Static Adsorption Research Articles

Preparation of 6-Amino-N-hydroxyhexanamide-Modified Porous Chelating Resin for Adsorption of Heavy Metal Ions.

The pollution of water bodies by heavy metal ions has recently become a global concern. In this experiment, a novel chelating resin, D851-6-AHHA, was synthesized by grafting 6-amino-N-hydroxyhexanamide (6-AHHA) onto the (-CH2N-(CH2COOH)2) group of the D851 resin, which contained a hydroxamic acid group, amide group, and some carboxyl groups. This resin was developed for the purpose of removing heavy metal ions, such as Cr(III) and Pb(II), from water. The findings from static adsorption experiments demonstrated the remarkable adsorption effectiveness of D851-6-AHHA resin towards Cr(III) and Pb(II). Specifically, the maximum adsorption capacities for Cr(III) and Pb(II) were determined to be 91.50 mg/g and 611.92 mg/g, respectively. Furthermore, the adsorption kinetics of heavy metal ions by D851-6-AHHA resin followed the quasi-second-order kinetic model, while the adsorption isotherms followed the Langmuir model. These findings suggest that the adsorption process was characterized by monolayer chemisorption. The adsorption mechanism of D851-6-AHHA resin was comprehensively investigated through SEM, XRD, FT-IR, and XPS analyses, revealing a high efficiency of D851-6-AHHA resin in adsorbing Cr(III) and Pb(II). Specifically, the (-C(=O)NHOH) group exhibited a notable affinity for Cr(III) and Pb(II), forming stable multi-elemental ring structures with them. Additionally, dynamic adsorption experiments conducted using fixed-bed setups further validated the effectiveness of D851-6-AHHA resin in removing heavy metal ions from aqueous solutions. In conclusion, the experimental findings underscored the efficacy of D851-6-AHHA resin as a highly efficient adsorbent for remediating water bodies contaminated by heavy metal ions.

A thorough investigation into the adsorption behavior of sophorolipid-modified fly ash towards compound pollution of lead and tetracycline

Heavy metal ions and antibiotics were simultaneously detected in authentic water systems. This research, for the first time, employed synthesized sophorolipid-modified fly ash(SFA) to eliminate tetracycline(TC) and lead(Pb2+) from wastewater. Various characterization techniques, including SEM-EDS, FTIR, XPS, BET, and Zeta, were employed to investigate the properties of the SFA. The results showed that the sophorolipid modification significantly improved the fly ash's adsorption capacities for the target pollutants. The static adsorption experiments elucidated the adsorption behaviors of SFA towards TC and Pb2+ in single and binary systems, highlighting the effects of different Environmental factors on the adsorption behavior in both types of systems. In single systems, SFA exhibited a maximum adsorption capacity of 128.96 mg/g for Pb2+ and 55.57 mg/g for TC. The adsorption of Pb2+ and TC followed pseudo-second-order kinetics and Freundlich isotherm models. The adsorption reactions are endothermic and occur spontaneously. SFA demonstrates varying adsorption mechanisms for two different types of pollutants. In the case of Pb2+, the primary mechanisms include ion exchange, electrostatic interaction, cation-π interaction, and complexation, while TC primarily engages in hydrogen bonding, π-π interaction, and complexation. The interaction between Pb2+ and TC has been shown to improve adsorption efficiency at low concentrations. Additionally, adsorption-desorption experiments confirm the reliable cycling performance of modified fly ash, highlighting its potential as a cost-effective and efficient adsorbent for antibiotics and heavy metals.

