Weak Alkali Research Articles

A highly sensitive fluorescent probe for ozone based on coumarin-benzothiazole derivative

Ozone is widely used in daily life, but studies have shown that O3 can damage human trachea and lungs, leading to diseases such as asthma, emphysema, and bronchitis. Therefore, it is of great significance to develop a simple and efficient detection method for monitoring O3 in living cells. In this study, 3-(but-3-en-1-yl)-2-(7-(but-3-en-1-yloxy)-2-oxo-2H-chromen-3-yl)benzo[d]thiazol-3-ium (BCT) as a new type of water-soluble fluorescent probe was synthesized by substitution reaction of 4-bromo-1-butene and hydroxycoumarin-benzothiazole derivatives, which can specifically detect ozone in aqueous solution. The interaction of ozone on the probe can be completed within 20 min, the fluorescence intensity is significantly enhanced, and it has the advantages of high sensitivity (detection limit LOD = 43 nM). The influence of pH on the fluorescent performance of BCT shows that the probe with super stability under weak alkali and acidic environment, which provides the necessary conditions for its detection of ozone in physiological system detection. Therefore, BCT is expected to become an effective tool for detecting ozone in cellular organisms.

Versatile surface modification of millimeter‐scale “aqueous pearls” with nanoparticles via self‐polymerization of dopamine

The millimeter‐scale calcium alginate aqueous core capsules (mm‐CaSA‐Caps), which own high entrapment efficiency and excellent biocompatibility, have broad applications in food additives and drug delivery. However, due to pH sensitivity and thermal instability of Ca‐alginate, many chemical modifications with intense conditions are hardly conducted on the mm‐CaSA‐Caps. In this work, layer‐by‐layer assembly coating on the surface of the mm‐CaSA‐Caps was proceeded with in situ self‐polymerization of dopamine (DA) and nanoparticles under mild conditions. The colorless and transparent mm‐CaSA‐Caps became beautiful dark “pearls” of polydopamine (PDA) modified mm‐CaSA‐Caps (mm‐PDA@CaSA‐Caps), which had uniform coating of PDA. Obviously, deposition of PDA on mm‐CaSA‐Caps accelerated with higher concentration of DA, weak alkali condition of pH = 8.5, and oxidant of sodium periodate. Water retention ratio of mm‐PDA@CaSA‐Caps also increased because of the PDA coating. The nanoparticles were easily coated on the mm‐PDA@CaSA‐Caps due to the strong adhesive property of PDA. Two‐dimensional laminar montmorillonites were adhered to mm‐PDA@CaSA‐Caps, which lead to better barrier property of capsules than that of the one‐dimensional linear multiwalled carbon nanotubes modified capsules. It was ascribed to increasing of the path length of water by sheet‐like morphology of montmorillonites. This work provided a versatile path for enhancement of barrier property of millimeter‐scale hydrogel capsules.

CMC and CNF-based intelligent pH-responsive color indicator films integrated with shikonin to monitor fish freshness

Intelligent pH-responsive color indicator films based on carboxymethyl cellulose (CMC) and cellulose nanofibers (CNF) were prepared using shikonin extracted from Lithospermum erythrorhizon roots. The addition of shikonin did not affect the thermal stability and water vapor barrier properties of the film; however, the surface hydrophobicity increased significantly. The shikonin-added films showed high antioxidant activity, especially in aqueous solutions. The color indicator films showed a noticeable color response function for various pH values, showed reddish-pink at pH below 7, and turned reddish-purple, purple, and light blue as the pH increased from 7 to 12. When the indicator film was used to monitor the fish freshness, it showed a reddish-pink for fresh fish (pH = 5.7) and turned blue-violet after 36 h, indicating that it was spoiled (pH = 6.9). The shikonin-added color indicator films with a distinct discoloration function between a weak acid and weak alkali are likely to be applied to monitor seafood quality.

