Concentration Of 10ppm Research Articles

Improving sunflower oil stability with propolis: A study on antioxidative effects of Turkish propolis during accelerated oxidation.

Propolis, a natural resinous substance collected by bees, is known for its potent antioxidant properties. This study investigates the antioxidant activities and total phenolic contents of propolis samples from 16 provinces of Türkiye and their effects on the oxidative stability of sunflower oil. The 1,1-diphenyl-2-picrylhydrazyl (DPPH) inhibition was in the range of 28.1%-92.5% in thirteen propolis samples, whereas this rate was 24.5% in butylated hydroxytoluene (BHT). Although 2,2'-azino-bis(3-ethylbenzotiazolin-6-sulfonic acid) (ABTS) value was 224µmol trolox/g in BHT, this value was in the range of 262-1370µmol trolox/g in propolis samples, except for one. Propolis methanol extracts 13 applied to sunflower oil at a concentration of 1000ppm were more efficient than BHT added at 200ppm for inhibiting the production of peroxide value (PV). Similarly, most propolis extracts (1000ppm) demonstrated antioxidant activity against the production of p-anisidine (p-AV) in sunflower oil under accelerated oxidation conditions. It was determined that Turkish propolis had strong antioxidant properties and delayed oxidation and may be utilized commercially in the food sector to delay the oxidation of fats and oils.

Insight into physiological and biochemical markers against formaldehyde stress in spider plant (Chlorophytum comosum L.).

Formaldehyde is a prominent volatile organic compound and also considered as an indoor air pollutant. Chlorophytum comosum, an indoor plant, has been reported to metabolize indoor formaldehyde. But the phytotoxic effects of formaldehyde, being a pollutant, on C. comosum are not well explored. Furthermore, C. comosum responses that can be considered as markers at the physiological and biochemical level against formaldehyde stress are not yet investigated. Therefore, the current research study was aimed to evaluate such potential markers against formaldehyde in C. comosum. Briefly, C. comosum was exposed to 5-, 10-, and 20-ppm formaldehyde doses in an airtight glass chamber. Plant samples were then taken to analyze morpho-anatomical, physiological, and biochemical responses after short (2, 4, and 6h), medium (12 and 24h), and extended durations (48 and 96h) for each tested dose. Application of 10 and 20ppm formaldehyde doses leads to a significant incline in enzymatic antioxidants. Formaldehyde concentration of 10ppm leads to a maximum increase in catalase (30.30 U/mg of protein), guaiacol peroxidase (135.64 U/mg of protein), and superoxide dismutase (44.76 U/mg of protein) compared to their respective controls. A significant change is also observed in non-enzymatic parameters, including total phenolic content, which ranged from 3.62mg GAE/g (control) to 10.51mg GAE/g, total antioxidants vary from 27.37% (control) to 85.05% in 20ppm formaldehyde, respectively. However, formaldehyde application negatively affected the physiological responses of C. comosum by reducing its photosynthetic rate, transpiration rate, and stomatal conductance. Additionally, extended exposure of C. comosum to 10- and 20-ppm formaldehyde doses leads to visible leaf damage. Principal component analysis indicated that enzymatic parameters including SOD, CAT, and GPX and non-enzymatic parameters including MDA, TPC, TFC, TAOs, carotenoids, TSS, and intercellular CO2 contributed the most to the total variance. Thus, these parameters have potential to serve as physiological and biochemical markers in C. comosum against formaldehyde stress.

Solar driven highly efficient photocatalyst based on Dy2O3 nanorods deposited on reduced graphene oxide nanocomposite for methylene blue dye degradation.