Synthesis of customized zeolite X with outstanding CO2 selectivity over CH4 and N2 using facile activated spent fluid catalytic cracking catalysts

Efficient separation of CO2 from natural gas mixtures (CO2/CH4) and flue gas (CO2/N2) is pivotal for effective carbon capture and sequestration. Utilizing adsorbents derived from solid waste provides additional benefit for the carbon capture industry. This study introduces a convenient activation method at 200 °C for SFCC. Utilizing the activated SFCC as raw material under mild hydrothermal conditions, highly crystalline zeolite X (referred to as SFCC-X-200) of commercial quality with exceptional CO2 separation ability from CH4 and N2 is obtained. The static water adsorption rate of SFCC-X-200 meets the requirements of the national standard for commercial zeolite X (GB6287-86). Moreover, the ideal adsorbed solution theory (IAST) selectivity of SFCC-X-200 for CO2 from CO2/N2 (15/85, v/v) and CO2/CH4 (50/50, v/v) mixtures is significantly higher, at 797 and 199, respectively, compared to commercial X zeolite. SFCC-X-200 demonstrates tremendous potential for separating CO2/N2 and CO2/CH4 mixtures due to its outstanding adsorption capacity and selectivity, rapid attainment of adsorption equilibrium, complete desorption at ambient temperature, and extremely low cost.

Enhanced high-temperature iodine capture through band-edge control in covalent organic frameworks

The effective capture of radioactive iodine species is crucial in nuclear waste treatment, particularly under high-temperature industrial conditions (≥150 °C), yet it poses a significant challenge. Here, we propose a novel approach for constructing highly efficient iodine traps by precisely controlling band edges in covalent organic frameworks (COFs) through the incorporation of fluorine atoms. This strategy facilitates the transformation of I2 into I5−, thereby enhancing the interactions between the COF host and radioiodine species, leading to a remarkable iodine uptake capacity of up to 2.36 g/g under static adsorption condition at 150 °C, and 36.12 wt% under dynamic adsorption condition at 150 °C. Moreover, the captured iodine can be released by immersing the solid form in DMF solvent, providing a mean to modulate reaction conditions gently. Notably, TFA-COF material can be reused multiple times without significant loss in its iodine capture performance.

Whole-Waste synthesis of Kilogram-Scale Macropores adsorbent materials for Wide-Range oil and heavy metal removal

The rapid pace of social development leads to the generation of significant quantities of oily wastewater and heavy metal ions, posing severe threats to the environment and human health. Therefore, finding cost-effective and efficient adsorbent materials is crucial. In the present study, a porous organic polymer based on waste cooking oil was synthesized as a macropores material called POP-WCO, allowing for preparation in kilogram quantities (more than one kilogram in a single batch). This material effectively removes oil and heavy metals, exhibiting excellent hydrophobic and superoleophilic properties, enabling the adsorption of various common oils within 22 s. POP-WCO is designed to swiftly remove and recover eight common oils through simple mechanical extrusion, maintaining a consistent oil recovery efficiency of 94% after 10 cycles. It can effectively treat and recover oil spills at sea through static and continuous adsorption. In addition, the POP-WCO material removes over 99% of the heavy metal mercury, showing exceptional resistance to acid, alkali, and salt, as well as economic value. The mechanism of Hg(II) adsorption by POP-WCO has been confirmed through density functional theory (DFT) calculations and X-ray photoelectron spectroscopy (XPS) analysis, elucidating the microdynamics process of the adsorption mechanism. This research presents an important strategy for achieving resource sustainability by transforming waste into valuable materials.

Construction of hollow CMPs microspheres based on the kinetic quantum sieving effect for highly efficient adsorption of Iodide/Cesium ions

