Ratio Of Chloride Research Articles

Interfacial electron modulation of Cu2O by Co3O4 embedded in hollow carbon cube skeleton for boosting oxygen reduction/revolution reactions

Copper (Cu) oxides with various oxidation states are known to be extremely active for oxygen reduction/evolution reactions (ORR/OER). Here, Cu2O-based composites by combining with Co3O4 are designed as non-noble catalysts for ORR/OER by using density-functional-theory (DFT) calculations. Cu-sites in Cu2O-Co3O4 (111) structure are the main active-sites for ORR/OER, which can obtain desirable interfacial charge transfer through favorable energy band arrangements. As inspired by calculation results, Cu2O nanoparticles (20–30 nm) coated on hollow zeolitic imidazolate framework-67 (ZIF-67)-derived nitrogen (N)-doped carbon-cube (HZCNC) with skeleton Co3O4 are prepared as a hollowly-wrapped structure (Cu2O/HZCNC) for boosting ORR/OER, which makes it have the fast electron/mass transfer characteristics. Catalyst marked as Cu2O/HZCNC-0.425 (mass ratio of copper chloride to HZCNC is 0.425) exhibits better ORR activity (E1/2 of 0.90 V) and methanol tolerance than Pt/C, a lower overpotential (350 mV) than RuO2 for OER, and a stable cell voltage gap (0.941 V, average) in a primary zinc-air battery even after 200 h. As indicated by density functional theory results, Cu2O can energetically supply the electrons to the closely-contacted HZCNC (Co3O4) to enhance ORR/OER activities and stabilities. It highlights the excellent functions of Cu-oxides in oxygen electrocatalysis, and provides new insights for development of highly-efficient electrocatalysts with hollow structure.

Micellization of conventional and gemini surfactants in aquoline: A case of exclusively water based deep eutectic solvent

Deep eutectic solvents (DES) based on water as the only hydrogen bond donor (HBD) have been introduced recently (aquoline). There is not a single report on surfactant association behaviour in aquoline. This study deals with the determination of physical properties (rheology, specific conductance, pH, micro polarity and apparent dielectric constant) of pure aquoline (with different molar ratios of choline chloride (ChCl): water, DES I - DES IV) and association behaviour of ionic surfactants in such aquoline systems. DESs were found Newtonian and highly polar / conducting fluids with nearly neutral pH (6.9–7.1). Micellization behaviour of different ionic surfactants (sodium dodecyl sulphate (SDS), sodium dodecane-1-sulphonate (SDSo), sodium dodecyl benzene sulphonates (SDBS), P, P'-1,4-butanedieyl, P, P'-didodecylester, disodium salt (12-4-12A), cetyltrimethylammonium ammonium bromide (CTAB) or dodecyl trimethyl ammonium bromide (DTAB)) has been studied fluorometrically in various aquolines and compare data with an aqueous medium. In most of the cases, critical micelle concentration (CMC) values have been found lower than water which may be due to the presence of choline chloride (ChCl, one of the components of aquoline), which can interact micelle electrostatically and hydrophobically. For different head groups in anionic surfactant, CMC follows the order 12-4-12A < SDBS < SDS < SDSo, which fits in the Hoffmeister like series of head groups. For cationic surfactants (CTAB and DTAB), CMC shows a similar chain length effect as observed in water. Overall, CMC data allow to propose that CMC decreases with an increase in molar content of water in a typical aquoline under eutectic limit. Micellar aggregation number (Nm), Stern-Volmer constant, micellar polarity, and apparent dielectric constant were also computed. It has been observed that micelles of lower Nm, with high polarity, are formed in a typical aquoline system (DES III). The study may find applications where organized assemblies are required in highly polar solvents.

