Search results for "Humic"

Hydration and water holding properties of cross-linked lignite humic acids

2014

Abstract Lignite and lignite humic acids, which are used as soil amendments sometimes, are supposed to improve soil properties such as water holding capacity. The structure of those materials is composed of various organic molecules stabilized mostly by weak interactions. Therefore, excess of water causes only partial swelling, but most of the physical structure is destabilized. This accelerates the desiccation and hampers their application as natural hydrogel-like substances. In order to stabilize the structure of lignite humic acids and improve the water holding capacity, we applied formaldehyde cross-linking procedure based on covalent coupling of aromatic humic acids moieties. By combin…

On-fibre solid-phase microextraction coupled to conventional liquid chromatography versus in-tube solid-phase microextraction coupled to capillary li…

2006

This paper compares the advantages and disadvantages of two different configurations for the extraction of triazines from water samples: (1) on-fibre solid-phase microextraction (SPME) coupled to conventional liquid chromatography (LC); and (2) in-tube SPME coupled to capillary LC. In-tube SPME has been effected either with a packed column or with an open capillary column. A critical evaluation of the main parameters affecting the performance of each method has been carried out in order to select the most suitable approach according to the requirements of the analysis. In the on-fibre SPME configuration the fibre coating was polydimethylsiloxane (PDMS)-divinylbenzene (DVB). The limits of de…

Biodeterioration of cardboard-based liquid containers collected for fibre reuse.

1999

Liquid packaging board (LPB) collected in Germany is processed in Finland as recycled fibre and as plastic reject for incineration. The chemical, biological and physical changes occurring in recycled LPB bales were monitored during storage of six and 18 months. The moisture content in the core of the bales ranged from 7% to 53%, and pH values varied from 6.0 to 8.5. The average amount of mesophilic bacteria per container was 1.5 x 10(7) - 5 x 10(8), which means that recycled LPB pulp cannot be recommended for sanitary use. The concentration of CO2 inside the bale is an indicator of the activity of aerobic microorganisms and might be suitable for identifying deteriorated bales and removing t…

Pyrolysis-GC-MS and CuO-oxidation-HPLC in the characterization of HMMs from sediments and surface waters downstream of a pulp mill

1998

Abstract High molecular mass fractions of lignin and humic compounds in sediments and waters downstream of a pulp mill were characterized applying pyrolysis-gas chromatography-mass spectrometry. The results were compared to those obtained using reversed phase HPLC on the cupric oxide oxidation products. The chromatographic data of both pyrolysis and cupric oxide oxidation were also subjected to the principal component analysis (PCA). The sediment samples and fractions obtained by ultrafiltration of river water samples were freeze dried prior to characterization. The sediment samples were also extracted using 2 M sodium hydroxide solution. The extracts were ultrafiltrated, freeze dried and c…

The Impact of Humic Substances as Remediation Agents to the Speciation Forms of Metals in Soil

2013

Abstract Humic substances (HS) are the most widespread group of organic substances in natural environment and have high stability. The main terrestrial reserves are found in the form of naturally occurring ore, peat or lignite. The aim of this paper is to study possibilities to use HS as agents for remediation of contaminated with heavy metals soil and impacts of HS of metal speciation forms in it. It has been proved that HS are able to bind to metal ions and change their speciation forms in soils. The ability to form complexes with metal ions depends on the type of soil, type of metal, as well as concentrations of HS in soil. The study was carried out in experimental conditions and analyti…

Removal of total organic carbon from peat solution by hybrid method—Electrocoagulation combined with adsorption

2018

Abstract Humic substances end up in water from the drainage basin causing eutrophication and the spread of algae. These natural organic substances have an influence on the physical, chemical and biological properties of the water system. Adsorption and electrocoagulation (EC) are commonly used purification methods in the water and wastewater treatment. Both methods are used by themselves for removing a wide range of impurities. In this research, the novelty was to study the effect of combined activated carbon (AC) adsorption and electrocoagulation method on the removal of organic substances as total organic carbon (TOC) from the peat solution. With the hybrid method, TOC content was efficie…

Native and planted forest species determine different carbon and nitrogen pools in Arenosol developed on Holocene deposits from a costal Mediterranea…

2016

In a coastal Mediterranean area, the effects of two native [Quercus ilex (Holm), Alnus glutinosa and Fraxinus oxycarpa (Hygro)] and one planted [Pinus pinaster (Pine)] forest species on both content and quality of organic C and total N pools in Arenosols was assessed. Three soil profiles per each forest cover were opened and sampled. Total N in the organic layers was not affected by forest covers, whereas total organic C ranged from 36.1 to 63.2 Mg ha−1, being organic layers under Hygro those with the highest contents. Total organic C in the first 50 cm of mineral soil was 64 Mg ha−1 under Holm and 36.7 and 37.6 Mg ha−1 under Pine and Hygro, respectively. Soil covered by Holm and Hygro stor…

Characterization of the volatile components relased from natuaral organic substances

2008

Effects of Humic Substances and Soya Lecithin on the Aerobic Bioremediation of a Soil Historically Contaminated by Polycyclic Aromatic Hydrocarbons (…

2004

The high hydrophobicity of polycyclic aromatic hydrocarbons (PAHs) strongly reduces their bioavailability in aged contaminated soils, thus limiting their bioremediation. The biodegradation of PAHs in soils can be enhanced by employing surface-active agents. However, chemical surfactants are often recalcitrant and exert toxic effects in the amended soils. The effects of two biogenic materials as pollutant-mobilizing agents on the aerobic bioremediation of an aged-contaminated soil were investigated here. A soil historically contaminated by about 13 g kg(-1) of a large variety of PAHs, was amended with soya lecithin (SL) or humic substances (HS) at 1.5% w/w and incubated in aerobic solid-phas…

Conformational behaviour of humic substances at different depths along a profile of a Lithosol under loblolly (Pinus taeda) plantation

2009

The conformation of natural organic matter (NOM) plays a key role in many physical and chemical processes including interactions with organic and inorganic pollutants and soil aggregates stability thus directly influencing soil quality. NOM conformation can be studied by solid state NMR spectroscopy with cross polarization and magic angle spinning (CPMAS NMR). In the present study we applied CPMAS 13C NMR spectroscopy on three humic acid fractions (HA) each extracted from a different horizon in a Lithosol profile under Pinus taeda. Results showed that the most superficial HA was also the most aliphatic in character. Amount of aromatic moieties and hydrophilic HA constituents increased along…