Considering the dangers of radioactive elements to the human body and the environment, the efficient and rapid removal of radioactive ions in water is an urgent matter. In this paper, an efficient adsorption material based on kinetic quantum sieving (KQS) effect through skillfully molecular design with specific space structure conjugated microporous polymer hollow spheres (CMPs-1) for disposal of radioactive iodide/cesium ions is reported. The adsorption properties of iodide/cesium ions at different concentrations at 10℃ were investigated. Moreover, the test results show that the iodide ions adsorption capacity of the CMPs-1 will increase with the increase of iodine ions concentration when the temperature, volume, and other conditions are fixed. The CMPs-1 exhibited up to the highest 16.93 mg g−1 iodide adsorption capacity for the solution containing 0.10 mmol L-1 iodide ions within 6 h under static adsorption experiments at a low temperature of 10℃, and the adsorption rate fitted by the pseudo-second-order kinetic model was 0.11 g mg-1 h−1. Besides, the CMPs-1 maintained an effective adsorption capacity of 16.93, 7.51 and 5.92 mg g-1 at pH = 7, 10 and 13, respectively. Furthermore, unexpectedly, the constructed CMPs-1 showed superior heat resistance with higher adsorption capacity (26.32 mg g-1, 1.6 times) at 30℃ compared to 10℃. The improvement reason is that the expansion of pores (significantly increased at 4–20 nm), and the developed porosity can provide enough space to accelerate the diffusion rate of reactants and intermediates, exposing more active sites. And the π-conjugated system and hollow structure of CMPs materials can effectively solve the problem of low diffusion rate caused by low temperature and microporous structure in the transfer of iodide/cesium ions. Therefore, this work demonstrates the customizable potential of materials in the field of molecular adsorption applications and also provides a new idea for the design of unique hollow structure adsorption materials.

Synthesis, Characterization and Application of New Polymers Imprinted with Zinc (II) Ions

In this work, molecularly imprinted polymers with zinc imprints and their comparison polymers without imprints were synthesized. A comparative characterization of the physical parameters of the synthesized zinc-imprinted (ZnIP) and non-imprinted (NIP) polymers was carried out using the methods of elemental analysis, conductometry, scanning electron microscopy, and IR-Fourier spectroscopy. The ability of the resulting polymers to molecularly recognize zinc was evaluated. Based on experimental data on static adsorption, the adsorption capacity of ZnIP and NIP was determined using an atomic emission spectrometer. It was found that ZnIP is characterized by better physical parameters and a higher ability for molecular recognition of zinc compared to NIP. ZnIP with zinc imprints were found to have better sorption capacity for zinc than their reference polymers. The sorption of zinc by molecular imprinted ZnIP is mainly due to the complex formation and pores of the initial carbon product. The synthesized ZnIP have increased porosity. The presence of pores with a diameter <50 nm in ZnIP is associated with voids formed after acid hydrolysis, which is clearly visible in images recorded by scanning electron microscopy. Thus, the possibility of using ZnIP as a selective sorbent has been established.

Intermolecular Electrostatic Interactions in Cytochrome c Protein Monolayer on Montmorillonite Alumosilicate Surface: A Positive Cooperative Effect.

Montmorillonite (MM) crystal nanoplates acquire anticancer properties when coated with the mitochondrial protein cytochrome c (cytC) due to the cancer cells' capability to phagocytize cytC-MM colloid particles. The introduced exogenous cytC initiates apoptosis: an irreversible cascade of biochemical reactions leading to cell death. In the present research, we investigate the organization of the cytC layer on the MM surface by employing physicochemical and computer methods-microelectrophoresis, static, and electric light scattering-to study cytC adsorption on the MM surface, and protein electrostatics and docking to calculate the local electric potential and Gibbs free energy of interacting protein globules. The found protein concentration dependence of the adsorbed cytC quantity is nonlinear, manifesting a positive cooperative effect that emerges when the adsorbed cytC globules occupy more than one-third of the MM surface. Computer analysis reveals that the cooperative effect is caused by the formation of protein associates in which the cytC globules are oriented with oppositely charged surfaces. The formation of dimers and trimers is accompanied by a strong reduction in the electrostatic component of the Gibbs free energy of protein association, while the van der Waals component plays a secondary role.

Selective Adsorption of Hazardous Substances from Wastewater by Hierarchical Oxide Composites: A Review.

