In-situ synthesis of high thermal stability and salt resistance carbon dots for injection pressure reduction and enhanced oil recovery

Carbon dots(CDs)show great potential as a new type of oil-displacing agent for unconventional oil and gas development.However,the instability and easy aggregation epitomize the challenges that accompany the application of CDs in high temperature and high salinity(HT/HS)reservoirs.In this research,novel benzene sulfonate-modified carbon dots(BS-CDs)with remarkable thermal stability and salt resistance were fabricated through an in-situ electrochemical exfoliation method.Molecular simulation verifies that the introduction of benzene sulfonate groups substantially strengthens the electrostatic repulsion between BS-CDs,leading to outstanding dispersibility and stability even at a temperature of 100℃ and salinity of 14×10^(4) mg/L.Core flooding tests show that 0.05 wt.%BS-CDs nanofluid can significantly reduce the water injection pressure by 50.00%and enhanced oil recovery(EOR)to 68.39%under HT/HS conditions.According to the atomic force microscopy(AFM)scanning results,the adhesion force between the core(after BS-CDs treatment)and oil decreased by 11.94 times,indicating that the hydrophilicity of the core surface was increased.In addition,the distribution of the adhesion force curve is more concentrated,which means that the micro-scale wettability of the core changes from oil-wet to more homogeneous water-wet.This study provides a feasible way for the development and application of good thermal stability and salt resistance CDs in unconventional reservoir development.

Characterization of salt tolerance and Fusarium wilt resistance of a sweetpotato mutant

The variant LM1 was previously obtained using embryogenic cell suspension cultures of sweetpotato variety Lizixiang by gamma-ray induced mutation, and then its characteristics were stably inherited through six clonal generations, thus this mutant was named LM1. In this study, systematic characterization of salt tolerance and Fusarium wilt resistance were performed between Lizixiang and mutant LM1. LM1 exhibited significantly higher salt tolerance compared to Lizixiang. The content of proline and activities of superoxide dismutase（SOD） and photosynthesis were significantly increased, while malonaldehyde（MDA） and H_2O_2 contents were significantly decreased compared to that of Lizixiang under salt stress. The inoculation test with Fusarium wilt showed that its Fusarium wilt resistance was also improved. The lignin, total phenolic, jasmonic acid（JA） contents and SOD activity were significantly higher, while H_2O_2 content was significantly lower in LM1 than that in Lizixiang. The expression level of salt stress-responsive and disease resistance-related genes was significantly higher in LM1 than that in Lizixiang under salt and Fusarium wilt stresses, respectively. This result provides a novel and valuable material for improving the salt tolerance and Fusarium wilt resistance of sweetpotato.

Alleviative effects of Bacillus coagulans strains on irritable bowel syndrome-unraveling strain specificity through physiological and genomic analysis

The high intraspecies heterogeneity of Baciillus coagulans leads to significant phenotypic differences among different strains.Thus,6 B.coagulans strains were tested in the present study using an irritable bowel syndrome(IBS)animal model to determine whether the IBS-alleviating effects of B.coagulans strains are strain-specific.The results of this study showed that the ingestion of B.coagulans GBI-30,6086,and B.coagulans CCFM1041 significantly alleviated IBS symptoms in mice.In contrast,other B.coagulans strains showed no or limited alleviating effects on IBS symptoms.According to our experimental results,the two main common features of these strains were as follows:1)The resistance of vegetative cells to bile salts,and 2)ability to synthesize specific lipids and secondary metabolites.Screening strains based on these two indicators may greatly reduce costs and provide a basis for mining new functional B.coagulans strains.Our results also suggest that administration of B.coagulans could significantly regulate microbiota dysbiosis in animal models.Moreover,the close relationships between the gut microbiota,gut microbiota metabolites,and IBS were further confirmed in this study.

