D. Bieniek

Synthesis of carboxyl group containing hydrazine-modified polyacrylonitrile fibres and application for the removal of heavy metals

Abstract Carboxyl group containing hydrazine-modified polyacrylonitrile (PAN) fibre was prepared by a modified method of T. Miyamatsu and N. Oguchi. The first investigation of this modified ion exchange fibre (IEF) revealed that the maximum capacities of the modified PAN fibre for the heavy metal ions Cu 2+ , Cd 2+ , Zn 2+ , Co 2+ , Pb 2+ , Cr 3+ , Ni 2+ and Hg 2+ were 1.33, 1.30, 1.03, 1.02, 0.98, 0.96, 0.95 and 0.63 mmol/g (dry weight), respectively. According to the distribution coefficients the order of decreasing selectivity of the cation exchanger for the various metal ions was Cu 2+ > Zn 2+ > Cr 3+ > Hg 2+ > Cd 2+ > Pb 2+ > Ni 2+ > Co 2+ . The product could be reused after regeneration with diluted nitric acid. The high exchange capacity for copper, which offers possibilities for the application of the material for industrial purposes, was examined in additional experiments.

Investigation of the binding of heavy metals in thermally treated residues from waste incineration

The use of thermal treatment (sintering, vitrification) enables the inertization of heavy metals in residues of waste against leaching. In this work thermally treated fly ash is leached in a six step sequential extraction procedure that enables the description of the binding and with that of the inertization of heavy metals. It is shown that, regarding the energetic factor, sintering at high temperatures could be the more convenient way to inert fly ash against leaching of heavy metal compounds.

Determination of monomeric sugar and carboxylic acids by ion-exclusion chromatography

Abstract The influence of the temperature and the eluent (proton) concentration on the retention and separation of thirty organic compounds, including sugar acids, lactones, hydroxy acids, mono acids and dicarboxylic acids, on the Merck cation- exchange column Polyspher OA-HY was studied by applying ion-exchange chromatographic methods and HPLC instrumentation. The different responses of the various groups of compounds to changes of the chromatographic parameters were used to select the optimized separation conditions. A combination of two parameter sets (I: temperature of 45°C, sulphuric acid eluent concentration of 0.01 N , flow-rate of 0.5 ml min −1 ; II: 10°C, 0.1 N H 2 SO 4 , same flow-rate) was found to enhance the chromatographic versatility and substance identification. Five-point linear calibrations were conducted under both conditions, and the respective relative standard deviations, mean percentage errors and detection limits were determined.

Analysis of aliphatic car☐ylic acids and amino acids in effluents of landfills, composting plants and fermentation plants by ion-exclusion and ion-exchange chromatography

Abstract Short chain aliphatic acids, including volatile fatty acids (VFAs), di-/tricar☐ylic acids, hydroxy- and keto-acids were analyzed in landfill leachates and related water samples by two independently operated ion-exclusion chromatographic systems, differing mainly in the retention characteristics of the separation columns (Merck Polyspher OA-HY, Dionex HPICE AS6), and in the detection mode (UV absorbance at 210 nm, conductivity). The amino acid content of the samples was determined by ion chromatography. Because methods for amino acids analysis are widely standardized, the main efforts were undertaken to optimize the determination of car☐ylic acids. The VFAs (7 compounds) contributed between 33% and 89% to the samples dissolved organic carbon (DOC) content. The DOC proportions of the multifunctional acids (9 compounds) ranged from 1.1–49%. Between 0.9% and 13% of the DOC content was apportioned to amino acids. Main components were alanine, valine and leucine. The analytical efficiencies of the ion-exclusion chromatography systems were compared and the specific application properties are discussed.

Heavy metal leaching of fly ash from waste incineration with gluconic acid and a molasses hydrolysate

Abstract The application properties of sugar acids and a hydrolysate containing sugar acids were investigated in order to evaluate their potential for removing heavy metals from waste incineration residues. Exemplarily the biomass residue molasses, which is rich in carbohydrates, was oxidized under acidic conditions to yield a hydrolysate containing natural chelating agents. The leaching capacities of the complexing agents containing solutions were examined in a series of batch tests with a fly ash from municipal waste incineration. Gluconic acid with a concentration of 0.5%, 2% and 5% and a molasses hydrolysate with a sugar acid content of approx. 1.8% were applied. It is demonstrated that sugar acids, as well as a biomass hydrolysate, which contains sugar acids, can be used as effective agents for the remediation of heavy metals which are bound to or included in the matrix of waste incineration residues. Advantageous for the leaching process is that sugar acids are particularly effective in the pH range which is normally measured for waste incineration residues.