Large volumes of wastewater containing toxic contaminants (e.g., heavy metal ions, organic dyes, etc.) are produced from industrial processes including electroplating, mining, petroleum exploitation, metal smelting, etc., and proper treatment prior to their discharge is mandatory in order to alleviate the impacts on aquatic ecosystems. Adsorption is one of the most effective and practical methods for removing toxic substances from wastewater due to its simplicity, flexibility, and economics. Recently, hierarchical oxide composites with diverse morphologies at the micro/nanometer scale, and the combination advantages of oxides and composite components have been received wide concern in the field of adsorption due to their multi-level structures, easy functionalization characteristic resulting in their large transport passages, high surface areas, full exposure of active sites, and good stability. This review summarizes the recent progress on their typical preparation methods, mainly including the hydrothermal/solvothermal method, coprecipitation method, template method, polymerization method, etc., in the field of selective adsorption and competitive adsorption of hazardous substances from wastewater. Their formation processes and different selective adsorption mechanisms, mainly including molecular/ion imprinting technology, surface charge effect, hard-soft acid-base theory, synergistic effect, and special functionalization, were critically reviewed. The key to hierarchical oxide composites research in the future is the development of facile, repeatable, efficient, and scale preparation methods and their dynamic adsorption with excellent cyclic regeneration adsorption performance instead of static adsorption for actual wastewater. This review is beneficial to broaden a new horizon for rational design and preparation of hierarchical oxide materials with selective adsorption of hazardous substances for wastewater treatment.

Removal of tetracycline by La(OH)3 modified MIL-101(Cr) adsorbent with multiple adsorption sites

The impressive water stability demonstrated by MIL-101(Cr) highlights its considerable potential for the effective elimination of organic contaminants from wastewater. Nevertheless, the limited availability of adsorption sites within MOFs leads to an unsatisfactory capacity for tetracycline (TC) adsorption. In this case, the lanthanum modified MIL-101(Cr) porous adsorbents, termed as nLa-MIL-101(Cr), were successfully synthesized using a post-synthetic modification method. Through various characterization analyses, it was confirmed that lanthanum exists in the form of La(OH)3 within the adsorbents, and all adsorbents also preserved the original structure as MIL-101(Cr). The results of static adsorption experiments demonstrated that, compared to the original material, the adsorption capacity of 1La-MIL-101(Cr) for TC increased by 3.5 times. Further experiments demonstrated that the adsorbent exhibits remarkable ion interference resistance and cycle stability. Finally, based on X-ray photoelectron spectroscopy, the adsorption mechanism was primarily attributed to the coordination between TC molecules and metals active site, while electrostatic interactions also played a significant role in the process. This study has developed a highly efficient adsorbent for the treatment of TC-contaminated wastewater, which reflects promising practical application prospects.

Selective Adsorption of Sr(II) from Aqueous Solution by Na3FePO4CO3: Experimental and DFT Studies.

The efficient segregation of radioactive nuclides from low-level radioactive liquid waste (LLRW) is paramount for nuclear emergency protocols and waste minimization. Here, we synthesized Na3FePO4CO3 (NFPC) via a one-pot hydrothermal method and applied it for the first time to the selective separation of Sr2+ from simulated LLRW. Static adsorption experimental results indicated that the distribution coefficient Kd remained above 5000 mL·g-1, even when the concentration of interfering ions was more than 40 times that of Sr2+. Furthermore, the removal efficiency of Sr2+ showed no significant change within the pH range of 4 to 9. The adsorption of Sr2+ fitted the pseudo-second-order kinetic model and the Langmuir isotherm model, with an equilibrium time of 36 min and a maximum adsorption capacity of 99.6 mg·g-1. Notably, the adsorption capacity was observed to increment marginally with an elevation in temperature. Characterization analyses and density functional theory (DFT) calculations elucidated the adsorption mechanism, demonstrating that Sr2+ initially engaged in an ion exchange reaction with Na+. Subsequently, Sr2+ coordinated with four oxygen atoms on the NFPC (100) facet, establishing a robust Sr-O bond via orbital hybridization.

