Environmental assessment of 2-mercaptobenzimidazole based on the surface plasmon resonance band of gold nanoparticles

A colorimetric assay method is described for the environmental detection of 2-mercaptobenzimidazole (MBI) using surface plasmon resonance of gold nanoparticles (AuNPs). Stable and dispersed AuNPs with intensified plasmon resonance were prepared in situ using a simple, rapid, and eco-friendly procedure by applying ascorbic acid as a reducer and cetyltrimethylammonium bromide as a stabilizer. The presence of MBI has a strong effect on the plasmon absorbance of AuNPs, which was employed for the detection of MBI. The calibration curve was linear in the range of 1.0?×?10^?6–5.5?×?10^?5 mol/L of MBI; the detection limit was 8.4?×?10^?7 mol/L. The relative standard deviations for eight replicate measurements of 3.0?×?10^?6 and 5?×?10^?5 mol/L MBI were 3.9 and 1.4 %, respectively. The method was successfully applied to the determination of MBI in tap, river, sea, and heat exchanger cooling water samples.     

Organochlorines and PCBs in Tilapia zillii from Lake El-Manzala,Egypt

Abstract

The mercury content has been determined in samples of fumarolic gases, phreatic waters, soil and vegetation collected at Vulcano, Aeolian Islands, Italy. Volcanic activity is demonstrated as a source of natural mercury pollution whose extent has been evaluated here by studying the contribution of different components of the surface environment. The possible influences for living organisms are examined.     

Multiplex-PCR and PCR-RFLP assays to monitor water quality against pathogenic bacteria

In this work we developed and optimized two molecular-based approaches to monitor rapidly, sensitively and specifically bacterial pathogens from three different genera, Escherichia coli, Pseudomonas aeruginosa, and Salmonella spp., directly in waters. To achieve this aim, firstly a multiplex-PCR assay (M-PCR) was optimized using a primer pair specific for each pathogen. Secondly, as a molecular confirmatory test after isolation of the pathogens by classical microbiological methods, PCR-RFLP of their amplified 16S rDNA genes was performed. It was observed from the results that the developed M-PCR assay has significant impact on the ability to detect sensitively, rapidly and specifically the three pathogens directly in water within a short time (5 h from sampling to obtain final results), therefore it represents a considerable advancement over other known more time-consuming and less-sensitive methods for identification and characterization of these kinds of pathogens.     

Applying physicochemical approaches to control phosphogypsum heavy metal releases in aquatic environment

One of the most important sources of solid waste in the Mediterranean Basin ecosystem originated from the phosphate fertilizer industries, which discharge phosphogypsum (PG) directly into aquatic environments or are stacked on stockpiles. The present study investigates metal release from PG under the influence of variable pH, increasing PG mass content, and complexing organic matter ligands. Major ions from PG leachates, grain size and charge, main functional groups along with metal leachability (Pb, Cd, Cr, Cu, and Zn) were determined using ion chromatography, laser diffraction, zetameter, Fourier transform infrared spectroscopy, and atomic absorption spectroscopy, respectively. The complete dissolution of PG recorded is at 2 g/L. Saturation and supersaturation with respect to PG may occur at concentrations of 3 and 4 g/L, respectively, revealing a clustering phenomenon leading to heavy metal encapsulation within the aggregates. Organic ligands such as citrate may trigger the cationic exchange within the PG suspension leading to ion release. As these factors are considered as specific process involving the release of contaminants from PG during storage under natural conditions, this study could set the foundations for PG remediation in aquatic environment. Organic ligands under controlled pH conditions could be utilized in treating fertilizer industrial wastes by taking into consideration the particularity of the receiving area, thus decreasing metal hazardous impact on natural media.     

Synthesis, physicochemical characterizations and catalytic performance of Pd/carbon-zeolite and Pd/carbon-CeO2 nanocatalysts used for total oxidation of xylene at low temperatures

In this work, xylene removal from waste gas streams was investigated via catalytic oxidation over Pd/carbon-zeolite and Pd/carbon-CeO₂ nanocatalysts. Activated carbon was obtained from pine cone chemically activated using ZnCl₂ and modified by H₃PO₄. Natural zeolite of clinoptilolite was modified by acid treatment with HCl, while nano-ceria was synthesized via redox method. Mixed supports of carbon-zeolite and carbonceria were prepared and palladium was dispersed over them via impregnation method. The prepared samples were characterized by X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), Brunauer-Emmett-Teller surface area (BET), Fourier transform infrared spectroscopy (FTIR) and thermogravimetric (TG) techniques. Characterization of nanocatalysts revealed a good morphology with an average particle size in a nano range, and confirmed the formation of nano-ceria with an average crystallite size below 60 nm. BET analysis indicated a considerable surface area for catalysts (～1000 m²·g^?1). FTIR patterns demonstrated that the surface groups of synthesized catalysts are in good agreement with the patterns of materials applied in catalyst synthesis. The performance of catalysts was assessed in a low-pressure catalytic oxidation pilot in the temperature range of 100° C-250°C. According to the reaction data, the synthesized catalysts have been shown to be so advantageous in the removal of volatile organic compounds (VOCs), representing high catalytic performance of 98% for the abatement of xylene at 250°C. Furthermore, a reaction network is proposed for catalytic oxidation of xylene over nanocatalysts.     

Assessment of anticipated performance index of some deciduous plant species under dust air pollution

Environmental Science and Pollution Research - Green vegetation improvement is an economical strategy to mitigate dust air pollution. The anticipated performance index (API) is considered a main...     

Efficient microwave-assisted diastereoselective synthesis of indole-based 4,5-dihydrofurans via a one-pot,three-component reaction in water

Environmental Chemistry Letters - The combination of two or more different heterocyclic moieties in a single molecule would enhance biological activity significantly. The indole and furan scaffolds...     

A Three-Dimensional Hydro-Environmental Model of Dublin Bay

In this study, the impact of Escherichia coli emissions from a sewage treatment plant on the bathing water quality of Dublin Bay (Ireland) is assessed using a three-dimensional hydro-environmental model. Before being discharged, the effluent from the plant is mixed with cooling water from a thermal?Celectrical power generation plant, creating a warm buoyant sewage plume that can be 7?C9°C higher and is less saline than the ambient water in the bay. The ability of the three-dimensional model in representing such a stratified condition is assessed based on a comparison of its results with two-dimensional modelling results. Hydrodynamic simulations of water levels and flow velocities in Dublin Bay were obtained using the TELEMAC-3D model in one case and the depth-averaged TELEMAC-2D model in the other. The results of each model were separately used as inputs to the water quality model SUBIEF-3D to simulate the transport and fate of E. coli in the bay and to generate maps of E. coli concentrations over the bay. In addition, the necessity for three-dimensional modelling in simulating the effects of wind direction on the dispersion of E. coli was demonstrated by comparing the results of three-dimensional and two-dimensional model simulations with a number of different wind directions. The comparison showed that the three-dimensional model performed better than the depth-averaged model in simulating the hydrodynamics and resulted in better simulation of the water quality processes in the bay. In particular, the three-dimensional model had reasonably simulated the timing of the delivery of E. coli to the bay. Moreover, the effect of wind on the movement of the buoyant plume of pollution and on the E. coli distribution was found to be more pronounced with the three-dimensional hydrodynamics. The results demonstrate the need for three-dimensional simulations in situations of density differences or significant wind influences.