Bioinspired fabrication of CuONPs synthesized via Cotoneaster and application in dye removal: antioxidant and antibacterial studies

Environmental Science and Pollution Research - In this study, bioinspired fabrication of copper oxide nanoparticles (CuONPs) which are widely researched in nanotechnology field with Cotoneaster...     

Evaluation of a fast wastewater odour characterisation procedure using a chemical sensor array

Sewage treatment works are one of the major sources that cause atmospheric odour pollution. The increase in the number of complaints about odour nuisance is due to the increase in environmental concerns. Unfortunately, the legislation on odour nuisance from sewage treatment works is very limited. In order to determine suitable thresholds on which to base legal standards, reliable and efficient odour measurement methods need to be defined. A chemical sensor array was developed for the purpose of measuring wastewater odour. This paper describes the development of the chemical sensor system which is specifically tuned to odours of wastewater origin and which can give an electronic measure of the wastewater odours. Odour emissions from a wastewater treatment facility were detected by using a quartz crystal microbalance (QCM) sensor array. The array consists of nine sensor elements, which were coated with different materials. In this paper, the usage of these novel instruments in the water industry was shown.     

Diel vertical migration of Sagitta setosa as inferred acoustically in the Black Sea

Swimming trajectories of chaetognaths Sagitta setosa Müller in the Black Sea were studied using an echosounder operating at 120 and 200 kHz and an acoustic Doppler current profiler (ADCP) operating at 150 kHz. S. setosa were acoustically discriminated with respect to vertical migration and swimming speed, according to dissolved oxygen (DO) concentration and the timing of migrations. S. setosa formed a concentration layer thicker than Calanus euxinus did (1–3 m). The migration was completed in about 2.5–4 h, upward migration starting before C. euxinus and downward migration after C. euxinus. Adult Sagitta swam fast only in the well-oxygenated layer (subsurface maximum DO). The DO was found to be a significant (p<0.05) variable by partial correlation between the speed and hydrographical parameters. This feature constituted an oxygen-dependent influence on S. setosa’s vertical swimming and distinguished S. setosa from C. euxinus. Chaetognaths migrated daily between the nearsurface and the oxycline or the suboxic zone (OMZ, see Fig. 3b for the layers characterized by DO). Whether the deepest depth limit of migration was the oxycline or the OMZ depended on the relative abundance of adult and immature (young) individuals in the concentration layer. In July and September, individuals belonging to a new generation did not migrate but stayed in subsurface water day and night.     

The modeling and analysis of transesterification reaction conditions in the selection of optimal biodiesel yield and viscosity

Among alternative fuels, biodiesel has been emphasized as a substantial candidate for diesel engines because of many advantages. However, the main shortcomings preventing more widespread use of biodiesel are high production cost and viscosity. In order to simultaneously overcome both of these shortcomings, the reaction conditions for the transesterification of waste cooking oil (WCO) were optimized using Taguchi and the full factorial design approaches. The analyses of signal to noise ratio and variance were also performed to identify the dominance of reaction conditions on viscosity and biodiesel yield. As a result, the optimal reaction conditions giving the lowest kinematic viscosity (3.991 cSt) and the highest biodiesel yield (98.19%) were determined to be as follows: sodium methoxide amount of 1.00 wt%, reaction time of 60 min, reaction temperature of 55 °C, and methanol to oil molar ratio of 6:1. The catalyst amount and methanol to oil molar ratio were found to be the most significant conditions influencing on the viscosity (10.36% and 78.87% contributions) and the yield (58.48% and 20.17% contributions), respectively. Finally, all physicochemical properties of final waste cooking oil biodiesel (WCOB) produced under optimal reaction conditions were found to meet the EN 14214.     

The recovery of ammonia and hydrogen sulfide from ground-level area sources using dynamic isolation flux chambers: bench-scale studies

Controlled bench-scale laboratory experiments were conducted to evaluate the recovery of ammonia (NH3) and hydrogen sulfide (H2S) from dynamic isolation flux chambers. H2S (80-4000 ppb) and NH3 (5000-40,000 ppb) samples were diffused through the flux chamber to simulate ground level area source emissions while measuring the inlet and outlet flux chamber concentrations simultaneously. Results showed that the recovery of H2S during a 30-min sampling time was almost complete for concentrations >2000 ppb. At the lowest concentration of 80 ppb, 92.55% of the H2S could be recovered during the given sampling period. NH3 emissions exhibited similar behavior between concentrations of 5000-40,000 ppb. Within the 30-min sampling period, 92.62% of the 5000-ppb NH3 sample could be recovered. Complete recovery was achieved for concentrations >40,000 ppb. Predictive equations were developed for gas adsorption. From these equations, the maximum difference between chamber inlet and outlet concentrations of NH3 or H2S was predicted to be 7.5% at the lowest concentration used for either gas. In the calculation of emission factors for NH3 and H2S, no adsorption correction factor is recommended for concentrations >37,500 ppb and 2100 ppb for NH3 and H2S, respectively. The reported differences in outlet and inlet concentration above these ranges are outside the fullscale sensitivity of the gas sensing equipment. The use of 46-90 m of Teflon tubing with the flux chambers has apparently no effect on gas adsorption, because recovery was completed almost instantaneously at the beginning of the tests.     