Fouling behavior of nanofiltration membrane during the refining treatment of morphlines-dominant reverse osmosis concentrate

Nanofiltration (NF) has been proven to be with great potential for the separation of morpholines with molecular weight less than 200 Da in refining reverse osmosis concentrate (ROC), but its application is significantly restricted by the membrane fouling, which can reduce the rejection and service time. To enable the long-term operation stability of nanofiltration, this work focuses on the fouling behavior of each substance in the hydrosaline organic solution on nanofiltration membrane, aiming to give insight into the fouling mechanism. To this end, in this work, the effects of salts (i.e NaCl and Na2SO4), organic substances (including N-(2-hydroxypropyl)morpholine(NMH) and 4-morpholineacetate(MHA)) and representative divalent ions (Ca2+ and Mg2+) on the performance and physicochemical properties of DK membrane were systematically investigated. The results show that both salts and organics can induce DK membrane swelling, leading to an increase of the mean effective pore size. After the filtration of Na2SO4–NaCl–H2O, the mean pore size increased by 0.002 nm, resulting in the decrease of the removal ratio of NMH and MHA for 3.82% and 13.10%, respectively. With static adsorption of NMH and MHA, the mean pore size of DK membrane increased by 0.005 and 0.003 nm. The swelling slowed the entrance of more organic molecules into membrane pores. Among them, MHA led to the terrible irreversible pore blocking. As the concentration of Ca2+ increased, gypsum scaling was formed on the membrane surface. During this process, NMH and MHA played different roles, i.e. NMH accelerated the CaSO4 crystallization while MHA inhibited. As a conclusion, the fouling behavior of substances in the high saline organic wastewater on DK membrane were systematically revealed with the fouling mechanisms proposed, which could provide an insightful guidance for membrane fouling control and cleaning in the treatment of high salinity and organic wastewater.

Modified Ordered Mesoporous Carbons for Cr(VI) Removal from Wastewater.

The pristine CMK-3 carbon was ozonized and then chemically modified by the Zr and Fe compounds. The synthesized carbonaceous materials were characterized with physicochemical methods. The obtained carbons had a high specific surface area (ca. 800 m2 g-1) and an acidic surface. The Cr(VI) adsorption properties of the oxidized and Zr/Fe-modified carbon were studied. The highest static adsorption capacity towards Cr(VI) ions was evaluated for Zr/Fe-modified carbon (50.1 mg g-1) at pHeq = 5.8 after 240 min. The Elovich and Freundlich theoretical models were well fitted to the Cr(VI) adsorption kinetic and isotherm data on the Zr/Fe-modified CMK-3-type carbon. The leading Cr(VI) adsorption mechanism acting on the Zr/Fe-modified carbon was probably based on the redox reactions between Cr(VI) and the carbonaceous surface. Electrostatic attraction and surface complexation processes could also occur during Cr(VI) adsorption in the studied system. The effect of the competitive anions on the concentration level, such as in the galvanic wastewater for Cr(VI) adsorption onto chemically modified carbon, was negligible. The HCl and HNO3 media were insufficient for the Zr/Fe-modified carbon regeneration after Cr(VI) adsorption. The Zr/Fe-modified carbon was successfully applied for the efficient (>90%) Cr(VI) removal from the model galvanic wastewater.

Highly selective separation of sulfur dioxide in a triphenylamine-based nanoporous organic polymer

The urgent need for effective SO2 capture materials has driven research into the development of novel nanoporous organic polymers (NOPs). Herein, we developed a triphenylamine-based nanoporous organic polymer, designated as ANOP-5, through the self-condensation of an AB2 triphenylamine monomer. The adsorption/separation properties of SO2 and CO2 are comparatively evaluated through the investigation of static gas adsorption isotherms. At 273 K and 100 kPa, ANOP-5 displays a high SO2 adsorption capacity of 399 cm3 g−1 and a high selectivity of 388 for SO2/CO2, with a molar ratio of SO2 to CO2 at 10/90. The exceptional performance of desulfurization is attributed to the strong interaction between ANOP-5 and SO2, in addition to the ultramicroporous structure. These findings are further supported by the dispersion-corrected density functional theory calculations. This study contributes valuable insights into the design and preparation of NOPs with high gas adsorption properties, particularly for addressing environmental pollution challenges related to SO2 emissions.

