TPS/PCL Composite Reinforced with Treated Sisal Fibers: Property, Biodegradation and Water-Absorption

Sisal fibers bleached with sodium-hydroxide followed by hydrogen peroxide treatment were incorporated in a thermoplastic starch/ε-polycaprolactone (TPS/PCL) blend via extrusion processing. These samples with smooth and homogenous surfaces were examined for their property, biodegradability and water absorption. Scanning electron microscopy revealed that the fibers were well dispersed in the matrix. In addition, it was found that the fibers and matrices interacted strongly. Blends with 20 % (dry weight-basis) fiber content showed some fiber agglomeration. Whereas blends with 10 % fibers showed increased crystallinity and lower water absorption capacity. The CO₂ evolution study showed that the thermoplastic starch samples without any additives had the highest rate and extent of degradation whereas the neat PCL samples had the lowest degradation rate. Addition of fiber to the TPS/PCL blend exhibited the degradation rates and extents that were somewhere in between the pure TPS and neat PCL. This work demonstrates that TPS/PCL composites reinforced with bleached sisal has superior structural characteristics and water resistance and thus, can be used as polymeric engineering composites for different applications.     

Source and distribution of organic matter in surface sediments from mangroves on the island of Itaparica, Bahia/Brazil

Elemental analysis and isotopic composition evaluated the impact of human activity at the surface sediments in the largest island of Todos os Santos Bay, northeastern Brazil. Saturated hydrocarbons (n-alkanes and isoprenoids) by gas chromatography coupled with a flame ionization detector and ¹³C by mass spectrometer were determined from 30 surface sediment samples in mangroves at the Itaparica Island (Bahia-Brazil) in the rainy and dry season. These data, distribution, and ratio of carbon/nitrogen showed a mixture of sources: continental, marine, and anthropogenic ones. From the chromatographic profiles, light oil contamination was observed in the dry regions of Baiacu, Campinas, and Ponta Grossa, while in Jiribatuba it was observed during the rainy season. However, δ¹³C results during dry and rainy season in the presence of oil also showed in Misericordia and Cacha Prego districts for both periods and Ponta Grossa during the rainy season. Principal component analysis, using a correlation matrix, revealed the latent relationships among all the surface sediment stations investigated and confirmed our analytical results.     

Measurement of arsenic compounds in littoral zone algae from the Western Mediterranean Sea. Occurrence of arsenobetaine

The determination of arsenic compounds in algae collected on the Catalan coast (Western Mediterranean) is reported. Ten algae species and the seagrass Posidonia oceanica were analyzed. Total arsenic in the samples was determined by microwave digestion and inductively coupled plasma mass spectrometry (ICPMS). Arsenic speciation in water extracts of samples was analyzed by liquid chromatography with both anionic and cationic exchange with ICPMS detection (LC-ICPMS). The total arsenic content of the algae samples ranged from 2.96 to 39.0mg As kg(-1). The following compounds were detected: arsenite (As(III)), arsenate (As(V)), methylarsonate (MA), dimethylarsinate (DMA), sulfonate sugar (SO3-sug), sulfate sugar (SO4-sug), phosphate sugar (PO4-sug), arsenobetaine (AB), arsenocholine (AC), trimethylarsine oxide (TMAO) and glycerol sugar (Gly-sug). The main arsenic species found were arsenosugars. Significant percentages of arsenobetaine (0.54 mg As kg(-1), 28% of the extractable arsenic and 0.39 mg As kg(-1), 18% of the extractable arsenic) were found in Ulva rigida and Enteromorpha compressa. These results are discussed in relation to the presence of epiphytes.     

The Effect of Extraction Conditions on the Chemical Characteristics of Pectin from Opuntia ficus indica Cladode Flour

Pectin from the cladode flour of Opuntia ficus indica was extracted at different ethylenediaminetetraacetate concentrations (10 or 20 %), temperatures (40 or 80 °C), pH values (2 or 11), and times (10, 20, 30 40, 50 or 60 min). The effects of the extraction conditions on the yield, purity, and chemical composition of pectin were assessed. The highest pectin yield was observed for pectin obtained under alkaline conditions and 20 % of EDTA. However, pectin produced from alkaline extractions had a lower content of GalA than pectin produced from acid extractions. Higher temperatures favored the extraction of pectin under acid conditions, but these conditions diminished the arabinose content of pectins in a time-dependent manner. The tested extraction conditions caused only slight changes in the molecular weight of the extracted pectin as a function of time.     

