Solution pH Research Articles

Influence of solution pH on the dynamics of oxygen bubbles on the surface of TiO2-NTAs electrodes

The rise of concentration resistance caused by bubble growth is a key factor affecting the photoelectrochemical water splitting efficiency. In this research, we employed an electrochemical workstation, a synchronized measuring system, and a CCD camera to investigate the in-situ evolution of oxygen bubbles on the surfaces of TiO2-NTAs and C/TiO2-NTAs electrodes. The connection among the critical nucleation, growth and departure behavior of a single bubble on the photoanode surface and photocurrent curves at different solution pH (1 - 13) has been investigated. For TiO2-NTAs, it was found that strong alkalinity significantly reduces the voltage required for critical bubble nucleation. The photocurrent rises approximately 1.5 times when the control voltage is 0.10 V (vs. Ag/AgCl) by pH increasing from 1 to 13 and while the bubble evolution cycles decline by approximately 3.2 times. The photocurrent rises by 10.4 times compared with pH = 9 and by 7.3 times compared with pH = 13 when the control voltage is 0.71 V (vs. RHE), respectively. We also found that the oxygen bubble evolution of C/TiO2-NTAs is similar to TiO2-NTAs. When pH = 3 - 13, the average photocurrent of C/TiO2-NTAs electrode is higher than that of TiO2-NTAs, and the average bubble evolution cycles are lower than those of TiO2-NTAs at the same pH. According to the results, carbon films can rise the absorption capacity of TiO2-NTAs and significantly improve the effectiveness of photogenerated holes and electrons departure. Meanwhile, based on the oxygen bubble force balance model on the photoanode surface, the concentration Marangoni force rises with the increase of pH, which leads to the growth of bubble departure diameter. The outcomes demonstrate that oxygen bubbles on the photoanode surface can be successfully eliminated in strongly alkaline settings.

Selected Beneficial Microbes Alleviate Salinity Stress in Hydroponic Lettuce and Pak Choi

Hydroponics is widely used in greenhouse and vertical farming production because these facilities can precisely control environmental conditions such as lighting, temperature, and vapor pressure deficit. However, the fertilizer solutions have a short life span, and they often do not have adequate microbial populations to enhance plant growth. Previous studies have shown the potential of beneficial microbes to promote plant production and alleviate abiotic and biotic stressors in the field, and studies on their use in controlled environments such as greenhouses and vertical farms are limited in the literature. In this study, we selected several plant growth promoting microbes (PGPMs) and tested their effects on alleviating salinity stress in ‘Rex’ lettuce (Lactuca sativa) and ‘Red Pac’ pak choi (Brassica chinensis) grown in deep water culture hydroponics. Our goal was to use one stressor, salinity, that induces profound symptoms in plant morphology. A three-cycle study was conducted using five PGPMs [Bacillus, Glomus, Lactobacillus, Trichoderma, and Bacillus/Pseudomonas/Trichoderma (B/P/T) mix] and two salinity levels [no salinity and salinity treatment, with 120 mM, 40 mM, and 80 mM sodium chloride (NaCl) solution used for the first, second, and third cycles, respectively]. We measured the effects of PGPMs and salinity on plant growth and quality and the solution pH and electrical conductivity (EC). Salinity stress decreased lettuce and pak choi leaf area and shoot fresh weight and increased plant leaf chlorophyll and anthocyanin contents with increased solution EC. Under high-salinity stress (120 mM NaCl), the addition of Trichoderma reduced pak choi leaf area and fresh weight but increased solution pH, whereas under low salinity stress (40 mM NaCl), Trichoderma increased pak choi leaf chlorophyll content. Under moderate-salinity stress (80 mM NaCl) condition, the addition of Glomus sp. increased lettuce fresh weight and leaf area, and B/P/T mix increased pak choi leaf area. In conclusion, using the selected PGPMs in low to moderate-salinity stress could increase lettuce and pak choi growth and quality parameters. These results have some practical applications in the future when more saline water is used for production.

