Integrated Capacitive Deionization and Humidification-Dehumidification System for Brackish Water Desalination
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Date
2021-11-15
Journal Title
Journal ISSN
Volume Title
Publisher
MDPI
Abstract
A hybrid capacitive deionization and humidification-dehumidification (CDI–HDH) desalination system is theoretically investigated for the desalination of brackish water. The CDI system
works with two basic operations: adsorption and regeneration. During adsorption, water is desalted,
and during the regeneration process the ions from electrodes are detached and flow out as wastewater,
which is higher in salt concentration. This wastewater still contains water but cannot be treated
again via the CDI unit because CDI cannot treat higher-salinity waters. The discarding of wastewater
from CDI is not a good option, since every drop of water is precious. Therefore, CDI wastewater
is treated using waste heat in a process that is less sensitive to high salt concentrations, such as
humidification-dehumidification (HDH) desalination. Therefore, in this study, CDI wastewater was
treated using the HDH system. Using the combined system (CDI–HDH), this study theoretically
investigated brackish water of various salt concentrations and flow rates at the CDI inlet. A maximum distillate of 1079 L/day was achieved from the combined system and the highest recovery rate
achieved was 24.90% from the HDH unit. Additionally, two renewable energy sources with novel
ideas are recommended to power the CDI–HDH system.
Sustainable Development Goals
SDG 6: Clean Water and Sanitation, SDG 12: Responsible Consumption and Production, SDG 7: Affordable and Clean Energy.
Keywords
Humidification-dehumidification, Capacitive deionization, Brackish water, Hybrid system