Effect of DMDHEU treatment on properties of bacterial cellulose material

The aim of this study was to estimate the influence of purification and treatment with textile finishing agent procedures on structural, mechanical, and water barrier properties of bacterial cellulose (BC) in order to predict the end-use properties. Kombucha fungus generated by Komagataeibacter xylinus species, formerly known as Gluconacetobacter xylinus, was used to produce the BC material. The BC was purified with 0.5% sodium hydroxide (NaOH) solution and treated with 5%, 10%, and 20% concentration of N, N-dimethylol 4,5-dihydroxy-ethylene urea (DMDHEU). By Fourier transform spectroscopy (FTIR) and X-ray diffractometer (XRD) was estimated, that the purification with a weak alkali solution was effective to remove amorphous matter of the BC material. Scanning electron microscope (SEM) images demonstrated the BC structure, similar to a non-woven textile fabric with clearly visible three-dimensional networks of fine cellulose fibers. After the purification process, the BC material tensile strength increased by 52%; however, the strain decreased by 93%. BC material after treatment with 20% DMDHEU regained deformability and tensile properties analogous to untreated samples. Water vapor permeability (WVP) values increased and water absorption capacity (WAC) decreased in BC material with increasing DMDHEU concentration. According to the FTIR results, the crosslinking reaction of DMDHEU and adjacent BC molecules was proved. The treatment with DMDHEU restores the amorphous properties of BC material, and therefore blocks water absorption, and the decrease in the water absorption parameter might be determined.

Discussion on comprehensive adjustment technology of weak alkali ASP flooding in stage development of second-class reservoir

The application of ASP flooding development by stages and comprehensive adjustment technology plays a very important role in the development of the second-class reservoir, which is directly related to the development effect of the second-class reservoir and also improves the development effect of the reservoir to a certain extent. In this paper, the author analyzes and studies the comprehensive adjustment technology of ASP flooding in different stages. Taking SD block as an example, the development of the second-class reservoir is expounded, and the weak alkali ASP flooding technology is applied in different stages of the development of the second-class reservoir in SD block.

Analysis on the Effective Characteristic of Different Displacement Ways of Tertiary Oil Recovery in the Class II Reservoir of Sazhong Development Zone

The first industrial tertiary oil recovery of the class II reservoir in the Sazhong Development Zone was the polymer flooding carried out in Block X at the end of 2002, and achieved noticeable effect. As the class II reservoir blocks were exploited one after another, by combining different geological structures and reservoir characteristics with distribution characteristics of remaining oil, the displacement modes successively went through polymer flooding, strong alkali ASP flooding, weak alkali ASP flooding, and salt-resistant polymer flooding, etc. Considering there are big differences in the geological structure, reservoir characteristics and layer combination of different class II reservoir blocks in the Sazhong Development Zone, and the development effects of different displacement modes are different as well; therefore, it is necessary to learn from the phased results achieved in typical blocks and leading pilot, on this basis, further conduct in-depth comparative study of the characteristics of effective rule and the changes of injection-production parameters of the class II reservoir blocks that have carried out tertiary oil recovery under different displacement modes, provide technical support and selection basis for betting modes up and down of the class II reservoir in the future, and it is of great practical significance to the realization of quality and efficiency improvement and sustainable development of the oilfield.

Effect of Sodium Benzenesulfonate on SO42− Removal from Water by Polypyrrole‐Modified Activated Carbon

Sodium benzenesulfonate was doped into polypyrrole‐modified granular activated carbon (pyrrole‐FeCl3·(6H2O)‐sodium benzenesulfonate‐granular activated carbon; PFB‐GAC) with the goal of improving the modified GAC’s ability to adsorb sulfate from aqueous solutions. At a GAC dosage of 2.5 g and a pyrrole concentration of 1 mol L−1, the adsorption capacity of PFB‐GAC prepared using a pyrrole:FeCl3·(6H2O):sodium benzenesulfonate ratio of 1000 : 1500 : 1 reached 23.05 mg g−1, which was eight times higher than that for GAC and two times higher than that for polypyrrole‐modified GAC without sodium benzenesulfonate. Adsorption was favored under acidic conditions and high initial sulfate concentrations. Doping with sodium benzenesulfonate facilitated polymerization to give polypyrrole. Sodium benzenesulfonate introduced more imino groups to the polypyrrole coating, and the N+ sites improved ion exchange of Cl− and SO42− and increased the adsorption capacity of sulfate. Adsorption to the PFB‐GAC followed pseudo‐second‐order kinetics. The adsorption isotherm conformed to the Langmuir model, and adsorption was exothermic. Regeneration using a weak alkali (NH3·H2O), which released OH− slowly, caused less damage to the polypyrrole than using a strong alkali (NaOH) as the regeneration reagent. NH3·H2O at a concentration of 12 mol L−1 (with the same OH− concentration as 2 mol L−1 NaOH) released 85% of the sorbed sulfate in the first adsorption‐desorption cycle, and the adsorption capacity remained >6 mg g−1after five adsorption‐desorption cycles.

