The increase of iron phytoavailability in soils ammended with paper mill sludge

In soils characterized by low organic matter and high pH values (7.5-8.59) iron availability to plants is limited even if the content of total Fe(III) is high. We have studied by Hordeum distichum plants the capability of paper mill sludge to increase the iron phytoavailable fraction in an alkaline soil. The effect of paper mill sludges adding to an iron-deficient soil was evaluated both considering the phyto-available fraction of iron and the distribution of organic carbon (hydrophobic, fulvic and humic carbon) in the soil before and after sludge adding. Iron concentration was determined in the different portions of Hordeum distichum plants grown on soils with and without paper mill sludges. Application of paper mill sludge induces an increase in the concentration of available Fe. This effect is probably due to the production of Fe chelators by soil microorganisms acting on sludge organic matter. The Fe chelators produced result in the solubilization of not soluble Fe-complexes present in the soil.     

Fulvic acid enrichment in the microlayer of the Gerlache Inlet Sea (Antarctica): preliminary results

The aim of this work was to study the presence of fulvic acids in Antarctic waters, as they appear to be principal film-forming components in the surface microlayer. We obtained a series of samples during two Antarctic Italian Expeditions in 1998/99 and 2000/01 and studied the distribution and the structural differences between fulvic acids extracted from both microlayer and subsurface waters.

Fulvic acids are concentrated in the microlayer and the enrichment factor between microlayer and subsurface water differs between samples. The enrichment factor values for fulvic acids lie between those found for dissolved organic carbon (DOC) and particulate organic carbon (POC) in the literature. Fulvic acids extracted from the microlayer were found to be different in structure from those present in the subsurface layer and enriched in sulphur content. We hypothesised that sulphur-containing compounds are slightly bound and/or occluded in fulvic acid structures. The sulphur-containing compounds analysed in the microlayer could be dimethylsulfide (DMS) and/or its products stemming from photochemical and biological oxidation reactions.     

Complexity of 3-orbifolds

We extend Matveev's theory of complexity for 3-manifolds, based on simple spines, to (closed, orientable, locally orientable) 3-orbifolds. We prove naturality and finiteness for irreducible 3-orbifolds, and, with certain restrictions and subtleties, additivity under orbifold connected sum. We also develop the theory of handle decompositions for 3-orbifolds and the corresponding theory of normal 2-suborbifolds.     

Determination of organophosphorus pesticides by thin-layer chromatography

Analysis for 13 common organophosphorus pesticides by thin-layer chromatography is described; 17 solvent systems were examined. With channel thin-layer chromatography, linear calibration graphs were obtained for the range 1-10 mug.     

Some applications of ligand-exchange--I. Recovery of phenolic compounds from water

The properties of a chelating ion-exchanger in the iron(III) form in contact with an aqueous solution containing phenolic compounds have been studied. The phenols retained are completely displaced by elution with an ethanolic sodium hydroxide solution.     

Characterization and evaluation of material used for the recovery of organic compounds from water

Summary A general procedure that should be applied when a sorbent material is examined in order to recover organic pollutants from water is shown. This method recommends determination of specific retention volumes, the break-through of test compounds and the influence on these of the interfering substances. An expanded hydrophobic perlite was characterized as a suitable adsorbent for the recover of polycyclic aromatic hydrocarbons (PAHs).     

Some applications of ligand-exchange-II Separation of phenolic compounds

The separation of phenol, 2-nitrophenol, 2,4-dichlorophenol and pentachlorophenol by ligand-exchange chromatography was studied with Chelex 100 resin in the Fe(3+) form as stationary phase and sodium hydroxide solution (pH 7.5, 11.5, 12) as the mobile phase.     

Laboratory studies on waste water sludge application for acid soil remediation

In this work the effects of sludge disposal on pH values, buffer capacity and adsorption capacity of an acid soil were studied. A stabilized waste water sludge and a paper mill sludge were employed; the pH values of both sludges were higher than 8. The observed differences between soil-urban sludge and soil-paper mill sludge systems can be ascribed to the nature of the compounds present in the sludges and adsorbed on the soil. Both kinds of sludge are able to modify the natural pH of the soil, the buffer capacity and its capacity to retain metal. These modifications increase with increasing soil-sludge contact time and are higher for paper mill sludges. Temperature affects only the modifications due to urban sludge treatment.     

Paper mill sludge-soil mixture: kinetic and thermodynamic tests of cadmium and lead sorption capability

Paper mill sludge (characterized by 29.0% of organic substances such as cellulose, lignin and tannins and 71.0% of inorganic substances such as kaolinite and carbonates) was studied in a mixture with soil in order to evaluate its effects on soil capability for retaining heavy metals. Attention was focused on cadmium and lead sorption and two parameters were investigated, the contact time of paper mill sludge-soil mixture and the paper mill sludge-soil ratio in the mixture. Results showed that paper mill sludge and soil interact to form ‘new’ sorbing sites. Taking into account sorption results of lead, the retention of which by soil is substantially increased by sludge addition, can highlight this modification. Also, the amount of sorbed cadmium was increased by sludge addition.