Determination of short chain aliphatic acids in silage effluents by ion exclusion chromatography

SummaryShort chain aliphatic acids are important components of the dissolved organic matter in silage effluents. Although ion exclusion chromatography offers some advantages for the analysis of these compounds, no attempt has yet been made to prove the suitability of this method for silage effluent analysis. In order to gain experience in this field, the separation characteristics of a Dionex ion exclusion column (IonPac-ICE As5) have been evaluated, the separation conditions have been improved, and several sample clean-up methods have been checked.Ten effluents generated during silaging of five different crops were collected from Bavarian farms and analyzed. Lactic and acetic acids were the predominant aliphatic acids. Pyruvic, formic, propionic, and succinic acid were detected in all samples, whereas glyceric and iso-citric acid were found in a few samples only.If some restrictions of substance specificity and separation efficiency can be accepted, the analytical method presented will be a reliable tool for the analysis of carboxylic acids in silage effluents.

Desorption of Heavy Metals from Typical Soil Components (Clay, Peat) with Glycine

Abstract Natural organic chelating agents take part in the mobilization and translocation of heavy metals in unpolluted and polluted soils. They also have to be considered as possible extracting agents for the decontamination of heavy metal polluted soils. For an assessment of the desorption capability of glycinc, heavy metals (Cd, Cu, Ni, Pb, Zn) were adsorbed onto typical soil components (bentonite and peat). The metal loaded sorbents were resuspended in aqueous solutions of glycine at pH 7.0 and 4.5 and the quantities of the desorbed metals were analysed in the liquid phase. Furthermore, the dependency of the desorption rate on the duration of experiments and the metal content were investigated. The remobilization of heavy metals from bentonite by glycine at pH 7.0 decreases following the order Cu > Ni > Zn > Cd > Pb and ranges from 95% to 9.5%. The desorption rate was significantly lower at pH 4.5 and in suspensions of peat.

Synthesis of amidoxime-containing modified starch and application for the removal of heavy metals

Abstract Amidoxime-containing modified starch was prepared by reaction of acrylonitrile with crosslinked starch, catalyzed by ceric ions, and subsequent derivatization with free hydroxylamine in methanol. First investigations of this new cation exchange material revealed that the maximum capacities of the modified starch for the heavy metal ions Cu2+, Hg2+, Pb2+ and Zn2+ were 1.86, 0.59, 0.52 and 0.37 mmol g−1 (dry weight), respectively. At pH 5, the order of decreasing selectivity of the cation exchanger for the various metal ions was: Hg2+ > Cu2+ > Pb2+ > Zn2+ > Ni2+ > Cr3+. The product could be reused after regeneration with diluted hydrochloric acid. The high exchange capacity for copper, which offers possibilities for applications of the material for industrial purposes, were examined in detail.

Chemical Characterization of Silage Effluents and their Influence on Soil Bound Heavy Metals

Abstract Silage effluents, generated during silaging of various crops, are produced in high amounts in cattle breeding farms. Due to their acidity and high content of dissolved organic matter, they are causing disposal problems. On the other hand, their ability to mobilise soil bound trace elements (i.e. heavy metals) might be useful for the decontamination of polluted soils. With an aim to perform metal leaching studies, silage effluents from various ensiled crops (maize, rape, grass, clover, sugar-beet leaves) were collected from Bavarian farms and analysed for their main inorganic and organic constituents. Important TOC sources (TOC concentrations from 13.9 to 53.6 gl−1) are short chain aliphatic acids (concentrations between 235 and 638 mM·D1−1; predominant compound: lactic acid), amino acids (ranging from 22.8 to 151 mM·D1−1) and polypeptides (concentrations from 3.8 to 20.0 g·D1−1). The release of heavy metals from two adsorbents (bentonite and peat) and from a polluted soil under the influence of s...

Removal of heavy metals from polluted soil with grass silage juice

Abstract Grass silage effluents, generated during the silaging of grass for their conservation as green stuff, contain a lot of organic compounds, which are able to complex heavy metals. To assess the leaching potential with respect to metals bound on soils, an effluent from ensiled grass was collected and analyzed. A polluted soil was treated with the effluent in batch and column tests. The leaching rates obtained are: Cd 74,7%, Zn 55,7%, Cu 53,5%, Ni 38,9%, Cr 12,7% and Pb 8,9%.