Wood - a renewable resource for production of sugar and biofuel

Albies Alba wood samples were subjected to autohydrolysis extraction at different severities (180, 190 and 200°C), delignification with sodium chloride, and acid hydrolysis of pretreated and delignified substrates. After autohydrolysis pre-treatment under selected operation conditions, cellulose and lignin, in solid phases, and liquors containing hemicellulose products (monosaccharides, oligosaccharides and inhibitory compounds) have been obtained. The purpose of this study is to obtain glucose by autohydrolysis, delignification and acid hydrolysis of fir wood. Fir wood was pretreated at 180, 190 and 200 °C for 5, 10 and 15 minutes, followed by delignification with sodium chloride and acid hydrolysis. The acid hydrolysis of pretreated material and pretreated-delignified material was hydrolyzed using H2SO4 in two stages of impregnation with acid. The results show that elimination of hemicellulose by autohydrolysis pretreatment and lignin by delignification method improve acid hydrolysis yield

Assessing the bioavailability and translocation efficiency of mineral elements in Lycium barbarum species from R. Macedonia and R. China

Goji berries or wolfberries (Lycium barbarum L.) have been traditionally used as food and a medicinal plant. The interest in the chemical composition of goji berries has intensified because of an increased awareness of their possible health benefits. On the other hand, the toxic elements can also be interacting in the plant tissue through the bioavailable pathway of the root-soil system. The present work reports the results obtained by the proposed method for the simultaneous determination of metals (Na, Mg, K, Ca, Mn, Fe, Cu and Zn) and nonmetals (P and S) in goji berries by using inductively coupled plasma–optical emission spectrometry (ICP-OES), following digestion using a diluted oxidant mixture in a closed-vessel microwave oven. Determinations of Cr, As, Pb, Cd and Ni were realized using the graphite furnace atomic absorption spectrometer (GFAAS). Mercury quantification was realized on the solid samples by the TDAAS method, with the automated direct mercury analyzer hydra-C. The obtained data for element contents reports the multi-element characterization of different plant parts, and variation in multi-elements content between Macedonian and Chinese species. Bioaccumulation and bioconcentration factor scores revealed the translocation efficiency of metals and nonmetals across the Lycium barbarum plant parts

ASSESSMENT OF Pb, Cd, Cu AND Zn AVAILABILITY FOR PLANTS IN BAIA MARE MINING REGION

In order to evaluate the mobility of heavy metals in soil from Baia Mare mining region, the total, water and DTPA extractable metal contents were determined. The results showed that despite the high total metals contents and the high percentages of plant available metals only a low percent was water soluble, indicating a potential accumulation of metals in trophic chain and a potential risk for public health. Among the investigated metals, the plant available Pb and Cd species are the most severe contaminants. Significant correlations between total and DTPA extractable metals were found for Cu (r=0.510) and Pb (0.418), and also an affinity between total and water extractable metals were identified for Cu (0.366), Pb (0.502) and Zn (0.597)

Biodegradation studies of polylactic acid copolymers

Medium molecular weight copolymers were synthesized by the condensation of L-lactic acid (LA), terephthalic acid (TPA) and 1,3-propanediol (PDO). The obtained copolymers were characterized for acid value, hydroxyl value and number average molecular weight. Also, the biodegradation behavior by different fungal species (A spergillus niger, A spergillu s versicolor, A lternaría altern a ta and P enicilliu m ) was performed. The degree of biodegradation was examined by weight loss. It was observed that the biodegradation of copolymer with higher quantity of lactic acid was faster and more effective than the biodegradation of copolymer with smaller quantity of lactic acid

Progress, Challenges and Opportunities in Divalent Transition Metal-Doped Cobalt Ferrites Nanoparticles Applications

Engineered nanomaterials with tailored properties are highly required in a wide range of industrial fields. Consequently, the researches dedicated to the identification of new applications for existing materials and to the development of novel promising materials and cost effective, eco-friendly synthesis methods gained considerable attention in the last years. Cobalt ferrite is one of the nanomaterials with a wide application range due to its unique properties such as high electrical resistivity, negligible eddy current loss, moderate saturation magnetization, chemical and thermal stability, high Curie temperature and high mechanical hardness. Moreover, its structural, magnetic and electrical properties can be tailored by the selection of preparation route, chemical composition, dopant ions and thermal treatment. This chapter presents the recent applications of nanosized cobalt ferrites doped or co-doped with divalent transition ions such as Zn2+, Cu2+, Mn2+, Ni2+, Cd2+ obtained by various synthesis methods in ceramics, medicine, catalysis, electronics and communications

Environmental and socioeconomic assessment of impacts by mining activities—a case study in the Certej River catchment, Western Carpathians, Romania