Molecular insights into the structure-property relationships of 3D printed polyamide reverse-osmosis membrane for desalination

3D-printing is an emerging method for manufacturing polyamide (PA) reserve osmosis (RO) membranes for water treatment and desalination, which can precisely control membrane structural properties, such as thickness, roughness, and resolution. However, the synthesis-structure (i.e., degree of cross-linking (DC), m-phenylenediamine/trimesoyl chloride (MPD/TMC) ratio, and membrane thickness) to property (permeability and water-salt selectivity) relationships for these membranes has not been well understood. At the same time, a microscopic understanding of the physical mechanism of water and salt transport is needed to guide the design of high-performance 3D-printed membranes and improve the printing efficiency. Thus, the atomic-scale transport features and energetics of water and salt ions are studied at high pressure for the 3D-printed PA RO membranes with the different DCs and MPD/TMC ratios through non-equilibrium molecular dynamics (NEMD) simulations. Factoring in membrane structure properties, rejection ratio of salt ions and pressure-dependent water flux, 3D-printed PA membranes having an MPD/TMC ratio of 3.0:2.0 and a DC between 80%∼90% attains ideal performance: high water flux, high rejection of salt ions, and excellent structural integrity. Mechanistically, water permeability for highly cross-linked PA RO membranes depends on the temporary on-and-off channels that allow water molecules to jump from one cavity to another at high pressure. In addition, higher pressures cause rapid compaction of PA membranes’ free volume and membrane thickness. Membrane failure at high pressure is determined by the DC and MPD/TMC ratios-dependent compressive yield strength. In short, these findings provide physical insights for optimizing existing PA membranes and designing next-generation desalination membranes at the molecular level.

Effect of different molar ratios of choline chloride–citric acid monohydrate in deep eutectic solvents as plasticizers for Averrhoa bilimbi pectin films

Effect of different molar ratios of choline chloride–citric acid monohydrate in deep eutectic solvents as plasticizers for Averrhoa bilimbi pectin films

A comprehensive experimental and modeling study on CO2 solubilities in the deep eutectic solvent based on choline chloride and butane-1,2-diol

In this study, the performance of a novel DES, consisting of butane-1,2-diol as the hydrogen bond donor (HBD) and choline chloride as the hydrogen bond acceptor (HBA), was investigated thermodynamically for carbon dioxide absorption. The molar ratio of choline chloride to butane-1,2-diol was 1:4. Carbon dioxide solubilities in this DES were measured experimentally in a high-pressure equilibrium cell. The solubility measurements were carried out in a temperature range of 303.2 to 333.2 K, and pressures up to almost 3.4 MPa. The P-x isotherms showed an almost linear increase of solubility with increasing pressure. Based on the measured experimental data, the values of Henry's constants at very dilute concentrations were calculated, as well as the standard enthalpies, entropies, and Gibbs free energies of dissolution. By analyzing the calculated parameters, it was concluded that the dissolution process is exothermic, and that stronger interactions prevail in the mixture of carbon dioxide and the investigated DES, as compared to the interactions within the neat components. Finally, the Cubic Plus Association (CPA) and Soave-Redlich-Kwong (SRK) equations of state (EoSs) were used to model the experimental solubility data. Absolute average relative deviation percent (AARD%) values of 3.78% and 5.48% for the CPA and SRK EoSs, respectively, indicated good agreement with experimental values for both models. However, the CPA EoS achieved higher accuracy, and with much smaller values of binary interactions parameters, thus indicating the importance of considering association interactions for the accurate modeling of carbon dioxide solubilities in DESs.

Synthesis of multi-branched Au nanocomposites with distinct plasmon resonance in NIR-II window and controlled CRISPR-Cas9 delivery for synergistic gene-photothermal therapy

Clinical implementation of photothermal therapy (PTT) is mainly hampered by limited tissue penetration, undesirable thermal damage to normal tissues, and thermotolerence induced by heat shock proteins (HSPs). To overcome these obstacles, we constructed a novel gene-photothermal synergistic therapeutic nanoplatform composed of a multi-branched Au nanooctopus (AuNO) core and mesoporous polydopamine (mPDA) shell, followed by CRISPR–Cas9 ribonucleoprotein (RNP) loading and then polyethylene glycol-folic acid (PEG-FA) coating. AuNO was simply synthesized by adjusting the ratio of cetyltrimethylammonium chloride (CTAC) and cetyltrimethylammonium bromide (CTAB), which showed significant localized surface plasmon resonances in the NIR-II window, and exhibited an excellent tissue penetration capability and high photothermal conversion efficiency (PCE, 47.68%). Even, the PCE could be further increased to 66.17% by mPDA coating. Furthermore, the sequential modification of AuNO@mPDA using RNP and PEG-FA can down-regulate HSP90α expression at tumor sites, enhance apoptosis and reduce the heat resistance of cancer cells. The synergistic effect of enhanced photothermal capacity and reduced thermoresistance addressed the multiple limitations of PTT, and presented excellent in vitro and in vivo antitumor efficacy, having great potential for the clinical application of PTT.

