The Effect of Betaine Surfactant on Carbonate Reservoir Wettability in Self-Diverting Acidizing Stimulation

Contact angle alterations of carbonate cores after immersing in spent acid with oleyl amido propyl betaine surfactant were measured to clarify the effect of viscoelastic surfactant on the wettability of carbonate reservoir during self-diverting acidizing. The results showed that spent acid solutions with hydrochloric acid and betaine surfactant induced core wettability to water-wetting for initially oil-wet rocks, and oil-wetting for initially water-wet rocks. Longer immersion time and higher concentration of surfactant enhanced the effects. The adverse wettability reversal for water-wet reservoir was eliminated by mutual solvent or brine postflush. Chemical mechanisms of the wettability alteration were interpreted

Freestanding Mo3N2 nanotubes for long‐term stabilized 2e− intermediate‐based high energy efficiency Li–CO2 batteries

Abstract Li–CO2 batteries are considered one of the promising power sources owing to ultrahigh energy density and carbon fixation. Nevertheless, the sluggish reaction kinetics of 4e− discharged process (Li2CO3) impede its potential application. One of the efficient strategies for developing cathode catalysts is to stabilize 2e− intermediate Li2C2O4 and improve reaction reversibility. However, long‐term catalysts of stabilized Li2C2O4 are barely achieved, whereas cycle stability is far from satisfactory level. Herein, non‐noble metal–based Mo3N2 is synthesized and employed as freestanding cathodes for Li–CO2 batteries. Owing to rich delocalized electrons of Mo2+ and reversible electron localization structure, freestanding Mo3N2 cathodes exhibit a low charge potential (3.28 V) with an ultralow potential gap (0.64 V), high energy efficiency of up to 80.46%, fast rate capability, and outstanding cycle stability (>910 h). In situ experiments and theoretical calculation verify that Mo3N2 stabilizes 2e− Li2C2O4 intermediate by the interaction of Mo2+ as active sites where Mo2+ promotes the transfer of outer electrons to O, prevents its disproportionation to Li2CO3, and promotes reaction kinetics, contributing to high energy efficiency and outstanding cycle reversibility. In addition, the pouch‐cells deliver ultrahigh energy density of up to 6350.7 W h kg−1 based on the mass of cathode materials

Ultrastretchable, Multihealable, and Highly Sensitive Strain Sensor Based on a Double Cross-Linked MXene Hydrogel

The ability of a flexible strain sensor to directly adapt the complicated human biological motion or combined gestures and remotely control the artificial intelligence robotics could benefit the wearable electronics such as intelligent robotics and patient healthcare. However, it is a challenge for the flexible strain sensor to simultaneously achieve high sensing performances and stretchability and long sustainability under various deformation stress or damage. Herein, a dual-cross-linked poly(acrylic acid–stearyl methacrylate)/MXene [P(AA–SMA)M] hydrogel with enhanced mechanical stretchability and self-healability is fabricated by importing reversible coordination and hydrophobic interaction into polymer networks. As a result, the hydrogel film not only exhibits high tensile strength (525 kPa) and stretchability (∼2600%) but also achieves repetitive healable property with 843% elongation even after the 20th broken/self-healing cycle. More importantly, the resultant strain sensor delivers a low detection limit, wide sensing range, fast response time, and repeatability of 1000 cycles even after repeated self-healing. So, the sensor can monitor subtle human motions and recognize different handwriting and gestures, which reveals potential applications toward health-care devices, flexible electronics, and human–machine interfacing

Adsorption-Enhanced Ceramic Membrane Filtration Using Fenton Oxidation for Advanced Treatment of Refinery Wastewater: Treatment Efficiency and Membrane-Fouling Control

With the development of the refining industry, the treatment of refinery wastewater has become an urgent problem. In this study, a ceramic membrane (CM) was combined with Fenton-activated carbon (AC) adsorption to dispose of refinery wastewater. The effect of the combined process was analyzed using excitation–emission matrix (EEM), ultraviolet-visible (UV-vis) and Fourier transform infrared spectroscopies (FTIR). Compared with direct filtration, the combined process could significantly improve the removal of organic pollution, where the removal rate of the COD and TOC could be 70% and the turbidity removal rate was above 97%. It was found that the effluent could meet the local standards. In this study, the membrane fouling was analyzed for the impact of the pretreatment on the membrane direction. The results showed that Fenton-AC absorption could effectively alleviate membrane fouling. The optimal critical flux of the combined process was increased from 60 to 82 L/(m2·h) compared with direct filtration. After running for about 20 d, the flux remained at about 55 L/(m2·h) and the membrane-fouling resistance was only 1.2 × 1012 m−1. The Hermia model revealed that cake filtration was present in the early stages of the combined process. These results could be of great use in improving the treatment efficiency and operation cycle of refinery wastewater

