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Contamination of water due to arsenic has been extensively reported all over the world. It has led to massive epidemics of arsenic poisoning. An urgent need is being felt to develop efficient techniques for the removal of arsenic from contaminated water. In this context, cerium (Ce) loaded chitosan (CHT)-polyvinyl alcohol (PVA) composite (Ce-CHT/PVA) nanofibers were developed by electrospinning technique and have been employed for removing As(III). The Ce-CHT/PVA composite nanofibers efficiently adsorb As(III) and purify water below the prescribed limit of WHO/EPA. As(III) adsorption over the surface of Ce-CHT/PVA has been confirmed by scanning electron microscopy and energy dispersive X-ray spectroscopy (SEM-EDAX), Fourier transform infrared spectroscopy (FTIR) and X-ray diffraction (XRD). The quantitative estimation of As(III) has been carried out by flameless atomic adsorption spectrophotometer-hydride generator (AAS-HG) system. The As(III) adsorption efficiency of Ce-CHT/PVA composite nanofibers has been established as a function of pH, time, temperature and adsorbent dose. The adsorption data were best fitted to Langmuir isotherm, and the maximum adsorption capacity (q m ) was found to be 18.0 mg g À1 . The interference studies of several ionic species individually as well multi-element for As removal have also reported. The measurement of the uncertainty of As(III) determination was calculated after determining the contributing factors. The data are reported with a confidence level of 95% (K ¼ 2). TheCe-CHT/PVA composite nanofibers are non toxic and can be directly used for water purification or after being embedded in the form of membrane or candles.

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Guar gum based hydrogel was optimally synthesized using a response surface methodology (RSM) approach for enhanced swelling capacity. Maximization of the water absorption capacity of the synthesized hydrogel was achieved through sequential experimental design based optimization. A fractional factorial screening (Resolution-IV) approach was used to screen significant process variables for maximization of percentage swelling in phase-1. Studied reaction parameters were: (i) monomer concentration, (ii) initiator concentration, (iii) cross linker concentration, (iv) polymerization time, (v) reaction temperature, (vi) vacuum level, and (vii) pH of reaction mixture. A Pareto chart indicated monomer concentration, pH and initiator concentration as significant process variables which were further optimized using full factorial design (2 3 ) in phase-2. RSM based center composite design (CCD) was applied to maximize the percentage swelling for the two most significant variables (pH and initiator concentration) in phase-3. Statistical modeling using ANOVA predicted a near neutral range for pH ($7.0) and an initiator concentration of 21-23 Â 10 À6 mol L À1 as optimum operating conditions for maximizing the percentage of swelling (5307%). Hydrogels were found to be highly pH sensitive and should be kept in a narrow range for maximization of percentage swelling. Thus, the sequential experimental design was helpful in achieving two fold increases in percentage swelling in a systematic way. Synthesized super absorbent polymers can be used as effective water-saving materials for horticultural and agricultural applications.

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