Size distributions of fine and ultrafine particles in the city of Strasbourg: correlation between number of particles and concentrations of NO(x) and SO(2) gases and some soluble ions concentration determination

An Electrical Low Pressure Impactor (ELPI) was used during spring and autumn 2003 in the centre of Strasbourg for the measurement of atmospheric aerosols size distribution. The concentration of NO(x) and SO(2) in air was simultaneously measured with specific analysers. Samples were collected in the range 0.007-10 microm in equivalent aerodynamic diameter size. Number distributions are representative of a pollution originating from urban traffic with a particle size distribution exhibiting a nucleation mode below 29 nm and an accumulation mode around 80 nm in size. A mean particle density equal to 39000+/-35000 total particles per cm(3) with a size ranging from 7 to 10 microm was obtained after a sampling period of 2 weeks in spring. About 86.9% of the number of particles have an aerodynamic diameter below 0.1 microm and 13.1% between 0.1 and 1 microm. Correlation coefficients between the number of particles impacted on each ELPI plate and gas concentrations (SO(2) and NO(x)) showed that the numbers of particles with diameter between 0.10 and 0.62 microm are highly related to the NO(x) concentration. This result indicates that particles are traffic induced since NO(x) is mainly emitted by cars as shown by measurements on various sites. Particles are less clearly correlated to the SO(2) concentration. Particle analysis on different ELPI plates for a sampling period of 2 weeks in autumn showed high level of soluble NO(3)(-), SO(4)(2-) and NH(4)(+) ions. Indeed, up to 90% b.w. of these three species were found in the particle range 0.1-1 microm. The formation of particulate NH(4)NO(3) is favoured by high NO(x) concentration, which induces the formation of gaseous HNO(3).     

Opportunities for adaptation-mitigation synergies in geothermal energy utilization- Initial conceptual frameworks

In this article, the role of geothermal energy in mitigation and potential role in adaptation are discussed, and synergies between them developed. The article creates the Geothermal Adaptation-Mitigation (Geo-AdaM) conceptual frameworks that can be used in combining mitigation and adaptation in geothermal projects, e.g. by introducing adaptation additionality in Clean Development Mechanism or mitigation projects, using geothermal energy in climate vulnerable sectors, combining geothermal development with carbon forestry to improve recharge of geothermal systems in water stress areas, displacing fossil fuels in heating and cooling, and use of geothermal heat in raising tree seedlings in cold regions, and in greenhouses to create carbon sinks and green areas. The conceptual frameworks created in this research can cut across most regions, and types of utilization schemes with mitigation/adaptation co-benefits. The resulting co-benefits come with net positive environmental, economic and social impact. However, the co-benefits cannot be homogenous across all projects and regions. Tradeoffs may occur when using geothermal energy in adaptation projects, whose upstream activities are carbon intensive, or in adaptation and mitigation projects that have the potential of increasing vulnerability. The foreseen limitations of creating the synergies include; inadequate research on geothermal energy and adaptation, nature and scale of adaptation, involvement of different institutions and actors, access to finance and other resources especially in developing countries and lack of clear legal framework. Without proper legislation, fiscal incentives, to attract investment in adaptation aspects of geothermal energy, and to guard against tradeoffs, the interelationships between the two will remain a pipe dream.     

The potential of pigeonpea (Cajanus cajan (L.) Millsp.) in Africa

Pigeonpea is a tropical grain legume grown mainly in India. Though largely considered an orphan crop, pigeonpea has a huge untapped potential for improvement both in quantity and quality of production in Africa. More than any other legume adapted to the region, pigeonpea uniquely combines optimal nutritional profiles, high tolerance to environmental stresses, high biomass productivity and most nutrient and moisture contributions to the soil. The legume can be utilized in several diverse ways while the high genetic variability that exists within the cultivated and wild relatives remains to be explored for further uses. This article highlights the need for popularizing pigeonpea as a major legume crop in Africa. The main constraints to productivity are discussed and recent breeding efforts in Africa highlighted. Important opportunities for improvement are further provided.     

Synthesis and characterization of FSB@Fe3O4 composites and application in removal of indigo carmine dye from industrial wastewaters

Environmental Science and Pollution Research - The syntheses and characterization of fish scale biochar magnetic composites (FSB@Fe3O4) and their applications in the removal of indigo carmine dye...     

Influence of Glutaraldehyde Crosslinking and Alkaline Post-treatment on the Properties of Chitosan-Based Films

Depending on the modifications proposed, chitosan films present different characteristics, for instance correlated to hydrophilicity, chemical and mechanical properties. The aim of this study was to evaluate the influence of glutaraldehyde crosslinking and an alkaline post-treatment with NaOH on the characteristics of chitosan based films. Films were obtained by casting and characterized by thickness, swelling degree, mechanical and thermal properties and chemical structure. The water vapor permeability (WVP) was also evaluated for food packaging application. It was observed that crosslinking and NaOH post-treatment have great influence on the chitosan films characteristics. Crosslinking reduced the swelling degree of films and increased its fragility, whereas NaOH treatment also reduces the swelling degree and changes mechanical properties, acting in the same way as a crosslinker. The WVP analyses showed that the basic treatment could substitute the glutaraldehyde crosslinking for film water stability, without greatly compromising the barrier properties of chitosan based films.     

Adsorption and detection of some phenolic compounds by rice husk ash of Kenyan origin

Rice husk ash (RHA) obtained from a rice mill in Kenya has been used as an inexpensive and effective adsorbent (and reagent) for the removal (and detection) of some phenolic compounds in water. The abundantly available rice mill waste was used in dual laboratory-scale batch experiments to evaluate its potential in: (i) the removal of phenol, 1,3-dihydroxybenzene (resorcinol) and 2-chlorophenol from water; and (ii) the detection of 1,2-dihydroxybenzene (pyrocatechol) and 1,2,3-trihydroxybenzene (pyrogallol) present in an aqueous medium. The studies were conducted using synthetic water with different initial concentrations of the phenolic compounds. The effects of different operating conditions (such as contact time, concentration of the phenolic compounds, adsorbent quantity, temperature, and pH) were assessed by evaluating the phenolic compound removal efficiency as well as the extent of their color formation reactions (where applicable). RHA exhibits reasonable adsorption capacity for the phenolic compounds and follows both Langmuir and Freundlich isotherm models. Adsorption capacities of 1.53 x 10(-4), 8.07 x 10(-5), and 1.63 x 10(-6) mol g(-1) were determined for phenol, resorcinol and 2-chlorophenol, respectively. Nearly 100% adsorption of the phenolic compounds was possible and this depended on the weight of RHA employed. For the detection experiments, pyrocatechol and pyrogallol present in water formed coloured complexes with RHA, with the rate of colour formation increasing with temperature, weight of RHA, concentration of the phenolic compounds and sonication. This study has proven that RHA is a useful agricultural waste product for the removal and detection of some phenolic compounds.