Microbial Communities Shaped by Treatment Processes in a Drinking Water Treatment Plant and Their Contribution and Threat to Drinking Water Safety

Bacteria play an important role in water purification in drinking water treatment systems. On one hand, bacteria present in the untreated water may help in its purification through biodegradation of the contaminants. On the other hand, some bacteria may be human pathogens and pose a threat to consumers. The present study investigated bacterial communities using Illumina MiSeq sequencing of 16S rRNA genes and their functions were predicted using PICRUSt in a treatment system, including the biofilms on sand filters and biological activated carbon (BAC) filters, in 4 months. In addition, quantitative analyses of specific bacterial populations were performed by real-time quantitative polymerase chain reaction (qPCR). The bacterial community composition of post-ozonation effluent, BAC effluent and disinfected water varied with sampling time. However, the bacterial community structures at other treatment steps were relatively stable, despite great variations of source water quality, resulting in stable treatment performance. Illumina MiSeq sequencing illustrated that Proteobacteria was dominant bacterial phylum. Chlorine disinfection significantly influenced the microbial community structure, while other treatment processes were synergetic. Bacterial communities in water and biofilms were distinct, and distinctions of bacterial communities also existed between different biofilms. By contrast, the functional composition of biofilms on different filters were similar. Some functional genes related to pollutant degradation were found widely distributed throughout the treatment processes. The distributions of Mycobacterium spp. and Legionella spp. in water and biofilms were revealed by real-time quantitative polymerase chain reaction (qPCR). Most bacteria, including potential pathogens, could be effectively removed by chlorine disinfection. However, some bacteria presented great resistance to chlorine. qPCRs showed that Mycobacterium spp. could not be effectively removed by chlorine. These resistant bacteria and, especially potential pathogens should receive more attention. Redundancy analysis (RDA) showed that turbidity, ammonia nitrogen and total organic carbon (TOC) exerted significant effects on community profiles. Overall, this study provides insight into variations of microbial communities in the treatment processes and aids the optimization of drinking water treatment plant design and operation for public health

Construction of Dual-Biofunctionalized Chitosan/Collagen Scaffolds for Simultaneous Neovascularization and Nerve Regeneration

Biofunctionalization of artificial nerve implants by incorporation of specific bioactive factors has greatly enhanced the success of grafting procedures for peripheral nerve regeneration. However, most studies on novel biofunctionalized implants have emphasized the promotion of neuronal and axonal repair over vascularization, a process critical for long-term functional restoration. We constructed a dual-biofunctionalized chitosan/collagen composite scaffold with Ile-Lys-Val-Ala-Val (IKVAV) and vascular endothelial growth factor (VEGF) by combining solution blending, in situ lyophilization, and surface biomodification. Immobilization of VEGF and IKVAV on the scaffolds was confirmed both qualitatively by staining and quantitatively by ELISA. Various single- and dual-biofunctionalized scaffolds were compared for the promotion of endothelial cell (EC) and Schwann cell (SC) proliferation as well as the induction of angiogenic and neuroregeneration-associated genes by these cells in culture. The efficacy of these scaffolds for vascularization was evaluated by implantation in chicken embryos, while functional repair capacity in vivo was assessed in rats subjected to a 10 mm sciatic nerve injury. Dual-biofunctionalized scaffolds supported robust EC and SC proliferation and upregulated the expression levels of multiple genes and proteins related to neuroregeneration and vascularization. Dual-biofunctionalized scaffolds demonstrated superior vascularization induction in embryos and greater promotion of vascularization, myelination, and functional recovery in rats. These findings support the clinical potential of VEGF/IKVAV dual-biofunctionalized chitosan/collagen composite scaffolds for facilitating peripheral nerve regeneration, making it an attractive candidate for repairing critical nerve defect. The study may provide a critical experimental and theoretical basis for the development and design of new artificial nerve implants with excellent biological performance