Porous glass-ceramics made from microwave vitrified municipal solid waste incinerator bottom ash

Global warming and depletion of resources have fueled research towards innovative building materials of low environmental impact and high performance engineering properties. Porous glass-ceramics were synthesized using municipal solid waste incinerator (MSWI) bottom ash (BA) as a starting material. BA was initially milled and then vitrified, as a purification step, by direct microwave heating, characterized by a high glass yield. Highly porous glass-ceramics were produced by intensive mechanical stirring of vitrified bottom ash (VBA) aqueous suspensions under weak alkali activation (1 M NaOH and 2.5 M NaOH) and sinter-crystallization at 800 °C or 900 °C. The obtained glass ceramics, with up to 70 vol% porosity, exhibited compressive strength well above 1 MPa, being comparable to lightweight construction materials, such as aerated concrete. High relative permittivity was measured for the 10 wt% soda-lime glass doped porous VBA material sintered at 800 °C, paving the way for its use as a potential semiconductor catalyst.

Enhancing the degradation of bisphenol A by dioxygen activation using bimetallic Cu/Fe@zeolite: Critical role of Cu(I) and superoxide radical

Copper-iron bimetallic material shows a high reactive activity in dioxygen activation processes (DOAs) but presents a significant challenge for enhancing superoxide radical (•O2−) generation. In this study, a practical strategy was developed to enhance •O2− generation for BPA degradation using a zeolite-supported Cu-Fe bimetallic system (called Cu/Fe@zeolite), which was simply prepared by impregnation method. The results verified that the Cu(I) regeneration at the zeolite surface contributes •O2− generation and the H2O2 that is further generated induces •OH production via a further Fenton reaction. In the reaction process, the initial generation of •O2− was primarily enhanced by the Cu(I) loaded onto the zeolite surface and the adsorbed BPA was easily degraded by the •OH. Under optimal operating conditions (i.e., Cu/Fe@zeolite = 3 g/L, Cu:Fe = 1:2, pH = 5, t = 120 min), it was found that 87% of BPA can be removed from wastewater. It is also important to note that the weak alkali buffering property of zeolite not only provides BPA adsorption sites under acidic conditions but also accelerates the precipitation efficiency for metallic ions and reduced the adverse effect of metallic residue on the effluent quality.

Study on Comprehensive Adjustment Countermeasures of Weak Alkali ASP Flooding in Low Water Cut Period

The problems occurred in the production process of weak alkali ASP flooding industrial demonstration area in Class II oil layer of Block A are systematically analyzed, such as the injection pressure of some injection wells rising too fast, the low energy and low yield of some production wells after ASP flooding, and the water cut rising too fast. Aiming at the problem of time, the research work of comprehensive adjustment was carried out, and the effective ways to improve the test effect were summarized Improve the injection-production relationship of well groups and reduce the plane and interlayer differences; Better development results have been achieved by improving the effectiveness of oil wells.

