Removal of safranin dye from water using polypyrrole nanofiber/Zn-Fe layered double hydroxide nanocomposite (Ppy NF/Zn-Fe LDH) of enhanced adsorption and photocatalytic properties Fatma Mohamed a,b , Mostafa R. Abukhadra b,c, ⁎, Mohamed Shaban b a Polymer Research Laboratory, Chemistry Department, Faculty of Science, Beni-Suef University, Beni-Suef, Egypt b Nanophotonics and Applications Lab, Physics Department, Faculty of Science, Beni-Suef University, Beni-Suef 62514, Egypt c Geology Department, Faculty of Science, Beni-Suef University, Beni-Suef, Egypt HIGHLIGHTS • Ppy NF/Zn-Fe LDH composite was syn- thesized and characterized by several techniques. • It exhibits higher surface area and lower band gap than the individual compo- nents. • It shows clear enhancing in the adsorp- tion and the photocatalytic properties. • It can be used efficiently for the removal of dye from raw water samples. GRAPHICAL ABSTRACT abstract article info Article history: Received 1 February 2018 Received in revised form 19 May 2018 Accepted 25 May 2018 Available online xxxx Editor: Zhen (Jason) He Polypyrrole nanofiber/Zn-Fe layered double hydroxide (Ppy NF/Zn-Fe LDH) was synthesized as nanocomposite of enhanced adsorption and photocatalytic properties. The formation of the composite was confirmed by XRD, FT-IR, HSEM, HRTEM, BET surface area and UV-vis spectrophotometer. Ppy NF/Zn-Fe LDH composite exhibits clear enhancing in the specific surface area and obvious reducing in the band gap energy (from 2.8 eV for Zn- Fe LDH to 2.31 eV for the composite). This was reflected in a considerable improvement in the adsorption capac- ity and photocatalytic removal of safranin dye. The adsorption capacity was enhanced by about 22% higher than Ppy NF and by 31% higher than Zn-Fe LDH. The photocatalytic removal was improved by 41.6% higher than Ppy NF and by about 54% higher than Zn-Fe LDH. The adsorption of safranin dye by the composite is chemisorption adsorption and occurs in a multilayer form. The complete photocatalytic removal of 5 mg/L of safranin dye can be achieved after 120 min illumination time using 0.05 g of the composite as photocatalyst and the best results can be obtained at neutral to alkaline conditions. Realistic application of the composite for the removal of dye from raw water samples revealed the applicability of the product for the purification of tap water, groundwater, and sewage water. Moreover, it can be used for six cycles of safranin dye removal from water. The photocatalytic degradation process appears to be controlled by the created hydroxyl radicals and formed photogenerated holes as the dominant active oxidizing radicals. © 2017 Elsevier B.V. All rights reserved. Keywords: Polypyrrole Zn-Fe LDH Composite Adsorption Photocatalysis Visible light 1. Introduction Clean and healthy water is a serious concern and one of the most im- portant priorities for the human life (Anderson et al., 2017). However, the widespread pollution of fresh drinking water by discharged Science of the Total Environment 640–641 (2018) 352–363 ⁎ Corresponding author at: Polymer Research Laboratory, Chemistry Department, Faculty of Science, Beni-Suef University, Beni-Suef, Egypt. E-mail address: Abukhadra89@Science.bsu.edu.eg (M.R. Abukhadra). https://doi.org/10.1016/j.scitotenv.2018.05.316 0048-9697/© 2017 Elsevier B.V. All rights reserved. Contents lists available at ScienceDirect Science of the Total Environment journal homepage: www.elsevier.com/locate/scitotenv