Purification of effluent contg heavy metals - by electrochemical displacement with a more electro positive metal

摘要

Industrial effluent is treated by removal of heavy metal (A) ions by chemical displacement with a more electropositive cheaper metal (B) e.g. Fe, Al in a bed of metal particles where ions of (B) exchange with (A) which deposits on the particles. Effluent specif. contains chromium (VI), cyanides, nitrates, lead. The deposits are released by abrasion between particles produced by air fluidisation in presence of sand. When (B) is Al or Zn in the surface is activated by acids or based. When (B) is Fe an oxidiser may be added. The reaction zone contains anode and cathode at a potential difference. The heavy metals are pptd. an easily recoverable deposits on (B).