Sustainable Desalination by 3:1 Reduced Graphene Oxide/Titanium Dioxide Nanotubes (rGO/TiONTs) Composite via Capacitive Deionization at Different Sodium Chloride Concentrations

The capability of novel 3:1 reduced graphene oxide/titanium dioxide nanotubes (rGO/TiONTs) composite to desalinate using capacitive deionization (CDI) employing highly concentrated NaCl solutions was tested in this study. Parameters such as material wettability, electrosorption capacity, charge efficiency, energy consumption, and charge-discharge retention were tested at different NaCl initial concentrations—100 ppm, 2000 ppm, 15,000 ppm, and 30,000 ppm. The rGO/TiONTs composite showed good material wettability before and after CDI runs with its contact angles equal to 52.11° and 56.07°, respectively. Its two-hour electrosorption capacity during CDI at 30,000 ppm NaCl influent increased 1.34-fold compared to 100 ppm initial NaCl influent with energy consumption constant at 1.11 kWh per kg with NaCl removed. However, the percentage discharge (concentration-independent) at zero-voltage ranged from 4.9–7.27% only after 30 min of desorption. Repeated charge/discharge at different amperes showed that the slowest charging rate of 0.1 A·g−1 had the highest charging time retention at 60% after 100 cycles. Increased concentration likewise increases charging time retention. With this consistent performance of a CDI system utilizing rGO/TiONTs composite, even at 30,000 ppm and 100 cycles, it can be a sustainable alternative desalination technology, especially if a low charging current with reverse voltage discharge is set for a longer operation.

[1]  R. Doong,et al.  Deionization utilizing reduced graphene oxide-titanium dioxide nanotubes composite for the removal of Pb2+ and Cu2+ , 2020 .

[2]  Haibo Li,et al.  Mesoporous carbon derived from ZIF-8 for high efficient electrosorption , 2017, Desalination.

[3]  R. Doong,et al.  Synthesis of Reduced Graphene Oxide/Titanium Dioxide Nanotubes (rGO/TNT) Composites as an Electrical Double Layer Capacitor , 2018, Nanomaterials.

[4]  Chia-Hung Hou,et al.  Highly porous activated carbon with multi-channeled structure derived from loofa sponge as a capacitive electrode material for the deionization of brackish water. , 2018, Chemosphere.

[5]  K. Dermentzis,et al.  Continuous capacitive deionization with regenerative rotating film electrodes , 2018, Electrochemistry Communications.

[6]  F. Kang,et al.  GO/auricularia-derived hierarchical porous carbon used for capacitive deionization with high performance , 2018, Colloids and Surfaces A: Physicochemical and Engineering Aspects.

[7]  Lianjun Wang,et al.  Hollow ZIFs-derived nanoporous carbon for efficient capacitive deionization , 2018 .

[8]  Miao Wang,et al.  Phosphorus-doped 3D carbon nanofiber aerogels derived from bacterial-cellulose for highly-efficient capacitive deionization , 2018 .

[9]  S. Tewari,et al.  Capacitive deionization: Processes, materials and state of the technology , 2018 .

[10]  Lei Wang,et al.  Water-enhanced performance in capacitive deionization for desalination based on graphene gel as electrode material , 2018 .

[11]  L. Chai,et al.  Capacitive deionization of chloride ions by activated carbon using a three-dimensional electrode reactor , 2018 .

[12]  R. L. Zornitta,et al.  Simultaneous analysis of electrosorption capacity and kinetics for CDI desalination using different electrode configurations , 2018 .

[13]  Lu Lu,et al.  Resin-enhanced rolling activated carbon electrode for efficient capacitive deionization , 2017 .

[14]  Ruey-an Doong,et al.  Hierarchically ordered mesoporous carbons and silver nanoparticles as asymmetric electrodes for highly efficient capacitive deionization , 2016 .

[15]  Haibo Li,et al.  Improved capacitive deionization performance by coupling TiO2 nanoparticles with carbon nanotubes , 2016 .

[16]  Peng Wu,et al.  Electrosorption of fluoride on TiO2-loaded activated carbon in water , 2016 .

[17]  C. Ma,et al.  Comparative insight into the capacitive deionization behavior of the activated carbon electrodes by two electrochemical techniques , 2016 .

[18]  Chaoyang Wang,et al.  Fabrication of mesoporous graphene electrodes with enhanced capacitive deionization , 2015 .

[19]  J. Tirado,et al.  On the use of carbon black loaded nitrogen-doped carbon aerogel for the electrosorption of sodium chloride from saline water , 2015 .

[20]  R. Doong,et al.  Activation of hierarchically ordered mesoporous carbons for enhanced capacitive deionization application , 2015 .

[21]  Heyang Yuan,et al.  Enhancing desalination and wastewater treatment by coupling microbial desalination cells with forward osmosis , 2015 .

[22]  Tzahi Y. Cath,et al.  Long-term pilot scale investigation of novel hybrid ultrafiltration-osmotic membrane bioreactors , 2015 .

[23]  Khalil Abdelrazek Khalil,et al.  TiO2 nanorod-intercalated reduced graphene oxide as high performance electrode material for membrane capacitive deionization , 2015 .

[24]  Wei Zhang,et al.  Toward anti-fouling capacitive deionization by using visible-light reduced TiO_2/graphene nanocomposites , 2015 .

[25]  Volker Presser,et al.  Review on the science and technology of water desalination by capacitive deionization , 2013 .

[26]  Shichang Xu,et al.  Performance comparison and energy consumption analysis of capacitive deionization and membrane capacitive deionization processes , 2013 .

[27]  Linda Zou,et al.  A study of the capacitive deionisation performance under various operational conditions. , 2012, Journal of hazardous materials.

[28]  Wei Liu,et al.  Preparation and electrosorption desalination performance of activated carbon electrode with titania , 2011 .

[29]  Xiaowei Sun,et al.  Kinetic and isotherm studies on the electrosorption of NaCl from aqueous solutions by activated carbon electrodes , 2011 .

[30]  Y. Oren,et al.  Capacitive deionization (CDI) for desalination and water treatment — past, present and future (a review) , 2008 .

[31]  W Steckelmacher,et al.  Surface science techniques , 1995 .