Search results for "Biomass c"
showing 10 items of 22 documents
Determination of enzymatic activities using a miniaturized system as a rapid method to assess soil quality
2014
Summary Soil quality determination requires the analysis of a number of soil attributes using different approaches. In recent years, one of the most promising approaches has been the determination of enzymatic activities. Generally, only a few enzymes have been analysed and related to other soil properties such as total carbon, nitrogen content or microbial biomass carbon. The aim of this work was to investigate the possible use of the API ZYM strip, a semi-quantitative miniaturized system that determines 19 enzymatic activities, to study soil quality. To this end, we tested the system in different soil types, including albic Arenosols, mollic Leptosols, rendzic Leptosols, haplic Leptosols …
Palladium clusters on BNNT as catalysts for biomass conversion
2015
The construction of a heterogeneous catalytic systems by a bottom-up approach is a fascinating strategy well assisted by molecular level characterizations. In this sense, DFT investigations can be used with predictive and descriptive purposes both for the treatment of the catalyst/support and for the substrate/catalyst characterization. This should be particularly useful for highly perspective but scarcely treated systems such as boron nitride based supports. Among these, boron nitride nanotubes (BNNT) have been demonstrated to have high chemical and thermal stability as well as great mechanical strength and high thermal conductivity.[1] Moreover, a high affinity toward hydrogen [2] as well…
Formation of high added value chemicals by photocatalytic treatment of biomass
2020
The depletion of fossil fuel requires the search for alternative renewable feedstock and environmentally friendly methods for the production of high value-added compounds and fuels. In this context, the efficient use of biomass has emerged as a significant research field as it represents an alternative green and renewable carbon source. Various technologies have been explored for this purpose and heterogeneous photocatalysis represents a valid alternative to the catalytic methods since it can be carried out under mild experimental conditions without the addition of harmful oxidizing agents. Different biomass components have been used as the starting materials, and many valuable chemicals h…
Accelerated mineralisation of atrazine in maize rhizosphere soil
2002
International audience; The mineralisation rate of atrazine measured in soil pre-treated with this herbicide, was significantly higher in the maize rhizosphere than in bulk soil. Maize rhizosphere was also shown to significantly increase microbial biomass C as compared with bulk soil. Ribosomal intergenic spacer analysis conducted on nucleic acids extracted directly from soil samples revealed that the structure of microbial communities observed in the rhizosphere was slightly different from that of bulk soil. The quantification of the relative amount of the gene atzC, which encodes an enzyme involved in atrazine mineralisation, was carried out on soil nucleic acids by using quantitative-com…
The effect of feedstock origin and temperature on the structure and reactivity of char from pyrolysis at 1300–2800 °C
2018
This study reports the effect of feedstock origin, residence time, and heat treatment temperature on CO2 and O2 reactivities, nanostructure and carbon chemistry of chars prepared at 1300, 1600, 2400, and 2800 °C in a slow pyrolysis reactor. The structure of char was characterized by transmission electron microscopy and Raman spectroscopy. The CO2 and O2 reactivity of char was investigated by thermogravimetric analysis. Results showed that the ash composition and residence time influence the char reactivity less than the heat treatment temperature. The heat treatment temperature and co-pyrolysis of pinewood char with biooil decreased the CO2 reactivity, approaching that of metallurgical coke…
Effects of compost input and tillage intensity on soil microbial biomass and activity under Mediterranean conditions
2010
Organic amendment and tillage reduction are two common practices to contrast soil organic matter decline, thus promoting sustainable cropping and carbon sequestration. In a horticultural land use system under Mediterranean climate, we evaluated the 9-year effects of two compost inputs (15 and 30 t ha−1 y−1, low and high input, respectively) and two tillage intensities (intensive and reduced) on soil macronutrients concentration, microbial biomass and activity. Total organic C, total N and POlsen were smaller in plots amended at low input, whilst intensive tillage decreased them at both compost inputs. These decreases in intensively tilled plots was ascribed to the disruption of soil aggrega…
Microbial biomass carbon dynamics in a long-term tillage and crop rotation experiment under semiarid Mediterranean conditions
2015
Microbial biomass carbon (MBC) of soil is an important ecological indicator of nutrient cycling and soil fertility. In addition, it responds to the changes of soil fertility more rapidly than soil organic matter. The aim of the present work was to evaluate the effect of a long-term implementation of a conservative soil management strategy (No Tillage [NT]) compared to the inversion tillage (conventional tillage [CT]) on the soil MBC in a range of crops - continuous durum wheat (WW), wheat after fababean (FW) and faba bean after wheat (WF). MBC of NT plots was higher than CT. In addition, the content of MBC varied with sampling time during the growing season; this variation did not show a co…
Influence of Biomass Combustion Products on Element Content and Thermal Stability of Latvian Sheep Breed Wool Filter Fibres
2020
Sheep wool is natural, easy obtainable, renewable and biodegradable material with a perspective application as a sorbent in filters for purification of industrial emissions from various environmental pollutants. The element content and thermal stability of Latvian dark-headed sheep wool filter fibres was analysed and described before and after exposure to biomass combustion products. Based on the obtained results, it is concluded that the sheep wool filter fibres can sorb various gaseous combustion products, such as carbon monoxide (CO), carbon dioxide (CO2) and nitrogen oxides (NOx), however, the sorption processes of these gases are irreversible. The obtained results of total reflection X…
Response of microbial biomass and carbon dynamics to changing hydrological conditions in old peat deposits
2018
Peatlands play key roles in the global ecosystem carbon (C) balance, as important C-stores. Their efficiency as long-term C-stores or atmospheric C sink is affected by the rate of microbial mineralization. Most studies on the climate change effects on the microbial communities and C-cycling in peatlands have focused on the surface layers. This thesis compared microbial biomass, community composition and internal C cycling processes in drained vs. natural peat profiles with focus on deep old peat. Using the phospholipid fatty acid (PLFA) and rRNA gene analyses, the study particularly looked at the impact of long-term drainage and the short-term effects of temperature and water content on the…
Microwave-assisted conversion of novel biomass materials into levulinic acid
2018
Levulinic acid is considered one of the most important platform chemicals. It is currently produced mainly from lignocellulosic biomasses. However, there are also other abundant biomass materials, which could be used as raw materials for levulinic acid production. In this work, levulinic acid was produced from two novel biomasses in the presence of Brønsted (H2SO4) and Lewis acid (CrCl3·6H2O or AlCl3·6H2O) catalysts. The studied materials were carbohydrate-rich potato peel waste and sporocarps of the fungus Cortinarius armillatus. Reaction conditions, i.e., time, temperature, H2SO4, and Lewis acid concentrations, were studied by utilizing full 24-factorial experimental designs. Microwave ir…