Impact of Silver Nanoparticles Synthesized by Irradiated Polyvinylpyrrolidone on Spodoptera littoralis Nucleopolyhedrosis Virus Activity

Journal of Polymers and the Environment - A Green nanomaterial synthesis could be considered as an alternative bio-controller source of insect pest management as well as saving the environment....     

Mechanochemical activation for lead extraction from spent cathode ray tube

Journal of Material Cycles and Waste Management - In this study, a mechanochemical activation technique to effectually extract lead from the funnel glass of cathode ray tube (CRT) is proposed. A...     

Nano-sized Prussian blue immobilized costless agro-industrial waste for the removal of cesium-137 ions

Environmental Science and Pollution Research - For human health and safety, it is of great importance to develop innovative materials with a vast capacity for powerful removal of radioactive ions...     

Cobalt separation from waste mobile phone batteries using selective precipitation and chelating resin

Separation of cobalt from mixed-waste mobile phone batteries containing LiCoO₂ cathodic active material was investigated using selective precipitation and chelating resin. Cobalt was recovered from the active powder materials containing 47 % Co oxide together with Mn, Cu, Li, Al, Fe, and Ni oxides. The metal ions were leached sufficiently using 4 M HCl. The metal ions detected spectrophotometrically were removed from the leaching solution by selective precipitation at pH 5.5, with cobalt loss of 27.5 %. Conditions for achieving a recovery of Co in the filtrate by chelating resin were determined experimentally by varying the pH and time of the reaction, as well as the initial resin-to-liquid ratio. The cobalt was efficiently determined by absorption spectrometry at λ _max 510 nm. Chelating polyamidoxime resin was synthesized by polymerization of acrylonitrile and followed by amidoximation reaction. Physically cross-linked gel of polyacrylonitrile was made by a cooling technique.     

Ligand-less in situ surfactant-based solid phase extraction for preconcentration of silver from natural water samples prior to its determination by atomic absorption spectroscopy

A simple and rapid ligand-less in situ surfactant-based solid phase extraction method for preconcentration of silver from water samples is developed. In this method, a cationic surfactant containing a proper alkyl group (n-dodecyltrimethylammonium bromide) is dissolved in the aqueous sample and then a proper ion-pairing agent (ClO₄^?) is added. Due to the interaction between surfactant and ion-pairing agent, solid particles are formed and used for adsorption of silver carbonate. After centrifugation, the sediment is dissolved in 2.0 mL 1 M HNO₃ in ethanol and then aspirated directly into the flame atomic absorption spectrometer. Variables affecting the extraction efficiencies such as pH, concentrations of surfactant and CO₃^2?, ion pair concentration, and extraction time, are optimized. Under such conditions, the calibration curve is linear from 3 to 700 μg L^?1. Detection limit is 1.1 μg L^?1 with an enrichment factor of 37. The relative standard deviation for eight replicate measurements of 100 μg L^?1 is 2.1%. The method has been applied for the determination of silver in water samples.     

Evaluation of membrane bioreactor for hypersaline oily wastewater treatment

Produced water is a significant waste stream generated in association with oil and gas production. It contains high concentrations of hydrocarbon constituents and different salts. In this study, a membrane sequencing batch reactor (MSBR) was used to treat synthetic and real produced water. The MSBR was evaluated in terms of biodegradation of hydrocarbons in the synthetic produced water with various organic loading rates (OLR) (0.281, 0.563, 1.124, 2.248, and 3.372 kg COD/(m³ day)), cycle time (12, 24, and 48 h), and membrane performance. The effects of salt concentrations at different total dissolved solids (TDS) (35,000, 50,000, 100,000, 150,000, 200,000, and 250,000 mg/L) on biological treatment of the pollutants in the synthetic and real wastewater were studied. At an OLR of 1.124 kg COD/(m³ day), an HRT of 48 h and TDS of 35,000 mg/L, removal efficiencies of 97.5%, 97.2%, and 98.9% of COD, total organic carbon (TOC), and oil and grease (O&G), respectively were achieved. For the real produced water, removal rates of 86.2%, 90.8%, and 90% were obtained for the same conditions. However, with increasing salt content, the COD-removal efficiencies of the synthetic and real produced water were reduced to 90.4% and 17.7%, respectively at the highest TDS.     

Measurements of 210Pb concentrations in airborne in Kuwait

The concentrations of ²¹⁰Pb in the atmosphere of Kuwait Cityhave been monitored over a period of five years (January 1994 toDecember 1998) using cellulose air filters for analysis with liquid scintillation counting for gross beta. Results show thatthe distribution of daily averaged ²¹⁰Pb concentrations varied from 0.002 to 2.53 mBqm^-3 with an average of 0.896 mBqm^-3 and a geometric mean of 0.687 mBqm^-3. The studysuggests that the existence of ²¹⁰Pb in air in Kuwait originates mainly from re-circulated fraction of ²¹⁰Pb whichwas already deposited on ground surface, not from direct decay of radon.The long-term trend pattern for the five years shows a seasonalvariation with maximum concentrations occurring in the autumn season.     

The impact of economic factors and governance on greenhouse gas emission

Environmental Economics and Policy Studies - Governance is a basic factor explaining the poor economic, social and environmental performance of many developing countries. Since good governance...     

Post-irradiation physicochemical features of polymer composite for the removal of Co(II) and Nd(III) from aqueous solutions

Environmental Science and Pollution Research - The scientific impact of this work is the protection of the environment from hazardous pollutants. Gamma irradiation was employed for the preparation...     

Safety performance functions with measurement errors in traffic volume

One of the most common and important predictors in safety performance functions (SPFs) is traffic volume which is known to be measured with uncertainty. Such measurement errors (ME) can attenuate the respective predictors’ effect and also increase dispersion. This paper proposes an approach which involves the use of a ME model based on traffic flow time series data. The model is used in conjunction with the negative binomial SPF to circumvent the bias in predicting the aggregate number of accidents during the time period under study. The proposed approach (denoted by MENB), was compared with the traditional negative binomial (NB) technique by way of Monte Carlo simulation. Furthermore, both approaches were applied to two datasets corresponding to 131 and 130 road segments in British Columbia. The full Bayes method was utilized for parameter estimation, performance evaluation and inference through the use of Markov Chain Monte Carlo (MCMC) techniques. The simulation results showed that MENB has outperformed NB when large measurement errors are present. The goodness-of-fit statistics showed that MENB has provided a slightly better fit to the data. However, in the presence of measurement errors, the NB has underestimated the predicted number of accidents for heavy traffic on long road segments and vice versa. The use of MENB is justified when the variance in volume between years is large otherwise both approaches yield comparable results.