1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 z Materials Science inc. Nanomaterials & Polymers A Facile Synthesis of Hematite Nanorods from Rice Starch and Their Application to Pb(II) Ions Removal Md. Ikram Ul Hoque,* [a, b, c] Yusuke Yamauchi,* [d, e, f] Ravi Naidu, [a] Rudolf Holze, [g] Rahman Saidur, [h, i] Qunting Qu, [g, j] Mohammad Mahmudur Rahman, [a] Nagy L. Torad, [e] Md. Shahriar A. Hossain, [d] Minjun Kim, [d] Jeonghun Kim, [d] Syed Haseeb Ali Ahmad, [i] Ateeq Ur Rehman, [d] Md. Shakhawat Hossain Firoz, [c] Ummayhanni Luba, [k] Shahriar Chowdhury, [c] and Al-Nakib Chowdhury [c] 1D hematite (α-Fe 2 O 3 ) nanorods were synthesized in the presence of rice starch solution. The size of the nanorods was about 250 nm and 50 nm in length and diameter, respectively. The synthesized nanorods possessed a single α-Fe 2 O 3 phase without any impurities and crystal defects. The obtained hematite nanorods were employed as an adsorbent for lead (II) removal. The isotherms and kinetic studies indicated that our material would be a potential candidate for heavy metal adsorption and removal. INTRODUCTION Green chemistry routes to one-dimensional (1D) iron oxide- based nanomaterials including nanorods, nanotubes, nano- needles, nanofibers and nanowires have drawn considerable attentions because of their superior physicochemical properties compared to two-dimensional (2D) and three-dimensional (3D) analogues. [1–2] Five polymorphs of iron oxides are classified as hematite (α-Fe 2 O 3 ), maghemite (γ-Fe 2 O 3 ), beta hematite (β- Fe 2 O 3 ), epsilon hematite (ε-Fe 2 O 3 ) and magnetite (Fe 3 O 4 ). Among them, a synthesis of hematite (α-Fe 2 O 3 ) nanoparticles is one of current hot topics since their active surface is very useful for some specific applications. [3–6] Although a number of 2D and 3D spherically shaped iron oxide nanoparticles have been reported, controlled synthesis protocols to synthesize 1D hematite nanorods are still ambiguous. To date, most of synthesis methods reported in the literature, including hydro- thermal, microwave-assisted synthesis, template synthesis methods require the use of toxic reagents which are not non- viable for mass production. Therefore, a large-scale production of 1D hematite nanorods, preferably through a green chemical process, is paramount. Especially, a green chemistry-based method for a large-scale production of hematite nanorods is still a challenging issue. On the other hand, the adsorption properties and removal efficiencies of toxic ions including Pb(II) ions using nano- particles are being rigorously investigated. [7–8] Lead, one of the most dangerous biologically relevant poisons found in water and waste water is non-biodegradable. It can cause numerous health problems, including lung diseases, brain stroke, kidney problems, high blood pressure, nausea, convulsions, coma, renal failure, and even cancer. [9–10] Many methods have been employed to remove Pb(II) ions from water. There are several methods including chemical coagulation, precipitation, floccu- lation, activated sludge, membrane separation/reverse osmosis, evaporation, filtration/ultrafiltration, ion exchange, chemical [a] Md. I. U. Hoque, Prof. R. Naidu, M. M. Rahman Global Centre for Environmental Remediation (GCER), Faculty of Science, University of Newcastle, University Drive, Callaghan NSW 2308, Australia E-mail: md.ikramul.hoque@uon.edu.au [b] Md. I. U. Hoque Department of Chemistry, Dhaka University of Engineering & Technology, Gazipur, Gazipur-1700, Bangladesh [c] Md. I. U. Hoque, Md. S. H. Firoz, S. Chowdhury, A.-N. Chowdhury Department of Chemistry and Department of Mechanical Engineering, Bangladesh University of Engineering and Technology, Dhaka-1000, Bangladesh [d] Prof. Y. Yamauchi, Dr. Md. S. A. Hossain, M. Kim, Dr. J. Kim, A. U. Rehman School of Chemical Engineering, School of Mechanical & Mining Engineering, and Australian Institute for Bioengineering and Nano- technology (AIBN), The University of Queensland, Brisbane, QLD 4072, Australia. E-mail: y.yamauchi@uq.edu.au [e] Prof. Y. Yamauchi, Dr. N. L. Torad International Centre for Materials Nanoarchitectonics (WPI-MANA), Na- tional Institute for Materials Science (NIMS), 1–1 Namiki, Tsukuba, Ibaraki 305-0044, Japan [f] Prof. Y. Yamauchi Department of Plant & Environmental New Resources, Kyung Hee University, 1732 Deogyeong-daero, Giheung-gu, Yongin-si,12 Gyeonggi- do 446-701, South Korea [g] R. Holze, Q. Qu InstitutfürChemie, AG Elektrochemie, Technische Universität Chemnitz, 09111 Chemnitz, Germany [h] R. Saidur Research Centre for Nano-Materials and Energy Technology, School of Science and Technology (RCNMET), Sunway University, No. 5, Jalan University, 47500, Petaling Jaya, Selangor, Malaysia [i] R. Saidur, S. H. A. Ahmad Center of Research Excellence in Renewable Energy (CoRE-RE), King Fahd University of Petroleum and Minerals, Dhahran 31261, Saudi Arabia [j] Q. Qu College of Physics, Optoelectronics and Energy, Soochow University, Suzhou, Jiangsu 215006, P. R. China [k] U. Luba Department of Mathematics, Jahangirnagar University, Savar-1342, Dhaka, Bangladesh Supporting information for this article is available on the WWW under https://doi.org/10.1002/slct.201802462 Full Papers DOI: 10.1002/slct.201802462 3730 ChemistrySelect 2019, 4,3730–3736 © 2019 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim