Disadvantages Of Reverse Osmosis

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Reverse osmosis (RO) is the leading desalination technology around the globe and is used to remove different types of ions, molecules and larger particles from solvents (e.g. water). In the standard osmosis process, a solvent naturally moves from an area of low solute concentration, through a semipermeable membrane, to an area of high solute concentration. By equalizing the solute concentrations on each side of the membrane, an osmotic pressure is created. In order to obtain clean water, a pressure is applied, in order to overcome the osmotic pressure, by pressing water (contaminated with metals) against the surface of a membrane, causing pure water (solvent) to move through the membrane, leaving behind the metal salts (solute).[7,17] However,…show more content…
However, none of these technologies is perfect with respect to environmental impact and economical and technical feasibility. In table 1, an overview of the advantages and disadvantages of each discussed technology can be found:
Table SEQ Table \* ARABIC 1. An overview of the most important advantages and disadvantages of the most commonly applied heavy metal technologies.[7, 17 19, 25]
Advantages Disadvantages
Chemical precipitation Relatively simple
Metal selective
Deal with the production of large amounts of toxic sludge and its disposal
Coagulation/flocculation High removal percentage in the right pH range Expensive and large amounts of chemicals are consumed
Production of large amounts of toxic sludge
Ion exchange Metal selective
Resins can be reused and regenerated
High metal removals can be obtained
Relatively eco-friendly
Enrichment of the aqueous phase with hydrogen, sodium, hydroxyl or chloride ions could lead to a change in pH of treated
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They are formed by a combination of organic cations and various organic or inorganic anions (some common cations and anions can be found in figure 6). Due to their composition, ILs are able to stabilize charged species, such as ions. Each IL has different physical properties, such as viscosity, density, melting point, water miscibility and lipophilicity, depending on the composition. Nevertheless, their physical properties can be tailored by changing the cation-anion combination. In general ILs have the following

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