Water is one of the most common ingredients in laboratories and in our everyday life. In the case of scientific fields and in researches, water is commonly used as a solvent, which means that is used for cleaning. Besides, is the basis for cell cultures, buffers and reagents. As everything inside your lab, the water quality is one of the most important aspects making it the key factor to the success in your experiments. Tap water is not pure, but it turns out those five contaminants classes might represent a problem in you laboratory tasks: inorganic ions, organics, particulates/colloids, bacteria and gases. That is why it is important to have an appropriate purification technique so that water quality will not affect your research. Some of the most common purification techniques are distillation, ultrafiltration, photo-oxidation, reverse osmosis, and deionization.
Removes the widest spectrum of impurities. In this process, water is boiled and the steam passes to a condenser where it returns to the liquid state, free of impurity. The impurities are left behind in the boiler. To save water, the cooling water supply to the condenser is reused to feed the boiler with warmer water. Some models provide a second distillation process, to guaranteed water purity. From this water, it is possible to produce Type II or Type III quality water, but only 6% of the water used is produced as distilled water.
Is based on ultrafilters to remove particles and macromolecules. A pore size is around 0.01 micron. Models vary according to the nominal molecular weight limit. It operates similar to reverse osmosis membranes, and they are generally used in the last step of ultrapure systems. This system removes effectively colloids, enzymes, and microorganism with low energy consumption and maintenance. However, it does not remove dissolved inorganic or organic substance and gases. The membranes must be regularly replaced or sanitised to keep effectiveness.
Is based on the use of UV irradiation to kill microorganism and ionize organic molecules. The light is generated at two wavelengths, 185nm and 254nm. This process is generally used to produce Type I water. This method is ineffective at removing ions, particles and colloids and C02 is released and produces a decrease in resistivity.
Is a process in which two different solutions are prepared using the same solvent and are separated by a semi-permeable membrane, so molecules from the solvent pass through the membrane to the more dilute solution to equalize the concentration. Reverse osmosis purification system consists in applying pressure to the concentrated solution forcing to migrate in the opposite direction. The water passes through the membrane and the impurities are trapped in the membrane. This process is highly efficient at removing micro-organism, pyrogens, solids and colloids with lower energy consumption. However, the membranes are expensive to replace and are very fragile, and the pressure of water supply must be consistent (if not, the resulted water may not fit your standards)
Is also known as demineralization or ion exchange. This is a chemical process which removes ionic contamination. Water passes over an ion exchange resin so hydrogen and hydroxyl ions are released. It is important to periodically replace or regenerate the quality of the resin to guarantee the appropriate process due to the finite capacity of the resin. This process has low energy consumption, wastage of water and little maintenance. However, it is not effective in removing organic particles, bacteria or pyrogens.
In laboratories, there are two types of water to think about: ultra-pure and general purpose. General purpose water is obtained from the distillation, reverse osmosis or deionizer system. It is appropriate for routine laboratory procedures. Ultra-pure water is the product of combining different techniques and depends on the focus of the laboratory scientist, for example, for clinical analysis, molecular biology, chemical analysis. Study carefully the advantages or disadvantages of each system to decide on the appropriate one according to your needs. Kalstein offers several water systems according to your needs.
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