, feed flow rate and operating time on the membrane pervaporation performance were investigated. It was found that with the increase of temperature or butanol concentration in the feed, the total flux through the membrane increased while the separation factor decreased slightly. As the feed flow rate increased, the total flux increased gradually while the separation factor changed little. At 40°C and 1% (by mass) butanol in the feed, the total flux and separation factor of the membrane reached 457.4 g·m?2·h?1 and 26.1, respectively. The membrane with high flux is suitable for recovering butanol from ABE fermentation broth.

Development and Extension of Seawater Desalination by Reverse Osmosis

Seawater desalination has been peoples fond dream since ancient times, the dream is now becoming a reality. This paper presents a brief development history of reverse osmosis. Much attention was paid to innovative development in membranes, modules, equipments and applied technology, including asymmetric and composite membranes, spiral-wound element and hollow fiber module, energy recovery equipments and different technological processes. The extension of reverse osmosis, such as desalination, pre-concentration, integrated processes and nanofiltration, is also briefly mentioned.

Fabrication of graphene oxide composite membranes and their application for pervaporation dehydration of butanol

As a new kind of2D nanomaterials, graphene oxide （GO） with 2-4 layers was fabricated rio a modified Hummers method and used for the preparation ofpervaporation （PV） membranes. Such GO membranes were prepared via a facile vacuum-assisted method on anodic aluminium oxide disks and applied for the dehydration of butanol. To obtain GO membranes with high performance, effects of pre-treatments, including high-speed centrifugal treat- ment of GO dispersion and thermal treatment of GO membranes, were investigated. In addition, effects of operation conditions on the performance of GO membranes in the PV process and the stability of GO membranes were also studied. It is of benefit to improve the selectivity of GO membrane by pre-treatment that centrifuges the GO dispersion with 10000 r· min^- 1 for 40 min, which could purify the GO dispersion by removing the large size GO sheets. As prepared GO membrane showed high separation performance for the butanol/water system. The separation factor was 230, and the permeability was as high as 3.1 kg·m^- 2·h^-1 when the PV temperature was 50 ℃ and the water content in feed was 10% （by mass）. Meanwhile, the membrane still showed good stability for the dehydration of butanol after running for 1800 min in the PV process. GO membranes are suitable candidates for butanol dehydration via PV process.

Increased intestinal macromolecular permeability and urine nitrite excretion associated with liver cirrhosis with ascites

AIM： To determine intestinal permeability, the serum tumor necrosis factor （TNF）-α level and urine nitric oxide （NO） metabolites are altered in liver cirrhosis （LC） with or without ascites. METHODS： Fifty-three patients with LC and 26 healthy control subjects were enrolled in the study. The intestinal permeability value is expressed as the percentage of polyethylene glycol （PEG） 400 and 3350 retrieval in 8-h urine samples as determined by high performance liquid chromatography. Serum TNF-α concentrations and urine NO metabolites were determined using an enzyme-linked immunosorbent assay （ELISA） and Greiss reaction method, respectively. RESULTS： The intestinal permeability index wassignificantly higher in patients with LC with ascites than in healthy control subjects or patients with LC without ascites （0.88 ± 0.12 vs 0.52 ± 0.05 or 0.53 ± 0.03, P 〈 0.05） and correlated with urine nitrite excretion （r = 0.98）. Interestingly, the serum TNF-α concentration was significantly higher in LC without ascites than in control subjects or in LC with ascites （198.9 ± 55.8 pg/mL vs 40.9 ± 12.3 pg/mL or 32.1 ± 13.3 pg/mL, P 〈 0.05）. Urine nitrite excretion was significantly higher in LC with ascites than in the control subjects or in LC without ascites（ 1170.9± 28.7 μmol/L vs 903.1 ± 55.1 μmol/L or 956.7 ± 47.7 μmol/L, P 〈 0.05）. COMCLUSIOM： Increased intestinal macromolecular permeability and NO is probably of importance in the pathophysiology and progression of LC with ascites, but the serum TNF-α concentration was not related to LC with ascites.

Integral PVA-PES Composite Membranes by Surface Segregation Method for Pervaporation Dehydration of Ethanol

A facile surface segregation method was utilized to fabricate poly（vinyl alcohol）-polyethersulfone （PVA-PES） composite membranes. PVA and PES were first dissolved in dimethyl sulfoxide （DMSO）, then casted on a glass plate and immersed in a coagulation bath. During the phase inversion process in coagulation bath, PVA spontaneously segregated to the polymer solution/coagulation bath interface. The enriched PVA on the surface was further crosslinked by glutaraldehyde. Scanning electron microscopy （SEM）, X-ray photoelectron spectroscopy （XPS） and energy dispersive spectrometer （EDS） confirmed the integral and asymmetric membrane structure with a dense PVA-enriched surface and a porous PES-enriched support, as well as the surface enrichment of PVA. The coverage fraction of the membrane surtace by PVA reacned up to 86.8% when me PVA content m me membrane recipe was 16.7% （by mass）. The water contact angle decreased with the increase of PVA content. The effect of coagulation bath type on membrane structure was analyzed. The membrane pervaporation performance was evaluated by varying the PVA content, the annealing temperature, feed concentration and operation temperature. The membrane exhibited a fairly good ethanol dehydration capacity and long-term operational stability.