In recent years, the demand for rare earth elements has surged due to their unique characteristics and diverse applications. This investigation focuses on utilizing the rare earth element dysprosium oxide (Dy2O3) for the photocatalytic oxidation of model pollutants under solar light irradiation. A novel RGO-Dy2O3 nanocomposite photocatalyst was developed using a solvothermal approach, Dy2O3 nanorods uniformly deposited onto reduced graphene oxide (RGO) nanosheets. Comprehensive characterization techniques, including Brunner-Emmett-Teller (BET), X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD), Fourier transform-infrared spectroscopy (FTIR), Raman spectroscopy, high resolution - transmittance electron microscopy (HR-TEM), field emission-electron scanning microscopy (FE-SEM), atomic force microscopy (AFM), electron paramagnetic resonance spectroscopy (EPR), photoluminescence spectroscopy (PL), and electrochemical impedance spectroscopy EIS techniques. The UV-visible diffusive reflectance spectroscopy (UV-Vis-DRS) studies revealed a band gap energy of 3.18eV and a specific surface area of 114 m2/g for the fabricated RGO-Dy2O3 nanocomposite. The RGO-Dy2O3 nanocomposite demonstrated a high photocatalytic degradation efficiency of 98.1% at neutral pH for methylene blue (MB) dye for the dye concentration of 10ppm. The remarkable photocatalytic performance was achieved within 60min under solar light irradiation. Reusability tests demonstrated stability, maintaining over 90% photocatalytic efficiency after three cycles. The EPR spectra and quenching experiments confirmed that photogenerated hydroxyl radicals significantly influence the photodegradation processes. The RGO-Dy2O3 nanocomposite photocatalyst, with its green, easy preparation process and recycling capabilities, presents an ideal choice for various applications. It offers a viable alternative for the photocatalytic degradation of organic dyes in real wastewater, contributing to sustainable environmental remediation.

Bacillus thuringiensis israelensis VCRC B650 culture filtrate useful for mosquito oviposition attractant and larvicidal action

Oviposition attractants hold the potential attention for monitoring and controlling mosquitoes by enticing them to deposit eggs at specific locations. In this study, the bacterial culture filtrate of Bacillus thuringiensis var. israelensis VCRC B650, previously isolated from clay soil at an agricultural site in U.T of Puducherry, was investigated for the first time. This larvicidal bacterium was assessed for oviposition attractancy against dengue and filarial vectors, namely, gravid females of Aedes aegypti and Culex quinquefasciatus, respectively. The investigation revealed that, at 1:1 dilution of bacterial culture filtrate and water, Cx. quinquefasciatus exhibited significant attraction, with an oviposition activity index (OAI) value of +0.92, surpassing the standard threshold value of +0.30. The OAI of Bti culture filtrate at a 1:1 dilution was also compared with a standard oviposition attractant, p-cresol, at a concentration of 10ppm. It was observed that the Bti culture filtrate demonstrated a significant oviposition attractant effect, with 80 per cent more egg rafts laid, compared to p-cresol at 20 per cent. GC-MS analysis showed that there were 25 compounds present in the Bti culture supernatant, and out of those, only one compound, namely, benzaldehyde, was effective in showing oviposition attraction.

Optimization of Engines performance and emission for Biodiesel blended with Nanoparticle using regression analysis approach

Conventional Fuels used in IC engines such ad diesel, petrol etc. are on the verge of extent. Bio-diesel acts an alternative to conventional fuels as it is renewable, bio degradable, nontoxic, less polluting in nature. Present study investigate the effect of various blend of biodiesel & nanoparticle on the performance of engine and emission level. During the study, it is observed that the important parameter that affects the performance concentration of Bio Diesel & nanoparticle in diesel and Engine load are independent parameter. Effect of emission output parameter such as NOX, CO2, CO, HC, are measured. Performance of engine such as brake power and SFC are also measured. Mathematical relation was established among mentioned independent and dependent variables. The ANOVA method is establish relation between these parameters. Experiments were carried out for the nanoparticles (GO) concentration of 10ppm, 20 ppm and 30ppm, biodiesel blend of 20% and 40% at different varying engine load of 25%, 50%, 75% and 100%. Equations are formulated to establish relation between the independent and dependent parameters. The accuracy was calculated in terms of root mean square and to be 0.9094, 0.96, 0.98, 0.96, and 0.949 for NOx, CO, HC, and CO2 and Brake power. From the regression study, optimum BP, NOx, CO, HC, CO2 were found to be 3.49KW, 137.77ppm, 0.7262%, 122.66 ppm, and 3.22%.

Evaluation of potential increase in photosynthetic efficiency of cassava (Manihot esculenta Crantz) plants exposed to elevated carbon dioxide.