Antioxidant activity and stability of the flavonoids from Lycium barbarum leaves during gastrointestinal digestion in vitro

Abstract In this study, stability including the total flavonoids content (TFC) and main monomers composition and antioxidant activity of the flavonoids extract (LBLF) from Lycium barbarum leaves were investigated in the process of simulated oral and gastrointestinal digestion in vitro. During digested through the simulated oral fluid (SOF), gastric fluid (SGF), and intestinal fluid (SIF) in order, TFC of LBLF in the lyophilized digestive fluid samples were determined at different time points. It was shown that compared with the initial TFC of 811.72 ± 0.72 mg RE/g DW, the total flavonoids did not change significantly during oral digestion, while definitely increased at gastric digestion stage (p < 0.05) where the pH value is the lowest in the digestive system, indicating that the release of flavonoids from LBLF was promoted by pepsin, trypsase, and bile, however decreased during intestinal digestion probably due to the instability of LBLF in weak alkali media. Moreover, the antioxidant capacity and bioaccessibility of LBLF were significantly improved by SGF and SIF digestion (p < 0.05). The scavenging effect of the fluid sample after gastric digestion on free radicals followed as O2 − · > ABTS+ · > DPPH > ·OH > FRAP, while the clearance effect of intestinal digestion sample expressed as ABTS+ · > O2 − · > DPPH > FRAP > ·OH. High performance liquid chromatography (HPLC) results suggested that chlorogenic acid and rutin in LBLF had low stability during the gastrointestinal digestion in vitro. Our study suggests that LBLF may show the instability in the contents of total flavonoids and some main monomers, but an enhancement in the antioxidant activity during gastrointestinal digestion, providing a reference for the stability improvement of LBLF in the next step.

Corrosion resistance and cleanability of glazed surface

AbstractThis work aimed to study the effect of surface properties on the corrosion resistance and cleanability of glazed surface. The samples were zircon‐containing raw glaze, zirconium‐based frit glaze, double‐glazed transparent glaze, and raw glaze coated with TiO2 film. The corrosion resistance of the samples in acidic, alkaline, and household detergent solutions was investigated by the changes in contact angle and surface roughness. Besides, the cleanability of the samples before and after corrosion was also compared. It was found that the corrosion resistance of a glaze was affected by the presence of crystals and their distribution, while the corrosion resistance of TiO2 film was closely related to itself and the nature of the substrate. The cleaning test showed that although adding a layer of transparent glaze reduced the surface roughness, it did not improve the cleanability. The TiO2 film had excellent cleaning performance, especially after ultraviolet light irradiation, but it had weak alkali corrosion resistance. Therefore, a zirconium‐based frit glaze is the right choice for sanitary ware in terms of durability and easy cleaning.

Alkali Effect on Alkali-Surfactant-Polymer (ASP) Flooding Enhanced Oil Recovery Performance: Two Large-Scale Field Tests’ Evidence

Alkali-surfactant-polymer (ASP) flooding is very promising chemical enhanced oil recovery (EOR) technology which can make an incremental oil recovery factor (IORF) of 30% original oil in place (OOIP). How to choose alkali in ASP flooding remains a question for a long time. As the world’s only and largest ASP flooding application place, Daqing Oilfield has always adhered to the strategy of parallel development of strong alkali ASP flooding (SASP) and weak alkali ASP flooding (WASP), but SASP is in a dominant position, indicated by more investments and more project numbers. This leaves an impression that SASP is better than WASP. However, WASP is drawing more interest than SASP recently. Moreover, as the ASP flooding in Daqing went from field tests to commercial applications since 2014, how to comprehensively consider the benefit and cost of ASP flooding has become a new focus at low oil prices. This paper compares two typical large-scale field tests (B-1-D SASP and B-2-X WASP) completed in Daqing Oilfield and analyzes and discusses the causes of this difference. The injection viscosity and interfacial tension (IFT) for the two field test areas are substantially equivalent under the conditions of Daqing Oilfield, and WASP is better than SASP when reservoir geological conditions are considered. WASP exhibits the same IORF of 30% as SASP while having a much better economic performance. For the SASP field test, the injected strong alkali NaOH makes the test behave unlike a typical strong ASP flooding due to the presence of CO2 in the formation fluid, which well explains why IORF is much higher than all the other SASPs but scaling is less severe than others. This paper confirms that under Daqing Oilfield reservoir conditions, it is the alkali difference that caused the performance difference of these two tests, although some minor uncertainties exist. WASP is better than the SASP providing the same conditions . In addition, the detailed information of the two ASP field tests provided can give reference for the implementation of ASP flooding in other oilfields. After all, the study of ASP flooding enhanced oil recovery technology under low oil prices requires great foresight and determination.

