title: Cellulose Derived Graphenic Fibers for Capacitive Desalination of Brackish Water.
abstract: We describe a simple and inexpensive cellulose-derived and layer-by-layer stacked carbon fiber network electrode for capacitive deionization (CDI) of brackish water. The microstructure and chemical composition were characterized using spectroscopic and microscopic techniques; electrochemical/electrical performance was evaluated by cyclic voltammetry and 4-probe electrical conductivity and surface area by Brunauer-Emmett-Teller analysis, respectively. The desalination performance was investigated using a laboratory batch model CDI unit, under fixed applied voltage and varying salt concentrations. Electro-adsorption of NaCl on the graphite reinforced-cellulose (GrC) electrode reached equilibrium quickly (within 90 min) and the adsorbed salts were released swiftly (in 40 min) back into the solution, during reversal of applied potential. X-ray photoelectron spectroscopic studies clearly illustrate that sodium and chloride ions were physisorbed on the negative and positive electrodes, respectively during electro-adsorption. This GrC electrode showed an electro-adsorption capacity of 13.1 mg/g of the electrode at a cell potential of 1.2 V, with excellent recyclability and complete regeneration. The electrode has a high tendency for removal of specific anions, such as fluoride, nitrate, chloride, and sulfate from water in the following order: Cl->NO3->F->SO4(2-). GrC electrodes also showed resistance to biofouling with negligible biofilm formation even after 5 days of incubation in Pseudomonas putida bacterial culture. Our unique cost-effective methodology of layer-by-layer stacking of carbon nanofibers and concurrent reinforcement using graphite provides uniform conductivity throughout the electrode with fast electro-adsorption, rapid desorption, and extended reuse, making the electrode affordable for capacitive desalination of brackish water.
authors: DST Unit of Nanoscience (DST UNS) and Thematic Unit of Excellence (TUE), Department of Chemistry, Indian Institute of Technology Madras , Chennai 600 036, India.
authors: Nalenthiran
authors: N
authors: Pugazhenthiran
authors: DST Unit of Nanoscience (DST UNS) and Thematic Unit of Excellence (TUE), Department of Chemistry, Indian Institute of Technology Madras , Chennai 600 036, India.
authors: Soujit
authors: S
authors: Sen Gupta
authors: DST Unit of Nanoscience (DST UNS) and Thematic Unit of Excellence (TUE), Department of Chemistry, Indian Institute of Technology Madras , Chennai 600 036, India.
authors: Anupama
authors: A
authors: Prabhath
authors: DST Unit of Nanoscience (DST UNS) and Thematic Unit of Excellence (TUE), Department of Chemistry, Indian Institute of Technology Madras , Chennai 600 036, India.
authors: Muthu
authors: M
authors: Manikandan
authors: DST Unit of Nanoscience (DST UNS) and Thematic Unit of Excellence (TUE), Department of Chemistry, Indian Institute of Technology Madras , Chennai 600 036, India.
authors: Jakka Ravindran
authors: JR
authors: Swathy
authors: Centre of Excellence (Biotechnology) & Water and Wastewater Technology, Thermax Limited , Pune 411019, India.
authors: V Kalyan
authors: VK
authors: Raman
authors: DST Unit of Nanoscience (DST UNS) and Thematic Unit of Excellence (TUE), Department of Chemistry, Indian Institute of Technology Madras , Chennai 600 036, India.
authors: Thalappil
authors: T
authors: Pradeep
mesh_terms: D000327:Adsorption; D018441:Biofilms / Q000187:drug effects; D057219:Biofouling; D002244:Carbon / Q000737:chemistry / Q000494:pharmacology; D000077482:Carbon Fiber; D002482:Cellulose / Q000737:chemistry*; D002712:Chlorides / Q000737:chemistry; D004553:Electric Conductivity; D004566:Electrodes; D006108:Graphite / Q000737:chemistry*; D007477:Ions / Q000737:chemistry; D056951:Photoelectron Spectroscopy; D016062:Porosity; D016958:Pseudomonas putida / Q000502:physiology; D000068357:Saline Waters / Q000737:chemistry*; D012964:Sodium / Q000737:chemistry; D018508:Water Purification
chemical_list: D000077482:Carbon Fiber; D002712:Chlorides; D007477:Ions; D002244:Carbon; D006108:Graphite; D002482:Cellulose; D012964:Sodium
keywords: adsorption; capacitive deionization; graphene; nanofiber; water purification