A static and dynamic analysis of nonionic-based binary surfactant systems for adsorption mitigation in a carbonate reservoir with high salinity

Surfactants are crucial in chemical enhanced oil recovery, but high adsorption onto rocks reduces their efficiency and economic viability. Sacrificial agents, such as alkalis, nanoparticles, and polymers have been investigated to mitigate this issue but they in turn present drawbacks such as poor oil interaction, compatibility issues, pore plugging, and increased costs. Binary surfactant systems, due to their favorable potential synergistic interactions, are proposed as solutions for reducing surfactant adsorption. Static adsorption experiments were conducted to assess the effect of the binary surfactants on adsorption efficiency, and the impact of salinity on the adsorption process equilibrium was also studied. Five core flooding experiments under reservoir temperature (41∘C), reservoir pressure (21 MPa), and high salinity (23.4 wt.%) were conducted to evaluate dynamic adsorption. The surfactant concentrations in supernatant and effluent, after the adsorption process were determined via interfacial tension tests using a spinning drop method. The results showed a significant reduction in surfactant adsorption on carbonate rocks, from 9.99 mg/g-rock to 0.68 mg/g-rock for anionic surfactants and from 5.38 mg/g-rock to 0.19 mg/g-rock for zwitterionic surfactants, with corresponding dynamic reductions of 61% and 89%. Our results were further evidenced by the little to no changes in the differential pH curves in the adsorption process of the binary surfactant systems. This study presents a cost-effective approach for significantly reducing surfactant adsorption on carbonate rocks and aids in designing surfactant formulations for adsorption reduction in high-temperature, high-salinity carbonate reservoirs.

A highly efficient molecularly imprinted fluorescence sensor for selective and sensitive detection of tetracycline antibiotic residues in pork

Tetracyclines (TCs) residues in animal-based foods may cause consumer poisoning or allergic reactions, as well as resistance of pathogenic microorganisms. Therefore, a method to accurately monitor TCs is urgently needed. Here, a sensitive and greenificated molecularly imprinted fluorescent sensor (CDs@MIP) for detecting TCs residues using non-covalent imprinting binding method has been synthesized in a simple and safe manner. The sensor was demonstrated to contain specific adsorption sites and high adsorption capacity by static adsorption test results and Freundlich and Langmuir model analyses, and the maximum adsorption capacity was 45.8 mg/g. Moreover, the sensor exhibited intense blue-green fluorescence under UV light, and the fluorescence was gradually quenched as TCs was adsorbed to achieve the detection. The fluorescent spectrum experiment demonstrated that the prepared sensor has good recognition and detection performance for TCs with a linear range of 0.02–50 mg/L and a detection limit of 0.18 μg/L. Furthermore, This sensor is recyclable and can be used to determine TCs content in pork with a recovery rate of 98 %–108 %. Therefore, the constructed sensor provides a new convenient strategy for detecting TCs residues.