Synthesis of metal–organic framework ZIF-9-Mel and its application as an electrochemical modifier in Pb2+ detection

In this study, a selective electrochemical sensor was introduced for determination of lead ions based on a metal–organic framework (MOF)-melamine together with carbon black (CB) on the glassy carbon electrode (GCE). Herein, the zeolitic imidazolate framework-9-Mel (ZIF-9-Mel), which is a type of MOF, was synthesized and used as an electrode modifier. The interaction between Pb2+ and amine groups is conditioned by dative attachment, which causes the complexation of Pb2+-N through soft–soft interactions. To enhance the performance of the modified electrode, several parameters such as the pH of the buffer solution, the deposition potential, and the deposition time that affect response were optimized. Under optimized conditions (pH = 3, deposition time = 270 s, deposition potential = −0.7 V) the ZIF-9-Mel/CB/GCE sensor shows two linear ranges (0.5 nM–50 nM and 50 nM–1000 nM), low detection limit (0.16 nM), long-term stability, good repeatability and desirable reproducibility by differential pulse voltammetry (DPV) technique. To display the sensor ability for actual application, ZIF-9-Mel/CB/GCE was used for Pb2+ detection in lettuce and tomato samples with excellent results. According to the introduced method, MOFs are satisfactory materials for fabricating effective electrochemical sensors to detect Pb2+ ions simply and cost-effectively.

Adsorption of antiretroviral drugs, abacavir, nevirapine, and efavirenz from river water and wastewater using exfoliated graphite: isotherm and kinetic studies

In this work, exfoliated graphite was used to adsorb antiretroviral drugs from river water and wastewater. The exfoliated graphite was prepared from natural graphite by intercalating it with the acids and exfoliating it at 800˚C. It was characterized using Fourier Transform Infrared Spectroscopy which showed phenolic, alcoholic, and carboxylic functional groups between 1000 cm-1 and 1700 cm-1. Energy-dispersive X-ray spectroscopy results showed carbon as the main element with splashes of oxygen. The Scanning Electron Microscopy images showed increased c-axis distance between graphene layers after intercalation, which further increased after the exfoliation. The exfoliation resulted in elongated distorted cylinders, which were confirmed by the lower density (0.0068 g/mL) of exfoliated graphite material compared to the natural graphite (0.54 g/mL). The X-ray diffraction pattern showed the characteristics of hexagonal phase graphitic structure by the diffraction plane (002) at 26.74°. Raman spectroscopy results showed the natural graphite, graphite intercalated, and exfoliated graphite contained the D, G, D', and G' peaks at about 1350 cm-1, 1570 cm-1, 2440 cm-1, and 2720 cm-1, respectively indicating that the material’s crystallinity was not affected by the modification. The highest antiretroviral drugs removal (95-99%), from the water was achieved with a solution pH of 7, an adsorbent mass of 30 mg, and an adsorption time of 30 minutes. The kinetic model and adsorption isotherm studies showed that the experimental data fit well in pseudo-second-order kinetics and is well explained by Freundlich’s adsorption isotherm. The maximum adsorption capacity of the exfoliated graphite for antiretroviral drugs ranges between 1.660-197.0, 1.660-232.5, and 1.650-237.7 mg/g for abacavir, nevirapine, and efavirenz, respectively. The obtained removal percentages were 100% in river water, 63-100% in influent and 70-100% in effluent wastewater unspiked samples.

Synthesis, characterization, and evaluation of the anticancer properties of pH-responsive carvacrol-zinc oxide quantum dots on breast cancer cell line (MDA-MB-231).

Since most solid tumors have a low pH value, a pH-responsive drug delivery system may offer a broad method for tumor-targeting treatment. The present study is used to analyze the anticancer activity of carvacrol-zinc oxide quantum dots (CVC-ZnO QDs) against breast cancer cells (MDA-MB-231). CVC-ZnO QDs demonstrate pH responsive and are specifically released within the acidic pH tumor microenvironment. This property enables targeted drug delivery exclusively to cancer cells while minimizing the impact on normal cells. To the synthesized ZnO QDs, the CVC was loaded and then examined by X-ray diffraction, ultraviolet-visible, Fourier transform infrared spectrophotometer, scanning electron microscopy-energy dispersive X-ray, and transmission electron microscopy. For up to 20 h, CVC release was examined in different pH-buffered solutions. The results showed that carvacrol release was stable in an acidic pH solution. Further, cytotoxicity assay, antioxidant, and lipid peroxidation activity, reactive oxygen species, mitochondrial membrane potential, nuclear damage, and the ability of CVC-ZnO QDs to cause apoptosis were all examined. Apoptosis markers such as Bcl2, Bax, caspase-3, and caspase-9, were also studied. In conclusion, the CVC-ZnO QDs destabilized the MDA-MB-231cells under its acidic tumor microenvironment and regulated apoptosis.

