Theoretical and Electrochemical Characterization of δ-RuCl2(Nazpy)2: Application to Oxidation of D-Glucose

The heterogenized δ-RuCl2(Nazpy)2 deposited on carbon toray (CT) was studied for the first time as electrochemical catalyst. Before, it was characterized by visible-ultraviolet spectra and theoretically by TDDFT method at B3LYP/Lanl2DZ level. It displayed an MLCT t2geg → π* transition where t2geg due to the structure of Nazpy that considerably reduces energy between d AOs of Ru represents the HOMO of the complex and π* is identified as the LUMO. Electrochemistry study shows two redox ranges in both negative and positive sides of the potential. The positive side that corresponds to the couple RuIV/RuIII of catalyst appears to be active for oxidation of D-glucose in carbonate buffer with a high turnover. Therefore, Keto-2-gluconic and gluconic acids were the two main products obtained with respectively 80% and 17.6% of selectivity. Moreover, a small amount of tartaric and glycol acids coming from the c-c bond cleavage due to non-protection of the anomeric carbon of D-glucose were also observed.

Rain-Flow Modeling Using a Multi-Layer Artificial Neural Network on the Watershed of the Cavally River(Cote d’Ivoire)

Water resources management is nowadays a significant stake for the world. However, missing or bad quality of the hydro-climatic historical data available of the studied area makes sometimes hydrological studies difficult. Generally, conceptual rain-flow models are designed to bring an appropriate answer with the correction of gaps and prediction of the flows. Historical hydro-climatic data of the Ity station, located on Cavally River, contain gaps which must be bridged. This study aims to establish a rainfall-runoff model through artificial neural networks for filling the gaps into the flow data series of the hydrometric station of Ity on the watershed of Cavally River. A multi-layer perceptron of feed forwards with two entries (monthly average rain and evapotranspiration) and an exit (flows) was established with flow evapotranspiration data. Comparison of the criteria of performance of the various architectures of the neural network model showed that architecture 2-3-1 gives best results. This architecture provides Nash coefficients of 75.79% and correlation linear coefficient of 95.64% for the calibration and Nash coefficients of 73.32% and correlation linear coefficient of 98.33% for the validation. The correlations between simulated flows and observed flows are strong. The correlation coefficients are 83.89% and 83.08% respectively for the calibration and validation.

Phosphorus and Nitrogen Removal by Saturated Vertical-Flow Constructed Wetlands (SVCWs) Type Micro-Pilot Using Shale from Ivory Coast as a Substrate

This study evaluates the performance of shale from Ivory Coast used as substrate in vertical-flow constructed wetlands in removal of phosphates and nitrogen. The pilot-scale artificial wetland has been duplicated: filter planted with Panicum maximun and unplanted. They were set up outdoors, and fed with a municipal wastewater. The wetlands have been fed with three batches per week (intermittent) over a period of 3 months. During the operation period, the hydraulic residence time (HRT) 52 h was used, while wastewater temperatures varied from about ~33°C. The removal performance of the constructed wetland units was very good, since it reached on an average 98%, 89.4%, 89.4%, 84%, 80%, 84.8% and 92% for TSS, DOC, BOD5, , TKN, TP and respectively. In addition, the vegetation did not demonstrate superior performance to unplanted controls. Therefore, this study focuses on the role of shale in the phosphorus and nitrogen removal from wastewater by constructed wetland.

Physico-Chemical Pollution and Trophic State of Biétry Bay (EbriéLagoon, Abidjan, Ivory Coast)

The analysis of data from the National Observation Network (RNO) of the water quality of the Ivorian Anti-Pollution Center (CIAPOL) relating to the physico-chemical quality and the trophic state of the lagoon bays of C&#244te d’Ivoire has allowed apprehending the degree of pollution of the bays of Biétry. This bay is heavily polluted, overall, there is a high salinity at depth between 22.5‰ and 27.5‰, a slightly basic character with a pH oscillating between 7.8 and 8.1 for surface waters and between 7, 6 and 7.8 for bottom waters. This is a very marked surface oxygenation between 100.94% and 114.72%;a slightly elevated temperature oscillating between 28.6&degC and 29&degC for surface waters and between 26.6&degC and 27.1&degC for bottom waters. This is high turbidity due to suspended solids and high nitrogen and phosphorus concentrations as well. As a result, these waters evolve towards a “mesotrophic” character according to the OECD (1982) and they are “eutrophic” according to Carlson (1977). This water is therefore impure according to the WHO concerning water intended for bathing activities.