Cassava (Manihot esculenta Crantz), an important tropical crop, is affected by extreme climatic events, including rising CO2 levels. We evaluated the short-term effect of elevated CO2 concentration (ECO2 ) (600, 800 and 1000ppm) on the photosynthetic efficiency of 14 cassava genotypes. ECO2 significantly altered gaseous exchange parameters (net photosynthetic rate (P n ), stomatal conductance (g s ), intercellular CO2 (C i ) and transpiration (E )) in cassava leaves. There were significant but varying interactive effects between ECO2 and varieties on these physiological characteristics. ECO2 at 600 and 800ppm increased the P n rate in the range of 13-24% in comparison to 400ppm (ambient CO2 ), followed by acclimation at the highest concentration of 1000ppm. A similar trend was observed in g s and E . Conversely, C i increased significantly and linearly across increasing CO2 concentration. Along with C i , a steady increase in water use efficiency [WUEintrinsic (P n /g s ) and WUEinstantaneous (P n /E )] across various CO2 concentrations corresponded with the central role of restricted stomatal activity, a common response under ECO2 . Furthermore, P n had a significant quadratic relationship with the ECO2 (R 2 =0.489) and a significant and linear relationship with C i (R 2 =0.227). Relative humidity and vapour pressure deficit during the time of measurements remained at 70-85% and ~0.9-1.31kPa, respectively, at 26±2°C leaf temperature. Notably, not a single variety exhibited constant performance for any of the parameters across CO2 concentrations. Our results indicate that the potential photosynthesis can be increased up to 800ppm cassava varieties with high sink capacity can be cultivated under protected cultivation to attain higher productivity.

A comparative study on the removal and recovery of hexavalent chromium from tannery wastewater using an isolated strain Aspergillus proliferans LA and a known strain Aspergillus terreus

Isolation of a potent microorganism from the soil near tanneries and a comparative analysis of the removal and recovery of different concentrations of hexavalent chromium using known strain Aspergillus terreus and isolated strain Aspergillis proliferansLA are done. The isolated fungal species from the chromium contaminated soil sites located in the industrial area of Kanpur, U.P. were tested for its potential for the removal of hexavalent chromium from wastewater streams. The experiments were conducted comparing the biosorption efficiency of the isolated species Aspergillus proliferansLA and Aspergillus terreus by varying the initial Cr (VI) concentration and media constituents. The highest removal efficiency of 99.19% was shown by the isolated species Aspergillus proliferansLA for an initial Cr (VI) concentration of 10ppm followed by increasing the concentration to 50ppm whereas Aspergillus terreus showed 78.43% removal of hexavalent chromium. This was then followed by desorption using 0.8M NaOH and 75.12% hexavalent chromium was desorbed from the cells. The isolated strain Aspergillus proliferansLA was seen to show better removal and recovery results than the known strain Aspergillus terreus.

Determination of Total Phenolic Compounds and SPF ( Sun Protection Factor)Value of Methanol Extract & Fraction Brotowali Leaves ( Tinospora crispa L.)

Flavonoid is one of the compounds that are important for the body because it has a function as an antidote to free radicals by overcoming and preventing the occurrence of oxidative stress conditions are antioxidants. Phenolic compounds are known to have antioxidant activity due to the substitution of hydroxy groups at the ortho and para positions to the – OH and –OR groups. Phenolic compounds are known to have various pharmacological activities, one of that is photoprotective which useful for protecting the skin from the dangers of UV exposure. Brotowali contains secondary metabolites such as alkaloids, phenolics, steroids, and tannins. The presence of these compounds indicates that brotowali has the ability to inhibit free radical compounds. This study aims to determine the total phenolic levels and SPF (Sun Protection Factor) in methanol extract and leaf fraction of brotowali (Tinospora crispa L.). The research methods include maceration, fractionation, phytochemical screening test, specific and non-specific parameter testing, assay by Folin-Ciocalteau method using gallic acid as a standard, and SPF (Sun Protection Factor) value. Based on the research results obtained, the ethyl acetate fraction of brotowali leaves contains phenolic compounds of 675.6522 mg GAE/gram sample with the highest SPF value at a concentration of 1000ppm of 48.79.

The Impacts and Analysis of Individual and Social Risks of the Stochastic Emission of Benzene from Floating-Roof Tanks Using Response Surface Analysis and MPACT Model.