Investigating the Effect of Water Softening on Polymer Adsorption onto Carbonates through Single-Phase and Two-Phase Experiments

Summary Polymer retention is considered a major challenge in polymer flooding applications, especially in carbonates. This is due to the prevailing conditions of low permeability (<100 md), high temperature (>85°C), and high salinity (>100,000 ppm) generally found in these formations, which limit the effectiveness of commonly used polymers such as hydrolyzed polyacrylamide (HPAM) and xanthan gum. To address these challenges, a polymer based on acrylamide tertiary butyl sulfonate (ATBS) has been used due to its tolerance to high-temperature and -salinity conditions. However, the high cost of manufacturing these polymers, combined with their anionic properties that promote adsorption onto positively charged carbonate rocks, necessitates the exploration of methods to reduce polymer retention. In this study, we aim to determine the sufficient concentration of hardness ions (Ca2+ and Mg2+) required to significantly reduce the adsorption of this polymer. The study is unique in its focus on mitigating polymer retention in carbonate formations using softened brine, as no prior research has investigated this aspect. Four different brines were investigated with a salinity of 8,000 ppm total dissolved salts (TDS) and varying ionic composition designed mainly by eliminating the hardness-causing ions, Ca2+ and Mg2+. A geochemical study was performed using the PHREEQC software to analyze the interaction between these injected brines and the rock. Furthermore, comprehensive rheological and static adsorption studies were performed at a temperature of 25°C using the potential ATBS-based polymer to evaluate the polymer performance and adsorption in these brines. Later, dynamic adsorption studies were conducted in both single-phase and two-phase conditions to further quantify polymer adsorption. The geochemical study showed an anhydrite saturation index (SI) of less than 0.5 for all the brines used when interacting with the rock, indicating a very low tendency for calcium sulfate precipitation. Furthermore, the rheological studies showed that polymer viscosity significantly increased with reduced hardness, where a polymer solution viscosity of 7.5 cp was obtained in zero hardness brine, nearly 1.5 times higher than the polymer viscosity of the base makeup brine of 8,000 ppm. Moreover, it was observed that, by carefully tuning the concentrations of the divalent cations, the polymer concentration consumption for the required target viscosity was reduced by 40–50%. For the single-phase static adsorption experiments, the polymer solution in softened brines resulted in lower adsorption in the range of 37–62 µg/g-rock as opposed to 102 µg/g-rock for the base makeup brine. On the other hand, the single-phase dynamic adsorption results showed an even lowered polymer adsorption of 33 µg/g-rock for the softened brine compared with 45 µg/g-rock for the base makeup brine. Additionally, the single-phase dynamic adsorption studies showed a remarkable improvement in polymer injectivity using softened brine. The polymer retention in wettability-altered cores was further reduced. The study highlights that water softening improves the performance of polymers, specifically in terms of lowering polymer adsorption. It concludes that a threshold hardness level (Ca2+ and Mg2+) of approximately 100 ppm is sufficient to achieve a significant reduction in polymer adsorption for the tested experimental conditions. In this paper, we show that the softened water increases the polymer viscosity and reduces polymer adsorption, which leads to an overall reduction in polymer consumption. Hence, the softened makeup water has the potential to enhance the application envelope of this potential polymer for polymer flood, especially in the case of carbonate reservoirs.

A green and simple method for enrichment of major diterpenoids from the buds of Wikstroemia chamaedaphne with macroporous resins and their activation of latent human immunodeficiency virus activity

In this study, a green and efficient enrichment method for the four majors active diterpenoid components: pimelotide C, pimelotide A, simplexin, and 6α,7α-epoxy-5β-hydroxy-12-deoxyphorbol-13-decanoate in the buds of Wikstroemia chamaedaphne was established using macroporous resin chromatography. The adsorption and desorption rates of seven macroporous resins were compared using static tests. The D101 macroporous resin exhibited the best performance. Static and dynamic adsorption tests were performed to determine the enrichment and purification of important bioactive diterpenoids in the buds of W. chamaedaphne. Diterpenoid extracts were obtained by using D101 macroporous resin from the crude extracts of W. chamaedaphne. Liquid chromatography-tandem mass spectrometry (LC-MS/MS) analysis demonstrated that most of the diterpenoids were enriched in diterpenoid extracts. These results confirmed that diterpenoids in the buds of W. chamaedaphne could be enriched using macroporous resin technology, and the enriched diterpenoid extracts showed more efficient activation of the latent human immunodeficiency virus. This study provides a novel strategy for discovering efficient and low-toxicity latency-reversing agents and a potential basis for the comprehensive development and clinical application of the buds of W. chamaedaphne.