반응표면분석을 이용한 카파 카라기난과 염화칼슘 첨가 고령친화형 젤라틴 젤의 최적 배합비율 확립

The objective of this study was to determine the optimal mixing ratios of pork skin gelatin, κ-carrageenan, and calcium chloride for manufacturing senior-friendly gelatin gels with hardness for tongue or gum intake, as well as fulfilling protein, dietary fiber, and calcium contents of the Korean industry standard (KS) for senior-friendly foods. The optimal mixing ratio of the ingredients was determined within 6.60~33.3% (w/v) pork skin gelatin, 2.50~6.25% (w/v) κ-carrageenan, and 0.235~2.351% (w/v) calcium chloride using response surface methodology. The mixing ratios for the senior-friendly gelatin having the hardness of 2 to 5 N/cm2 were predicted as 6.605~11.331% (w/v) pork skin gelatin, 2.74~6.25% (w/v) κ-carrageenan, and 0.235% (w/v) calcium chloride. The amounts of nutrients (proximate composition, calcium, and dietary fiber contents) in the senior-friendly gelatin gels were significantly affected by changing the mixing ratio of the three ingredients. In conclusion, thereby mixing 6.605~11.331% (w/v) pork skin gelatin, 2.74~6.25% (w/v) κ-carrageenan, and 0.235% (w/v) calcium chloride, it could be confirmed to control the hardness corresponding to 2nd to 3rd hardness grades of senior-friendly gelatin gels, with fulfilling the nutrients standards for 6 g of protein, 80 mg of calcium, and 2.5 g of dietary fiber per 100 g of product.

Features of the Process Obtaining of Mg-Zn-Y Master Alloy by the Metallothermic Recovery Method of Yttrium Fluoride Melt

At present, magnesium master alloys with such rare earth metals (REM) as yttrium are used in the production of alloys of magnesium and aluminum. These alloys especially the system Mg-6Zn-1Y-0,5Zr are commonly used in the aircraft and automotive industries. The article is devoted to the exploration of the synthesis process features for ternary magnesium master alloys with yttrium and zinc. The authors used X-ray fluorescence analysis (XRF), differential thermal analysis (DTA), and X-ray spectral analysis (XRD). Optical microscopy was used to conduct microstructural studies. The thermal effects that occur during metallothermic reactions of yttrium reduction from the YF3-NaCl-KCl-CaCl2 salt mixture with a melt of magnesium and zinc were investigated, and the temperatures of these effects were determined. It has been confirmed that the metallothermic reaction of yttrium reduction proceeds from the precursors of the composition: Na1.5Y2.5F9, NaYF4, Na5Y9F32, and KY7F22, and starts at a temperature of 471 °C. The results of experimental studies of the process of metallothermic reduction of yttrium from the salt mixture YF3-NaCl-KCl-CaCl2 are presented in detail. These experiments were carried out in a pit furnace at temperatures ranging from 650 to 700 °C, and it was found that, at a synthesis temperature of 700 °C, the yttrium yield is up to 99.1–99.8%. The paper establishes rational technological regimes for the synthesis (temperature 700 °C, exposure for 25 min, the ratio of chlorides to yttrium fluoride 6:1, periodic stirring of the molten metal) at which the yttrium yield reaches up to 99.8%. The structure of the master alloy samples obtained during the experiments was studied. That structure can be distinguished by a uniform distribution of ternary intermetallic compounds (Mg3YZn6) in the bulk of the double magnesium–zinc eutectic. Studies have been carried out on testing the obtained ternary master alloy as an alloying material in the production of alloys of the Mg-6Zn-1Y-0.5Zr system, while the digestibility of yttrium ranged from 91 to 95%.

