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The study presents a breakthrough of a balanced charge separation for heterojunction CuWO4-TiO2 cocatalyst to efficiently enhance visible light photocatalytic degradation of ciprofloxacin (CIP). A solvothermal-synthesized nanopyramid-like CuWO4 semiconductor was assembled before sol–gel treatment with TiO2 precursors to generate CuWO4-TiO2 nanocomposites. The optical, structural, and morphological properties of CuWO4-TiO2 were elucidated using UV–Vis DRS, XRD, FTIR, Raman spectroscopy, and TEM/SEM techniques. The UV–Vis DRS spectroscopy of as-synthesized CuWO4-TiO2 cocatalyst demonstrated enhanced visible light absorbance. The XRD patterns of CuWO4-TiO2 revealed a triclinic phase nanocrystal. The O-Ti–O functionality was confirmed by FTIR spectroscopy. The photoactive bands corresponding to anatase redshift were observed from Raman spectroscopy of CuWO4-TiO2 nanocomposite. The PL studies attributed this redshift to the elevated extra energy bands that aid electron/hole pair charge separation in a co-catalyst heterojunction CuWO4-TiO2 nanocomposite afforded by embedding CuWO4-MOF within TiO2 crystalline. The TEM showed that un-sintered CuWO4.MOF mimicked a pyramidal shape and converted to nanoflakes upon sintering, while TiO2 and CuWO4-TiO2 retained a tetragonal shape. The photocatalytic activity of CuWO4-TiO2 cocatalyst was studied using CIP, as a model pollutant. The innovative design of 5CuWO4-TiO2 charge separation nanocomposite completely degraded 10 mg L−1 CIP solution at pH = 6.31 (natural pH) and 9 under 120 min of sunlight irradiation. [ABSTRACT FROM AUTHOR]

Azo dyes effluent can cause severe and chronic effects to living organisms since they are toxic, carcinogenic, and mutagenic. They color water, reduce dissolved oxygen, block light penetration, decrease the rate of photosynthesis and adversely affect the whole aquatic biota. Catalysis is one of the methods used in degrading azo dyes to less harmful species. Catalytic palladium nanoparticles (Pd NPs) are effective in the degradation of azo dyes owing to their large surface area and unique electronic properties. However, they are costly, unstable and easily aggregate; hence, a substrate is necessary to enhance their stability, reusability, durability, catalytic efficiency, and cost effectiveness. Herein, Pd NPs were in‐situ synthesized and immobilized in beta cyclodextrin (β‐CD) modified polyvinylidene‐fluoride (PVDF) membranes. The fabricated membranes were characterized using different techniques. Pd NPs slightly improved the properties and performance of the membranes. A complete catalytic degradation of methyl orange azo dye was carried out within 20 min in the presence of sodium borohydride and the increase in Pd NP content increased the rate of degradation. The membranes were recycled and reused five times with no considerable loss of catalytic performance. Therefore, PVDF/β‐CD‐Pd membranes proved to be self‐cleaning, reusable, and efficient in removal of methyl orange from water. [ABSTRACT FROM AUTHOR]

This study describes the applicability of lignocellulosic fiber dispersed in ethylene vinyl acetate (EVA) to adsorb Pb(li), Cr(lll), and Cr(VI) ions in aqueous solutions. Water absorption studies revealed that metal-ion uptake does not only take place on the surface of the adsorbent but ions can also diffuse into the composite. The adsorption of the metal ions under different experimental conditions was studied. Solute concentration, pH, and contact time were used to assess the adsorption capacity and efficiency. The amount of metal adsorbed increased to 7 mg/g with an increase in solute concentration but compromising the efficiency. Adsorption equilibrium was reached after 3 h, when the maximum lead adsorption was above 80%. The optimum pH for the adsorption of Pb(ll) and Cr(lll) was 6.5, and pH 2.5 was used for the adsorption of Cr(VI). Competitive adsorption revealed the order of adsorption to be: Pb(tl) > Cr(VI) > Cr(lll). POLYM. ENG. SCI., 52:760-767, 2012. ©2011 Society of Plastics Engineers, INTRODUCTION The presence of heavy metals like lead and hexavalent chromium in water poses a serious threat to human beings If the threshold amount in drinking water is exceeded. These [...]