AbstractIncreased growth of textile industries leads to the tremendous accumulation of dyes on water and surrounding environments. This terrific increase of dyes is the major cause of water pollution which in turn adversely affects the aquatic lives and the balance of our ecosystem. Purpose of the present study is to report the synthesis and characterization of a composite namely zinc oxide incorporated nanocellulose (ZnO/NC) for effective degradation of an anionic dye, Congo red. Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), Brunaeur, Emmett and Teller (BET) surface area analysis and scanning electron microscopy (SEM) studies have helped to characterize the composite. The optical properties of the samples were studied by UV-Visible spectroscopy. Feasibility of the photocatalyst in the degradation of Congo red was tested. Experimental conditions such as time of contact, concentration of the dye solution, catalyst dosage, pH were altered to find out the optimum conditions of degradation. The optimum pH was found to be 5.5 and dosage of ZnO/NC was optimized as 0.075 g for a dye concentration of 20 ppm. Equilibrium was attained at 120 min. The studies reveal that the photocatalyst ZnO/NC is efficient for the photodegradation of Congo red. Photodegradation was due to electron hole interaction between metal oxides and nanocellulose.

In the present study, CuO, polypyrrole (PPy), and CuO/PPy nanocomposites were synthesized to compare the selective adsorption behavior of hazardous metal ions such as Pb(II) ions. The synthesized nanomaterials were characterized by X-ray diffraction, scanning electron microscopy, transmission electron microscopy, BrunauerEmmett-Teller surface area analysis, and energy dispersive X-ray spectroscopy. The adsorption studies clearly showed that CuO/PPy nanocomposites exhibited much higher adsorption performance than individual CuO and PPy. Kinetic data followed the pseudo-second-order model. The equilibrium attained at 120 min and isotherm follows the order Sips > Langmuir > Freundlich. The adsorbed Pb(II) is desorbed using 0.1 m HCl. The adsorption-desorption studies conducted over six cycles illustrate the viability and repeated use of the adsorbent for the removal of Pb(II) from aqueous solutions. The adsorbent's practical efficiency and usefulness were tested using real industrial wastewater, and 0.55 g/L of adsorbent is adequate for the complete removal of Pb(II). Cytotoxicity results show that CuO/PPy nanocomposites were biocompatible at lower concentrations, and they were used as an ecofriendly nanoadsorbent for industrial and environmental applications.

Abstract-This study investigates the applicability of SnO 2 nanoparticles for the removal of Pb(II) from waste water . SnO 2 nano particles of 15 nm size were synthesized using a solgel method and characterized by X-ray diffraction (XRD), FTIR, SEM and transmission electron microscope (TEM). Batch experiments were carried out to study the adsorption kinetics of Pb(II) on SnO 2 . The effect of varying parameters such as contact time and P H on the adsorption process were examined. The adsorption process was found to be highly P H dependent. Experimental kinetic data were tested with pseudofirst -order and pseudo-second-order kinetic equations. The equilibrium data were modeled using general isotherm models. The experimental data agreed well with Langmuir isotherm model.Index Terms-Sol-gel method, adsorption, removal of lead.

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