Process Design of Continuous-Flow Pervaporation Separation for Alcohol Dehydration

The separation characteristics of the PVA-CS (polyvinyl alcohol-chitosan) blended composite membrane for dehydration of ethanol-water mixture are examined. The relationships of flux and separation factor with the feed concentration and operation temperature are established. Using this correlated equation, the continuous-flow pervaporation process about 500 kilolitres/year dehydrated ethanol is designed. The numbers of stage and reheater are calculated by stage-by-stage method for two kinds of cascades: one with equal membrane area and the other with 10℃ of temperature decrement per section. The results show that when the numbers of stage and reheater are the same, the cascade with 10℃ of temperature decrement has more advantages than that with equal membrane area. The influences of feed concentration and flow rate on the numbers of stage and reheater in the cascades are discussed.

Pervaporation of Aqueous Solution of Acetaldehyde Through ZSM-5 Filled PDMS Composite Membrane

Hydrophobic ZSM-5 zeolite filled polydimethylsiloxane （PDMS） composite membranes with Nylon micro-filtration membrane as the support layer were prepared to separate acetaldehyde from its aqueous solution. The composite membranes were characterized by Fourier transform infrared spectroscopy and X-ray diffraction. Their structural morphology and thermal stability were also examined. The swelling study showed that the composite membranes presented higher degree of swelling in aqueous solution of acetaldehyde than in pure water at 25℃,

Economic and Technical Analysis of a Reverse-Osmosis Water Desalination Plant Using DEEP-3.2 Software

Reverse osmosis （RO） is proved to be the most reliable, cost effective, and energy efficient in producing fresh water compared to other desalination technologies. It is the fastest-growing desalination technology with a greater number of installations around the world. The economic and technical performance of a medium-capacity RO desalination plant （2,000 m^3/day） proposed to be installed in Umm Qasr city south of Basra, Iraq is analyzed using DEEP-3.2 software created by the International Atomic Energy Agency （IAEA）. This port city is located on the Gulf shore and does not have any fresh water resources. The analysis shows that the cost of fresh water produced by this plant is US$0.986/m^3 with a good quality of fresh water （279 ppm）, which is a reasonable price for this remote area. The analysis also shows an increase in water production cost of about 12% at increased electricity price from 0.06 to 0.1 US$/kWh, 53% when the seawater salinity increased from 35,000 to 45,000 ppm, 2.5% when the seawater temperature decreased from 33 ℃ to 20 ℃, and 0.71% when the interest rate increased from 0% to 5%. Pumping fresh water from the Basra purification plant （located 175 km north of Umm Qasr） is 22.16 times the cost and 236.7% poorer quality than the fresh water produced by the RO plant.

Changes in growth and osmoregulation during acclimation to saltwater in juvenile Amur sturgeon Acipenser schrenckii

We evaluated the ability of juvenile Amur sturgeon (Acipenser schrenckii) to osmoregulate and grow in saltwater. Hatchery-reared juveniles (mean weight 106.8 g, 5-month old) were transferred from freshwater to 10, 20, and 25 salinity saltwater over a period of 20 d. We measured the growth, serum osmolality, ion concentrations, and Na+/K+-ATPase activity. In addition, we prepared samples of gill tissue to quantify morphological changes in gill ultrastructure. Rearing in up to 25 saltwater for 30 d had no significant effect on growth. Similarly, serum osmolality and ion concentrations were similar to levels reported in other teleosts following acclimation to saltwater. Serum osmolality and Na+, Cl- concentrations increased significantly with the initial increase in salinity. Afterwards, levels tended to stabilize and then decrease. Serum K+ levels did not change during acclimation to saltwater. Gill Na+/K+-ATPase activity increased initially as salinity was increased. However, the activity later decreased and, finally stabilized at 3.7±0.1 μmol Pi/mg·prot·h in 25 saltwater (1.6 times higher than the level in those in freshwater). In fish that were held only in freshwater, the chloride cells were located in the interlamellar regions of the filament and at the base of the lamella. Following acclimation to 25 saltwater for 30 d, the number and size of chloride cells increased significantly. Our results suggest that juvenile Amur sturgeon is able to tolerate, and grow in, relatively high concentrations of saltwater.