Synthesis of CS-Fe3O4/GO nanocomposite for adsorption of heavy metal in aqueous environment.

In this study, magnetic material based on graphene oxide (GO) was developed for enhanced adsorption capacity for heavy metals. The Fe3O4 nanoparticles were combined with the GO material using a chitosan (CS) binder to obtain the CS-Fe3O4/GO nanocomposite. The adsorption capacity of this nanocomposite was evaluated by removing heavy metals including Ni2+ ions. When GO was composed with Fe3O4 and CS, the GO films were densely covered with ferromagnetic particles, which were bound and densely distributed on the GO film surface due to the interaction between GO and CS. The optimal conditions for the complexation of Ni2+ and 4-(2-pyridyl azo)-rezoxine (PAR) are 1 mL Ni2+, 2 mL PAR 100 mg/L, pH = 6 (adjusted with 0.7 mL of the 0.1 M K2HPO4 solution) and a complexation time of 20 min. After 50 min of adsorption, the Ni2+ removal efficiency of the CS-Fe3O4/GO nanocomposite reached 81.21 % and the corresponding adsorption capacity was 2.03 mg/g. The Ni2+ removal process followed the first-order model and Freundlich isotherm. This process was spontaneous (∆Go < 0) and an exothermic process (∆Ho = -1128.875 J.mol-1). In addition, the factors affecting this process were investigated, including the pH solution, the dosage of the CS-Fe3O4/GO nanocomposite and the initial Ni2+ concentration. The CS-Fe3O4/GO nanocomposite showed a potential adsorption capacity in removing Ni2+ at low concentrations from wastewater.

EDTA functionalized pine needle biochar (EDTA@BC); a valorized bio-material for removal of Ni(II) from aqueous solution.

The preparation of ethylenediaminetetraacetic acid (EDTA) functionalized pine needles biochar (EDTA@BC) as a low-cost active adsorbent and its effectiveness in removing Ni(II) from aqueous solution at various conditions is reported in this paper. First, alkali activation was selected to render the pine needle biochar with an excellent porous structure and increased concentration of hydroxyl groups to facilitate grafting. Subsequently, a simple method was utilized to graft EDTA onto the biochar. The prepared EDTA@BC was characterized by Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), and energy dispersive x-ray spectrometry (EDX). Batch adsorption studies were conducted to assess the impact of various parameters such as solution pH, adsorbent dosage, adsorbate volume, and shaking time on the removal efficiency of Ni(II). At pH 6, 100 mg dosage, 4 mL of adsorbate volume, and 10 min of shaking time, the maximum removal efficiency of Ni(II) was observed to be 89%. EDTA@BC showed reasonable sorption performance still after the third cycle of regeneration. The effect of interfering ions such as Pb, Cr, Cu, and Hg was evaluated, resulting a decrease of 69%, 78%, 76%, and 68%, respectively, in its sorption capacity. The Langmuir model provided a better fit for Ni(II) in the concentration range of 0.1-2000 ppm under optimized conditions, with qmax of 46.69 ± 1.031 mg/g and KL of 0.001, compared with the Freundlich isotherm, which yielded n = 0.234 and χ2 = 2.7899, Temkin isotherm (R2 = 0.9520), and Redlich-Peterson isotherm (R2 = 0.9725). The removal of Ni(II) by EDTA@BC was found to be the pseudo-second-order kinetics. Thermodynamic studies indicated adsorption process to be endothermic and nonspontaneous. Hence, a sustainable valorized bio-material (EDTA@BC) is prepared having better sorption efficiency of Ni(II) from aqueous solution with possible wide applicability. RESEARCH HIGHLIGHTS: New EDTA functionalized indigenous pine needles biochar (EDTA@BC) was prepared. This low-cost active adsorbent found effective in removing Ni(II) from aqueous solution. FTIR, SEM, and EDX proved synthesis and uptake of Ni(II) from aqueous solution. Ni(II) removal, regeneration, interfering and adsorption studies were performed by UV-Vis spectroscopy.

