Synthesis and characterization of RGO/zeolite composites for the removal of arsenic from contaminated water† M. Khatamian, * a N. Khodakarampoor, a M. Saket Oskoui a and N. Kazemian b In this study, composites of Cu-exchanged zeolite/RGO (reduced graphene oxide) with different zeolites (clinoptilolite, ZEA, and ZSM-5) were synthesized. Cu-ZEA/RGO composites with different ratios (namely, 1 : 1 and 3 : 1) were also prepared. X-ray diffraction (XRD) and Fourier transform infrared spectroscopy (FTIR) analyses showed that Cu-zeolite/RGO composites were successfully synthesized. The morphologies of the obtained samples were studied by scanning electron microscopy (SEM). Moreover, the Brunauer–Emmett–Teller (BET) technique was used to measure the specific surface area of the samples. The synthesized composites were evaluated as an adsorbent to remove arsenic from contaminated water. According to the results of atomic absorption spectroscopy (AAS), the use of ZEA for preparing the mentioned composite (Cu-exchanged zeolite/RGO) can produce a more efficient performance compared with other zeolites (clinoptilolite and ZSM-5). The Cu-ZEA/RGO composite with 1 : 1 Cu-ZEA/RGO ratio exhibited the best performance in the removal of arsenic. 1. Introduction A great challenge for this century lies in cleaning-up the waste generated during industrial, domestic and agricultural activi- ties. Water, an essential uid on which all life depends, is heavily affected by such activities. Among the various contam- inants found in water, heavy metals require special attention because of their toxic effect on humans and the environment, even at very dilute concentrations. 1 Among toxic metals, a check on arsenic contamination of natural water sources has been recorded by the World Health Organization as a rst priority issue. Industrial waste water contains very high levels of arsenic (around 1000 mg L 1 ), which is a major concern especially in the developing countries. 2 Among several technologies involved in arsenic removal, such as adsorption, membrane ltration, coagulation, and ion exchange, adsorption is regarded as one of the most promising technologies because it is cost-effective, produces a small amount of by-product, and is simple to operate. 3 Graphene, as a unique two-dimensional carbon material, has received considerable attention from both the experimental and theoretical scientic communities 4 owing to its fascinating mechanical, electrical, thermal and optical properties, as well as potential applications in nanoelectronics, sensors, catalysis, batteries, supercapacitors and transistors. 5 Features like large surface area and presence of surface functional groups make single sheets of carbon and their composites an attractive adsorbent candidate for water purication. 1 However, the use of graphenic materials for large-scale and simple applications like water purication is limited due to the difficulty faced in large- scale synthesis. The ability to synthesize GO through chemical methods and its subsequent reduction to reduced graphene oxide (RGO) opened up the possibility for the mass production of graphene in solution phase. 1 Moreover, graphene-based composites are emerging as a new class of materials that hold promise for several applications. 6 It is believed that these composites exhibit modied properties compared with their individual components. On the one hand, the layer structure of graphene prevents the anchored particles from agglomeration and enables their uniform dispersion; on the other hand, particles separate graphene sheets and prevent their reassembly into graphite. 7 It can be proposed that zeolites can be consid- ered as proper candidate for preparation of graphene-based composites due to their valuable properties. Zeolites are considered as natural and synthetic hydrated microporous and crystalline aluminosilicates with an innite, open and rigid three-dimensional structure having a high internal surface area. The three-dimensional framework consists of tetrahedral (AlO 4 ) 5 and (SiO 4 ) 4 units that are linked through shared oxygen atoms. 8 In addition, it should be noted that zeolites are more compatible with the environment; they are stable at high temperature and in acidic and corrosive environments, and they have potential selectivity toward some cations. In addition, a Physical Inorganic Chemistry Research Laboratory, Department of Inorganic Chemistry, Faculty of Chemistry, Tabriz, Iran. E-mail: khatamianm@yahoo.com; Fax: +98-411-3340191; Tel: +98-411-3393129 b East Azarbayjan Water and Waste Water Company's Laboratory, Iran † Electronic supplementary information (ESI) available. See DOI: 10.1039/c5ra02949j Cite this: RSC Adv. , 2015, 5, 35352 Received 15th February 2015 Accepted 2nd March 2015 DOI: 10.1039/c5ra02949j www.rsc.org/advances 35352 | RSC Adv. , 2015, 5, 35352–35360 This journal is © The Royal Society of Chemistry 2015 RSC Advances PAPER