The pressure effects on the Amine-Based DES performance in NG Sweetening: Insights from molecular dynamics simulation

Deep eutectic solvents (DESs) have gained considerable attentions as novel green solvents in the natural gas (NG) sweetening processes Using molecular dynamics simulations, the performance of an amine-based DES composed of a 6: 1 M ratio of methyl diethanolamine (MDEA) and choline chloride (ChCl) for NG sweetening process is investigated. To this end, the effect of pressure on the performance of amine-based DESs for sweetening of the NG, and the penetration of acid gasses from the NG to the DES are examined. The results of the H2S and CO2 solubility in the DES phase demonstrate that H2S and CO2 solubilities are proportional to the pressure, and the maximum values of 0.225 and 0.04 are obtained for H2S and CO2 solubilities, respectively, at 2 MPa and 310 K. Additionally, calculations of the solubility selectivity parameter at various pressures reveal monotonic behaviors for the solubility selectivity of H2S over CH4. The solubility selectivity of H2S over CH4 has a larger value, by a factor of 10 to 20, than the solubility selectivity of CO2 over CH4 at pressure range from 0.1 MPa to 2 MPa. It can be concluded that the MDEA-based DES used here, have higher efficiency for H2S separation, and greater selectivity towards CO2 and CH4 compared to aqueous MDEA-solvent. The structural and dynamical analyses are computed to assist interpreting of the observed behavior at the molecular level. Moreover, diffusion coefficient of H2S (102 Å2/n) and CO2 (302.3 Å2/ns) in MDEA-based DES at 2 MPa and 310 K have the lowest values among all the considered pressures. Our findings indicate that MDEA-based DES can compete with the conventional amine solvents in the NG sweetening processes.

Enhanced Extraction Efficiency of Flavonoids from Pyrus ussuriensis Leaves with Deep Eutectic Solvents

In this study, deep eutectic solvents (DESs) were synthesized using different ratios of choline chloride (CC) and dicarboxylic acids, and their eutectic temperatures were determined. The DES synthesized using CC and glutaric acid (GA), which showed a higher extraction efficiency than conventional solvents, was used for the extraction of flavonoid components from Pyrus ussuriensis leaves (PUL), and the extraction efficiency was evaluated using the response surface methodology. The flavonoid components rutin, hyperoside, and isoquercitrin were identified through high-performance liquid chromatography (HPLC), equipped with a Waters 2996 PDA detector, and HPLC mass spectrometry (LC-MS/MS) analyses. The optimum extraction was achieved at a temperature of 30 °C using DES in a concentration of 30.85 wt.% at a stirring speed of 1113 rpm and an extraction time of 1 h. The corresponding flavonoid content was 217.56 μg/mL. The results were verified by performing three reproducibility experiments, and a high significance, with a confidence range of 95%, was achieved. In addition, the PUL extracts exhibited appreciable antioxidant activity. The results showed that the extraction process using the DES based on CC and GA in a 1:1 molar ratio could effectively improve the yield of flavonoids from PUL.

Deep Eutectic Solvents (DESs)-Ultrasonic-Assisted Extraction of Paeoniflorin and Paeonol from Moutan Cortex

Deep eutectic solvents (DESs-)-ultrasonic-assisted extraction technology was used to evaluate and optimize the extraction process of paeoniflorin and paeonol in Moutan Cortex. First of all, 10 kinds of choline chloride-based DESs were selected as potential extraction solvents, and the DES extraction effect of choline chloride: lactic acid was determined to be the best. Then, single-factor experiments were conducted to explore the effects of DES composition (molar ratio, water content, and ratio of material to liquid) and ultrasonic treatment (ultrasonic power, extraction time, extraction temperature, and vortex time) on the yield of paeoniflorin and paeonol in Moutan Cortex. On this basis, the response surface method was used to optimize the process of ultrasonic-assisted extraction of paeoniflorin and paeonol from Moutan Cortex with DESs. The results showed that the optimum process parameters of DESs-ultrasonic-assisted extraction of paeoniflorin and paeonol from Moutan Cortex were as follows: molar ratio of choline chloride to lactic acid was 1 : 2, water content was 30%, ratio of material to liquid was 1 : 30 (g/mL), ultrasonic power was 300 W, extraction time was 33 min, extraction temperature was 50°C, and vortex time was 5 min. Under these conditions, the yield sum of paeoniflorin and paeonol in the obtained Moutan Cortex was 9.279 mg/g. The difference between the experimental value and the theoretical value was 0.333 mg/g. The results showed that the response surface method can simulate and predict the yield of paeoniflorin and paeonol in Moutan Cortex under different extraction conditions, and it was feasible to optimize the process parameters. The results of this study show that DES has great potential to replace traditional solvents in the extraction of active components of the Moutan Cortex. The study on the extraction of active components of traditional Chinese medicine by DES is helpful to expand the scope of the application of DES in traditional Chinese medicine.