In the present study, the researchers used an integrated approach composed of response surface analysis (RSM) and MPACT model to predict fatality rates caused by benzene emitted from floating-roof tanks. RSM scenarios were configured in Expert Design (version 7.0) software using the central composite design (CCD) method and five variables of wind speed, relative humidity, atmospheric temperature, failure diameter, and emission height were considered. Continuous Pasquill-Gifford Gaussian model was used to estimate the results of the RSM scenarios. The response values were considered for exposure concentrations above 50ppm (slight damages), 150ppm (moderate damage), and 1000ppm (high damage). The analysis of individual and social risks for each scenario was done using the MPACT model in SAFETI program (version 8.22) by providing two variables of population characteristics and the frequency of tank wall failure. The results showed that atmospheric temperature, wind speed, failure diameter, and emission height have positive effects on the dispersion of the cloud of toxic benzene vapor with a concentration of 1000ppm. Intolerable individual risk distances were estimated to be lower for indoor environments than for outdoor. Maximum distances of intolerable individual risks for the worst-case scenarios were estimated up to 2500m from the emission point, which resulted from exposure to a concentration of 1000-ppm benzene. Results regarding the estimation of social risks showed that over 1600 fatalities should be expected under the worst-case scenarios. The three factors of high temperature, low wind speed, and low emission height play a major role in the occurrence of scenarios with the highest fatalities. High wind speed and high emission height were the most important factors in most scenarios with zero fatalities rate. Generally, the findings of this study show the necessity to provide an emergency response plan in the studied industry in both autumn and winter due to low wind speed. However, the coupling of the developed statistical models based on regional meteorological conditions with the MPACT model can help researchers to design an emergency response plan to deal with leakage incidents in petrochemical industries.

Synthesis and physicochemical evaluations of a novel MIL-101(Fe)-PMA-Biochar triple composite photocatalyst activated through visible-light and utilized toward degradation of organic pollutants: optimal operations and kinetics investigations.

A triple photocatalytic composite of biochar, metal-organic framework, and phosphomolybdic acid was prepared through hydrothermal treatment of iron (III) chloride hexahydrate, terephthalic acid, lavandulifolia-derived biochar, and phosphomolybdic acid. It was characterized and utilized for photodegradation of Rhodamine-B (RhB) dye under visible-light irradiation. Investigations of reaction variables confirmed that, the highest yield of 96.2% was achieved at ambient temperature using 0.07g of catalyst at pH of 7, and a dye concentration of 10ppm. Under these optimum conditions, Methyl Orange (MO) dye was also degraded to yield 93% removal. In addition, the kinetic and thermodynamic parameters for RhB were determined. It was revealed that the photodegradation of RhB followed a pseudo-first-order kinetics with no mass transfer limitations. A corresponding chemical mechanism for this process was also suggested. Adsorption isotherms were investigated for rate of adsorption as well as adsorption capacity of the catalyst under dark conditions. Notably, the catalyst could have been reused for five cycles with a loss of around 20% activity.

ANTIDIABETIC -GLYCOSIDASE ANTIDIABETIC ENZYME INVOLVING ACTIVITY TEST FROM BUTANOL FRACTION OF AREUY KIKUNTI LEAVES IN VITRO (Pothos Junghunii De Vreise)

Diabetes mellitus is a disease with high blood glucose levels due to body’s lack of hormone insulin. Examples of natural ingredients that can be used asa antidiabetic are several plants from the genus pothos. This study use the leaves of Aurey kikunti (Pothos junghuhnii de Vreise). The purpose of this study was to deteminate the inhibitory activity of the anti-diabetic α-glikosidase enzyme from the Carinol fraction of Areuy kikunti leaves. The test carried out were the inhibitor activity of the α-glucosidase enzyme with acarbose as a comparison. Antidiabetic activity tets using microplet and analyzed with Elisa reade. In the inhibitor activity (%inhibition) with a concentration of 1000ppm, the butanol fraction yield a value of 8,155%, while the inhibitory activity (%inhibition) of acarbose was 98,349%. From the results obtained, it shows that it has not been able to inhibit 50% of enzyme activity so that it is included in the week category, when compared to the inhibition value of acarbose. It can be concluded that the butanol fraction has no antidiabetic activity.

Enhanced Photocatalytic Degradationof Rhodamine-BDye using Photocatalyst ZNO Sensitized by Visible Light

