A micro-crosslinked amphoteric hydrophobic association copolymer as high temperature-and salt-resistance fluid loss reducer for water-based drilling fluids

During ultradeep oil and gas drilling,fluid loss reducers are highly important for water-based drilling fluids,while preparing high temperature-and salt-resistance fluid loss reducers with excellent rheology and filtration performance remains a challenge.Herein,a micro-crosslinked amphoteric hydrophobic association copolymer(i.e.,DADC)was synthesized using N,N-dimethyl acrylamide,diallyl dimethyl ammonium chloride,2-acrylamido-2-methylpropane sulfonic acid,hydrophobic monomer,and pentaerythritol triallyl ether crosslinker.Due to the synergistic effects of hydrogen bonds,electrostatic interaction,hydrophobic association,and micro-crosslinking,the DADC copolymer exhibited outstanding temperature-and salt-resistance.The rheological experiments have shown that the DADC copolymer had excellent shear dilution performance and a certain degree of salt-responsive viscosity-increasing performance.The DADC copolymer could effectively adsorb on the surface of bentonite particles through electrostatic interaction and hydrogen bonds,which bring more negative charge to the bentonite,thus improving the hydration and dispersion of bentonite particles as well as the colloidal stability of the drilling fluids.Moreover,the drilling fluids constructed based on the DADC copolymer exhibited satisfactory rheological and filtration properties(FLHTHP=12 m L)after aging at high temperatures(up to200℃)and high salinity(saturated salt)environments.Therefore,this work provided new insights into designing and fabricating high-performance drilling fluid treatment agents,demonstrating good potential applications in deep and ultradeep drilling engineering.

STUDY ON SYNTHESIS OF AMPHOTERIC POLYACRYLAMIDE IN INVERSE EMULSION

Amphoteric polyacrylamide was prepared first by the copolymerization of acrylamide with sodium acrylate and then through Mannich reaction.The copolymerization was carried out with a redox initiation system using the method of inverse emulsion polymerization.In this paper the reaction conditions and factors that affect emulsion stability were studied.Experiments show that a stable latex can be obtained under the following conditions:anionic degree is five percent,the ratio among acrylamide,formaldehyde and dimethylamine is 1∶1∶1.2,reaction temperature is 45 ℃,reaction time lasts four hours,and pH equals 5.0.The amphoteric copolymer has a higher molecular weight and cationic degree,so it is an ideal filler retention and drainage aid in paper making.

Adsorption/desorption behavior between a novel amphoteric granular lignin adsorbent and reactive red K-3B in aqueous solutions

A novel amphoteric granular lignin adsorbent(AGLA) was prepared using magnesium lignosulfonate as a raw material which was provided by a straw sulfite pulp mill in Guangdong Province, China. A reactive dye(red K-3B) was used as an adsorbate to investigate the adsorption behavior by static and mobile ways. The removal of reactive red K-3B was found to be initially pH and concentration dependent. Moreover, an increase of solution temperature ranging from 5℃ to 60℃ helped to enhance the rate of intraparticle diffusion of adsorbate and changes in the size of the pores of the adsorbent and thus to reduce the adsorption time. The total breakthrough adsorption capacity was 531 mg/g, and the saturated adsorption capacity was 560 mg/g, which prevailed over the activated carbons evidently. The reactive red K-3B adsorbed on AGLA could be recovered with a mixture of alcohol, NaCl and HCl aqueous solutions. The recovery percentage could reach 92.4%.

Hydrogen generation with acid/alkaline amphoteric water electrolysis

To reduce the energy consumption of the electrolytic hydrogen generation process, we propose a novel approach to generate hydrogen with acidic/alkaline amphoteric water electrolysis, wherein hydrogen is produced inside an acidic solution and oxygen evolved under alkaline condition, and a membrane is employed in the middle of the electrolyzer to restrain neutralization. The electrode polarization is greatly reduced due to the specific arrangement of the acidic/alkaline amphoteric electrolyzer. The rate of hydrogen production achieves over four times higher than that of the alkaline aqueous solution at 2.2 V, and the energy consumption is reduced approximately 30% under the current density of 200 m A/cm ^2. The investigation of transmembrane potential drop indicates water splitting on the membrane surfaces, which compensates for acid or alkaline loss on-site and maintains the concentration approximately constant during electrolysis process. The acidic/alkaline amphoteric water electrolysis is promising as an energy saving, clean and sustainable hydrogen production technology.

