Word: resins
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...simple process for taking the salts out of sea water, for the recovery of valuable metals dissolved in mine wastes, until recently seemed too good to be true. But such jobs have now been done in the laboratory with cheap synthetic resin (i.e., a "plastic") which can be recovered, used over & over. These "Amberlite" resins are now made in quantity by Resinous Products & Chemical Co. of Philadelphia under patents owned by the British Government. Not for years have chemists seen such a big new field of research opened. They have huge potential uses. Examples...
...process was born in 1935 when Basil Albert Adams and Eric Leighton Holmes of the British Department of Scientific & Industrial Research (which has no counterpart in the U.S.) prepared L, phenol-formaldehyde resin which was more useful for its chemical properties than as a plastic. When immersed in "hard" water, which contains salts of calcium, it entered an exchange: it took calcium atoms from the water, replaced them with sodium, thus softened the water...
This was not new, for natural "green-sands" and artificial zeolites have long been used for such softening. But a slightly more complex resin of the same type proved able to draw even sodium atoms out of solution, replace them with hydrogen. This merely substituted acid for salt, but still another resin, made with amines instead of phenol, extracted the acid intact, leaving pure water. Both resins were gradually used up but could be revived by reverse treatment with stronger solutions...
...salts can thus be taken out of any water solution. When the dissolved salts are small in amount, the process is cheaper than distillation. For strong solutions, such as sea water, distillation is cheaper, but the resins can be used where stills and heat for distillation are impossible. When valuable materials are thus taken out of water solution, they can be recovered by washing the resin...
Making It Stick. Wood veneer (plywood) planes are 25 years old. The first rickety-looking planes were flown in World War I-but mould and temperature changes ate away the casein (milk base) glues which held their veneers together. Not until the plastics industry evolved a phenolic resin glue with a permanent grip were strong wood airplanes possible...