Lucia Dumitrescu

Nanocomposites Based on Acrylic Copolymer, Iron Lignosulfonate and ZnO Nanoparticles Used as Wood Preservatives

The paper presents research concerning the synthesis and characterization of some new nanocomposite used as wood coating nanomaterials, consisting of a hybrid of organic (functionalized acrylic copolymers with iron lignosulfonate) and inorganic nanomaterials (ZnO nanoparticles obtained by sol-gel process). The presence of acrylic copolymers in water emulsion (based on monomers ethyl acrylate, butyl acrylate, acrylonitrile and the lignin derivative iron lignosulfonate) and ZnO nanoparticles enables the formation of a crosslinked nanometric network of inorganic and organic domains, emphasized by AFM analysis. The interphase characterization of the nanostructured materials synthesized was performed using FT-IR analysis. Considering the biocide activity for the acrylic copolymers, the lignin derivative iron lignosulfonate and ZnO nanoparticles, the obtained nanocomposites were biologically investigated and proposed as wood preservation agents.

Recycling Biomass Waste to Compost

Composting is nowadays an important and efficient process in sustainable organic waste management. Recycling process of biodegradable organic waste (animal and agriculture residues, sewage sludge, household refuse) by composting, also represents an ecological solution to synthesize new materials used as biofertilizers or adsorbents in wastewater treatment. The paper presents results obtained in composting vegetables waste, sewage sludge, beech sawdust and beech ash, monitoring the parameters of the composting process and investigation of the nutritional quality of the compost by germination test.

Compost Based on Biomass Wastes Used as Biofertilizers or as Sorbents

Recycling the biodegradable waste by composting represents a sustainable solution for developing new ecological compost-type substrates, useful both as biofertilizers and as sorbents for the removal of heavy metals from wastewaters. By this paper we aim to present an overview of our studies related to using composted biomass from biodegradable wastes, as viable solution for biofertilizers or sorbents for heavy metals removal from the environmental. The novelty of our studies consists of the new materials that were prepared by composting together different biomass wastes. Aerobic fermentation was used to obtain sixteen different composts from vegetables waste, sewage sludge, beech sawdust and beech ash, in different mixing ratio, and the composting process was monitored. Based on their composition, three of these mature and stable composts were selected, while their capacity as nutrients and suitability as bio-fertilizers were analyzed in terms of C/N ratio, germination tests. Furthermore, one of these composts was also demonstrated to be suitable as low-costs sorbent, specifically to remove heavy metals from polluted waters. For this application the topography and morphology of compost substrates were determined, before and after sorption of metal cations. The sorption parameters (contact time, ratio of wastewater volume: sorbent compost mass) were optimized. Both, kinetic and thermodynamic sorption mechanisms were discussed and the results were further correlated with the structural properties of the compost substrate. The advantaged of biodegradation wastes by composting different raw biomaterials for preparation of ecological soil fertilizers and sorbents to remove heavy metals from contaminated waters, as low cost and environmental friendly solutions were also discussed.

Investigation of Some Mannich Bases Corrosion Inhibitors for Carbon Steel

The paper presents the results obtained when using two ketonic Mannich bases (BM1 and BM2) as corrosion inhibitors in saline (standard sea water-3.5% NaCl) for different types of steel, with various alloying elements. The corrosion experiments were performed by potentiodynamic polarization studies. Based on the polarization curves, the corrosion current density and rate were calculated. The inhibitors efficiencies were evalued and the protection mechanisms were discussed.

Characterization of Biomass Used for Fischer-Tropsch Diesel Synthesis

The characteristics of biomass used at Combined Heat and Power (CHP) plant Gussing (Austria) were determined over three samples taken from the wood chips, including proximate analysis: moisture, ash, cellulose and lignin content, and ultimate analysis: total organic carbon, concentration of H, S, N, and O, high and low heating value and FT-IR. Based on the characteristics of biomass, investigation of the syngas composition has been performed. The results showed that most of the proximate and ultimate analysis, as well as FT-IR analysis of wood chips were comparable with the standards and with other results found in literature. Extrinsic moisture higher than the standard value was obtained due to high humidity in the atmosphere during harvesting, causing difficulties of the feeding inside the fluidized bed gasifier and affecting the quality of the syngas. Low concentrations of S and N determined low emissions of NH3 and H2S, providing a synthesis gas suitable for Fischer-Tropsch synthesis.

PARAMETERS EFFECT ON THE PRODUCT DISTRIBUTION IN THE BIOMASS TO FISCHER-TROPSCH FUELS PROCESS

The increasing of energy consumption and fossil fuel emissions (especially CO2, SO2 and NOx) and the limitation of crude oil reserves, determined a growing trend toward renewable energy technologies, like solar, wind, geo-thermal energy and biomass for biofuels. From all the renewable energies sources, biomass attracts more and more interest being a renewable resource with economic potential, which can be found all over the world, with positive environmental properties due to neutral emissions of CO2 and low sulphur content. Biofuels obtained from biomass are becoming competitive with fossil fuels because of their environmental friendliness, availability, biodegradability, contribution to sustainable development and even economic benefits. One modern technology of producing biofuels, especially biodiesel, from biomass is Fischer-Tropsch process. The short or long chain hydrocarbons are obtained using syngas (H2 and CO) as feedstock. For the past five decades, the syngas was provided by coal or natural gas, being a well-establish technology. Today, because of the environmental concerns, researchers are more interested in obtaining liquid hydrocarbons also from syngas produced by biomass gasification. In this paper the Fischer-Tropsch technology that uses syngas obtained from wood chips gasification at the Combined Heat and Power (CHP) plant G ssing was investigated. The main objective was to establish the products distribution of Fischer-Tropsch synthesis over Co-based catalyst, under different temperatures (230 C, 240 C), and flow gas variation (5 Nm3/h and 4 Nm3/h). For this purpose, during Fischer-Tropsch synthesis, the composition of syngas before and after the slurry-bed reactor was analysed and the degree of CO conversion was determined. The product distribution of Fischer-Tropsch synthesis was characterised by Anderson-Schulz-Flory plots. Reliable results of chain growth probability were obtained with temperature and space velocity variation. These results showed that temperature and space velocity are critical parameters for the Co-based catalyst productivity and the selectivity to C5+ hydrocarbons in Fischer-Tropsch synthesis.