Adsorption thermodynamics and kinetic investigation of aromatic amphoteric compounds onto different polymeric adsorbents

The adsorption behavior ofp-aminobenzoic acid and o-aminobenzoic acid onto the different polymeric adsorbents was systematically investigated as a function of the solution concentration and temperature. Experimental results indicated that the equilibrium adsorption data of the four polymeric adsorbents fitted well in the Freundlich isotherm. The adsorption capacity of multi-functional polymeric adsorbent NJ-99 was the highest, which might be attributed to the strong hydrogen-bonding interaction between the amino groups on the resin and the carboxyl group of aminobenzoic acid. The adsorption capacity of o-aminobenzoic acid onto any adsorbent was higher than p-aminobenzoic acid. Thermodynamic studies suggested the exothermic, spontaneous physical adsorption process. Adsorption kinetics results showed that the adsorption followed the pseudo-second-order kinetics model and the intraparticle mass transfer process was the rate-controlling step.

Facile fabrication of amphoteric semi-interpenetrating network membranes for vanadium flow battery applications

For improvement of vanadium redox flow battery （VRB） performance, novel amphoteric semi- interpenetrating membranes （ASIPN） were prepared using poly（ether ether ketone） （PEEK） and polysul- fone （PSf）, the former bearing sulfonic groups and the latter imidazolium. These two groups form ionic crosslinks between PEEK and PSf; meanwhile, covalent cross links were built between PSf chains with ad- dition of N-（3-aminopropyl）-imidazole. The amphoteric nature of the membrane allows facile proton and anion transport; the IPN structure and the presence of imidazolium cation effectively suppress vanadium ion crossover through the membrane. Therefore, the ASIPN based VRBs show higher Coulombic efficiency and energy efficiency than that assembled with pristine SPEEK and Nation 212 membranes. Our work demonstrates that the ASIPN membranes are promising for VRB applications.

Tangutidines A-C,Three Amphoteric Diterpene Alkaloids from Aconitum tanguticum

Three new diterpene alkaloids,tangutidines A-C(1-3),and four known alkaloids(4-7)were isolated from the whole plant of Aconitum tanguticum,from which amphoteric diterpene alkaloids(1-3)were obtained for the first time.The structures of 1-3 were elucidated by detailed interpretation of spectroscopic data,including MS and NMR data.All of them were evaluated for their cytotoxic activities.

Interface Reversible Electric Field Regulated by Amphoteric Charged Protein-Based Coating Toward High-Rate and Robust Zn Anode

Metallic interface engineering is a promising strategy to stabilize Zn anode via promoting Zn^(2+) uniform deposition.However,strong interactions between the coating and Zn^(2+) and sluggish transport of Zn^(2+) lead to high anodic polarization.Here,we present a bio-inspired silk fibroin(SF)coating with amphoteric charges to construct an interface reversible electric field,which manipulates the transfer kinetics of Zn^(2+) and reduces anodic polarization.The alternating positively and negatively charged surface as a build-in driving force can expedite and homogenize Zn^(2+) flux via the inter-play between the charged coating and adsorbed ions,endowing the Zn-SF anode with low polarization voltage and stable plating/stripping.Experimental analyses with theo-retical calculations suggest that SF can facilitate the desolvation of[Zn(H_(2)O)_(6)]^(2+) and provide nucleation sites for uniform deposition.Consequently,the Zn-SF anode delivers a high-rate performance with low voltage polarization(83 mV at 20 mA cm^(−2)) and excellent stability(1500 h at 1 mA cm^(−2);500 h at 10 mA cm^(−2)),realizing exceptional cumulative capacity of 2.5 Ah cm^(−2).The full cell coupled with Zn_(x)V_(2)O_(5)·nH_(2)O(ZnVO)cathode achieves specific energy of~270.5/150.6 Wh kg^(−1)(at 0.5/10 A g^(−1))with-99.8% Coulombic efficiency and retains~80.3%(at 5.0 A g^(−1))after 3000 cycles.