PHYSIOLOGY OF WOODY PLANT UNDER SALT CONDITION

Some advances in researches on the physiology of woody plants under salt condition are reviewed. The salt tolerant woody plants can be divided into two main groups. glycophytes and halophyes. They have different mechanisms for maintaining normal metabolism under salt condition. Halophytes usually are salt accumulators and glycophytes are salt excludors. However,the criteria for salt exclusion is not always coear. Although salt responses of different types of woody plants ard not the same some major changes are identilied identilied in net photosynthesis rate and in growth.Four mechamsms are proved to be related to the salt resitance of woody plants(1) Regulation of ion intake;(2) avoidance of toxicity; (3) maintaining meinbrane mtegrity and (4) ion compartmentation. Currently,conventional plant breeding and bioteclogy are both used to improve salt tolerance of woody plant.

Research Progress in Glycine Betaine Improving Plant Salty Stressful Tolerance

Many plants accumulate compatible solutes in response to the imposition of environmental stresses.Glycine betaine, which is one of compatible solutes in cell of plants,has been shown to have surviving ability for plant from salt stress.Effect of glycine betaine on improving plant salt resistance was discussed in plants under salt stress.The accumulation of glycine betaine protects plants against the damaging effects of stress.Strategies of glycine betaine against the damaging effects of stress were analyzed to clarify the roles of glycine betaine in salt stress tolerance of plants.

Laboratory Study on 210°C High Temperature and Salt Resistant Drilling Fluid

Combined with the current research status in this area at home and abroad, with the improvement of salt and high temperature resistance as the research goal, the laboratory research of salt and high temperature resistant drilling fluid system has been carried out, and lubricants, inhibitors and stabilizers have been optimized. The final drilling fluid formula is: water + 3% sepiolite + 0.3% Na2CO3 + 3% RH-225 + 3% KCOOH + 3% G-SPH + 3% CQA-10 + 1.5% ZX-1 + Xinjiang barite, density 2.2 g/cm3, using hot-rolling furnace, environmental scanning electron microscope, high temperature and high pressure plugging instrument and Zeiss microscopes and other instruments use core immersion experiments, permeability recovery value experiments, and static stratification index methods to perform temperature resistance, reservoir protection, plugging performance, and static settlement stability performance of the configured drilling fluid., Inhibition performance, biological toxicity, salt resistance, anti-pollution performance have been tested, and it is concluded that the temperature resistance is good under the condition of 210°C, and the salt resistance can meet the requirements of 20% NaCl + 0.5% CaCl2 concentration. It has a good reservoir protection effect, the permeability recovery value can reach more than 90%, the performance of restraining water dispersion and cuttings expansion is good, the heat roll recovery rate can reach more than 85%, and the SSSI value shows that its settlement stability performance is good;Its plugging performance is good under high temperature and high pressure. It laid the foundation for the next step to promote the field application of the drilling fluid system.

Effect of Salt Spray Corrosion on Tribological Properties of HVOF Sprayed NiCr-Cr3C2 Coating with Intermediate Layer

The objective of the present work was to determine the influence of the neutral salt spray corrosion on the wear resistance of HVOF sprayed NiCr-Cr3C2 coating with intermediate layer. Ni-Zn-Al2O3 coatings as interlayers were prepared by low pressure cold spray（LPCS） between NiCr-Cr3C2 cermet coatings to form a sandwich structure to enhance the corrosion resistance properties. The tribological properties were examined using the UMT-3 fricition and wear tester by line-contact reciprocating sliding under dry and salt spray one week corrosion. The morphology, element distribution, and phase compositions of the coating and worn sufaces were analyzed by using scanning electron microscopy, energy dispersive spectrometry, and X-ray diffraction respectively. The corrosion behavior of the coating was studied by the open-circuit potential, the electrochemical impedance spectroscopy, potentiodynamic polarization, and salt spray corrosion methods. It is found that the sandwich structured coating has better corrosion resistance than the single layer coating. The results show that under dry wear conditions, the wear mechanism is abrasive and adhesive wear, whereas under salt spray corrosion conditions it becomes corrosion wear. The friction coefficient of the sandwich structured coating after salt spray corrosion is slightly lower than the dry friction coefficient, but the weight of the wear loss is lower than that under dry condition.