In the current study, zinc oxide nanoparticles in different concentrations were synthesized by environmentally friendly biosynthesis method using Argyreia nervosa leaf extract and used to remove Rhodamine-B dye. The structure, optical activity, morphology and porosity of the obtained nanomaterials were determined using different techniques including These include X-ray diffraction (XRD), field emission scanning electron microscopy (FE-SEM), elemental spectroscopy (EDX), and scanning electron microscopy (TEM), and fluorescence imaging. ultraviolet. The reflection spectroscopy (DRS) and Brunauer-Emmett-Teller (BET), and the zinc oxide chemical bond formations were confirmed by FT-IR, then the XRD results showed that the zinc oxide nanoparticles were successfully synthesized. TEM images of (ZnO-NPs) showed that the majority of the particles were spherical and weakly agglomerated, the best RhB stain removal was approached under ideal conditions (RhB = 5 ppm,10ppm,15ppm, pH = 11, catalyst dose = 1.4 g/L and time irradiation = 180 minutes). The high efficiency of the catalyst showed enhanced photocatalytic behavior for the degradation of RhB dye with a removal rate (48% ) at 5ppm concentration, at a concentration of 10ppm about 31% and at concentration 15ppm the decomposition efficiency is 19%, without using any metal doping Keywords: green synthesis, ZnO, Photodegradation, RhodamineB, Argyreia nervosa, mechanism.

Cerium and europium doped TiO2 thin films deposited by a sol-gel dip-coating process: characterization and photocatalytic activity toward dye degradation

Cerium (Ce) and europium (Eu)-doped TiO2 thin films were obtained by sol-gel dip-coating technique. SEM micrographs showed that the surfaces are covered by agglomerated particles due to the repeating coating process. XRD patterns showed the presence of TiO2 anatase phase. Raman spectra revealed that the peaks recorded at 146 cm-1(Eg) and 397 cm-1(B1g) were related to the anatase phase. EIS measurements proved that Ce-TiO2 (1wt%) and Eu-TiO2 (0.1wt%) photocatalysts possessed a lower electron transfer resistance than pure TiO2, which can lead to effective separation of electron/ hole pairs during the photoreactions. The photoactivity of Ce and Eu-doped TiO2 was investigated by the degradation of amido black10B dye (AB) under UV excitation and varying the initial pH and concentrations. It was found that Eu-TiO2 (0.1wt%) exhibited higher photocatalytic activity, reaching a first-order reaction rate of kapp(0.036min-1), t1/2 was around 12 min and AB removal was 98.94%, under optimal pH of 3.5 and AB concentration of 10ppm compared to (t1/2 = 45 min, t1/2=30 min), (kapp = 0.022 min-1, kapp = 0.026min-1) and AB removal (94.78%, 96.44%), respectively for pure TiO2 and Ce-TiO2 (1wt%). Further increase in Eu/Ce amount up to optimal concentration (1wt% Ce and 0.1wt% Eu) led to a decrease in the AB removal. The mineralization of AB using Eu-TiO2 photocatalyst was confirmed by HPLC analysis.

Effect of Phytohormones on rooting behaviour in air layers of Phoebe cooperiana, an economically important tree species of Arunachal Pradesh, India

This study reports the response of air layers of Phoebe cooperiana (Common name: Tapil) to different concentrations of rooting hormones in mid hills of Arunachal Pradesh. Ten trees between the ages of 7 and 10 were selected at Boleng village of Siang district, Arunachal Pradesh, India for the experiment. Eight treatments comprising of IBA and NAA at concentrations of 1000ppm, 2000ppm and 3000ppm each, Rootex hormone for semi-hardwood and control were applied to a total of 240 layers during April 2020. After 60 days, rooting percentage, mean number of roots and length of the longest root were recorded. Significant variation (p<0.05) among treatments was observed for all root parameters. Among treatments, the highest rooting percentage and mean a number of roots were obtained in layers treated with NAA 3000ppm (80% and 21.33 respectively). The length of the longest root was the highest in layers treated with NBA 2000ppm (4.23cm). The highest survival percentage of layers two months after transplanting was observed in those treated with NAA 3000ppm (54.16%) and the least in control (23.07%). The technique offers an easy and cheap method of propagation for farmers as well as for government and private agencies to enhance seedling production of the species.

Fabrication of visible light active Mn-doped Bi2WO6-GO/MoS2 heterostructure for enhanced photocatalytic degradation of methylene blue.