Dolomite apatite separation by amphoteric collector in presence of bacteria

Bioflotation represents one of the growing trends to enhance the selectivity of conventional flotation processes. It utilizes the micro-organisms to replace or to interact with the chemical reagents to increase the gap between surface properties of similar minerals and to enhance the separation selectivity. In this work, dolomite-phosphate separation was investigated using amphoteric collector （dodecyl-N-carboxyethyl-N-hyroxyethyl-imidazoline） in presence of bacteria. Two types of bacteria, Corynebacterium- diphtheriae-intermedius （CDI）, and Pseudomonas aeruginosa （PA）, were used. The collector-bacteria interaction was characterized by Fourier transform infra-red （FTIR）, frothing height and Zeta potential. The results show that the collector-bacteria interaction improves the flotation selectivity. Although, the PA positively affects the separation results, the CDI cannot lower the MgO to less than 1%. A phosphate content of 0.7% MgO and 31.77% P205 with a recovery of 68% at pH 11, 3.0 kg/t amphoteric collector, 4× 10^7 cells of PA is obtained.

A new long-side-chain sulfonated poly(2,6-dimethyl-1,4-phenylene oxide)(PPO)/polybenzimidazole(PBI)amphoteric membrane for vanadium redox flow battery

A new amphoteric membrane was prepared by blending long-side-chain sulfonated poly(2,6-dimethyl-1,4-phenylene oxide)(S-L-PPO)and polybenzimidazole(PBI)for vanadium redox flow battery(VRFB)application.An acid-base pair structure formed between the imidazole of PBI and sulfonic acid of S-L-PPO resulted in lowered swelling ratio.It favors to reduce the vanadium permeation.While,the increased sulfonic acid concentration ensured that proton conductivity was still at a high level.As a result,a better balance between the vanadium ion permeation(6.1×10^-9 cm^2·s^-1)and proton conductivity(50.8 m S·cm^-1)in the S-L-PPO/PBI-10%membrane was achieved.The VRFB performance with S-L-PPO/PBI-10%membrane exhibited an EE of 82.7%,which was higher than those of pristine S-L-PPO(81.8%)and Nafion 212(78.0%)at 120 m A·cm^-2.In addition,the S-LPPO/PBI-10%membrane had a much longer self-discharge duration time(142 h)than that of Nafion 212(23 h).

SYNTHESIS AND CHARACTERIZATION OF AMPHOTERIC HYDROGELS BASED ON N-CARBOXYETHYLCHITOSAN

New amphoteric hydrogels based on carboxyethylchitosans (CECH) with various degrees of substitution (DS) were prepared using different amounts of epichlorohydrin (ECH) as the crosslinking agent. The equilibrium swelling ratio (SW) was determined as functions of pH and salt concentration. The hydrogels show typical amphoteric character responding to pH change of the external medium. At isoelectric point (IEP), the hydrogels shrink. The DS value has important effect on the swelling properties of the hydrogels. When the DS of N-carboxyethylchitosan increases from 0.32 to 0.72, the equilibrium swelling ratio (SW) of the hydrogel changes from 76 to 290 at pH 7.3 and from 117 to 499 at pH 11.3. A marked volume decrease was observed in hydrogels with increasing salt concentration in the surrounding solution. The viscoelastic properties of the hydrogels were studied by oscillatory shear measurements under small-deformation conditions. The elastic modulus G' of all the samples has no dependence on frequency and is one order of magnitude larger than the loss modulus G '', corresponding to a strong gel behavior.

