Treatment of paper mill efﬂuent using Polyethersulfone/functionalised multiwalled carbon nanotubes based nanocomposite membranes R. Saranya a , G. Arthanareeswaran a,⇑ , Dionysios D. Dionysiou b a Membrane Research Laboratory, Department of Chemical Engineering, National Institute of Technology, Tiruchirappalli 620015, India b Environmental Engineering and Science Program, Department of Biomedical, Chemical and Environmental Engineering (DBCEE), 705 Engineering Research Center, University of Cincinnati,Cincinnati, OH 45221-0012 highlights  CNTs have offered higher hydrophilicity to PES/f-MWCNTs nanocomposite membranes.  PES/f-MWCNTs membranes showed good rejection capability.  Rejection efﬁciency has improved without compromising the permeability. graphical abstract Nanocomposite membrane formed from Polyethersulfone and functionalised multi walled carbon nanotubes. . article info Article history: Received 25 July 2013 Received in revised form 24 September 2013 Accepted 26 September 2013 Available online 6 October 2013 Keywords: Polymer nanocomposite Polyethersulfone Functionalised multi-walled carbon nanotubes Hydrophilicity Paper mill efﬂuent abstract Functionalised multi-walled carbon nanotubes (f-MWCNTs) in different concentrations were incorpo- rated into polyethersulfone (PES) to fabricate PES/f-MWCNTs nanocomposite membranes for ultraﬁltra- tion studies. MWCNTs were synthesized by chemical vapour deposition method that were later functionalised using concentrated acids (H 2 SO 4 /HNO 3 ) to impart hydroxyl and carboxyl functional groups on its side walls. Hydrophilic property of PES-f-MWCNTs, identiﬁed by the contact angle measurement, was improved by 18.7% more than that of neat PES membrane. The pure water ﬂux increased from 24.28 L m 2 h 1 to 53.91 L m 2 h 1 on addition of 0.5 wt.% of f-MWCNTs to PES. The increase in ﬂux is attributed to the surface hydrophilicity of PES-f-MWCNTs and it also clearly signiﬁes the impact of func- tionalised MWCNTs on PES. Solute separation studies were performed wherein 27–30% rejection, much higher than that of neat PES membrane, was observed. Treatment of Kraft paper mill efﬂuent with and without lignin recovery was also investigated by analysing the performance of PES-f-MWCNTs nanocom- posite membranes on colour, chemical oxygen demand (COD) and total dissolved solids (TDS) reduction. Ó 2013 Elsevier B.V. All rights reserved. 1. Introduction The development of polymer nanocomposites and rapid ad- vances in the ﬁeld of nanotechnology has created great opportuni- ties for major progress in the ﬁeld of membrane science. Polymer nanocomposite membranes composed of inorganic nanomaterials are developing due to their higher durability and performance in many separation applications [1,2]. Composite membranes con- taining nano-sized inorganic materials, blended or architecturally position in the membrane matrix, are attractive because of their enhanced properties, such as high perm-selectivity, higher hydro- philicity, and enhanced fouling resistance [3]. These advances have 1385-8947/$ - see front matter Ó 2013 Elsevier B.V. All rights reserved. http://dx.doi.org/10.1016/j.cej.2013.09.096 ⇑ Corresponding author. Tel.: +91 431 2503118; fax: +91 431 2500133. E-mail addresses: arthanaree10@yahoo.com (G. Arthanareeswaran), dionysios.d. dionysiou@uc.edu (D.D. Dionysiou). Chemical Engineering Journal 236 (2014) 369–377 Contents lists available at ScienceDirect Chemical Engineering Journal journal homepage: www.elsevier.com/locate/cej