desalination
Electrochemistry techniques of reducing salinity in water using aerogel carbon electrodes.
Wed, 2015-10-28 10:21 — Ismail WaradOne of the most environmental friendly technique for desalination where electricity applied instead of chemicals. Water with different species like anions, metals and other contaminantsis introduced to an electrochemical cell to purify it from contaminants including salt. During polarization, ions are electrostatically removed from the water and adsorbed in electric double layers at the surfaces o electrodes. The output of this process is cleaned water without contaminants. The Capacitive Deionization Technology (CDI) with carbon aerogel considered new and famous technique where 80% of saline water transferred to pure water with low energy consumption, and very simple method, without producing pollutants like NOX, SO, and other voltaile organics. This experiment based on applying current and the two anions, Na2+and Cl-were distributed between the twoelectrodes of carbon aerogel which they have high surface area. The absorption of NaClby the aerogel carbon electrodes reached more than 50% by varying the experimental parameters like voltage, pH, concentration, distance between electrodes and flow. The best conditions were using 2V, pH =5, and a 0.4 cm distance between electrodes. When the distance between electrodes decreased (0.4 cm) the absorption of ions increased due to the formation of electrical double layer and increasing potential between electrodes. For the best removal results a flow of 80 mL/min was used. From our results we can conclude that using capacitive desalination technology(CDI) enhanced the removal of salts from brackish water.
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Preparation of Thin-Film-Composite Polyamide Membranes for Desalination Using Novel Hydrophilic Surface Modifying Macromolecules
Wed, 2015-03-11 15:37 — Hassan ArafatA new concept for the preparation of thin-film-composite (TFC) reverse osmosis (RO) membrane by interfacial polymerization on porous polysulfone (PS) support using novel additives is reported. Hydrophilicsurface modifying macromolecules (LSMM) were synthesized both ex situ by conventional method (cLSMM), and in situ within the organic solvent of the TFC system (iLSMM). The effects of these LSMMs on the fouling of the TFC RO membranes used in the desalination processes were studied. FTIR results indicated that both cLSMM and iLSMM were present in the active layer of the TFC membranes. SEM micrographs depicted that heterogeneity of the surface increases for TFC membranes compared to the control PS membrane, and that higher concentrations of LSMM provided smoother surface. AFM characteristic data presented that the surface roughness of the skin surface increases for TFC membranes compared to the control. The RO performance results showed that the addition of the cLSMM significantly decreased the salt rejection of the membrane and slightly reduced the flux, while in the case of the iLSMM, salt rejection was improved but the flux declined at different rates for different iLSMM concentrations. The membrane prepared by the iLSMM exhibited less flux decay over an extended operational period.
Non-Conventional Options for Water Supply Augmentation in the Middle East: A Case Study
Sun, 2014-05-04 13:24 — Numan MizyedMiddle Eastern countries (ME) are expected to face severe water shortages in the near future. As most conventional water resources are already developed or over exploited, there is a need to develop non-conventional options to bridge water shortages. These options include brackish and sea-water desalination and fresh water imports from outside the region either by sea or land. Technically, non-conventional options are possible and feasible, however, depending on many factors, these options are available at a high capital investment with different costs and are associated with some environmental and ecological impacts and political considerations. Water and other conflicts in the region along with funding problems are the main obstacles to the implementation of such options in the ME. Integrating conventional and non-conventional water development options are found to be a more viable combination on the long term. Cooperation between ME countries is found to be a key factor to overcoming water shortage using non-conventional options. Therefore, it is concluded that non-conventional water options should be encouraged in the region and should be utilized to overcome not only water shortages but also to resolve conflicts and restore economic growth, peace, and stability among regional parties and people.
Non-Conventional Options for Water Supply Augmentation in the Middle East: A Case Study
Tue, 2014-04-01 12:10 — Marwan N. HaddadMiddle Eastern countries (ME) are expected to face severe water shortages in the near future. As most conventional water resources are already developed or over exploited, there is a need to develop non-conventional options to bridge water shortages. These options include brackish and sea-water desalination and fresh water imports from outside the region either by sea or land. Technically, non-conventional options are possible and feasible, however, depending on many factors, these options are available at a high capital investment with different costs and are associated with some environmental and ecological impacts and political considerations. Water and other conflicts in the region along with funding problems are the main obstacles to the implementation of such options in the ME. Integrating conventional and non-conventional water development options are found to be a more viable combination on the long term. Cooperation between ME countries is found to be a key factor to overcoming water shortage using non-conventional options. Therefore, it is concluded that non-conventional water options should be encouraged in the region and should be utilized to overcome not only water shortages but also to resolve conflicts and restore economic growth, peace, and stability among regional parties and people.
