A growing number of contaminants are entering water supplies from human activity, among which most can have bio-accumulative, persistent, carcinogenic, mutagenic and detrimental effects on the survival of aquatic organisms, flora, fauna as well as human health. Hence, effective, low-cost, robust methods to disinfect and decontaminate waters from source to point-of-use are needed, without further stressing the environment or endangering human health by the treatment itself [1]. In this work, single-walled carbon nanotube/graphene hybrid papers prepared by vacuum filtration are used as adsorbents for the removal of a series of aromatic compounds from aqueous systems. The configuration of these carbon nanostructures into flexible free-standing papers enables their direct use and easy recollection in water treatment, avoiding the need for additional solid-liquid separation procedures such as gravitational sedimentation, ?ltration, or coagulation [2]. Experimental data are collected via changes in optical absorption spectra of the different aqueous solutions and are used to extract all parameters required to implement a semi-empirical mass-transfer model. Agreement between experiment and theory is excellent and data from all compounds can be cast on a universal adsorption curve [3]. Results indicate that the as-prepared hybrid papers demonstrate the highest adsorption capacity of aromatic compounds to date [2,3]. Furthermore, spent hybrid papers are successfully regenerated by thermal oxidation and microwave irradiation after treatment such that the original adsorption capacity is significantly exceeded with a regeneration efficiency above 200% even after several saturation/regeneration cycles [4]. The prospect of using carbon nanotube/graphene free-standing papers as new generation adsorbents for organic compounds offer not only fast adsorption rates, improved stability and larger capacity, but also exhibit very high regeneration efficiency, potentially providing a sustainable/renewable solution for future purification systems.

References:

1. S. Chowdhury and R. Balasubramanian, Adv. Colloid Interface Sci. 2014, 204, 35.

2. A. B. Dichiara, T. J. Sherwood and R. E. Rogers, J. Mater. Chem. A, 2013, 1, 14480.

3. A. B. Dichiara, T. J. Sherwood, J. Benton-Smith, J. C. Wilson, S. J. Weinstein and R. E. Rogers, Nanoscale, 2014, 6, 6322.

4. A. B. Dichiara, J. Benton-Smith and R. E. Rogers, Environ. Sci.: Nano, 2014, 1, 113.

Anthony Dichiara

Rochester Institute of Technology

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