Preparation of iron doped carbon coated W18O49 and its photoactivity.

Iron doping to carbon coated W18O49 was carried out through solid-state reaction of WO2.9 with iron acetate at 400 oC,followed by carbonization with poly(vinyl alcohol) (PVA) as carbon precursor at 800 oC in N2 atmosphere. Photoactivitiesof these samples were confirmed by phenol photodecomposition in its aqueous solution. They revealed the photoactivityunder visible light irradiation. Carbon coated W18O49 with iron exhibited higher photoactivity than it without iron. Additionof 1 % iron and 90/10 mixing ratio (WO2.9 / PVA) derived the highest photoactivity to decompose the phenol

Enhancement of Adsorption Efficiency of Methylene Blue on Co3O4/SiO2 Nanocomposite

Single and well-crystalline Co3O4 phase imbedded in an amorphous SiO2 matrix has been obtained by novel aqueous solution method. The structural and morphological properties are investigated using X-ray diffraction, Fourier transform infrared spectrometer, and N2 adsorption–desorption techniques. The apparent crystallite size for Co3O4 was found to be about 13.5 nm, which elucidates the rule of poly ethylene glycol in preventing particle’s agglomeration; moreover, the pours structure of the composite enhances its adsorption ability. Co3O4/SiO2 has a high ability to absorb methylene blue from an aqueous solution. The removal percent of Methelene blue (MB) by Co3O4/SiO2 has reached 95.7%. The effect of various experimental parameters, such as initial dye concentration, contact time, and dose were investigated. Co3O4/SiO2 nanocomposite shows high adsorption capacity of 53.87 mg g−1, which is larger than the adsorption capacity of MB on other materials. Both of Langmuir and Freundlich models were used to analyze the equilibrium adsorption data. The pseudo-second-order model was found to be the most appropriate model to represent the present data. Co3O4/SiO2 nanocomposite material is proposed as a potential adsorbent for water treatment

Biosorption of cadmium and lead from aqueous solution by fresh water alga Anabaena sphaerica biomass

The present work represents the biosorption of Cd(II) and Pb(II) from aqueous solution onto the biomass of the blue green alga Anabaena sphaerica as a function of pH, biosorbent dosage, contact time, and initial metal ion concentrations. Freundlich, Langmuir, and Dubinin–Radushkevich (D–R) models were applied to describe the biosorption isotherm of both metals by A. sphaerica biomass. The biosorption isotherms studies indicated that the biosorption of Cd(II) and Pb(II) follows the Langmuir and Freundlish models. The maximum biosorption capacities (qmax) were 111.1 and 121.95 mg/g, respectively, at the optimum conditions for each metal. From the D–R isotherm model, the mean free energy was calculated to be 11.7 and 14.3 kJ/mol indicating that the biosorption mechanism of Cd(II) and Pb(II) by A. sphaerica was chemisorption. The FTIR analysis for surface function group of algal biomass revealed the existence of amino, carboxyl, hydroxyl, and carbonyl groups, which are responsible for the biosorption of Cd(II) and Pb(II). The results suggested that the biomass of A. sphaerica is an extremely efficient biosorbent for the removal of Cd(II) and Pb(II) from aqueous solutions