Preparation and performance improvement of chlorides/MgO ceramics shape-stabilized phase change materials with expanded graphite for thermal energy storage system

Cold compression and mixed sintering methods have attracted attention for their applicability to industrial mass production. Due to the wettability of expanded graphite (EG) and salt chlorides, the decoupling of the encapsulation effect of EG and ceramics should be considered in the form-stable composite materials ratio of ternary chlorides (TC)/MgO ceramics/EG. In this study, 40 wt%-55 wt% MgO and 5 wt%-20 wt% EG are added to the composites, respectively. It is found that the composite system can be loaded with nearly 45 wt% molten salts. The 45 wt% TC-15 wt% EG-40 wt% MgO sample named 15EG-40MgO is considered a close to optimal formulation in terms of thermal conductivity enhancement and energy density reduction. This proportional composite has a thermal conductivity of 8.86 W∙m−1∙K−1, and in the temperature range of 300–600 °C, the thermal storage density reaches 439.53 J·g−1. With the increase of TC content, the density of the composites shows a decreasing trend. However, all samples have excellent mechanical strength due to the MgO ceramics as the supporting material. Moreover, these composites can be easily integrated into a solar thermal storage system, which proposes a new strategy for applying a high-temperature packed-bed containing salt-based composite phase change materials.

Chemical Pretreatment on Flower Waste to Enhance the Production of Biogas through Anaerobic Digestion

Flowers are extensively used in many occasions in our country irrespective of auspicious or inauspicious functions. It is also adding to another biodegradable waste. But the improper disposal is causing pollution to environment. The same if used effectively will be converted into bioenergy that can find many applications further. Survey was conducted in Kengeri area for the number of temples, party halls, and market areas for producing flower waste. The amount of flower waste collected is estimated. The specific species of flower was taken for experimental study, knowing the species of flower waste it was tested for various parameters such as pH, temperature, moisture content, alkalinity, chloride, carbon and nitrogen ratio, BOD and COD. After obtaining the results for above parameters, sample was taken for pretreatment of physical, chemical Pretreatment and further subjecting to anaerobic decomposition. The investigation was undertaken to find out the biogas production potential of flower waste coming out from temples by building. Laboratory scale digesters of22L capacity and fed with flower waste with physical pretreatment. The waste was digested for retention period of 35 day under batch fed system at total solid concentration of 8 %( w/v) and constant temperature of 32±2°C. The optimum quantity of flower waste inoculums and water was used. The chemical pretreatment with NaOH (0.3N) as alkaline and HCL (0.2) as acid were given and after grinding it was added in the digestion process to enhance biogas production. The pressure of biogas is measured and the concentration of methane gas is determined by the gas chromatographer.

Nocturnal Atmospheric Oxidative Processes in the Indo-Gangetic Plain and Their Variation During the COVID-19 Lockdowns.

This study investigates selected secondary atmospheric responses to the widely reported emission change attributed to COVID‐19 lockdowns in the highly polluted Indo‐Gangetic Plain (IGP) using ground‐based measurements of trace gases and particulate matter. We used a chemical box‐model to show that production of nighttime oxidant, NO3, was affected mainly by emission decrease (average nighttime production rates 1.2, 0.8 and 1.5 ppbv hr−1 before, during and relaxation of lockdown restrictions, respectively), while NO3 sinks were sensitive to both emission reduction and seasonal variations. We have also shown that the maximum potential mixing ratio of nitryl chloride, a photolytic chlorine radical source which has not been previously considered in the IGP, is as high as 5.5 ppbv at this inland site, resulting from strong nitrate radical production and a potentially large particulate chloride mass. This analysis suggests that air quality measurement campaigns and modeling explicitly consider heterogeneous nitrogen oxide and halogen chemistry.

