PubMed Health⌕ Search

PubMed · 15823744

Carbonation of MSWI-bottom ash to decrease heavy metal leaching, in view of recycling.

Abstract

The 0.1-2 mm fraction of a MSWI-bottom ash cannot be used as granular construction material because leaching of Cu exceeds Flemish limit values. In addition, leaching of Ba, Mo and Sb exceeds informal limit values. Leaching characteristics thus need to be improved. Carbonation was the chosen treatment method and this was performed by placing samples in a CO2 chamber. The CO2 percentage and the temperature of the chamber atmosphere, as well as the initial humidity of the samples, were varied to optimize carbonation parameters. Metal leaching was tested with the EN 12457 extraction test. Carbonation decreased Cu leaching from 3.3 to 1.0 mg/kg, but not yet to below the official limit value of 0.5 mg/kg. Leaching of Mo and Sb remained fairly constant or even increased after carbonation, but their limit values are only informal. Ba leaching decreased to below the informal limit value. Carbonation also caused Cr leaching to increase, in some cases to above the official limit value. Of the tested parameters, a CO2 percentage of 10% and a carbonation temperature of 50 degrees C in the atmosphere, together with ash humidity between 13% and 25% appeared to give the best leaching results. The main carbonation reactions took place within the first 24 h.

Explore related subjects

Keep this discovery

Explore connections, maps & timelines

BibTeXRIS

T Van Gerven, E Van Keer, S Arickx, M Jaspers, G Wauters, C Vandecasteele. 2005. Carbonation of MSWI-bottom ash to decrease heavy metal leaching, in view of recycling.. https://doi.org/10.1016/j.wasman.2004.07.008

Cite the original work for its findings. Save a collection to share your selection of sources.

KEEP EXPLORING

Related citations

Phenotypic profiling of carbon utilization of Pectobacterium brasiliense (Pbr1692).

Pectobacterium brasiliense 1692 (Pbr1692) is a necrotrophic pathogen that infects many crops such as potatoes and ornamental plants and derives nutrients from degraded plant tissue. Previous studies have identified Pbr1692 genes required for ecological fitness and virulence, however there is a lack of information on nutrient utilization in Pbr1692. Carbon source utilization profiling in Pbr1692 could provide a platform to decipher its metabolic flexibility and adaptation. This study assessed the nutrient utilization of Pbr1692 in different carbon sources, using Biolog Phenotypic Microarray (PM). An array of carbon sources utilized by Pbr1692 were identified, 32 carbohydrates and 8 carboxylic acids were among the preferred carbon nutrients utilized by Pbr1692. The PM results also revealed that the citric acid cycle, amino acid metabolism, and pentose phosphate metabolic pathways might be used to produce energy for Pbr1692. In addition, growth of Pbr1692 cells in minimal medium supplemented with citric acid, glucose, and aspartic acid retained the typical rod shape, suggesting that nutrient variation did not influence Pbr1692 cell morphology adaptation. This study provides an understanding on the adaptation of Pbr1692 and lays a foundation for understanding carbon metabolism of Pbr1692.

Carbon↗

Quantitative analysis of EDC-condensed DNA on vertically aligned carbon nanofiber gene delivery arrays.

Vertically aligned carbon nanofibers (VACNFs) with immobilized DNA have been developed as a novel tool for direct physical introduction and expression of exogenous genes in mammalian cells. Immobilization of DNA base amines to the carboxylic acids on nanofibers can influence the accessibility and transcriptional activity of the DNA template, making it necessary to determine the number of accessible gene copies on nanofiber arrays. Polymerase chain reaction (PCR) and in vitro transcription (IVT) were used to investigate the transcriptional accessibility of DNA tethered to VACNFs by correlating the yields of both IVT and PCR to that of non-tethered, free DNA. Yields of the promoter region and promoter/gene region of bound DNA plasmid were high. Amplification using primers designed to cover 80% of the plasmid failed to yield any product. These results are consistent with tethered, longer DNA sequences having a higher probability of interfering with the activity of DNA and RNA polymerases. Quantitative PCR (qPCR) was used to quantify the number of accessible gene copies tethered to nanofiber arrays. Copy numbers of promoters and reporter genes were quantified and compared to non-tethered DNA controls. In subsequent reactions of the same nanofiber arrays, DNA yields decreased dramatically in the non-tethered control, while the majority of tethered DNA was retained on the arrays. This decrease could be explained by the presence of DNA which is non-tethered to all samples and released during the assay. This investigation shows the applicability of these methods for monitoring DNA immobilization techniques.

Carbon↗