MIL-68 (In) nano-rods for the removal of Congo red dye from aqueous solution Li-Na Jin a,⇑ , Xin-Ye Qian a , Jian-Guo Wang a , Hüsnü Aslan b , Mingdong Dong b,⇑ a Institute for Advanced Materials, and School of Materials Science and Engineering, Jiangsu University, Zhenjiang 212013, China b Center for DNA Nanotechnology (CDNA), Interdisciplinary Nanoscience Center (iNANO), Aarhus University, DK-8000 Aarhus, Denmark graphical abstract article info Article history: Received 24 December 2014 Accepted 4 May 2015 Available online 13 May 2015 Keywords: Metal–organic frameworks Nanomaterials Congo red Adsorption abstract MIL-68 (In) nano-rods were prepared by a facile solvothermal synthesis using NaOAc as modulator agent at 100 °C for 30 min. The BET test showed that the specific surface area and pore volume of MIL-68 (In) nanorods were 1252 m 2 g 1 and 0.80 cm 3 g 1 , respectively. The as-prepared MIL-68 (In) nanorods showed excellent adsorption capacity and rapid adsorption rate for removal of Congo red (CR) dye from water. The maximum adsorption capacity of MIL-68 (In) nanorods toward CR reached 1204 mg g 1 , much higher than MIL-68 (In) microrods and most of the previously reported adsorbents. The adsorption process of CR by MIL-68 (In) nano-rods was investigated and found to be obeying the Langmuir adsorp- tion model in addition to pseudo-second-order rate equation. Moreover, the MIL-68 (In) nanorods showed an acceptable reusability after regeneration with ethanol. All information gives an indication that the as-prepared MIL-68 (In) nanorods show their potential as the adsorbent for highly efficient removal of CR in wastewater. Ó 2015 Elsevier Inc. All rights reserved. 1. Introduction Water pollution, especially for dyes, has received great atten- tion due to their worldwide application in many industries, such as textile, paper, printing, food, and cosmetics [1]. It is well known that many dyes and pigments are inert, toxic and difficult to biode- grade when discharged into waste streams. In addition to be being a health threat, the presence of dyes and pigments in water is highly visible and affects the water transparency, resulting in reduction of light penetration, and oxygen gas solubility in water [2–4]. Thus, removal of such toxic dyes from the wastewater is a crucial issue. Metal–organic frameworks (MOFs), as a new class of inorganic– organic hybrid materials based on metal ions coordinated by multidentate organic bridging ligands, have received a great deal of attention because of their attractive potential applications in gas adsorption/separation, catalysis, sensing, drug delivery, and magnetism [5–10]. In the past few years, MOFs have been explored for the adsorption and removal of dyes from aqueous solution, due http://dx.doi.org/10.1016/j.jcis.2015.05.005 0021-9797/Ó 2015 Elsevier Inc. All rights reserved. ⇑ Corresponding authors. E-mail addresses: jinln@mail.ujs.edu.cn (L.-N. Jin), dong@inano.au.dk (M. Dong). Journal of Colloid and Interface Science 453 (2015) 270–275 Contents lists available at ScienceDirect Journal of Colloid and Interface Science www.elsevier.com/locate/jcis