Mechanism of efficient adsorption for arsenic in aqueous solution by zeolitic imidazolate framework‑8.

Arsenic (As) is one extremely hazardous and carcinogenic metalloid element. Due to mining, metal smelting, and other human activities, the pollution of water (especially groundwater) and soil caused by As is increasingly serious, which badly threatens the environment and human health. In this study, a zeolite imidazolate framework (ZIF-8) was synthesized at room temperature and employed as an adsorbent to facilitate the adsorption of As(III) and As(V) from the solution. The successful synthesis of ZIF-8 was demonstrated by X-ray diffraction (XRD), and scanning electron microscopy (SEM) revealed that its particle size was approximately 80nm. The adsorption kinetics, adsorption isotherm, solution pH, dose, coexisting ions, and the synonymous elements antimony (Sb) were conducted to study the adsorption of As by ZIF-8 nanoparticles. The maximum saturation adsorption capacity was determined to be 101.47mg/g and 81.40mg/g for As(III), and As(V) at initial pH = 7.0, respectively. Apparently, ZIF-8 had a good removal effect on As, and it still maintained a good performance after four cycles. The coexisting ions PO43- and CO32- inhibited the adsorption of both As(III) and As(V). ZIF-8 performed well in removing both As and Sb simultaneously, although the presence of Sb hindered the adsorption of both As(III) and As(V). Both FTIR and XPS indicated the adsorption mechanism of As on ZIF-8: ZIF-8 generates a large amount of Zn-OH on the surface through hydrolysis and partial fracture of Zn-N, both of which form surface complexes with As.

Avocado seed as a natural coagulant for removing dyes and turbidity from wastewater: Behnken Box design, sustainable reuse, and economic evaluation

In wastewater treatment, conventional coagulants are becoming very complex with environmental concerns. For this purpose, using an alternative natural coagulant such as fruit waste becomes essential. This study explores the potential of avocado seed powder as a novel biocoagulant for treating wastewater contaminated with dyes and turbidity. It was characterized by X-ray diffraction, Fourier-transform infrared spectroscopy, Scanning Electron Microscopy coupling with Energy-dispersive X-ray spectroscopy, and X-ray fluorescence. The coagulation-flocculation process was optimized using a Box-Behnken design, evaluating the effects of coagulant dose (300–1000 mg. L−1), initial solution pH (3–9), and granulation (63–112 μm), on the removal of methylene blue, crystal violet, and turbidity. The response surface methodology revealed statistically significant quadratic models (R2 > 0.94) for maximizing pollutant removal. Under optimal conditions (1000 mg. L−1 dose, pH 9, 63 μm granulation for methylene blue; 950 mg. L−1, pH 7, 108 μm for crystal violet; 300 mg. L−1, pH 8, 63 μm for turbidity), avocado seed powder achieved maximum removal efficiencies of 94.34 % for methylene blue, 95.28 % for crystal violet, and 99.64 % for turbidity. Characterization techniques confirmed the involvement of avocado seed powder in the coagulation-flocculation mechanism. The biocoagulant has demonstrated significant reuse potential over five cycles. It also has a low estimated cost, of the order of 0.008–0.025 USD. m−3 as agricultural waste, compared with 1.5 USD. m−3 for aluminum sulfate. Overall, avocado seed is a sustainable and promising natural coagulant for wastewater treatment.

Effects of Alkaline Cleaning Agents on the Long-Term Performance and Aging of Polyethersulfone Ultrafiltration Membranes Applied for Treatment of Car Wash Wastewater

The commercial ultrafiltration polyethersulfone (PES) membranes (10 and 100 kDa) blended with polyvinylpyrrolidone (PVP) were applied for the filtration of car wash wastewater. Periodical membrane rinsing with water did not prevent fouling and a decrease in permeate flux was observed. Fouling was reduced by washing the membranes with cleaning agents, which are used in car washes to clean wheels and remove insects. In addition to surfactants, these agents contain NaOH, hence the pH value of cleaning solutions was over 11. Long-term contact with such solutions resulted in the removal of PVP from the membrane matrix and an increase in pore size. The PES membranes were soaked in an alkaline solution (pH = 11.5) for 20 months, after which the 200 kDa dextran rejection decreased from 95% to 80%. To compare with the static degradation conditions, 8 weeks of alkaline agent filtration was realized, after which the dextran (200 kDa) rejection decreased below 50%. This indicated that the cross-flow of alkaline agents can accelerate the removal of components building the membrane matrix. Despite membrane degradation, the separation efficiency (the rejection of chemical oxygen demand—COD, turbidity, and surfactants) during the treatment of synthetic car wash wastewater was similar to that obtained for pristine membranes.

Conversion of iron rusty waste into Fe dopant of TiO2 to increase its photocatalytic activity under visible light for photodegradation of rhodamine-B

This present research deals with a systematic study on doping TiO2 with Fe from iron rusty waste to improve the activity under visible light irradiation through gap narrowing in the TiO2 semiconductor structure. The doping was conducted by the sol-gel method by interacting titania tetra isopropoxide (TTIP) with Fe3+ ions dissolved from the iron rusty waste in aqua regia. The concentration of the Fe3+ was varied giving mole ratio to TiO2 as (1:0.04), (1:0.08), (1:0.12), (1:0.16), and (1:0.20). The activity of TiO2–Fe was examined for Rhodamine-B dye photodegradation through batch technique. The influences of the Fe fraction, irradiation time, photocatalyst weight, and solution pH were also evaluated to find the best condition for the dye degradation. The research results attribute that doping TiO2 with Fe3+ from the rusty waste has successfully shifted the band gap energy into the visible regime, which remarkably increases the TiO2 activity under visible light irradiation. The increase is controlled by the Fe fraction in the photocatalyst, and the best performance is shown by TiO2–Fe with a 1:0.12 mol ratio. From the dye photodegradation, it is found that the highest degradation effectiveness (99.20 %) of 5 mg/L Rhodamine B in 50 mL of the solution, can be obtained by using 50 mg of TiO2–Fe (1:0.12), pH 5, in 90 min. The photocatalyst can be reused twice in the photodegradation process without a significant decrease in photoactivity. It is implied that the rusty waste has potential as a Fe dopant source creating a better visible responsive photocatalyst.

Germination characteristics of Sorghum bicolor (L.) Moench. under different pH regimes after chemo-priming

AbstractSoil pH not only plays a regulatory role in seed germination but also influences seedling development, flowering, and crop yield. The study investigated the germination characteristics of sorghum [Sorghum bicolor (L.) Moench.] under varying pH to understand the potential ameliorative effects of seed priming using plant growth-promoting substances. Seeds were sown in Petri dishes with pH moistened solutions at 1, 3, 5, 7, 9, 11, and 13 respectively. These were replicated five times in the second stage, viable seeds were first primed in 150 ppm indole-3-acetic acid, gibberellic acid, and vitamin C before sowing in pH solutions. The experiment showed no significant changes in morphology or physiology of primed and unprimed seeds and no germination at extreme pH. However, there was a significant difference in the activity of enzymes, germination time, and speed as well as germination percentages of both primed and unprimed seeds. Although chemo-priming did not reverse the effect of pH, it was observed however that vitamin C had a significant effect on germination percentage at higher pH. Germination was observed to be impaired at extreme pH. Seeds did not respond to germination capacity suggesting an optimal pH range of 3 and 11 for germination without priming. However, priming did not show any improved germinability index. Seeds primed in the presence of light showed enhanced germination at pH 7. Generally, the germination index without priming showed better germination characteristics than primed seeds, which suggests pH interactions with primers may be a limiting factor.

Impact of pH modification of the empirically used tobramycin ophthalmic solution on MIC90 concentration in tears and aqueous humor of donkeys (Equus asinus)