Single nucleotide polymorphisms in GBBSI and SSIIa genes in relation to starch physicochemical properties in selected rice (Oryza sativa L.) varieties

Single nucleotide polymorphisms in GBBSI and SSIIa genes in relation to starch physicochemical properties in selected rice (Oryza sativa L.) varieties

Recovery Characteristics of Weak Alkali ASP Flooding in Second Oil Reservoir

Taking two weak alkali ASP flooding test blocks as the research object, the injection-production characteristics, effective characteristics, agent recovery characteristics, reservoir inhalation condition, pressure characteristics and emulsification characteristics were analyzed. The results showed that the weak alkali ASP flooding had strong injection-production ability, high oil recovery rate, improved suction condition, established effective driving pressure system, obvious emulsification, and not serious chromatographic separation. The apparent inhalation index decreased by 23%-33%, and the liquid production index decreased by 31-42%; The inhalation thickness ratio were 89.5%-92.7%, and the water cut decreased by 16%-20%; The enhanced recovery increased by over 20% in the weak alkali ASP flooding of the second oil reservoir.

Study on the sensitivities and damage mechanisms of ultra-low permeability sandstone reservoirs: taking Chang 6 reservoir in Jingbian oilfield as an example

This paper takes the ultra-low permeability sandstone reservoir of Jingbian oilfield in Ordos Basin as the research object, analyzes the petrological characteristics, diagenesis, physical characteristics and pore structure characteristics of the reservoir, and carries out reservoir sensitivity evaluation by using rock casting thin sections, X-ray diffraction, and sensitive flow experiments. The research results show that the ultra-low permeability Chang 6 sandstone reservoir has weak velocity sensitivity, medium-weak water sensitivity, weak salt sensitivity, weak alkali sensitivity and strong acid sensitivity; the damage mechanism of reservoir sensitivity mainly depends on the composition of clay minerals and pore structure after diagenesis. The clay mineral content from high to low is chlorite, illite, a small amount of illite / smectite layer, and kaolinite, of which the chlorite content is as high as 75 %; the reservoir has poor physical properties, the types of small hole-thin throat and small hole-fine throat. The reservoir is prone to blockage such as bridge plugging. Therefore, ultra-low permeability sandstone reservoirs are prone to different degrees of sensitivity. The reservoir characteristics are consistent with the reservoir sensitivity evaluation results.

The corrosion behavior of the Ni3Al intermetallic materials obtained by SPS in alkali solutions

The effect of boron additives on the corrosion resistance of Ni3Al intermetallic obtained by spark plasma sintering of powder mixtures with preliminary mechanical activation in alkali water is studied. It is established that monophasic nickel aluminide and alloyed with 0.1% B has high corrosion resistance in boiling solutions of strong alkalis, such as potassium and sodium hydrate. The corrosion rate in such medium is less than 0.05 mm/year, even when corrosion activators are added into the solution. High corrosion resistance is due to the processes of passivation of the material during the interaction of the surface of the material with the solution. Solutions of weak alkalis have a more aggressive effect on sintered nickel aluminide. It is shown that the corrosion rate of intermetallic in aqueous ammonia is 0.22…0.24 mm/year. With the boron addition, the corrosion rate increased to 0.29 mm/year.