THE SPECTROPHOTOMETRIC STUDY ON THE INTERACTION BETWEEN AMPHOTERIC SURFACTANT AND ANIONIC DYE

The interaction of an amphoteric surfactant, N-12alkylbetaine, and an acid dye in aqueous solution was studied by spectrophotometry. The results of the experiments show that the particle of dye interacts with one or several N-12alkylbetaine molecules when the concentration of the surfactant is less than the CMC. The aggregated dyes are disintegrated when the surfactant concentration is more than the CMC, and the individual dye ion interacts with the suffactant micelle.

INTERACTION MECHANISM OF AMPHOTERIC COLLECTOR-I WITH METALLIC IONS AND MINERALS

The electronic structure and bonding nature of adsorbing bonding complexes which consist of Amphoteric Collector-I and Mg^(2+), Ca^(2+), MgPO_4^-, CaPO_^-4, CaCO_3, as well aa MgCO_3, are studied using quantum chemistry CNDO/2, It is predicted that magnesium salts are more liable to form adsorbing chelates with Amphoteric Collector-I than calcium salts, and all results coincide with that obtained in flotation.

Interactions Mode of Amphoteric Molecules with Ordered Phospholipid Membrane

Aim To explore interaction mode between amphoteric molecules with the orderedphospholipid membrane. Methods Membrane interactions were determined by immobilized artificialmembrane (IAM) chromatography and solutes' hydrophobicity was measured by n-octanol/buffer system.Results The ampholytes, similar to bases, generally exhibited higher membrane affinity than expectedfrom their hydrophobicity, resulting from the attractive polar interaction with phospholipidmembrane. Furthermore, the strength of additional polar interaction with membrane (Δlg k_(IAM)) wasthen calculated. The Δlg k_(IAM) values were far greater for bases and ampholytes ranging from0.50 - 1.39, than those for acids and neutrals with the scope from - 0.55 - 0.44. ConclusionConsidering the microspecies distribution of amphoteric molecules, it was assumed that not onlyneutral and positive but also zwitterionic microspecies are capable of partitioning into orderedamphoteric lipid membrane with complementarily conformational and energetically favorableinteractions.

新型两性离子粘土稳定剂的制备及其性能研究

以丙烯酰胺(AM)、二甲基二烯丙基氯化铵(DMDAAC)、2-丙烯酰胺基-2-甲基丙磺酸(AMPS)和N-乙烯基吡咯烷酮(NVP)为反应单体,以过硫酸胺、亚硫酸氢钠为引发剂,制备了一种新型的两性离子粘土稳定剂,并采用红外光谱对其结构进行了表征。结果表明,在40℃下,当引发剂加量为0.55%,AM∶AMPS∶DMDAAC∶NVP物质的量比为160∶20∶13∶2,反应时间为3 h时,所制备的四元共聚物AM/AMPS/DMDAAC/NVP防膨率可达90.74%,具有良好的耐温耐盐性及耐酸碱性能,可以有效防止粘土水化膨胀、分散运移,有利于降低采油成本,在油气田领域具有良好的应用潜力。

纳米流体和两性表面活性剂改善钻井液性能实验研究

本文研究了碳化硅纳米流体和表面活性剂对水基钻井液物理和化学性质(热稳定性、黏度、表面张力和滤失特性)的影响。将碳化硅纳米流体、表面活性剂溶液和水基钻井液混合形成表面活性剂——碳化硅(Si C)钻井液,分别用流变仪、张力仪和压滤机对混合钻井液的黏度、表面张力和滤失性等性质进行了研究。实验结果表明,与常规表面活性剂相比,两性表面活性剂对钻井液黏度的增量最大,此外,混合钻井液具有更好的热稳定性,随着温度的升高,黏度平均变化率为9%,表面张力和滤失性分别下降了31.0%和22.2%。

