摘要:
A method for treatment with a reverse osmosis membrane to reduce decrease in flux that occurs even under the conditions that water supplied to a reverse osmosis membrane treatment apparatus contains only a trace amount of iron and that the formation of scales of substances such as calcium and silica is prohibited. A method for performing a treatment with a reverse osmosis membrane to treat raw water containing iron at 1000 μg/L or less as total iron with a reverse osmosis membrane, including a step of adding a compound having a sulfo group to the raw water.
摘要:
Provide is a method capable of effectively improving a rejection of a permeable membrane without remarkably reducing a permeation flux, even if the membrane is seriously degraded. The method for improving a rejection of a permeable membrane supplies an aqueous solution (excluding an aqueous solution having a pH of 7 or less) containing a compound having an amino group and a molecular weight of 1,000 or less through the permeable membrane (amino-treatment step). Since the low molecular weight amino compound is supplied through the permeable membrane, degraded portions of the membrane can be restored without remarkably reducing the permeation flux thereof, and the rejection thereof can be effectively improved.
摘要:
A method capable of effectively improving a rejection of a reverse osmosis membrane without remarkably reducing a permeation flux, even if the membrane is seriously degraded. An aqueous solution containing a first organic compound having a molecular weight of less than 200, a second organic compound having a molecular weight of 200 to less than 500, and a third organic compound having a molecular weight of 500 or more is passed through the reverse osmosis membrane. The first organic compound is preferably an amino acid or an amino acid derivative. The total concentration of the first organic compound and the second organic compound and the concentration of the third organic compound are each preferably 1 to 500 mg/L.
摘要:
A detergent and a method for washing applicable to selectively permeable membranes are proposed, which can attain washing of selectively permeable membranes deteriorated in its membrane performance, such as the flux, in an efficient manner within a brief time at a higher detergent effect without causing deterioration of the selectively permeable membranes and without damaging safety to human and to environment with superior handling aspect. A detergent comprising a polyol having a molecular weight not higher than 400 and, if necessary, an organic solvent is supplied to the concentrate chamber 3 of the module 1 to carry out washing of the selectively permeable membrane 2 by bringing it into contact with the selectively permeable membrane 2 and, on requirement, water or an alkaline solution is further supplied from the water tank 6 or from the alkali storage 8 to the concentrate chamber 3 of the module 1, in order to recover the membrane performance of the selectively permeable membrane 2.
摘要:
A silicon wafer after being cleaned by using a cleaning liquid is rinsed by using carbonic water. According to such a silicon wafer cleaning method, generation of static due to a rinsing treatment is not caused, so that an electrostatic breakdown is not caused, adhesion of dirt to a cleaned silicon wafer surface due to the static is not caused, adhesion of metal impurities can be prevented in the rinsing treatment of the silicon wafer and, while giving consideration to the cost, furthermore, a rinsing treatment using a clean rinsing liquid free from causing any residue can be performed.
摘要:
Provided is a method capable of effectively improving the rejection of a membrane without considerably lowering the permeation flux, even when the membrane has significantly degraded. The method of improving the rejection of a permeable membrane includes a step (amino treatment step) of passing an aqueous solution (amino treatment water) having a pH of 7 or less and containing an amino group-containing compound having a molecular weight of 1000 or less through the permeable membrane. After this amino treatment step, water having a higher pH than the amino treatment water is allowed to pass through the permeable membrane. Thus, by allowing the low-molecular-weight amino compound to pass through the membrane, a degraded portion of the membrane can be restored without considerably lowering the permeation flux of this permeable membrane, and the rejection can be effectively improved.
摘要:
A silicon wafer after being cleaned by using a cleaning liquid is rinsed by using carbonic water. According to such a silicon wafer cleaning method, generation of static due to a rinsing treatment is not caused, so that an electrostatic breakdown is not caused, adhesion of dirt to a cleaned silicon wafer surface due to the static is not caused, adhesion of metal impurities can be prevented in the rinsing treatment of the silicon wafer and, while giving consideration to the cost, furthermore, a rinsing treatment using a clean rinsing liquid free from causing any residue can be performed.
摘要:
An agent for increasing the rejection with a permeable membrane which comprises an ionic macromolecule having a weight-average molecular weight of 100,000 or greater; a process for increasing the rejection with a permeable membrane which comprises treating a permeable membrane with the agent; a permeable membrane which is treated in accordance with the process; and a process for water treatment which comprises using the permeable membrane are disclosed. By using the above agent, an increased rejection of inorganic electrolytes and organic compounds soluble in water can be maintained for a long time easily and safely at the location of the use of the membrane without extreme decrease in the flux of permeation in the membrane separation using a selective permeable membrane such as a nano filtration membrane and a reverse osmosis membrane.
摘要:
An agent for increasing the rejection of a nanofiltration membrane or a reverse osmosis membrane which comprises a compound having a polyalkylene glycol chain having a weight-average molecular weight of 2,000 to 6,000; a process for increasing the rejection of a nanofiltration membrane or a reverse osmosis membrane which comprises bringing the nanofiltration membrane or the reverse osmosis membrane into contact with an aqueous solution of a compound having a polyalkylene glycol chain which is obtained by diluting the agent for increasing the rejection of a nanofiltration membrane or a reverse osmosis membrane described above with water; a nanofiltration membrane or a reverse osmosis membrane exhibiting a rejection increased in accordance with the process; and a process and an apparatus for water treatment using the nanofiltration membrane or the reverse osmosis membrane. The rejection and, in particular, the rejection to nonionic solutes, of a nanofiltration membrane or a reverse osmosis membrane can be increased while the flux is kept at a great value.
摘要:
A method capable of effectively improving a rejection of a reverse osmosis membrane without remarkably reducing a permeation flux, even if the membrane is seriously degraded. An aqueous solution containing a first organic compound having a molecular weight of less than 200, a second organic compound having a molecular weight of 200 to less than 500, and a third organic compound having a molecular weight of 500 or more is passed through the reverse osmosis membrane. The first organic compound is preferably an amino acid or an amino acid derivative. The total concentration of the first organic compound and the second organic compound and the concentration of the third organic compound are each preferably 1 to 500 mg/L.