Using Magnetic Molecularly Imprinted Polymer Technology for Determination of Fish Serum Glucose Levels.

In this study, a highly efficient magnetic molecularly imprinted polymer nanocomposite material was prepared using multi-walled carbon nanotubes as carriers. The characterization of the obtained nanocomposite material was conducted using Fourier transform infrared spectroscopy, a vibrating sample magnetometer, a thermogravimetric analyzer, a scanning electron microscope, and a transmission electron microscope. The adsorption properties of the nanocomposite material were evaluated through adsorption experiments, including static adsorption, dynamic adsorption, and selective recognition studies. The prepared nanocomposite material, serving as a selective adsorbent, was applied in magnetic solid-phase extraction. Subsequently, the derivatized samples were analyzed for glucose in fish serum using liquid chromatography-tandem mass spectrometry. Under optimal conditions, the detection limit was 0.30 ng/mL, the quantitation limit was 0.99 ng/mL, satisfactory spiked recovery rates were obtained, and the relative standard deviation was less than 1.1%. Using 2-deoxy-D-ribose as the template molecule and a structural analog of glucose allowed us to eliminate the potential template leakage in qualitative and quantitative analyses, effectively avoiding the issues of false positives and potential quantitative errors, compared to traditional methods. A method for detecting glucose levels in fish serum based on molecularly imprinted polymer technology has been successfully developed to determine the stress and health levels of fish.

The Role of Amphiphilic Nanosilica Fluid in Reducing Viscosity in Heavy Oil

Heavy oil accounts for a considerable proportion of the world’s petroleum resources, and its exploitation helps to mitigate reliance on conventional oil resources and diversify energy supply. However, due to the high viscosity and high adhesion characteristics of heavy oil, conventional methods such as thermal recovery, emulsification, and dilution have significant limitations and cannot meet the growing demands for heavy oil production. In this study, 3-propyltrimethoxysilane (MPS) was used to modify and graft amphiphilic surfactants (AS) onto nanosilica to prepare a salt-resistant (total mineralization > 8000 mg/L, Ca2+ + Mg2+ > 1000 mg/L) and temperature-resistant (250 °C) nanosilicon viscosity reducer (NSD). This article compares amphiphilic surfactants (AS) as conventional viscosity-reducing agents with NSD. FTIR and TEM measurements indicated successful bonding of 3-propyltrimethoxysilane to the surface of silica. Experimental results show that at a concentration of 0.2 wt% and a mineralization of 8829 mg/L, the viscosity reduction rates of thick oil (LD-1) before and after aging were 85.29% and 81.36%, respectively, from an initial viscosity of 38,700 mPa·s. Contact angle experiments demonstrated that 0.2 wt% concentration of NSD could change the surface of reservoir rock from oil-wet to water-wet. Interfacial tension experiments showed that the interfacial tension between 0.2 wt% NSD and heavy oil was 0.076 mN/m. Additionally, when the liquid-to-solid ratio was 10:1, the dynamic and static adsorption amounts of 0.2 wt% NSD were 1.328 mg/g-sand and 0.745 mg/g-sand, respectively. Furthermore, one-dimensional displacement experiments verified the oil recovery performance of NSD at different concentrations (0.1 wt%, 0.15 wt%, 0.2 wt%, 0.25 wt%) at 250 °C and compared the oil recovery efficiency of 0.2 wt% NSD with different types of demulsifiers. Experimental results indicate that the recovery rate increased with the increase in NSD concentration, and 0.2 wt% NSD could improve the recovery rate of heavy oil by 22.8% at 250 °C. The study of nano-demulsification oil recovery systems can effectively improve the development efficiency of heavy oil.