BackgroundCommercial tobramycin ophthalmic solution is frequently used empirically to treat ocular disorders in equines, despite being primarily formulated for use in humans. It has been noted that tobramycin MIC90 concentration (minimal inhibitory concentration to 90% of microbial growth) rapidly declined following topical administration. It is hypothesized that adjustment of the pH of the empirically used tobramycin ophthalmic solution -prepared for human use- with the pH of the tears of donkeys, could increase the bioavailability of the drug and subsequently improve its penetration to the aqueous humor. Therefore, this study aimed to evaluate the impact of pH adjustment of the empirically used tobramycin ophthalmic solution on MIC90 concentration in tears and aqueous humor of donkeys (Equus asinus). The study was conducted on six (n = 6) clinically healthy donkeys. In each donkey, one eye was randomly selected to receive 210 µg tobramycin of the commercial tobramycin (CT) and used as a positive control (C group, n = 6). The other eye (treated eye) received 210 µg of the modified tobramycin ophthalmic solution (MT) (T group, n = 6). Tears and aqueous humor samples were collected 5-, 10-, 15-, 30- min, and 1-, 2-, 4-, and 6 h post-instillation.ResultsModifying the pH of the empirically used commercial tobramycin ophthalmic solution in donkeys at a pH of 8.26 enhanced the drug’s bioavailability. The MIC90 of the most hazardous bacteria isolated from equines’ eyes such as Pseudomonas aeruginosa (MIC90 = 128 µg/ml) and Staphylococcus aureus (MIC90 = 256 µg/ml) was covered early (5 min post-instillation) and over a longer period in donkey tears (239–342 min) and aqueous humor (238–330 min) with the modified tobramycin solution.ConclusionsAdjustment of the pH of the commercial tobramycin ophthalmic solution, empirically used by veterinarians to treat donkeys’ ophthalmic infections at a pH of 8.26, isotonic with the donkeys’ tears pH, resulting in higher concentrations of tobramycin in tears and aqueous humor for a longer time.

A molecularly imprinted electrochemical sensor MIP/Cu-MOF/rGO/AuNPs/GCE for highly sensitive detection of electroneutral organophosphorus pesticide residues.

A novel electrochemical sensor, MIP/Cu-MOF/rGO/AuNPs/GCE, was developed by depositing gold nanoparticles, coating Cu-MOF/GO on the surface of glassy carbon electrode (GCE) before electroreducing graphene oxide (GO) to rGO and covering molecularly imprinted membrane by electropolymerization for highly sensitive detection of electroneutral organophosphorus pesticide residues in agricultural product. Cyclic voltammetry, differential pulse voltametry, scanning electron microscopy, energy-dispersive spectroscopy, and atomic force microscopy were used to characterize the imprinted sensor. Several key factors such as chitosan concentration, suspension volume, pH of polymerization solution, and polymerization scanning rate during preparation of the imprinted sensor were optimized in detail. When electroneutral phosmet was used as a template, the linear range of MIP/Cu-MOF/rGO/AuNPs/GCE for detecting phosmet was 1.00 × 10-14-5.00 × 10-7 mol/L with the limit of detection of 7.20 × 10-15 mol/L at working potentials of - 0.2 to 0.6 V. The selectivity, reproducibility, and repeatability of MIP/Cu-MOF/rGO/AuNPs/GCE were all acceptable. The recoveries of this method for determining phosmet in real samples ranged from 94.2 to 106.5%. The MIP/Cu-MOF/rGO/AuNPs/GCE sensor could be applied to detect electroneutral pesticide residues in organisms and agricultural products.

A novel copper ion enhanced electrochemical DNA biosensor for the determination of epinephrine

A novel electrochemical biosensor was developed for the detection of epinephrine (EP) by immobilizing double-strand DNA (dsDNA) bound with copper ions on a gold electrode (Cu2+/dsDNA/MCH/AuE). The electrochemical behavior of EP at Cu2+/dsDNA/MCH/AuE was examined, and the results demonstrated a significant enhancement in the electrocatalytic oxidation peak current of EP due to the formation of a stable G-Cu(II)-G sandwich structure between Cu2+ and guanine at the modified electrode. The modification process of the electrode was characterized by scanning electron microscopy, infrared spectroscopy, electrochemical impedance spectroscopy, and differential pulse voltammetry. A study on the effect of pH in phosphate buffer solution on the electrochemical oxidation of EP indicated that the catalytic oxidation process was pH-dependent. A plot of catalytic current versus EP concentration exhibited a dual-linear relationship within two ranges: 1.0–12.5 μM and 12.5–1000.0 μM, with correlation coefficients of 0.995 and 0.997, respectively. The limit of detection was determined to be 47 nM (S/N = 3). According to the calculated Hill coefficient (0.99), it can be concluded that the electrocatalytic process followed the Michaelis-Menten kinetic mechanism. The maximum catalytic current Im was 25 μA, while the apparent Michaelis-Menten constant Km was 1.425 mM. These findings indicated excellent electrocatalytic activity of the modified electrode towards oxidation of EP. The developed biosensor successfully detected EP in spiked mouse serum as well as epinephrine hydrochloride injection with high selectivity, sensitivity, stability, and accuracy.

