Electroplating rinse waste water treatment by ion exchange

Abstract

Purification of copper containing waste waters from electroplating plants by means of different ion exchange units has been studied. The copper containing waste water with a range of copper concentration 55–60 mg/l, pH 3.3–3.5 has been treated of following schemes: (I) Weak base anion exchanger (OH-form) — weak acid cation exchanger (H-form) — strong base anion exchanger (OH-form); and (II) Modified with thiocarbamide strong acid cation exchanger — weak base anion exchanger (OH-form). It has been established that the breakthrough capacities of the tested weak acid cation exchangers (towards Cu 2+) are 1.40–1.80 eq/l and of the modified cation exchangers 1.45–1.90 eq/l. The concentration of Cu 2+ and SO 4 2− in the purified water is below 0.05 mg/l and the water can be reused. Twenty cycles of exhaustion with copper containing waste water-regeneration of tested ion exchangers were carried out. The total exchange capacities and the moisture content of non-used (new) and used ion exchangers were determined. The microscopically investigations and structural porosity studies have been also carried out. The data obtained show that the total capacities and the moisture content changes insignificantly.