Background, aim and scope: In the region of the Apuseni Mountains, part of the Western Carpathians in Romania, metal mining activities have a long-standing tradition. These mining industries created a clearly beneficial economic development in the region. But their activities also caused impairments to the environment, such as acid mine drainage (AMD) resulting in long-lasting heavy metal pollution of waters and sediments. The study, established in the context of the ESTROM programme, investigated the impact of metal mining activities both from environmental and socioeconomic perspectives and tried to incorporate the results of the two approaches into an integrated proposition for mitigation of mining-related issues. Study site: The small Certej catchment, situated in the Southern Apuseni Mountains, covers an area of 78km2. About 4,500 inhabitants are living in the basin, in which metal mining was the main economic sector. An open pit and several abandoned underground mines are producing heavy metal-loaded acidic water that is discharged untreated into the main river. The solid wastes of mineral processing plants were deposited in several dumps and tailings impoundment embodying the acidic water-producing mineral pyrite. Methods: The natural science team collected samples from surface waters, drinking water from dug wells and from groundwater. Filtered and total heavy metals, both after enrichment, and major cations were analysed by inductively coupled plasma optical emission spectroscopy (ICP-OES). Major anions in waters, measured by ion chromatography, alkalinity and acidity were determined by titration. Solid samples were taken from river sediments and from the largest tailings dam. The latter were characterised by X-ray fluorescence and X-ray diffraction. Heavy metals in sediments were analysed after digestion. Simultaneously, the socioeconomic team performed a household survey to evaluate the perception of people related to the river and drinking water pollution by way of a logistic regression analysis. Results and discussion: The inputs of acid mine waters drastically increased filtered heavy metal concentrations in the Certej River, e.g. Zn up to 130mg L−1, Fe 100mg L−1, Cu 2.9mg L−1, Cd 1.4mgL−1 as well as those of SO4 up to 2.2g L−1. In addition, river water became acidic with pH values of pH 3. Concentrations of pollutant decreased slightly downstream due to dilution by waters from tributaries. Metal concentrations measured at headwater stations reflect background values. They fell in the range of the environmental quality standards proposed in the EU Water Framework Directive for dissolved heavy metals. The outflow of the large tailing impoundment and the groundwater downstream from two tailings dams exhibited the first sign of AMD, but they still had alkalinity. Most dug wells analysed delivered a drinking water that exhibited no sign of AMD pollution, although these wells were a distance of 7 to 25m from the contaminated river. It seems that the Certej River does not infiltrate significantly into the groundwater. Pyrite was identified as the main sulphide mineral in the tailings dam that produces acidity and with calcite representing the AMD-neutralising mineral. The acid-base accounting proved that the potential acid-neutralising capacity in the solid phases would not be sufficient to prevent the production of acidic water in the future. Therefore, the open pits and mine waste deposits have to be seen as the sources for AMD at the present time, with a high long-term potential to produce even more AMD in the future. The socioeconomic study showed that mining provided the major source of income. Over 45% of the households were partly or completely reliant on financial compensations as a result of mine closure. Unemployment was considered by the majority of the interviewed persons as the main cause of social problems in the area. The estimation of the explanatory factors by the logistic regression analysis revealed that education, household income, pollution conditions during the last years and familiarity with environmental problems were the main predictors influencing peoples' opinion concerning whether the main river is strongly polluted. This model enabled one to predict correctly 77% of the observations reported. For the drinking water quality model, three predictors were relevant and they explained 66% of the observations. Conclusions: Coupling the findings from the natural science and socioeconomic approaches, we may conclude that the impact of mining on the Certej River water is high, while drinking water in wells is not significantly affected. The perceptions of the respondents to pollution were to a large extent consistent with the measured results. Recommendations and perspectives: The results of the study can be used by various stakeholders, mainly the mining company and local municipalities, in order to integrate them in their post-mining measures, thereby making them aware of the potential long-term impact of mining on the environment and on human health as well as on the local econom

Assessment of metals bioavailability to vegetables under field conditions using DGT, single extractions and multivariate statistics

Abstract Background The metals bioavailability in soils is commonly assessed by chemical extractions; however a generally accepted method is not yet established. In this study, the effectiveness of Diffusive Gradients in Thin-films (DGT) technique and single extractions in the assessment of metals bioaccumulation in vegetables, and the influence of soil parameters on phytoavailability were evaluated using multivariate statistics. Soil and plants grown in vegetable gardens from mining-affected rural areas, NW Romania, were collected and analysed. Results Pseudo-total metal content of Cu, Zn and Cd in soil ranged between 17.3-146 mg kg-1, 141–833 mg kg-1 and 0.15-2.05 mg kg-1, respectively, showing enriched contents of these elements. High degrees of metals extractability in 1M HCl and even in 1M NH4Cl were observed. Despite the relatively high total metal concentrations in soil, those found in vegetables were comparable to values typically reported for agricultural crops, probably due to the low concentrations of metals in soil solution (Csoln) and low effective concentrations (CE), assessed by DGT technique. Among the analysed vegetables, the highest metal concentrations were found in carrots roots. By applying multivariate statistics, it was found that CE, Csoln and extraction in 1M NH4Cl, were better predictors for metals bioavailability than the acid extractions applied in this study. Copper transfer to vegetables was strongly influenced by soil organic carbon (OC) and cation exchange capacity (CEC), while pH had a higher influence on Cd transfer from soil to plants. Conclusions The results showed that DGT can be used for general evaluation of the risks associated to soil contamination with Cu, Zn and Cd in field conditions. Although quantitative information on metals transfer from soil to vegetables was not observed.</p

Simulated Bioavailability of Heavy Metals (Cd, Cr, Cu, Pb, Zn) in Contaminated Soil Amended with Natural Zeolite Using Diffusive Gradients in Thin-Films (DGT) Technique

The aim of this study was to investigate the effect of natural zeolite amendment to contaminated soil on the heavy metal (Cd, Cr, Cu, Pb and Zn) simulated bioavailability over a three-month period of storage. Two pot experiments were created by amending soil with two different amounts of natural zeolite (3 and 6 wt.%). During the experiment, pH level, metal concentrations in soil solution (Csol) and metal concentrations in soil by the diffusive gradients in thin-films technique (CDGT) were determined. When the zeolite was added to the soil, a significant decrease (p = 95%, n = 3) for Cd and Pb concentrations, both in Csol and in CDGT, was observed. The Cu, Cr and Zn concentrations also showed a decreasing trend, but the changes in their concentrations were not statistically significant. The R ratio between CDGT and Csol was calculated for each metal in order to assess the resupply of metals from the soil solid phase to soil solution. The R values significantly decreased for Cd and Pb, showing a low resupply from the solid phase in the samples with added zeolite