Salt freezing resistance improvement of cement-based materials incorporated with calcined layered double hydroxide

Salt freezing damage has severe impacts on durability of cement-based materials(CBMs).Calcined layered double hydroxide(CLDH),as an efficient environmental-friendly adsorption material,can impart excellent salt freezing resistance to CBMs.In this work,salt freezing resistance improvement of CBMs incorporated with CLDH was experimentally evaluated by chloride binding capacity,mass loss rate,relative dynamic elastic modulus,setting time,compressive strength,and micro structure tests.Beside these,the salt freezing damage model was established to effectively express the quantitative relationship between influencing factors and evaluation indexes of the salt freezing resistance of CBMs.Results show that CLDH can reconstruct its original layered structure to form reconstructed layered double hydroxide(RLDH).RLDH combines with chloride ions to form RLDH-Cl recrystallization,which can improve chloride binding capacity and pore structures of CBMs to relieve the salt freezing damage.The salt freezing damage model indicates that the suitable CLDH content can evidently alleviate the salt freezing damage,which facilitates the quantitative analysis of the effect of CLDH on the salt freezing resistance of CBMs.

疏水缔合水溶性聚合物应用于钻井液中的性能研究(英文)

Hydrophobically associating water-soluble polymers (HPAP) have been synthesized from acrylamide(AM), acrylate (AA), 2-acrylamido-2-methyl propane sulfonic acid (AMPS) and hydrophobic monomer (AP) in aqueous solution by radical polymerization. New polymer drilling fluids are made up of HPAP, which is used as viscosifiers and encapsulation agents. Properties of this system are reported in this paper. Results indicate that this system has a high value of yield point to plastic viscosity (YP/PV≥0.7), high viscosity at a low-shear rate (LSRV≥30000mPa·s), excellent shear thinning behavior, good solid-carrying behavior, resistance to shear, good thermal stability (as high as 140℃) and salt resistance. The system has excellent behavior in high-density solution of NaCl and in calcium and magnesium rich saline solutions. Hence, HPAP also can be used in saltwater polymer drilling fluids.

Synthesis and Solution Properties of Comb-like Acrylamide Copolymers

A comb-like acrylamide copolymer （HCJ-1） was synthesized by using aqueous free radical polymerization of acrylamide （AM） as main monomer and ether carboxylate as functional monomer. The copolymers were characterized with FT-IR and SEM. The SEM results show that the molecular structure of copolymer is extended in salt water. It is proved that the copolymer shows good salt resistance.The solution properties of HCJ-1 were studied and compared with those of partially hydrolyzed polyacrylamide （HPAM）. The experimental results show that the obtained HCJ-1, compared with HPAM, exhibits a dramatic enhancement in the salt-resistant properties. The apparent viscosity retention rate of 1.5 g/L HCJ-1 aqueous solution and salt solution after 180 days at 60 ℃ are 70.6% and 64.5%, respectively, exhibiting good thermal stability. In addition, HCJ-1 solution also displays the excellent shearing resistance. In a word, the experimental results show the HCJ-1 is a promising profiling agent for high salinity reservoir.

