Multivariate statistical characterization of groundwater quality in Ain Azel plain, Algeria

Multivariate statistical techniques, cluster and principal component analysis were applied to the data on groundwater quality of Ain Azel plain (Algeria), to extract principal factors corresponding to the different sources of variation in the hydrochemistry, with the objective of defining the main controls on the hydrochemistry at the plain scale. Q-mode hierarchical cluster analysis grouped 54 groundwater samples into three clusters, that is, relatively less saline water (group 1), mixed water (group 2) and blended water (group 3), based on the similarity of groundwater quality characteristics. Principal component analysis, applied to the data sets of the three different groups obtained from hierarchical cluster analysis, resulted in four, five and three latent factors explaining 83.21, 83.36 and 87.30% of the total variance in groundwater quality data sets of group 1, group 2 and group 3, respectively. The varifactors obtained from PCA indicate that the parameters responsible for groundwater quality variations are mainly related to presence and dissolution of some carbonate, dolomitic and evaporite minerals; natural processes and water-rock interaction in the three water types. The results of this study clearly demonstrate the usefulness of multivariate statistical analysis in hydro chemical.Key words: Cluster analysis, principal component analysis, hydrochemistry, Ain Azel plain, Algeria

Interactions between Cd, Cu, Pb, and Zn and four different mine soils

International audienceThe chemical associations of Cd, Cu, Pb, and Zn in four mine soil samples from the Amizour-Bejaia Pb/Zn mine (Algeria) have been investigated by a five-step sequential extraction procedure. Although Cd preferentially binds to carbonates, Cu, Pb, and Zn are mainly associated with the organic and reducible fractions. Batch adsorption experiments with either mono- or multi-metallic solutions are described with the Freundlich isotherm model. Whatever the nature of the soil sample, the sorption behavior for each given metal except Pb is very similar, indicating that the binding sites at the soil surface are progressively occupied by the metal from the solution. On each soil sample, the decreasing order of sorption can be established as Pb >> Cu > Cd > Zn. When the four metals are simultaneously applied to each soil sample, their specific behavior is strongly affected by their interactions and/or competition for the available surface sites: we generally observed isotherm curves with a slight maximum before the plateau at higher solution concentration. Although Cu is only slightly affected by the other metals, in the case of Pb, Cd, and Zn, the sorbed amounts strongly decreased. © 2017, Saudi Society for Geosciences

L'organométallique au service des extraits naturels

Le Maroc est considéré parmi les pays méditerranéens les plus riches en ressources naturelles, notamment, les plantes aromatiques et médicinales. La valorisation des extraits naturels passe soit par des échantillons à l’état brut, soit en les transformant en d’autres structures chimiques nouvelles

Effet de la puissance micro-ondes sur la composition chimique de l'huile essentielle de l'Eucalyptus globulus

Dans le but de mettre au point les conditions optimales d’extraction des huiles essentielles sous micro-ondes, nous avons effectué une série de travaux en contrôlant l’effet de plusieurs facteurs sur la composition chimique des extraits : présence du solvant, quantité de solvant et puissance des micro-ondes. Dans le cas de l’Eucalyptus globulus récolté à Oujda, nous avons comparé la composition chimique de l’huile essentielle extraite par micro-ondes sous deux puissances différentes : 280W et 700W. 38 composés volatils ont été identifiés par GC/MS et GC/FID. La comparaison de la composition chimique, dans les deux cas de puissance d’extraction (280W et 700W), nous a permis de noter respectivement les résultats suivants : a-pinène (2,41%, 4,06%) ; transpinocarveol (2,94%, 3,28%) ; 1,8-cinéole (0,91%, 1,84%) ; (+)-aromadendrene (2,22%, 2,82) ; globulol (4,63%, 4%) ; g-eudesmol (4,66%, 4,2%) ; b-eudesmol (17,02%, 14,5%) ; 1,2,3,4-tetrahydro-2,3-methano-2,8-dimethoxynaphtalene (4,27%, 4,28%) ; anisole, p(m-chlorophenyl) (0 %, 0,24%). La puissance micro-ondes choisie a un effet direct sur la variation de la composition chimique de l’huile essentielle extraite par micro-ondes de point de vue quantitatif et qualitatif

