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Start Over Journal chemosphere Publisher elsevier
5 results

1. Optimum reaction ratio of coal fly ash to blast furnace cement for effective removal of hydrogen sulfide

Author

Kyunghoi Kim, Satoshi Asaoka, Shinjiro Hayakawa, Oikawa Takahito, Yuzuru Hatanaka, Hideo Okamura, Kazutoshi Hino, Kenji Nakamoto, and Tetsuji Okuda

Subjects
Geologic Sediments, Health, Toxicology and Mutagenesis, Hydrogen sulfide, 02 engineering and technology, 010501 environmental sciences, 01 natural sciences, chemistry.chemical_compound, X-Ray Diffraction, Hydrogen Sulfide, Environmental Restoration and Remediation, chemistry.chemical_classification, Waste management, General Medicine, respiratory system, Eutrophication, 021001 nanoscience & nanotechnology, Pulp and paper industry, Pollution, Coal, 0210 nano-technology, Environmental Monitoring, Blast furnace, Environmental Engineering, Sulfide, Environmental remediation, Mixing (process engineering), Industrial Waste, Coal Ash, complex mixtures, Adsorption, Environmental Chemistry, Recycle, 0105 earth and related environmental sciences, Ions, Cement, Hydroxyl Radical, Silicates, fungi, technology, industry, and agriculture, Public Health, Environmental and Occupational Health, General Chemistry, Calcium Compounds, Carbon, Kinetics, chemistry, Fly ash, Microscopy, Electron, Scanning, Coal-fired power plant, Environmental science, Particulate Matter, Sediment
Abstract

Reducing hydrogen sulfide concentration in eutrophic marine sediments is crucial to maintaining healthy aquatic ecosystems. Managing fly ash, 750 million tons of which is generated annually throughout the world, is another serious environmental problem. In this study, we develop an approach that addresses both these issues by mixing coal fly ash from coal-fired power plants with blast furnace cement to remediate eutrophic sediments. The purpose of this study is to optimize the mixing ratio of coal fly ash and blast furnace cement to improve the rate of hydrogen sulfide removal based on scientific evidence obtained by removal experiments and XAFS, XRD, BET, and SEM images. In the case of 10 mg-S L −1 of hydrogen sulfide, the highest removal rate of hydrogen sulfide was observed for 87 wt% of coal fly ash due to decreased competition of adsorption between sulfide and hydroxyl ions. Whereas regarding 100 mg-S L −1 , the hydrogen sulfide removal rate was the highest for 95 wt% of coal fly ash. However, for both concentrations, the removal rate obtained by 87 wt% and 95 wt% were statistically insignificant. The crushing strength of the mixture was over 1.2 N mm −2 when the coal fly ash mixing ratio was less than 95 wt%. Consequently, the mixing ratio of coal fly ash was optimized at 87 wt% in terms of achieving both high hydrogen sulfide removal rate and sufficient crushing strength.

Published
2017

2. A novel approach in revealing mechanisms and particular step predictors of pH dependent tartrazine catalytic degradation in presence of Oxone®

Author

Popadić, Marko, Marinović, Sanja, Mudrinić, Tihana, Milutinović Nikolić, Aleksandra, Banković, Predrag, Đorđević, Ivana, Janjić, Goran, Popadić, Marko, Marinović, Sanja, Mudrinić, Tihana, Milutinović Nikolić, Aleksandra, Banković, Predrag, Đorđević, Ivana, and Janjić, Goran

Abstract

The degradation of tartrazine in the presence of cobalt activated Oxone® (potassium peroxymonosulfate) was investigated at different initial pH values. Aluminum pillared clay had the role of a support for catalytically active cobalt oxide species. The degradation of tartrazine and the formation of a mixture of degradation products were monitored using the Ultraviolet–Visible (UV–Vis) spectroscopy and gas chromatography–mass spectrometry (GC-MS). The exact qualitative composition of this mixture and the determination of the most probable mechanism of degradation (the primary goal) were obtained using GC-MS. Besides, the main reaction pathway (reaction with SO4˙ˉ radical anion) and secondary pathways were proposed depending on the pH value. At pH = 6 the reaction with HO˙ radical was proposed. At pH = 11 decarboxilation was suggested as the first step of the secondary proposed reaction pathway. The combination of results acquired from the deconvolution of UV–Vis spectra and the theoretical UV–Vis spectra of degradation products, whose occurrence was predicted by quantum-chemical calculations, was proven to be beneficial for the identification of tartrazine degradation products and for defining UV–Vis predictors of particular degradation steps. An additional contribution of this paper, from the reactivity aspect, was the establishment of the critical structural demand for the radical degradation of any diazo compound. The existence of a hydrogen atom bound to a diazo group was found to be the essential prerequisite for the radical cleavage of diazo compounds.

