Removal of trace quantities of nickel from solution

Chitosan, which is produced from the natural polymer chitin, is a much more efficient scavenger of nickel ion than other natural ion exchange materials tested. An industrial waste containing about 7 ppm Ni 2+ and 10,000 ppm Na + was reduced to less than 0.1 ppm Ni 2+ by contact in a packed column of chitosan. Capacity of the chitosan substrate under these conditions was a little more than 1 meq/g. The substrate can be regenerated by contact with buffered NH 4 Cl at pH 10. The high sodium content of the nickel waste did not prevent sorption of Ni 2+ , but it apparently produced an interference with atomic absorption spectrophotometer analyses, giving a spurious reading of 0.8 ppm Ni 2+ when the major nickel line at 232 nm was used for analysis.