L'exraction par micro-ondes: un choix de qualité

Le but de ce travail est de comparer l’extraction faite par chauffage classique (CC) avec celle réalisée sous micro-ondes (MO). Deux modes d’extraction ont été réalisés : - L’hydro-distillation par chauffage classique (extraction par entraînement à la vapeur d’un solvant) et, - L’hydro-distillation activée par micro-ondes. Les MO permettent un gain de temps considérable. Par exemple, dans le cas du lavandula dentata : on note une cinétique 3 fois plus rapide, de plus le rendement est nettement supérieur (1% contre 0,6% par chauffage classique). Dans le cas de la plante fraiche, l’extraction est faite en absence de solvant sous MO. Ceci présente un grand intérêt sur le plan économique et environnemental. De plus, la qualité de l’huile extraite présente généralement une meilleure pureté. L’extraction par MO constitue une technique en accord avec la chimie verte. Grâce à ce procédé, on pourra alors réduire d'environ 60 % les besoins en énergie, ce qui diminuera d'autant les émissions de gaz à effet de serre

Removal of lead(II) from water using activated carbon developed from jujube stones, a low-cost sorbent

International audienceABSTRACT: The preparation of activated carbon from jujube stones with H2SO4 activation and its ability to remove lead from aqueous solutions were reported in this study. The surface structure of the activated carbon was characterized by various physico-chemical methods. Sorption studies were carried out by varying the initial metal ion and the pH: the amount of sorbed Pb(II) ions increased with increasing pH and initial Pb(II) ions concentration. The removal of lead ions was rapid and the kinetic of sorption can be well described by pseudo-second order modelling. The Langmuir model conveniently fits the data of isotherm experiments and the monolayer sorption capacity of Pb(II) ions was determined as 71.43 mg/g at pH 6.0 and 25°C. These results showed that activated carbon prepared from jujube stones could be considered for application as a potential sorbent for the removal of lead from wastewaters. © 2016 Taylor & Francis

Removal of Methylene Blue from aqueous solutions by adsorption on Kaolin: Kinetic and equilibrium studies

International audienceRemoval of Methylene Blue (MB) from aqueous solutions is studied using a raw Algerian kaolin sample as a low-cost adsorbent. The effects of pH, contact time, dye concentration and temperature are all taken into consideration. The adsorption kinetics results are adjusted to best fit the pseudo-second order model. The experimental data are analyzed by Langmuir isotherms, revealing that the maximum adsorption capacity of MB on this kaolin sample equals 52.76 mg/g at T = 25 °C and pH = 6.0. The calculated thermodynamic data demonstrates that adsorption is spontaneous and enhanced at higher temperatures. Desorption studies with water indicate that the adsorbent could successfully retain MB, even after four cycles. From these results, it can be considered that the raw Algerian kaolin sample tested herein is effective in the removal of MB from aqueous solutions and moreover may be used as an alternative to high-cost commercial adsorbents. © 2017 Elsevier B.V

Additional Cost Because of Pneumonia in Nursing Home Residents : Results From the Incidence of Pneumonia and Related Consequences in Nursing Home Resident Study

OBJECTIVES: Pneumonia is a frequent condition in older people. Our aim was to examine the total healthcare cost related to pneumonia in nursing home (NH) residents over a 1-year follow-up period. DESIGN: This was a prospective, longitudinal, observational, and multicenter study that was a part of the Incidence of Pneumonia and related Consequences in Nursing Home Resident study. SETTING: Thirteen NHs located in Languedoc Roussillon and Midi-Pyr\ue9n\ue9es regions in France were included. PARTICIPANTS: Resident in NH, older than 60 years and had a group iso-resource score ranging from 2 to 5. MEASUREMENTS: Pneumonia events were characterized according to the Observatoire du Risque Infectieux en Geriatrie criteria. Direct medical and nonmedical costs were assessed from the French health insurance perspective. Healthcare resources was retrospectively gathered from the French Social Health Insurance database and valued using the tariffs reimbursed by the French health insurance. Sociodemographic variables, clinical factors, vaccinations, cognition, depression, functional status, frailty index, as well as group iso-resource score were also recorded. RESULTS: Among the 800 patients initially included in the Incidence of Pneumonia and Related Consequences in Nursing Home Resident study, 345 which were listed in the database of the French Social Health Insurance were included in this economic study. Among them, 64 (18%) experienced at least 1 episode of pneumonia during the 1-year follow-up period. Mean annual total additional cost for a patient who experienced at least 1 episode of pneumonia during the 1 year follow-up period is 2813\u20ac. On average, total annual costs increased by 60% to 93% when a patient experienced at least 1 episode of pneumonia. CONCLUSIONS: NH-acquired pneumonia has a great impact on total cost of care for NH residents. Our results suggest the potential economic savings that could be achieved if pneumonia could be prevented in NHs