Genotypic Variation in Nutrient Selectivity in Populus under NaCl Stress

We used a salt-resistant poplar genotype Populus euphratica and two salt-sensitive genotypes, Populus 'popularis 35-44' (P. popularis) and the hybrid P. talassica Kom x (P. euphratica + Salix alba L.) to examine genotypic differences in nutrient selectivity under NaCl stress. One-year-old seedlings of P. euphratica and one-year-old hardwood cuttings of P. popularis were used in a short-term study (24 hours), while in a long-term study, up to 4 weeks, two-year-old seedlings of P. euphratica and the hybrid P. talassica Kom x (P. euphratica + Salix alba L.) were compared. In the short-term study, K+ concentration in the xylem sap ([K+]xylem) of P. euphratica significantly increased after salt stress was initiated, and maintained 1-2 fold higher than control levels during the period of salt stress (24 hours). Xylem Ca2+ and Mg2+ concentrations ([Ca2+]xylem, [Mg2+]xylem) in P. euphratica resembled the pattern of K+ despite a lesser magnitude in elevation. However, [K+]xylem, [Ca2+]xylem and [Mg2+]xylem in P. popularis exhibited a transient increase at the beginning of salt treatment, thereafter, they all returned to control levels at 4 hours and no further rise was observed in the following hours. Xylem Na+/K+, Na+/Ca2+ and Na+/Mg2+ in P. popularis increased sharply upon NaCl stress and steadily reached the maximum at 24 hours. In contrast, xylem Na+/K+, Na+/Ca2+ and Na+/Mg2+ in NaCl-treated plants of P. euphratica did not significantly increase during the period of salt stress (24 hours). Noteworthy, Na+/K+ markedly declined after the onset of stress. These results suggest that P. euphratica had a higher nutrient selectivity in face of salinity. A same trend was observed in a 4-week study. Xylem Na+/K+, Na+/Ca2+ and Na+/Mg2+ in salinised plants of the hybrid abruptly increased after 4 days of stress, and then continuously increased to reach the highest level at day 8 or day 15. In comparison, the magnitude of Na+/K+, Na+/Ca2+ and Na+/Mg2+ elevation in the xylem of P. euphratica was much lower during the observation period. In conclusion, salt-tolerant genotype P. euphratica maintained a higher nutrient selectivity under saline stress, as compared to the two salt-sensitive genotypes. The high capacity for nutrient uptake and transport presumably contributes to the salt tolerance of P. euphratica in a longer term.

Study on Plugging Technology in Oil Test

In view of the shortcomings of poor temperature resistance, poor pumpability and poor pressure-bearing capacity of commonly used gel plugging materials, polyacrylamide (HPAM) and N,N-methylene bisacrylamide (BIS) were selected for crosslinking and compounding to make a new type of gel plugging material with high temperature and pressure resistance. The compressive strength and yield stress were measured by inverted observation method to evaluate the gel strength. The anti-temperature, anti-pressure, anti-dilution and gel-breaking properties of the gel were evaluated. Finally, 71 type high temperature and high pressure water loss instrument and high temperature and high pressure filter with slit plate were used to evaluate the plugging capacity of gel plugging agent. The experimental results show that the new gel plugging system between 100°C - 120°C, gelation time can be controlled at about 5 h;it has strong temperature resistance, compression resistance, dilution resistance and gel breaking performance. In the face of permeability and fracture leakage simulation experiments, when the ambient temperature below 120°C, pressure within 5 MPa, the filter loss of gel plugging agent is far less than the market two conventional plugging agent, has excellent plugging performance.

Study on a Polyamine-Based Anti-Collapse Drilling Fluid System

In complex strata, oil-based drilling fluid is the preferred drilling fluid system, but its preparation cost is high, and there are hidden safety risks. Therefore, the new progress of high-performance anti-collapse water-based drilling fluid at home and abroad is analyzed. It is difficult to prevent and control the well collapse. Once the well wall instability problem occurs, it will often bring huge economic losses to the enterprises, and the underground safety accidents will occur. In order to ensure the stability of the well wall and improve the downhole safety, the key treatment agent of water-based collapse drilling fluid is selected, the anti-collapse drilling fluid system is formulated, the evaluation method of drilling fluid prevention performance is established, and a set of water-based drilling fluid system suitable for easy to collapse strata in China is selected to ensure the downhole safety. The development trend of high performance anti-collapse water-based drilling fluid is expected to provide a reference for the research of high performance anti-collapse water-based drilling fluid system and key treatment agent.

