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Two separate predictive models were developed for optimization and modeling of the relative permeate flux decline (J/J0) and Mg ion rejection (%) in nanofiltration (NF) of oily wastewater. Response surface methodology based on central composite design was employed to experimental design and a cumulative study of the effects of various operating parameters such as trans-membrane pressure (TMP), feed flow rate (QL), oil concentration (Coil), ion concentration (CMg), and pH on the NF separation process. Analysis of variance for developed quadratic models exhibited high significance and applicability. The oil and ion concentrations were the most significant factors and their interaction had a prominent effect on both permeate flux and Mg ion rejection. The effect of feed flow rate on the performance was also found to be negligible. The maximum relative permeate flux of 0.86 representing minimum membrane fouling phenomenon was obtained at low levels of input parameters at TMp = 3.4 bar,Coil = 200 mg/L,CMg = 40 mg/L, and pH 4. Whereas, high rejections were found at high levels of input factors. [ABSTRACT FROM AUTHOR]

High desalination performance, dye retention, and antibacterial properties were achieved with a multifunctional thin-film nanocomposite (MTFN) membrane, fabricated by the incorporation of a novel nanocomposite structure of reduced graphene oxide@TiO 2 @Ag (rGO@TiO 2 @Ag) into the polyamide active layer. The specific characteristics of the graphene-based nanocomposite, synthesized by the microwave-assisted irradiation process, favored water channelization and provided superhydrophilicity and antibacterial properties to the MTFN membranes. In comparison with the conventional methods, such as multistep chemical process using strong agents for reduction and long-term energy-consuming hydrothermal process, microwave irradiation facilitated a green, fast, and cost-effective route for the fabrication of GO-based nanocomposites for multifunctional applications. Interfacial polymerization was performed on a polyethersulfone/Si 3 N 4 robust hollow fiber substrate using m-phenylenediamine aqueous solution and 1,3,5-benzenetricarbonyltrichloride organic solution. The structural and chemical characteristics of the synthesized nanocomposites and the MTFN membranes were thoroughly studied by a series of characterization analyses (transmission electron microscopy, field emission scanning electron microscopy, X-ray diffraction, Fourier transform infrared, energy-dispersive X-ray spectroscopy, X-ray photoelectron spectroscopy, and atomic force microscopy). The physicochemical properties and the nanofiltration performance of the MTFN membranes were investigated after the incorporation of rGO@TiO 2 @Ag at various concentrations. The water contact angles confirmed the superb surface hydrophilicity of the MTFN membranes. High permeability (52 L·m -2 ·h -1 ), desalination (96% for 1 g/L Na 2 SO 4 feed solution), and dye retention (98% for 0.5 g/L rose bengal feed solution) were recorded for MTFN enriched with 0.2 wt % rGO@TiO 2 @Ag. A 90% reduction in the number of viable bacteria ( Escherichia coli), after 3 h of contact with MTFN membranes, confirmed the superior antibacterial activity of the produced membranes.

Single-phase white light-emitting Ca x Ba (9- x ) Lu 2 Si 6 O 24 :Eu 2+ /Mn 2+ codoped phosphors were successfully synthesized, and their photoluminescence properties were experimentally determined. The analysis of the experimental results suggests that the partial substitution of Ba 2+ ions by smaller Ca 2+ ions alters the distribution of the Eu 2+ luminescence center among the three available Ba 2+ sites in the host lattice, which enables the emission to be efficiently tuned from blue to blue-green-yellow region. The incorporation of Mn 2+ ions resulted in a red light emission at around 618 nm, through energy transfer from Eu 2+ to Mn 2+ ions via dipole-dipole interactions. The incorporation of Ca 2+ and Mn 2+ ions also resulted in improved thermal stability. The results qualify the produced Ca x Ba (9- x ) Lu 2 Si 6 O 24 :Eu 2+ /Mn 2+ composition as a potential ultraviolet-convertible white light-emitting phosphor., Competing Interests: The authors declare no competing financial interest.