In-situ deposition of silveriron oxide nanoparticles on the surface of fly ash for water purification Mahesh Kumar Joshi a,b , Hem Raj Pant a,c , Nina Liao a , Jun Hee Kim a , Han Joo Kim a,⇑ , Chan Hee Park a,⇑ , Cheol Sang Kim a,d,e,⇑ a Department of Bionanosystem Engineering, Graduate School, Chonbuk National University, Jeonju 561-756, Republic of Korea b Department of Chemistry, Tri-Chandra Multiple Campus, Tribhuvan University, Kathmandu, Nepal c Department of Engineering Science and Humanities, Institute of Engineering, Pulchowk Campus, Tribhuvan University, Kathmandu, Nepal d Division of Mechanical Design Engineering, School of Engineering, Chonbuk National University, Jeonju 561-756, Republic of Korea e Eco-friendly Machine Parts Design Research Center, Chonbuk National University, Jeonju 561-756, Republic of Korea graphical abstract article info Article history: Received 31 January 2015 Accepted 21 April 2015 Available online 5 May 2015 Keywords: Fly ash Composite particle Lead(II) ions Antibacterial activity abstract In this study, a fly ash based composite, Ag–iron oxide/fly ash, was synthesized via a facile one-pot hydrothermal process using fly ash, ferrous chloride, and silver nitrate as precursors. Field emission scan- ning electron microscopy (FE-SEM), EDX, transmission electron microscopy (TEM), X-ray diffraction (XRD), Fourier transform infra-red spectroscopy (FTIR), Photoluminescence (PL) and Brunauer–Emmet t–Teller (BET) surface area measurement confirmed the formation of composite particle. FA provided a suitable surface for the in-situ deposition of Fe 3 O 4 and Ag NPs during hydrothermal treatment. As a result, the particle size of Fe 3 O 4 and Ag NPs was sufficiently decreased, and the surface area of the NPs as well as, a whole matrix was increased. The antimicrobial activity of the composite was accessed by Escherichia coli inhibition assay. Lead(II) ion adsorption efficiency of the composite was analyzed from a series of batch adsorption experiments (the effects of concentration, contact time, pH and adsorbent dose on the adsorption of Pb(II) ion from aqueous solution). Results indicated that as-synthesized com- posite has high antibacterial capacity, and the metal ions uptake efficiency compared to fly ash particle. Furthermore, incorporation Fe 3 O 4 NPs onto the fly ash make it easily separable from a reaction system http://dx.doi.org/10.1016/j.jcis.2015.04.044 0021-9797/Ó 2015 Elsevier Inc. All rights reserved. ⇑ Corresponding authors at: Department of Bionanosystem Engineering, Gradu- ate School, Chonbuk National University, Jeonju 561-756, Republic of Korea (C.S. Kim). Fax: +82 63 270 2460. E-mail addresses: khanjoo@jbnu.ac.kr (H.J. Kim), biochan@jbnu.ac.kr (C.H. Park), chskim@jbnu.ac.kr (C.S. Kim). Journal of Colloid and Interface Science 453 (2015) 159–168 Contents lists available at ScienceDirect Journal of Colloid and Interface Science www.elsevier.com/locate/jcis