Three-dimensional porous photo-thermal fiber felt with salt-resistant property for high efficient solar distillation

The urgent need for fresh water resource is a public issue facing the world.Solar distillation for seawater desalination is a promising freshwater production method.Interfacial solar evaporation systems based on 2 D photo-thermal membranes have been widely studied,but salt pollution is one of the main challenges for solar distillation.In order to solve this problem,a hydrophilic three-dimensional(3 D)porous photo-thermal fiber felt(PFF)was obtained by one-step method,through a simple polydopamine(PDA)coating method with hydrophobic graphite felt as a substrate.The PFF had a good evaporation rate of 1.48 kg m^(-2)h^(-1)and its corresponding light-vapor conversion efficiency reached 87.4%.In addition,the PFF exhibited an excellent salt-resistant ability when applied to photo-thermal evaporation of highsalinity seawater with 10 wt%NaCl,owing to its intrinsic 3 D macroporous structure for the migration circulation of salt ions.The development of the PFF offers a new route for the exploration of salt-re sistant photo-thermal materials and is promising for the practical application of solar distillation.

Potato Responds to Salt Stress by Increased Activity of Antioxidant Enzymes

To understand the response of potato to salt stress, antioxidant enzyme activities and ion content were analyzed for a sensitive and a tolerant cultivar. Nodal cuttings of the tolerant cultivar, Kennebec, and the sensitive cultivar, Concord, were exposed to media without or with 30, 60, 90 or 120 mmol/L NaCI for 4 weeks. On exposure to NaCI, the length and fresh and dry weight of both shoots and roots of Concord showed greater decrease than those of Kennebec. The decrease in shoot growth was more severe than that of the root for both cultivars. The K^＋ content of shoots and roots of both cultivars was reduced in a dose-dependent manner by exposure to NaCl; the Na^＋ content increased. Activities of ascorbate peroxidase, catalase and glutathione reductase were increased in NaCl-exposed shoots of Kennebec; the corresponding activities in NaCI-exposed shoots of Concord were decreased. Roots of both cultivars showed similar changes in the activities of these enzymes on exposure to NaCI. These studies established that enzyme activities in Concord shoots are inversely related to the NaCI concentration, whereas those in Kennebec do not show a dose dependency, which is also the case for the roots of both cultivars. Our findings suggest that an increase in activity of antioxidant enzymes, such as ascorbate peroxidase, catalase and glutathione reductase, can contribute to salt tolerance in Kennebec, a salt resistant cultivar of potato.

Use of catalytic wet air oxidation (CWAO) for pretreatment of high-salinity high-organic wastewater

Catalytic wet air oxidation(CWAO)coupled desalination technology provides a possibility for the effective and economic degradation of high salinity and high organic wastewater.Chloride widely occurs in natural and wastewaters,and its high content jeopardizes the efficacy of Advanced oxidation process(AOPs).Thus,a novel chlorine ion resistant catalyst Bsite Ru doped LaFe_(1-x)Ru_(x)O_(3-)δin CWAO treatment of chlorine ion wastewater was examined.Especially,LaFe_(0.85)Ru_(0.15)O_(3-δ)was 45.5% better than that of the 6%RuO_(2)@TiO_(2)(commercial carrier)on total organic carbon(TOC)removal.Also,doped catalysts LaFe_(1-x)Ru_(x)O_(3-)δshowed better activity than supported catalysts RuO_(2)@LaFeO_(3) and RuO_(2)@TiO_(2) with the same Ru content.Moreover,LaFe_(0.85)Ru_(0.15)O_(3-)δhas novel chlorine ion resistance no matter the concentration of Cl^(−) and no Ru dissolves after the reaction.X-ray diffraction(XRD)refinement,X-ray photoelectron spectroscopy(XPS),transmission electron microscope(TEM),and X-ray absorption fine structure(XAFS)measurements verified the structure of LaFe_(0.85)Ru_(0.15)O_(3-)δ.Kinetic data and density functional theory(DFT)proved that Fe is the site of acetic acid oxidation and adsorption of chloride ions.The existence of Fe in LaFe_(0.85)Ru_(0.15)O_(3-)δcould adsorb chlorine ion(catalytic activity inhibitor),which can protect the Ru site and other active oxygen species to exert catalytic activity.This work is essential for the development of chloride-resistant catalyst in CWAO.