The Characterization of Co-Ni-Fe Coating in Different pH Environment

This study aims to produce a Co-Ni-Fe alloy coating on a mild steel hollow cylinder shape by electrodeposition process and analyze the effect of different pH on the corrosion performance of the alloy coating. During the electrodeposition process, the temperature and time are set to 50°C and 30 minutes, respectively. Different pH value consisting of pH 2.1 (strong acid), 5.2 (weak acid), 6.9 (neutral), 8.4 (weak alkali) and 12.3 (strong alkali) are used. From the results obtained it was found that the deposited Co-Ni-Fe alloy has excellent corrosion performance. Corrosion rate obtained for strong acid, weak acid, neutral, weak alkali and strong alkali are 5.88 mmpy, 2.95 mmpy, 1.17 mmpy, 2.16 mmpy and 5.72 mmpy, respectively. Hence this studied showed that Co-Ni-Fe coating alloy could be used as an alternative to prevent against corrosion due to its high corrosion resistance as well as high microhardness.

Transcriptome analysis reveals the effects of alkali stress on root system architecture and endogenous hormones in apple rootstocks

Soil alkalinity is a major factor that restricts the growth of apple roots. To analyze the response of apple roots to alkali stress, the root structure and endogenous hormones of two apple rootstocks, Malus prunifolia (alkali-tolerant) and Malus hupehensis (alkali-sensitive), were compared. To understand alkali tolerance of M. prunifolia at the molecular level, transcriptome analysis was performed. When plants were cultured in alkaline conditions for 15 d, the root growth of M. hupehensis with weak alkali tolerance decreased significantly. Analysis of endogenous hormone levels showed that the concentrations of indole-3-acetic acid (IAA) and zeatin riboside (ZR) in M. hupehensis under alkali stress were lower than those in the control. However, the trend for IAA and ZR in M. prunifolia was the opposite. The concentration of abscisic acid (ABA) in the roots of the two apple rootstocks under alkali stress increased, but the concentration of ABA in the roots of M. prunifolia was higher than that in M. hupehensis. The expression of IAA-related genes ARF5, GH3.6, SAUR36, and SAUR32 and the Cytokinin (CTK)-related gene IPT5 in M. prunifolia was higher than those in the control, but the expression of these genes in M. hupehensis was lower than those in the control. The expression of ABA-related genes CIPK1 and AHK1 increased in the two apple rootstocks under alkali stress, but the expression of CIPK1 and AHK1 in M. prunifolia was higher than in M. hupehensis. These results demonstrated that under alkali stress, the increase of IAA, ZR, and ABA in roots and the increase of the expression of related genes promoted the growth of roots and improved the alkali tolerance of apple rootstocks.

Flooding performance evaluation of alkyl aryl sulfonate in various alkaline environments.

Alkaline-Surfactant-Polymer (ASP) flooding is an efficient chemical enhanced oil recovery (EOR) method gaining popularity in the industry. In this paper, the characteristics of three flooding systems with alkyl aryl sulfonate surfactants and a weak alkali concentration, strong alkali concentration and no alkali concentration were investigated. The emulsification, interfacial tension, viscosity, stability, adsorption resistance as well as the oil displacement effect for the flooding systems and simulated oil of the fourth plant of the Daqing Oilfield were measured. The results show that the three alkyl aryl sulphonates surfactants have different emulsification indexes with the weak and strong alkali concentrations possessing the best and worst indexes at 67.00% and 55.17% respectively, and the combination of surfactant and no alkali concentration with an emulsification index of 63.03%. The interfacial tension between the three flooding systems and the simulated oil of the fourth plant of Daqing Oilfield gets as low as 10−3 mN/m, and reduces as far as 10-4mN/m in certain points detected, all with good anti-dilution performance. In terms of interfacial tension stability, the three flooding systems are seen to reach ultra-low interfacial tension within 90 days. For viscosity stability, the addition of a strong alkali and a weak alkali further hydrolyzes the polymer, leading to an initial rise in viscosity and viscosity retention rates above 80%. In terms of adsorption resistance, ultra-low interfacial tension occurs adsorption is reduced by five times for the strong and weak alkali systems, and reduced by four times for the alkali-free system. These results show that all three combination flooding systems have good adsorption resistance. In the evaluation of oil displacement effect, the average chemical flooding recovery rate (33.83%) of the weak alkali-surfactant-polymer (ASP) system is nearly three percent higher (31.34%) than that of the surfactant-polymer (SP) system, and over seven percent higher (26.71%) than that of the strong ASP system.