The increase in environmental pollution has led to an increased investigation in the development of novel ternary photocatalytic systems for remediation. These photocatalytic systems exhibit superior photocatalytic action for the removal of pollutants because of their visible light active bandgaps. A highly effective visible light active ternary heterojunction was fabricated using a hydrothermal method assisted by ultrasonication. Herein, we report the in situ hydrothermal synthesis of Mn-doped Bi2WO6-GO/ MoS2 photocatalyst, efficiently exhibiting greater photocatalytic activity for the wastewater treatment under solar light. The binary metal sulphide (MoS2) used as a co-catalyst, acted as an electron collector and graphene oxide (GO) as a support material for interfacial electron transfer to and from bismuth tungstate and MoS2. The as-prepared samples were characterized using SEM-EDX, FT-IR, XRD, XPS, BET, PL, and UV-Vis techniques. The bandgap of the novel photocatalyst was found in the visible region (2.2 eV) which helped in suppressing photoinduced electron-hole pairs recombination. The ternary Mn-doped Bi2WO6-GO/MoS2 showed 99% methylene blue removal after 60 minutes of sunlight irradiation at the optimum conditions of pH 8, catalyst dose 50 mg/100ml, and initial MB concentration of 10ppm under sunlight irradiation. The doped ternary heterostructure has proved to be an effective sunlight-active photocatalyst that can be reused without substantial loss in photocatalytic efficiency.

Nitric oxide delivery using nitric oxide-containing fluid in continuous hemofiltration: an in vitro study.

Administering nitrite has therapeutic effects on ischemic conditions wherein the enzymatic production of nitric oxide depends on oxygen. We developed a supplemental fluid containing nitric oxide (NO) and determined the clearance and supply between the pre- and post-dilution modes of continuous hemofiltration in vitro. Nitric oxide gas, 1000mL or 2000mL, at a concentration of 1000ppm, was injected into 2020mL of conventional supplemental fluid (experimental solution). The same volume of nitrogen gas was injected into the supplemental fluid (control solution). NO concentrations were measured using commercially available NO assay kit. Pre- or post-dilution continuous hemofiltration was performed using a control solution as supplemental fluid to determine the NO clearance. We determined the NO concentration of the outlet blood circuit to confirm the NO supply using the experimental solution as supplemental fluid. Also, using the bovine blood, white blood cell and platelet change rates and the dialysis membrane water flux during continuous hemodiafiltration were evaluated ex vivo as index of the biocompatibilities of a nitric oxide-containing solution. NO was not detected in the control solutions. The experimental solutions significantly increased in nitric oxide concentrations. NO clearance increased as the increase in supplemental and ultrafiltration flow rates using the control solution as supplemental fluid. However, using the experimental solution as supplemental fluid, nitric oxide supply showed a similar trend of NO clearance. Without any changes in biocompatibility using the supplemental fluid containing NO, it could maintain intravascular nitric oxide during continuous renal replacement therapy.

Cerium and europium doped TiO2 thin films deposited by a sol-gel dip-coating process: characterization and photocatalytic activity toward dye degradation.

Cerium (Ce) and europium (Eu)-doped TiO2 thin films were obtained by sol-gel dip-coating technique. SEM micrographs showed that the surfaces are covered by agglomerated particles due to the repeating coating process. XRD patterns showed the presence of TiO2 anatase phase. Raman spectra revealed that the peaks recorded at 146 cm-1(Eg) and 397 cm-1(B1g) were related to the anatase phase. EIS measurements proved that Ce-TiO2 (1wt%) and Eu-TiO2 (0.1wt%) photocatalysts possessed a lower electron transfer resistance than pure TiO2, which can lead to effective separation of electron/ hole pairs during the photoreactions. The photoactivity of Ce and Eu-doped TiO2 was investigated by the degradation of amido black10B dye (AB) under UV excitation and varying the initial pH and concentrations. It was found that Eu-TiO2 (0.1wt%) exhibited higher photocatalytic activity, reaching a first-order reaction rate of kapp (0.036min-1), t1/2 was around 12 min and AB removal was 98.94%, under optimal pH of 3.5 and AB concentration of 10ppm compared to (t1/2= 45 min, t1/2=30 min), (kapp= 0.022 min-1, kapp=0.026min-1) and AB removal (94.78%, 96.44%), respectively for pure TiO2 and Ce-TiO2 (1wt%). Further increase in Eu/Ce amount up to optimal concentration (1wt% Ce and 0.1wt% Eu) led to a decrease in the AB removal. The mineralization of AB using Eu-TiO2 photocatalyst was confirmed by HPLC analysis.

Isolation of a methane-oxidizing bacterium that bioremediates hexavalent chromium from a formerly industrialized Suburban River.