论《文学概论》“金课”建设

2018年教育部已提出建设中国“金课”的要求,但到目前为止,汉语言文学专业核心基础课程《文学概论》的“金课”建设研究尚未可见。基于“金课”“两性一度”的标准,建设《文概》金课可采九项具有可行性的举措。如结合学生自己的文学创作与文学评论阐释文学理论知识,同时指导学生提升作品、推荐参加省级以上的相关竞赛,以赛促学,利用“切身性”充分调动学生的学习积极性;教师在系统讲授相关版块知识后,精选相关前沿、权威、难易适中的学术论文,抽出约40%的课堂时间,要求学生课后分组合作探究、人人参与、制作PPT并在课堂上展示,训练学生的高级思维与综合能力;从教学内容到课堂状态全方位融入课程思政元素,等等。

耐盐两性聚丙烯酰胺的合成及其性能评价

以丙烯酰胺(AM)、2-丙烯酰胺基-2-甲基丙磺酸(AMPS)、二甲基二烯丙基氯化铵(DMDAAC)为单体制备两性聚丙烯酰胺AMPAM,测试耐盐性能。结果表明,AMPAM在20000 mg/L的NaCl溶液、10000 mg/L的CaCl_(2)溶液中,仍能保持10 mPa·s以上的黏度。对不同矿化度下0.5%浓度AMPAM溶液,使用SEM扫描电镜对其微观形貌的变化进行了观察,由于分子间引力和斥力的严重削弱,分子链开始靠拢、卷曲,形成大量的分子簇,最终形成完整的块状结构,此时溶液黏度变化很小,并逐渐趋于稳定。

耐温耐盐两性聚丙烯酰胺稠化剂的制备及其性能

为了提高压裂液稠化剂的耐温耐盐性能,以丙烯酰胺(AM)、丙烯酸(AA)、阴离子单体2-丙烯酰胺-2-甲基丙磺酸(AMPS)和阳离子单体丙烯酰氧乙基三甲基氯化铵(DAC)为单体,单体AM、AA、AMPS、DAC质量比为9∶1∶3∶1.5,将单体以总质量分数为30%溶于水中(水相),将质量分数为10%的乳化剂(Span-80、Tween-80质量比为9∶1)溶于白油(油相),油水相比为1∶2.5,合成了具有耐温耐盐性的油包水乳液稠化剂PAAD,其黏均相对分子质量为383×10^(4)。通过红外光谱和核磁共振氢谱表征了PAAD,测定了聚合物PAAD的耐温性、抗盐性、耐剪切和破胶性能。研究结果表明,PAAD具有良好的耐温抗剪切性能,在90℃、剪切速率为170 s^(-1)下,质量分数为1.5%的PAAD聚合物溶液剪切1.5 h后黏度保持在51.7 mPa·s。PAAD溶液在高剪切后进入低剪切区后可快速恢复黏度,可保障悬砂不沉降。PAAD具有良好的抗盐性,在矿化度为50 g/L的模拟高盐海水中,质量分数为1.5%的PAAD聚合物溶液的黏度为45 m Pa·s。在90℃下,破胶剂用量为0.2%时,质量分数为1.5%的PAAD聚合物溶液在3 h内可完成破胶,破胶液的表面张力为30 mN/m,油水界面张力为1.9 mN/m,残渣含量为220 mg/L,对岩心基质的伤害性为9%,达到行业标准要求。

EDTA滴定法准确测定钢铁除锈废酸中锌离子含量

针对钢铁除锈的废酸综合利用过程中锌离子含量不能准确测定的问题,本文提出了一种利用pH控制沉降铁离子,采用EDTA滴定法准确测定钢铁除锈废酸中的锌离子含量的方法,并通过多项式拟合,得到锌离子含量的拟合曲线的回归方程。研究分析了Fe^(3+)、Fe^(2+)对测量结果的影响,提出了解决方法,同时发现加入聚丙烯酰胺(PAM)做絮凝剂可加快Fe^(3+)的沉降。本方法可为此类废酸的综合利用提供检测依据。