Lyophilizable Stem Cell-Hybrid Liposome with Long-Term Stability and High Targeting Capacity.

The hybridization of liposome with stem cell membrane is an emerging technology to prepare the nanovehicle with the capacity of disease-responsive targeting. However, the long-term storage of this hybrid liposome has received limited attention in the literature, which is essential for their potential applicability in the clinic. Therefore, the preservation of long-term activity of stem cell-hybrid liposome using freeze-drying is investigated in the present study. Mesenchymal stem cell-hybrid liposome is synthesized and its feasibility for freeze-drying under different conditions is examined. Results revealed that pre-freezing the hybrid liposome at -20°C in Tris buffer solution (pH 7.4) containing 10% trehalose could well preserve the liposomal structure for at least 3 months. Notably, major membrane proteins on the hybrid liposome are protected in this formulation and CXCR4-associated targeting capacity is maintained both in vitro and in vivo. Consequently, the hybrid liposome stored for 3 months demonstrate a comparable tumor inhibition as the fresh-prepared ones. The present study provides the first insights into the long-term storage of stem cell hybrid liposome using lyophilization, which may make an important step forward in enhancing the long-term stability of these promising biomimetic nanovehicle and ease the logistics and the freeze-storage in the potential clinical applications. This article is protected by copyright. All rights reserved.

Investigation of the efficacy of Alhagi maurorum plant powder for Janus Green B dye removal from wastewater

The growth of industrial activities, has led to a significant increase in the influx of color pollutants into the environment. Phytoremediation can play a crucial role in enhancing wastewater quality. Accordingly, this study sought to evaluate the effectiveness of Alhagi maurorum plant powder in removing Janus Green B (JGB) dye from aqueous solutions. The adsorbent’s properties were characterized through Fourier-transform infrared spectroscopy. The study examined various parameters, including initial dye concentration (20–110 mg/L), adsorbent dosage (0.002–0.02 g), solution pH (2–10), and contact time (5–50 min). The experiments revealed that the maximum dye removal efficiency, 99.51%, was achieved under optimal conditions: pH 7, a contact time of 20 min, an adsorbent dosage of 0.01 g, and an initial dye concentration of 90 mg/L. The adsorption of JGB onto the adsorbent followed the Langmuir isotherm model, with a maximum adsorption capacity of 90.909 mg/g. The kinetic results supported a pseudo-second-order model for the adsorption process, with an R 2 value of 0.9999. The calculated Gibbs free energy changes (ΔG°) at temperatures of 288, 298, 308, 318, and 328 K were found to be −5354.28, −5993.61, −6439.66, −7026.51, and −7932.05 kJ/mol, respectively, indicating the spontaneity of the adsorption process.

Laboratory study on the transformation of oil-water interface properties under direct current electric field

Interface tension is one of the important mechanisms that affect crude oil recovery and plays an important role in the development of tight oil reservoirs. Electrical-enhanced oil recovery can be used as a technology to reduce interfacial tension and improve crude oil recovery. In the previous research process of Electrical-enhanced oil recovery, the focus was more on the influence of electric field on wettability, and the understanding of the changes in interfacial tension under electric field action is not yet comprehensive. This article designs an orthogonal experiment to study the effect of electric field on oil-water properties. The degree of influence of three factors, namely sodium chloride solution concentration (C), direct current voltage (V), and voltage action time (t), on interfacial tension is studied. Gas chromatography, four component analysis, and Fourier transform infrared spectroscopy are combined to discuss the mechanism of the influence of changes in solution pH, crude oil components, and oil phase functional groups on interfacial tension. The results show that an external electric field can effectively reduce the interfacial tension between oil and water, and the maximum change in interfacial tension after the experiment can be reduced from 23.21 mN/m to 0.37 mN/m; Through range analysis, it can be concluded that the concentration of sodium chloride solution has the greatest impact on interfacial tension, followed by DC voltage and voltage action time. The optimal experimental conditions are 0.5mol/L sodium chloride solution, 10V DC voltage, and a voltage action time of 18 hours, and the change in interfacial tension is related to the increase in pH value. The change in crude oil composition is also an important reason for the decrease in interfacial tension under external electric fields. Finally, Fourier transform infrared spectroscopy was used to determine that under the action of an electric field, the increase in pH of the sodium chloride solution resulted in the formation of carboxylate salts through chemical reactions between alkaline substances of solution and acidic substances of the oil, which were the key factors in reducing interfacial tension. This study helps to understand and explore the principles and mechanisms of Electrical-enhanced oil recovery in improving oil recovery, with the aim of contributing to the development and promotion of Electrical-enhanced oil recovery technology.

