Abstract
A. Seaweed.—By means of a three‐compartment cell with ceramic diaphragms, suspensions of dried ground Laminaria cloustoni stipe were electrodialysed to remove inorganic material. The total‐ash content of the seaweed was reduced from 33.4 to 7.4% in 30 minutes, representing a removal of 78% of the ash. Tests were also made on dried, ground frond, and a much smaller removal was effected. The total‐ash content was reduced from 28 to 22.8% in 30 minutes, representing a removal of about 18% of the ash. Duplicate tests were made to determine the amount of alkali and chlorine recovered and the energy required. The following figures were obtained (per Ib. of dry seaweed): alkali recovered, 0.053 Ib.; chlorine recovered (estimated), 0.056 Ib.; energy required, 3.03 kw.
B. Fish albumen.—A three‐compartment cell, with diaphragms of cellulosic material, was used for tests to reduce the ash content of fish albumen. It was found possible to reduce the ash content from 7.7 to 4.0% in 90 minutes, representing a removal of 52.3% of the inorganic material.
The fact that not all the inorganic material is removed in either A or B is tentatively attributed to the presence of a certain proportion of it in an insoluble form such as calcium alginate in seaweed and calcium citrate in fish albumen. Electrodialysis of calcium alginate and calcium citrate gave results which supported this view.