Effect of fulvic acid on the photochemical degradation of methylparathion

Photochemical degradation of methylparathion (O,O,–dimethyl O-4 nitrophenylphosphorothioate) in the presence of fulvic acid (FA) between pH 2 and 7 was studied by differential pulse polarography (DPP). Fulvic acid and its photoproducts were not electro-active under the experimental conditions used in this study, and only the pesticide exhibited polarographic signals. Photolysis of methylparathion in acid media was sensitized by fulvic acid since the pesticide did not degrade in the absence of this compound. Methylparathion degradation was observed at each of the studied pHs. The reaction was first-order with rate constant values ranging from 3.3 × 10^?3 to 8.8 × 10^?3min^?1.     

Kinetics of the sensitized photodegradation of nonylphenol

Nonylphenol (nonyl‐P) belongs to the classification of persistent organic pollutants. In this work we demonstrate that the contaminant suffers photooxygenation when exposed to visible light Eosin‐photosensitized irradiation. The mechanism was identified as a singlet molecular oxygen‐mediated photooxidation. Rate constants for the process, determined by time‐resolved phosphorescence detection of singlet molecular oxygen, are in the range 10⁵‐10⁷ M^‐1 s^‐1, depending on the characteristics of the reaction medium. The photooxidative process is more efficient when performed in highly polar alkaline medium.

The aggregation of nonyl‐P molecules in pure water decreases the rates of sensitized photooxidation of nonyl‐P and also those of polychlorophenolic contaminants, employed as photooxidizable model compounds, when photolyzed in the presence of nonylphenol. These results are discussed in terms of a micellar effect.     

Educating for sustainable production and consumption and sustainable livelihoods: learning from multi-stakeholder networks

This paper examines how education for sustainable development (ESD) can be concretely advanced using the theoretical approaches of sustainable consumption and production (SCP) and sustainable livelihoods (SL). Five case examples illustrate a diverse set of strategic educational interventions focusing on: (1) education of specific organizational actors about these theoretical frameworks illustrated with case examples (such as SCP training by the United Nations University Institute of Advanced Studies [UNU-IAS] and CSR-Asia of government and business representatives), (2) regional education strategies focused on production and consumption in specific sectors (such as the food sector in Sk?ne, Sweden), (3) social learning directed at innovation for sustainable development (such as competitions of solar boats developed by universities in the region of Friesland, the Netherlands), (4) education of consumers and firms made possible by the adoption of certification systems affirming SCP and SL (such as Cradle-to-Cradle certification of a paper company in the Netherlands or the establishment of Fair Trade cities in Sweden), or (5) reorienting communities to address underutilized productive physical capital within communities (such as the sharing productive capital project in rural areas of Saskatchewan, Canada). The cases are drawn from the projects that the UNU-IAS, four of its regional centers of expertise (RCE) on ESD and other affiliates have conducted. In addition to documenting the educational processes emerging from specific regions, the paper highlights findings related to the success of these projects and opportunities for further research, including regional and inter-regional approaches.     

(210)Pb and composition data of near-surface sediments and interstitial waters evidencing anthropogenic inputs in Amazon River mouth, Macapá, Brazil

Activity profiles of excess ²¹⁰Pb determined in three sediment cores from Amazon River mouth, Macapá city, Brazil, provided the evaluation of sedimentation rates, contributing to a better knowledge of the hydrological conditions in the site that is the capital of Amapá State and is drained by the waters of the huge Amazon River. Chemical data were also determined in the sediments, allowing identify signatures coupled to anthropogenic inputs held in the past in Amapá State. Significant direct relationships between LOI (loss on ignition) and organic matter were found for all sediments profiles. Silica was found to be inversely related to organic matter in the three profiles; its decrease accompanied an increase on the specific surface of the sediments. This relationship was confirmed by a great number of inverse significant correlations among silica and oxides Na₂O, K₂O, CaO, MgO, Al₂O₃, P₂O₅, Fe₂O₃ and MnO. It was possible to identify the role of organic matter on adsorption of several oxides in the core sediments profiles. Apparent sediment mass accumulation rates corresponding to values between 450 and 2510 mg cm⁻² yr⁻¹ were obtained, and are compatible with the results of others studies. The ²¹⁰Pb activities in one sampling point suggested the occurrence of anthropogenic inputs related to the initial period of the mining activities conducted in Serra do Navio, Amapá State, for the commercialization of Mn ores. This was reinforced by the abrupt fluctuations in chemical data obtained for the sediments and composition of the interstitial waters occurring there. The Atlantic hurricane activity also appeared to affect the sedimentation rates in the area, as two different values were recorded in each profile.