Non-targeted analysis and toxicity prediction for evaluation of photocatalytic membrane distillation removing organic contaminants from hypersaline oil and gas field-produced water.

Membrane distillation (MD) has received ample recognition for treating complex wastewater, including hypersaline oil and gas (O&G) produced water (PW). Rigorous water quality assessment is critical in evaluating PW treatment because PW consists of numerous contaminants beyond the targets listed in general discharge and reuse standards. This study evaluated a novel photocatalytic membrane distillation (PMD) process, with and without a UV light source, against a standard vacuum membrane distillation (VMD) process for treating PW, utilizing targeted analyses and a non-targeted chemical identification workflow coupled with toxicity predictions. PMD with UV light resulted in better removals of dissolved organic carbon, ammoniacal nitrogen, and conductivity. Targeted organic analyses identified only trace amounts of acetone and 2-butanone in distillates. According to non-targeted analysis, the number of suspects reduced from 65 in feed to 25-30 across all distillate samples. Certain physicochemical properties of compounds influenced contaminant rejection in different MD configurations. According to preliminary toxicity predictions, VMD, PMD with and without UV distillate samples, respectively contained 21, 22, and 23 suspects associated with critical toxicity concerns. Overall, non-targeted analysis together with toxicity prediction provides a competent supportive tool to assess treatment efficiency and potential impacts on public health and the environment during PW reuse.

A novel approach based on neutrosophic Bonferroni mean operator of trapezoidal and triangular neutrosophic interval environments in multi-attribute group decision making.

Neutrosophic multicriteria is a method of decision-making that uses indeterminacy to combine several criteria or elements, frequently with incomplete or ambiguous information, to find a solution. The neutrosophic multicriteria analysis enables the assessment of qualitative and subjective aspects and can assist in resolving conflicting goals and preferences. In the Neutrosophic Multi-Attribute Group Decision Making (NMAGDM) problems, all the information provided by the decision makers (DMs) is expressed as single value neutrosophic triangular and trapezoidal numbers examined in this study which can provide more flexibility and accuracy in capturing uncertainty and aggregating preferences. We offer a novel approach for determining the neutrosophic possibility degree of two and three trapezoidal and triangular neutrosophic sets and the concepts of neutrosophic possibility mean value. The trapezoidal and triangular neutrosophic Bonferroni mean (TITRNBM) operator and the trapezoidal and triangular neutrosophic weighted Bonferroni mean (TITRNWBM) operator are two aggregation methods we then create. Further, we examine the TITRNBM and TITRNWBM attributes and their uniqueness. The NMAGDM approach with trapezoidal and triangular information is suggested based on the TITRNWBM operator and possibility degree. Finally, a concrete example of manufacturing companies searching for the best supplier for assembling the critical parts is provided to validate the established strategies and show their practical applicability and efficacy.

Seasonal and annual variations of CO2 and CH4 at Shadnagar, a semi-urban site.

Carbon dioxide (CO2) and methane (CH4) are the most important greenhouse gases (GHGs) due to their significant role in anthropogenic global climate change. The spatio-temporal variations of their concentration are characterized by the terrestrial biosphere, seasonal weather patterns and anthropogenic emissions. Hence, to understand the variability in regional surface GHG fluxes, high precision GHGs measurements were initiated by the National Remote Sensing Center (NRSC) of India. We report continuous CO2 and CH4measurements during 2014 to 2017 for the first time from Shadnagar, a suburban site in India. Annual mean CO2 and CH4 concentrations are 399.56 ± 5.46 ppm and 1.929 ± 0.09 ppm, respectively, for 2017. After the strong El Niño of 2015-2016, an abnormal rise in CO2 growth rate of 5.5 ppm year-1 was observed in 2017 at the study site, compared to 3.03 ppm year-1 at Mauna Loa. Thus, the repercussion of the El Niño effect diminishes the net uptake by the terrestrial biosphere accompanied by increased soil respiration. Seasonal tracer to tracer correlation between CO2 and CH4 was also analyzed to characterize the possible source-sink relationship between the species. We compared CO2 and CH4 concentrations to simulations from an atmospheric chemistry transport model (ACTM). The seasonal phases of CH4 were well captured by the ACTM, whereas the seasonal cycle amplitude of CO2 was underestimated by about 30%.

Biosynthesis, characterization and cytotoxic effect of plant mediated silver nanoparticles using Morinda citrifolia root extract.

Silver has been used since time to control bodily infection, prevent food spoilage and heal wounds by preventing infection. The present study aims at an environmental friendly method of synthesizing silver nanoparticles, from the root of Morinda citrifolia; without involving chemical agents associated with environmental toxicity. The obtained nanoparticles were characterized by UV-vis absorption spectroscopy with an intense surface plasmon resonance band at 413 nm clearly reveals the formation of silver nanoparticles. Fourier transmission infra red spectroscopy (FTIR) showed nanopartilces were capped with plant compounds. Field emission-scanning electron microscopy (FE-SEM) and Transmission electron microscopy (TEM) showed that the spherical nature of the silver nanoparticles with a size of 30-55 nm. The X-ray diffraction spectrum XRD pattern clearly indicates that the silver nanoparticles formed in the present synthesis were crystalline in nature. In addition these biologically synthesized nanoparticles were also proved to exhibit excellent cytotoxic effect on HeLa cell.

A chemical switch for detecting insect infestation.

BACKGROUND: Plants emit phytochemicals as a defensive mechanism against herbivores. A small sensor switch that responds to these chemicals could be used to stop insect infestation at early stages. RESULTS: Polyethylene-co-vinyl acetate was chosen as the best polymer for this particular application, based on its swelling response to plant volatiles. When the carbon concentration of the active layer was low enough to be near the percolation threshold, the sensor could be used as a 'chemical switch'. The resistance of the sensor increased significantly, mimicking a 'switch-off' response when exposed to the analyte vapor. When the analyte vapor was no longer present, the sensor returned back to its original condition, showing a 'switch-on' response. The percolation point was obtained when the carbon concentration of the polymer/carbon composite was kept at 2.5 wt%. CONCLUSION: A low-mass-fraction carbon composite sensor has been designed and fabricated to detect γ-terpinene, α-pinene, p-cymene, farnesene, limonene and cis-hexenyl acetate. The sensor is inexpensive, easy to fabricate and highly stable in air.

An efficient approach to surface-initiated ring-opening metathesis polymerization of cyclooctadiene.

Surface-initiated ring-opening metathesis polymerization of cyclooctadiene (COD), a low ring-strain olefin, is reported for the first time. Polymerization was carried out in the vapor phase, which is advantageous compared to conventional solution methods in terms of minimizing chain transfer by reducing polymer chain mobility at the vapor/solid interface. Attachments of a norbornenyl-containing silane and a Grubbs catalyst to silicon substrates were carried out before samples were exposed to COD vapor. The thickness of grafted 1,4-polybutadiene films was controlled by reaction time and reached approximately 40 nm after 7 h. The polymer films were further chemically modified to afford a new polymer, head-to-head poly(vinyl alcohol).