Overlooked effects of chlorides and bicarbonates on the intensity of peroxydisulfate activation in Fe(II)/citric acid-S2O82− process

The influence of chlorides (Cl−) and bicarbonates (HCO3−) on the Fe(II)/citric acid peroxydisulfate based (Fe(II)/CA-S2O82−) process has been commonly attributed to the formation of secondary reactive species, such as Cl• and CO3•, and their different reactivity with the target pollutant compared to primary reactive species (e.g., SO4•−). However, this conclusion has been entirely based only on analyzing target pollutants removal without the context of S2O82− consumption and dissolved Fe concentration throughout the process. To address this knowledge gap, we conducted a series of batch experiments to investigate the influence of Cl− (2 mmol∙L-1) and HCO3− (1 mmol∙L-1) on the intensity of S2O82− activation within the Fe(II)/CA-S2O82− process with tetrachloroethene (PCE) as the target pollutant. Throughout the experiments, PCE removal efficiency, S2O82− consumption, pH, redox potential, and dissolved Fe were analyzed. Equilibrium hydrochemical modelling (Visual MINTEQ 4) and high-resolution transmission electron microscopy (TEM) were employed to analyze and interpret the data obtained. We found that both Cl− and HCO3− significantly affected the intensity of S2O82− activation. While Cl− influenced the steady-state dissolved Fe(II) concentration, HCO3− primarily increased solution pH, which led to the formation of CA-stabilized ferrihydrite nanoparticles. This resulted in the inaccessibility of dissolved Fe(III) to the Fe(III)/Fe(II) regeneration cycle, consequently suppressing S2O82− activation intensity and PCE removal. Overall, the findings in this study have deepened the fundamental knowledge of how Cl− and HCO3− influence the Fe(II)/CA-S2O82− process, which may help improve the design and operation of S2O82−-based advanced oxidation processes using the Fe(II)/CA activation method.

Impact of LaZnFe2O4 supported NiWO4@D400-MMT@CMS/MMA nanocomposites as a catalytic system in remediation of dyes from wastewater

Herein, a novel nanocomposite based on lanthanum zinc ferrite and nickel tungstate was created by incorporation between (MMT-jeffamine-400) nanoparticles (NPs), chloromethyl styrene as a binder and polymethyl methacrylate monomer using solution polymerization. The as-designed nanocomposites were employed to confiscate xylenol orange “X.O” as an acidic dye and rhodamine B “RhB” as “an amphoteric dye” from colored wastewater. The impact of several parameters such as solution pH, initial dye concentration, the effect of time, and the effect of temperature was explored. The consequences indicated that the pure organoclay had negligible adsorption while that composed of organoclay with PMMA@CMS-polymer incorporated with LaZnFe2O4@NiWO4 particles detached more than 90% for xylenol orange (XO) and 93% for “rhodamine B” molecules. Electrostatic interactions are the predominant factor in the adsorption of cationic and amphoteric adsorbates, as proven by zeta-potential measurement. Additionally, the adsorbent may be regenerate and utilized up to five times with good adsorption capabilities by adding sodium hydroxide. As a result, the removal can be effectively accomplished using the nanocomposite as an adsorbent. The actual and theoretical adsorption capacity values for both dyes at all doses were closely matched, which supported the adsorption kinetics data that fit the pseudo-first order rate model well. The adsorption data’s correlation values (0.995 for XO and 0.98 for RhB) indicated that both dyes’ Langmuir adsorption would perform well. Furthermore, the adsorption of XO and RhB dyes on the adsorbent is confirmed to be a viable reaction by the negative values of ΔGo. The enhanced adsorbent material for the removal of amphoteric and anionic dyes from waste water is the synthesized LaZnFe2O4 supported NiWO4@D400-MMT@CMS/MMA nanocomposites, which exhibits a reusability affinity of up to five cycles.