Sediment samples were taken from sediment adjacent to a suburban river in Sheffield in Northern England that had suffered heavy metal pollution due to previous activity of the steel industry (between the 17th and 19th centuries). The most abundant heavy metals found in the samples were lead, chromium, nickel, arsenic and cobalt, with maximum concentrations of 412·80, 25·232, 25·196, 8·123 and 7·66mgkg-1 , respectively. Enrichment cultures were set up using methane as carbon and energy source, as a result of which a strain of methanotroph was isolated that was shown via 16S rRNA gene sequencing to be a strain Methylomonas koyamae and given the designation SHU1. M. koyamae SHU1 removed hexavalent chromium from an initial concentration of 10ppm, which was inhibited by the metabolic inhibitor sodium azide or the methane monooxygenase inhibitor phenylacetylene. To the authors' knowledge, this is the first description of a strain of the widely environmentally distributed genus Methylomonas that is capable of remediating hexavalent chromium. SIGNIFICANCE AND IMPACT OF THE STUDY: Aerobic methanotrophic bacteria are known for bioremediation of an increasing range of organic and inorganic pollutants, using methane as carbon and energy source. Previously, one laboratory methanotroph strain, Methylococcus capsulatus Bath, was known to bioremediate toxic chromium (VI) by reducing it to chromium (III). Here, a newly isolated methanotroph strain, Methylomonas koyamae SHU1, has been shown able to remediate chromium (VI). This indicates that chromium (VI) bioremediation is not unique to M. capsulatus and moreover adds weight to the suggestion that methanotrophs may contribute directly to chromium (VI) detoxification in nature and in polymicrobial bioremediation fed with methane.

Photocatalytic degradation of a typical neonicotinoid insecticide: nitenpyrum by ZnO nanoparticles under solar irradiation.

The photodegradation and mineralization of the nitenpyrum [(E)-N-(6-chloro-3-pyridylmethyl)-N-ethyl-N'-methyl-2-nitrovinylidenediamine], which is one of the most popular neonicotinoid insecticides, were conducted in the presence of ZnO photocatalyst under solar irradiation. An initial nitenpyrum concentration of 10ppm was completely degraded in the presence of ZnO after 30 min irradiation, while only 70% degradation was observed in the absence of ZnO. The effect of different parameters, for example, amount of ZnO, initial pH, light intensity, reaction temperature, and irradiation time, on the photocatalytic degradation of nitenpyrum was also evaluated. The drop of total organic carbon (TOC) as a consequence of mineralization of nitenpyrum was observed during the photocatalytic process. The kinetics of photocatalytic degradation followed a pseudo-first order law according to Langmuir-Hinshelwood model, and the rate constant is 0.140min-1. CO2, chloride, and nitrate ions were observed as the end-products after completing degradation of nitenpyrum. The four kinds of intermediate products were identified by GC-MS during the decomposition of nitenpyrum. In order to investigate the degradation pathway of nitenpyrum, the point charge and frontier electron density at each atom on the molecule were determined using molecular orbital (MO) stimulation. The degradation mechanism was proposed, based on the identified intermediates. The solar photocatalytic degradation method can become an effective technique for the treatment of nitenpyrum-polluted water.

The effect of temperature and ionic solutes on the fluoride release and recharge of glass-ionomer cements

ObjectiveTo determine the effect of storage temperature and the presence of sodium chloride in solution on the fluoride uptake and release of glass-ionomer cements. MethodsSeveral commercial brands were used, and stored at either room temperature (21–23°C) or 37°C, in KF solution at a concentration of 1000ppm F− with and without 0.9% NaCl present. Fluoride levels in the storage solutions after 24h were measured using a fluoride-ion selective electrode. Specimens were then stored in water, and fluoride release after 24h was determined. Studies were also carried out to determine chloride levels when specimens were stored in 0.9% NaCl, with or without 1000 ppm fluoride, again using an ion selective electrode. ResultsAll glass-ionomer specimens took up fluoride, and most of the fluoride was retained over the next 24 h when the specimens were stored in water. There was a slight variation in the amount of fluoride taken up with storage temperature and with the presence of sodium chloride. All specimens also took up chloride, with greater uptake at higher temperatures, but little or no effect when KF was also present in solution. SignificanceThe substantial retention of fluoride after 24h in deionised water confirms previous findings and suggests that an insoluble species, possibly SrF2, forms in situ. Chloride uptake has not been reported previously, and its significance requires further investigation. Fluoride and chloride uptake were apparently independent of each other, which suggests that the ions are taken up at different sites in the cement. This may relate to differences in the respective sizes and hydration states of F− and Cl− ions.