窄能隙吸光型共轭聚苯并二噻唑:大规模界面合成及其强太阳能光热蒸发和温差发电性能

为了实现低能耗太阳能蒸发和纯净水富集,开发先进的吸光型共轭聚合物是非常重要的.本研究通过界面化学大规模合成了共轭聚苯并二噻唑微球,其带隙窄至0.274 eV,太阳光吸收率高达94.0%.由聚苯并二噻唑微球与聚乙烯醇水凝胶可组装成Janus型蒸发器.当聚苯并二噻唑微球涂布量为5 mg cm^(-2)时,自支撑Janus型太阳能蒸发器的蒸发速率和能量效率分别达到2.96 kg m^(-2) h^(-1)和98.8%.Janus型蒸发器对模拟海水、污水和酸/碱性溶液具有强效脱盐和净化性能.装配了Janus型蒸发器的便携式太阳能净水装置可将真实海水淡化至远高于饮用水标准,并将真实污水的化学需氧量净化至极低水平.Janus型蒸发器还可与温差发电模块相结合,以实现水电联产.在1个标准太阳光照下,真实海水的蒸发率和发电输出功率分别达到2.23 kg m^(-2) h^(-1)和1.04 W m^(-2),展现了优越的太阳能利用能力.

高蒸发速率的耐盐织物基全天候可用光热-电热蒸发器

太阳能驱动水蒸发是利用太阳能进行海水脱盐和清洁水生产的实用方法,具有最低的碳排放.但该方法在弱光照的阴天或夜间蒸发速率较低.本文基于光热和电热加热的耦合效应,提出了一种可以根据光照条件调节表面温度和蒸发速率的织物基全天候可用光热-电热蒸发器(P/ET-SG).由于电热层与光热层均匀的热分布,该P/ET-SG在1 V电压和1个太阳光辐照下其表面温度及蒸发速率可达52℃和2.61 kg m^(-2) h^(-1).P/ET-SG所采用的单向流体结构设计使其在连续24小时的海水脱盐过程中具备极高的耐盐性,且能除去蒸发表面的盐颗粒.此外,在高浓度盐水和污水净化中,P/ET-SG展现了高的蒸发速率(2.58 kg m^(-2) h^(-1))和净化效率(>99.9%).本文为全天候可用的高效太阳能蒸发器的设计提供了新思路,并提供了高浓度盐水和污水高效净化的新策略.

Oxalic acid cross-linked sodium alginate and carboxymethyl chitosan hydrogel membrane for separation of dye/NaCl at high NaCl concentration

Dye desalination is a challenge in the treatment of textile wastewater with high salt concentration. It is imperative to develop salt resistance membrane that is from sustainable materials to effectively treat dye/salt mixtures. And most polymer membrane materials are non-renewable petrochemical resources.In this paper, a green hydrogel membrane(CMCS-OA-Na Alg) was prepared by non-metallic ions of oxalic acid(OA) cross-linking of two natural macromolecules of sodium alginate(Na Alg) and carboxymethyl chitosan(CMCS). The membrane showed excellent anti-swelling at high salt concentration(swelling rate less than 8.0% in 10.0 wt% Na Cl solution) and good anti-fouling performance. The membrane exhibited a rejection higher than 95.0% for dyes(bright blue, direct black, direct red, and Congo red) and lower than7.0% for Na Cl, which can achieve better dye/Na Cl separation performance. This study provides a promising membrane material for high salt textile wastewater treatment only using water and carbohydrates as raw materials without any organic solvents.