Distribution and abundance of ctenophores and their zooplankton food in the Black Sea. II. Mnemiopsis leidyi

The distribution of Mnemiopsis leidyi Agassiz, 1865 in the Black Sea was determined using plankton samples collected above the anoxic zone (maximum depth 200 m) in the summer, winter, and spring from 1991 to 1995. Distribution was patchy. Average biomasses of 15 to 500 g m⁻² were measured, and abundances varied from 10 to 180 ind m⁻². Biomass and abundance peaked in winter, and there was a secondary peak in the summer. The distribution of M. leidyi was correlated with hydrographic features in the Black Sea with higher concentrations in anticyclonic gyres. The centers of the two main cyclonic gyres generally had a low biomass of M. leidyi. From July 1992 to March 1995, the populations were largely offshore. M. leidyi were confined to the upper part of the mixed layer both day and night. Some individuals displayed a negative taxis to daylight and were concentrated below the thermocline at night. Smaller M. leidyi (1.5 to 2 cm) were present in the winter, and individuals reached maximum size in the summer. Although reproduction was continuous throughout the year, there were two distinct peaks: the larger peak in the summer and the smaller peak in the winter. Microscopic analysis of stomach contents showed that copepods and molluscs form their main diet. Received: 1 November 1997 / Accepted: 30 August 1999     

The Recovery of Ammonia and Hydrogen Sulflde from Ground-Level Area Sources Using Dynamic Isolation Flux Chambers: Bench-Scale Studies

Abstract

Controlled bench-scale laboratory experiments were conducted to evaluate the recovery of ammonia (NH₃) and hydrogen sulflde (H₂S) from dynamic isolation flux chambers. H₂S (80–4000 ppb) and NH₃ (5000–40,000 ppb) samples were diffused through the flux chamber to simulate ground level area source emissions while measuring the inlet and outlet flux chamber concentrations simultaneously. Results showed that the recovery of H₂S during a 30-min sampling time was almost complete for concentrations >2000 ppb. At the lowest concentration of 80 ppb, 92.55% of the H₂S could be recovered during the given sampling period. NH₃ emissions exhibited similar behavior between concentrations of 5000–40,000 ppb. Within the 30-min sampling period, 92.62% of the 5000-ppb NH₃ sample could be recovered. Complete recovery was achieved for concentrations >40,000 ppb. Predictive equations were developed for gas adsorption. From these equations, the maximum difference between chamber inlet and outlet concentrations of NH₃ or H₂S was predicted to be 7.5% at the lowest concentration used for either gas. In the calculation of emission factors for NH₃ and H₂S, no adsorption correction factor is recommended for concentrations >37,500 ppb and 2100 ppb for NH₃ and H₂S, respectively. The reported differences in outlet and inlet concentration above these ranges are outside the full-scale sensitivity of the gas sensing equipment. The use of 46–90 m of Teflon tubing with the flux chambers has apparently no effect on gas adsorption, because recovery was completed almost instantaneously at the beginning of the tests.     

Monitoring of organic pollutants in marine environment by semipermeable membrane devices and mussels: accumulation and biochemical responses

This study involves the monitoring of organic pollutants using transplanted mussels (Mytilus galloprovincialis) as bioindicator organisms and semipermeable membrane devices (SPMDs) as passive samplers. Mussels and SPMDs were deployed to marinas, shipyards and shipbreaking yards on the coastal area of Turkey and retrieved after 60 days. Polycyclic aromatic hydrocarbons (PAH), polychlorinated biphenyls (PCB) and organochlorine pesticide (OCP) compounds were analysed with high-resolution GC-MS. Total PAH concentrations in SPMDs and mussels ranged from 200 to 4740 ng g sampler^?1 and from 7.0 to 1130 ng g^?1 in wet weight (ww). PCB and OCP concentrations in SPMDs changed between 0.04–200 and 4.0–26 ng g sampler^?1, respectively. The highest PCB (190 ng g^?1 ww) and OCP (200 ng g^?1 ww) concentrations in mussels were measured at shipyard stations. A strong correlation was observed between the PAH and PCB concentrations in SPMDs and mussels. Enzyme assays (acetylcholinesterase, ethoxyresorufin-O-deethylase, glutathione S-transferase, glutathion reductase and carboxylesterase activities) were performed as biomarkers to reveal the effects of pollution on the mussels. There was no clear relationship found between the enzyme levels and the pollutant concentrations in mussels. Integrated biomarker responses were calculated to interpret the overall effect of pollutants.

     

Analysis of winter thermal comfort conditions: street scenarios using ENVI-met model

Environmental Science and Pollution Research - Rapid migration to cities and the increasing demand for housing negatively affect living areas. Furthermore, uncontrolled population growth,...     

Performance of butyl rubber–based macroporous sorbents as passive samplers

Environmental Science and Pollution Research - In this study, two macroporous butyl rubber (BR)–based sorbents prepared in benzene (H-BR) and in cyclohexane (L-BR) with different porosities...