Multifunctional Graphene-Based Nanomaterials for Removal of Diverse Water Contaminants

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Importance of the quality of potable water is becoming more critical to the health and safety of the world’s population as widespread water crisis and risks of natural and man-made contamination are rising all around the world. Limitations of the conventional water treatment techniques has drawn attention of researchers to finding alternative methods of water treatment and contaminant removal. Based on these premises, with the increasing interest in sustainable, less energy-intensive technologies, graphene-based nanomaterials have gained a lot of attention due to their unique properties in a wide range of applications. From a wide array of materials, graphene and graphene oxide (GO) have taken a central focus due to impressive physical and chemical properties, as well as its scalable production. In recent years, there has been a growing interest among scientists in incorporating graphene-based nanomaterials into polymer matrices to create biocompatible polymer nanocomposites with multi-functional properties, enhancing the intended performance, making them reliable for future applications. The present cascade of studies aims to explore the properties of graphene for biofouling control, as well as the inclusion of GO into a polymeric matrix to develop a new class of nanocomposite for contaminant removal. A novel technique to remove biofouling by laser irradiating biofouled graphene-coated membrane surfaces was developed. A laser beam was used to heat the graphene structure, resulting in the microbial fouling to burn out, allowing the modified membrane to be used for several filtration cycles. The method was successfully employed with environmental water samples to validate the possibility of more realistic applications. Later, the studies were focused on incorporating GO into a polymeric matrix containing chitosan (CS) and polyethyleneimine (PEI) to form nanocomposites as membrane coatings and beads. The optimized CS-PEI-GO nanocomposite effectively removed heavy metals, nitrate, and microorganisms, indicating their multifunctionality. The nanocomposite was tested against diverse water chemistries showing its stability and effectivity, paving the way to the development of a technology that is applicable in real-world situations.

Graphene, Graphene oxide, Nanocomposites, Water purification
Portions of this document appear in: Bandara, Pasan C., Felipe Ibañez de Santi Ferrara, Hoang Nguyen, Greggy Santos, Wei-Chuan Shih, and Debora F. Rodrigues. "Investigation of Thermal Properties of Graphene-Coated Membranes by Laser Irradiation to Remove Biofoulants." Environmental science & technology 53, no. 2 (2018): 903-911. And in: Bandara, P. C., Nadres, E. T., & Rodrigues, D. F. (2019). Use of response surface methodology to develop and optimize the composition of a chitosan-polyethyleneimine-graphene oxide nanocomposite membrane coating to more effectively remove Cr (VI) and Cu (II) from water. ACS applied materials & interfaces.