Published
2021

3. Is Kragujevac city still a “hot spot” area, twenty years after the bombing?

Author

Milenković, Biljana, Stajić, Jelena M., Zeremski, Tijana, Štrbac, Snežana, Stojić, Nataša, Nikezić, Dragoslav, Milenković, Biljana, Stajić, Jelena M., Zeremski, Tijana, Štrbac, Snežana, Stojić, Nataša, and Nikezić, Dragoslav

Abstract

After NATO bombing of Serbia in 1999, UNEP has identified Kragujevac as one of the four heavily polluted environmental “hot spots”. Damaging of industrial and military targets caused the release of substantial amounts of hazardous chemical substances into the environment. This study was conducted in order to access the exposure of residents of Kragujevac city to persistent soil pollutants, twenty years after NATO air campaign. The paper reports the results of measuring radionuclides, polycyclic aromatic hydrocarbons (PAHs), polychlorinated biphenyls (PCBs) and heavy metals (As, Cd, Co, Cr, Cu, Mn, Ni, Pb, Zn, and Hg) in soil samples collected from two depths (0–15 cm and 15–30 cm) at 30 locations along the riverbank of the Lepenica River. The average specific activities of 226Ra, 232Th, 40K and 137Cs were comparable to average worldwide values; excess lifetime cancer risk (ELCR) from natural radionuclides ranged from 1.1·10−4 to 3.3·10−4. The measured concentrations of As, Co, Cr, Cu, and Ni exceeded the limit values in most of the samples. Non-carcinogenic risk (hazard quotient and hazard index) and carcinogenic risk from heavy metals were assessed. Total hazard index was 0.257 and 2.16 for adults and children, respectively. Sum of measured PAHs ranged from 110 to 1026 μg kg−1. Sum of PCBs exceeded the limit value of 20 μg kg−1 in all samples (it ranged from 48.8 to 196.8 μg kg−1), but it was still below the remediation level. The differences between two layers with respect to all measured variables were not statistically significant.

Published
2020

4. The role of analytical chemistry in exposure science: Focus on the aquatic environment

Abstract

Exposure science, in its broadest sense, studies the interactions between stressors (chemical, biological, and physical agents) and receptors (e.g. humans and other living organisms, and non-living items like buildings), together with the associated pathways and processes potentially leading to negative effects on human health and the environment. The aquatic environment may contain thousands of compounds, many of them still unknown, that can pose a risk to ecosystems and human health. Due to the unquestionable importance of the aquatic environment, one of the main challenges in the field of exposure science is the comprehensive characterization and evaluation of complex environmental mixtures beyond the classical/priority contaminants to new emerging contaminants.The role of advanced analytical chemistry to identify and quantify potential chemical risks, that might cause adverse effects to the aquatic environment, is essential. In this paper, we present the strategies and tools that analytical chemistry has nowadays, focused on chromatography hyphenated to (high-resolution) mass spectrometry because of its relevance in this field. Key issues, such as the application of effect direct analysis to reduce the complexity of the sample, the investigation of the huge number of transformation/degradation products that may be present in the aquatic environment, the analysis of urban wastewater as a source of valuable information on our lifestyle and substances we consumed and/or are exposed to, or the monitoring of drinking water, are discussed in this article. The trends and perspectives for the next few years are also highlighted, when it is expected that new developments and tools will allow a better knowledge of chemical composition in the aquatic environment. This will help regulatory authorities to protect water bodies and to advance towards improved regulations that enable practical and efficient abatements for environmental and public health protection.

Published
2019

5. Levels of PCDDs and PCDFs in farm cow's milk located near potential contaminant sources in Asturias (Spain). Comparison with levels found in control, rural farms and commercial pasteurized cow's milks

Author

Luis M. Hérnandez, Lourdes Ramos, María Jesús González González, L. Alonso, Josep Rivera, Ethel Eljarrat, Principado de Asturias, and Consejo Superior de Investigaciones Científicas (España)

Subjects
Polychlorinated Dibenzodioxins, Environmental Engineering, Health, Toxicology and Mutagenesis, Pasteurization, Incineration, Gas Chromatography-Mass Spectrometry, law.invention, Animal science, fluids and secretions, Reference Values, law, Product Surveillance, Postmarketing, Animals, Soil Pollutants, Environmental Chemistry, Benzofurans, Waste management, Pesticide Residues, Public Health, Environmental and Occupational Health, food and beverages, General Medicine, General Chemistry, Dibenzofurans, Polychlorinated, Raw milk, Metallurgical industry, Pollution, Milk, Congener, Spain, Chemical Industry, Metallurgy, Environmental science, Cattle
Abstract

Cows milk samples from 12 dairy farms in Spain and 23 samples of pasteurised cows milk were analysed for PCDD/F. Farms located in rural areas without specific dioxin sources (background levels) ranged from 1.3 to 2.47 pg TEQ/g fat basis. These values were slightly lower than those found in milk from the vicinity of potential dioxin emission sources (waste incinerator, chemical and metallurgical industry) and similar to milk near paper industry. The waste incinerator seems to be the emission source with the highest influence on the cows milk gathered in its vicinity. Thus, milk near the waste incinerator exhibited the highest PCDD/F levels, the highest PCDF/PCDD ratio and its congener PCDD pattern showed the highest difference respect to its control point. The PCDD/F average concentrations found in pasteurised commercial milk were lower than those found in raw milk and were comparable to those found in retail milk from other countries., The authors thank the CSIC and the Principado de Asturias (project PA-AGR94-02).

Published
1997