Research on Self-melting Snow Material of Asphalt Pavement

The effects of pozzolan and calcium chloride on the performance of asphalt mixtures were analyzed by laboratory performance tests. Using the maximum bulk density of mixed materials after vibration compaction, Determined the reasonable ratio of calcium chloride to fill the voids of pozzolanic material. The amount of surface modified material was determined based on the precipitation rate of the melting snow component and the effect on asphalt performance under cyclic water immersion conditions. Tested the performance of the asphalt mixture, self-melting snow material can improve the low temperature performance of the mixture. There is a certain reduction in high temperature performance and water stability, but all meet the requirements of normative indicators.

Rationally Designed Ternary Deep Eutectic Solvent Enabling Higher Performance for Non-Aqueous Redox Flow Batteries

Redox flow batteries hold promise as large-scale energy storage systems for off-grid electrification. The electrolyte is one of the key components of redox batteries. Inspired by the mechanism involved in solvents for extraction, a ternary deep eutectic solvent (DES) is demonstrated, in which glycerol is introduced into the original binary ethaline DES. Redox pairs (active substance) dissolved in the solvent have low charge transfer resistance. The results show that the viscosity of the solvent with the ratio of choline chloride to ethylene glycol to glycerol of 1:2:0.5 decreases from 51.2 mPa·s to 40.3 mPa·s after adding the redox pair, implying that the mass transfer resistance of redox pairs in this solvent is reduced. Subsequent cyclic voltammetry and impedance tests show that the electrochemical performance with the ternary DES as the electrolyte in redox flow batteries is improved. When the ratio of 1:2:0.5 ternary DES is used as the electrolyte, the power density of the battery (9.01 mW·cm−2) is 38.2% higher than that of the binary one (6.52 mW·cm−2). Fourier transform infrared spectroscopy further indicates that the introduction of glycerol breaks the hydrogen bond network of the solvent environment where the redox pair is located, unraveling the hydrogen bond supramolecular complex. Rational solvent design is an effective strategy to enhance the electrochemical performance of redox batteries.

Ultrastable Covalent Triazine Organic Framework Based on Anthracene Moiety as Platform for High-Performance Carbon Dioxide Adsorption and Supercapacitors.

Conductive and porous nitrogen-rich materials have great potential as supercapacitor electrode materials. The exceptional efficiency of such compounds, however, is dependent on their larger surface area and the level of nitrogen doping. To address these issues, we synthesized a porous covalent triazine framework (An-CTFs) based on 9,10-dicyanoanthracene (An-CN) units through an ionothermal reaction in the presence of different molar ratios of molten zinc chloride (ZnCl2) at 400 and 500 °C, yielding An-CTF-10-400, An-CTF-20-400, An-CTF-10-500, and An-CTF-20-500 microporous materials. According to N2 adsorption–desorption analyses (BET), these An-CTFs produced exceptionally high specific surface areas ranging from 406–751 m2·g−1. Furthermore, An-CTF-10-500 had a capacitance of 589 F·g−1, remarkable cycle stability up to 5000 cycles, up to 95% capacity retention, and strong CO2 adsorption capacity up to 5.65 mmol·g−1 at 273 K. As a result, our An-CTFs are a good alternative for both electrochemical energy storage and CO2 uptake.

The Effect of Magnesium Chloride on the Macroscopic and MI-Croscopic Properties of Phosphate Cement-Based Materials