Pretreatment of Isopropanol Solution from Pharmaceutical Industry and Pervaporation Dehydration by NaA Zeolite Membranes

NaA zeolite membranes with 80 cm in length and 12.8 mm in outer diameter were prepared by our research group cooperating with Nanjing Jiusi Hi-Tech Co., China. The influence of dissolved inorganic salts and pH value in the feed of isopropanol （IPA） solution on NaA zeolite membranes was investigated. It was found that both factors exhibited strong influence on the stability of NaA zeolite membranes. A set of pretreatment steps such as pH adjustment and distillation of the IPA solution were proposed to improve stability for pervaporation dehydration. An industrial-scale pervaporation facility with 52 m2 membrane area was built to dehydrate IPA solution from industrial cephalosporin production. The facility was continuously operated at 368-378 K to dehydrate IPA solution from water mass content of 15%-20% to less than 2% with a feed flow rate of 400-500 L·h^-1 and an average water flux of 1-1.5 kg·m^-2·h-1. The successful application of this facility suggested a promising application of NaA zeolite mem-brane for IPA recovery from pharmaceutical production.

Enhancing the separation performance by introducing bioadhesive bonding layer in composite pervaporation membranes for ethanol dehydration

A high performance composite membrane was prepared under the inspiration of bioadhesion principles for pervaporative dehydration of ethanol.Chitosan(CS)and polyacrylonitrile(PAN)ultrafiltration membranes were used as the active layer and the support layer,respectively.Guar gum(GG),a natural bioadhesive,was introduced as the intermediate bonding layer to improve the separation performance and stability of the fabricated CS/GG/PAN composite membranes.The contact angle of the GG layer was just between those of the CS layer and the PAN layer,minimizing the difference of hydrophilicity between the active layer and the support layer.The peeling strength of the composite membrane was significantly enhanced after the introduction of the GG layer.The effects of preparation conditions and operation conditions including GG concentration,operating temperature and ethanol concentration in feed on the pervaporation performance were investigated.The as-fabricated CS/GG/PAN composite membrane showed the optimum performance with a permeation flux of up to804 g·m-2·h-1and a separation factor higher than 1900.Besides,the composite membranes exhibited a desirable long-term operational stability.

Cascaded Simultaneous Nitrification and Denitrification Process for Nitrogen and Phosphorus Reduction from RO Reject Wastewater： A Bench-Scale Study

The use of the reverse osmosis （RO） process, for refining secondary or tertiary effluent from plants treating domestic wastewater, is rapidly increasing. However, the disposal of the RO reject water poses a problem due to the presence of very high concentrations of salts, metals, and nutrients in it. This paper contains results of a bench-scale study aimed at reducing nutrients from RO-discarded streams utilizing a sequential bioreactors system, under partial aerobic and anoxic conditions. The tests were performed on synthetic wastewater resembling RO-reject water of an operating treatment plant, with glucose, methanol or acetate added to the water as sources of carbon. Study results indicate that the RO process removed about 50-60% of the total nitrogen and 50% of the phosphate; it reduced chemical oxygen demand （COD） by 79 to 82%, and affected no change in the metal concentrations. A clear cut removal preference for any one of the external carbon sources was not observed, although a slight advantage of glucose and methanol was recorded. The process maintained about 20% of the rector volume in the anoxic environment.

Enhancing Structural Stability and Pervaporation Performance of Composite Membranes by Coating Gelatin onto Hydrophilically Modified Support Layer

The interfacial compatibility of composite membrane is an important factor to its structural stability, andseparation performance. In this study, poly （ether sulfone） （PES） support layer was first hydrophilically modified with poly（vinyl alcohol） （PVA） via surface segregation during the phase inversion process. Gelatin （GE） was then cast on the PVA-modified PES support layer as the active layer followed by crosslinking to fabricate composite membranes for ethanol dehydration. The enrichment of PVA on the surface of support layer improved interfacial compatibility of the as-prepared GE/PVA-PES composite membrane. The water contact angle measurement and X-ray photoelectron spectroscopy （XPS） data confirmed the surface segregation of PVA with a surface coverage density of -80%. T-peel test showed that the maxima/force to separate the support layer and the active layer was enhanced by 3 times compared with the GE/PES membrane. The effects of PVA content in the support layer, crosslinking of GE active layer and operating parameters on the pervaporative dehydration performance were investigated. The operational stability of the composite membrane was tested by immersing the membrane in ethanol aqueous solution for a period of time. Stable pervaporation performance for dehydration of 90% ethanol solution was obtained for GE/PVA-PES membrane with a separation factor of -60 and a permeation flux of -1910 g.m^-2.h1 without peeling over 28 days immersion.

Other Seawater Desalination Method

This method of desalination is based as the previous one, i.e. It applies the possibilities of the laws of inorganic chemistry precisely the laws of the precipitation to desalinate any water containing salt, with priority for seawater the most abundant source of water on our planet. It is good to remember that the industry always has used these laws for the preparation of certain compounds. As the above method, rather than consume energy such as reverse osmosis, distillation, electrodialysis, it requires no energy. On the contrary recycling products used delivers power.

The intercultural awareness in Korean Teaching

Language is the carrier of culture. We should not only focus on skills in teaching Korean culture, but also conduct a comprehensive analysis and guidance to penetrate culture and education of Korea in the teaching process. Which enhance the overall level. This thesis analyze and elaborate the characteristics of Korean teaching intercultural education. What＇ s more, it will propose corresponding solutions in penetration problems of culture and education for the Korean teaching.