Search results for "pollution"
showing 10 items of 2765 documents
Air Quality Assessment by the Determination of Trace Elements in Lichens (Xanthoria calcicola) in an Industrial Area (Sicily, Italy)
2022
This study provides data on variation in the content of metals and metalloids measured in the lichens (Xanthoria calcicola Oxner) collected in the Syracusan petrochemical complex (Sicily, Italy) which is considered one of the largest in Europe. Concentrations of eighteen trace elements measured in the lichens that were collected from 49 different points were analyzed using an inductively coupled plasma (ICP-MS) device. The concentrations of the typical elements of industrial emissions (As, Cr, Ni, and V) highlight the environmental criticality that exists in the study area. The interpretation of the data in terms of multi-element statistical analysis (FA) and enrichment factor (EFs) proved …
Effect of Mg2+ ions on competitive metal ions adsorption/desorption on magnesium ferrite: Mechanism, reusability and stability studies
2021
Abstract The adsorption behavior of magnesium ferrite in single- and multicomponent metal ions solutions in the presence of Mg2+ ions were studied. A dramatic decrease in the adsorption capacity of magnesium ferrite towards Mn2+, Co2+, and Ni2+ ions for comparison study of single- and multicomponent solutions was established. The affinity of the sorbent in accordance with the maximum sorption capacities increases in the following order Cu2+ > Co2+ > Ni2+ > Mn2+. High efficiency of magnesium ferrite regeneration (~100%) with aqueous solutions of magnesium chloride in the concentration range of 0.001–0.1 M was shown. The low degree of toxic metal ions desorption combined with XRD, IR spectros…
Effect of cadmium pre-exposure in cadmium accumulation by brine shrimp Artemia: Involvement of low-molecular-weight cadmium-binding ligands
1993
Abstract Cadmium is a ubiquitous non-essential element that possesses high toxicity and is easily accumulated from the environment by aquatic organisms. It is known that pre-exposure to cadmium increases the resistance of animals to a subsequent exposure. In this work, we report studies of the effect of pre-exposure to cadmium on the accumulation of this metal from seawater by brine shrimp Artemia, as well as the involvement of low-molecular-weight cadmium-binding ligands in this process. During the pre-exposure experiments, animals were kept in seawater containing 20 mg/litre Cd for 24 h and then transferred to clean seawater for 48 h. Afterwards, pre-exposed and control animals were expos…
Removal of Fe(III) from synthetic wastewater into raw and modified clay: Experiments and models fitting
2017
Water pollution by heavy metal ions has become a serious environmental issue especially due to their toxicity and tendency to bioaccumulation. Natural smectite clay was treated using sulfuric acid ...
Exposure to nitrogen dioxide and respiratory health at 2 years in the INMA-Valencia cohort
2018
Resumen Objetivo Analizar la relación entre la exposición a dióxido de nitrógeno (NO2) en las etapas prenatal y posnatal y la incidencia de problemas respiratorios en niños/as hasta los 2 años de edad. Método La población consistió en 624 niños/as de la cohorte INMA-Valencia. Se estimó la exposición individual al NO2 en el exterior de la vivienda durante el periodo prenatal y hasta los 2 años de edad, a partir de la combinación de datos empíricos y el desarrollo de métodos geoestadísticos. Se aplicó un cuestionario para obtener la información sobre los síntomas respiratorios a los 2 años. La asociación entre la exposición al NO2 y los eventos respiratorios se realizó mediante regresión logí…
Effects of NH3 and alkaline metals on the formation of particulate sulfate and nitrate in wintertime Beijing
2020
Sulfate and nitrate from secondary reactions remain as the most abundant inorganic species in atmospheric particle matter (PM). Their formation is initiated by oxidation (either in gas phase or particle phase), followed by neutralization reaction primarily by NH3, or by other alkaline species such as alkaline metal ions if available. The different roles of NH3 and metal ions in neutralizing H2SO4 or HNO3, however, are seldom investigated. Here we conducted semi-continuous measurements of SO4 2−, NO3 −, NH4 +, and their gaseous precursors, as well as alkaline metal ions (Na+, K+, Ca2+, and Mg2+) in wintertime Beijing. Analysis of aerosol acidity (estimated from a thermodynamic model) indicat…
“Release and catch” catalytic systems
2013
In this perspective article the “release and catch” catalytic system concept is discussed. A “release and catch” catalytic system is prepared by non-covalent immobilization of the catalytic moiety on a suitable support, but differently from the usual non-covalently supported catalyst, the catalytic moiety is released in solution over the course of the reaction and it is recaptured at the end of the reaction. Such a “catalyst- sponge like” or “boomerang” system allows one to combine the benefits of homogeneous and heterogeneous catalysis and can be applied to organometallic-based catalysts, organocatalysts and metal-based catalysts.
Sol-gel entrapped chromium(VI): a new selective, efficient and recyclable oxidizing system
2001
Abstract The sol-gel entrapment of chromium(VI) within a silica matrix, obtained by oxidation with ozone of the corresponding entrapped chromium(III), was found to be an efficient and recyclable oxidizing system (at least up to 16 times) for benzylic alcohols. No leaching of chromium in solution was observed, which prevented any environmental pollution.
ChemInform Abstract: Sol-Gel Entrapped Chromium(VI): A New Selective, Efficient and Recyclable Oxidizing System.
2010
Abstract The sol-gel entrapment of chromium(VI) within a silica matrix, obtained by oxidation with ozone of the corresponding entrapped chromium(III), was found to be an efficient and recyclable oxidizing system (at least up to 16 times) for benzylic alcohols. No leaching of chromium in solution was observed, which prevented any environmental pollution.
FeOOH-modified clay sorbents for arsenic removal from aqueous solutions
2019
The presence of arsenic (As) in natural and anthropogenic soils causes severe pollution of groundwater due to its harmful carcinogenic effects. The present work describes the research activities for searching of appropriate innovative sorbents based on clay material for As sorption using iron oxy-hydroxide modification. Natural and manufactured clay was chosen for comparison of modification efficiency in order to obtain best sorption results for As(V). The results of pilot testing were obtained and the sorption was studied as a function of initial arsenic concentration. Obtained results indicate that modification of clay with Fe compounds significantly improves the sorption capacity of a ne…