Phosphate cement-based materials are fast-hardening cement materials, which have been applied to the rapid repair of concrete structures. However, the excessive setting rate could lead to initial cracks in the cement-based matrix. Therefore, a proper retarder is required to reduce the setting rate, thus improving the strength of structures. In this study, a magnesium chloride retarder was selected, and its influence on the setting time, slump flow, and the mechanical strengths (flexural strength, compressive strength, and bond strength) of phosphate cement paste curing for 3 h~28 d was investigated. Scanning electron microscopy, X-ray diffraction, and thermal analysis were used to analyze the mechanism of the properties of phosphate cement paste. Results showed that the setting time increased exponentially with the mass ratio of magnesium chloride by the total mass of magnesium oxide. Meanwhile, the slump flow increased linearly with the increasing dosage of magnesium chloride, and the drying shrinkage rate exhibited a quadratic function with the curing age. The addition of magnesium chloride decreased the mechanical strengths of phosphate cement paste at earlier curing age (lower than 3 d) and effectively improved the mechanical strengths at a later curing age (equal to or higher than 3 d). Moreover, magnesium chloride could also decrease the drying shrinkage rate. It can be obtained from the microcosmic researching results that magnesium chloride can inhibit the hydration of phosphate cement and reduce cracks induced by drying shrinkage at later curing age (higher than 3 d).

Green Synthesis of Iron Oxide Nanoparticles Using Hibiscus rosa sinensis Flowers and Their Antibacterial Activity

Iron oxide nanoparticles (α- Fe2O3) were synthesized using an unconventional, eco-friendly technique utilizing a Hibiscus rosa sinensis flower (common name, China rose) extract as a reducer and stabilizer agent. The microwave method was successfully used for the synthesis of iron oxide nanoparticles. Various volume ratios of iron chloride tetrahydrate to the extract were taken and heated by the microwave oven for different periods to optimize iron oxide nanoparticle production. The synthesized iron oxide nanoparticles were characterized using the ultraviolet-visible spectrometer (UV-Vis), Fourier transform infrared spectroscopy (FTIR), transmission electron microscopy (TEM), and X-ray diffraction (XRD). X-ray diffraction confirmed the formation of α- Fe2O3 nanoparticles (hematite). The average size of iron oxide nanoparticles was found to be 51 nm. The antibacterial activity of the synthesized iron nanoparticles was investigated against different bacteria such as Staphylococcus aureus, Pseudomonas aeruginosa, Klebsiella pneumonia, and Escherichia coli. The results showed that the synthesized iron nanoparticles exhibited an inhabitation effect on all studied bacteria.

Effect of electrolyte composition on electrochemical oxidation: Active sulfate formation, benzotriazole degradation, and chlorinated by-products distribution

Electrochemical oxidation is an effective technique for treating persistent organic pollutants, which are hardly removed in conventional wastewater treatment plants. Sulfate and chloride salts commonly used and present in natural wastewater influence the electrochemical degradation process. In this study, the effect of electrolyte composition on the active sulfate species (SO4●⁻ and S2O82⁻) formation, benzotriazole degradation-a model organic compound, and chlorinated by-products distribution have been investigated while using a boron-doped diamond (BDD) anode. Different Na2SO4:NaNO3 and Na2SO4:NaCl ratios with constant conductivity of 10 mS/cm were used in the experiments and applied anode potential was kept constant at 4.3 V vs. Ag/AgCl. The electrogenerated SO4●⁻ and S2O82⁻ formation were faster in 10:1 and 2:1 Na2SO4:NaNO3 ratios than in the 1:0 ratio. The ●OH-mediated SO4●⁻ production has prevailed in 10:1 and 2:1 ratios. However, ●OH-mediated SO4●⁻ production has hindered the 1:0 ratio due to excess chemisorption of SO42⁻ on the BDD anode. Similarly, the faster benzotriazole degradation, mineralization, and lowest energy consumption were achieved in the 10:1 Na2SO4:NaNO3 and Na2SO4:NaCl ratio. Besides, chlorinated organic by-product concentration (AOX) was lower in the 10:1 Na2SO4:NaCl ratio but increased with the increasing chloride ratio in the electrolyte. LC-MS analysis shows that several chlorinated organic transformation products were produced in 0:1 to 2:1 ratio, which was not found in the 10:1 Na2SO4:NaCl ratio. A comparatively higher amount of ClO4⁻ was formed in the 10:1 ratio than in 2:1 to 0:1 ratio. This ClO4⁻ formation train evidence the effective ●OH generation in a sulfate-enriched condition because the ClO4⁻ formation is positively correlated to ●OH concentration. Overall results show that sulfate-enriched electrolyte compositions are beneficial for electrochemical oxidation of biorecalcitrant organic pollutants.