TREATMENT OF CHROMIUM PLATING RINSE WATER BY ION-EXCHANGE

Abstract

Waste rinse water from chromium plating process was treated with strong anion resin, Dowex 1. Column experiments were conducted with bed heights ranging from 15 to 35 cm, flowrates from 0.68 to 2.38 cm/sec and feed concentration from 0.1 to 1 g/l CrO3. Experimental results confirmed the dichromate exchange capacity of the resin. Data from the breakthrough curves indicated high degree of resin utilization. For feed concentration less than 0.3 g/l CrO3 and flowrate of about 1.36 cm/sec, a bed height of at least 30 cm can be used for practical application. For large scale application and for attainment of maximum concentration in the subsequent recovery of chromates upon regeneration, a bed height up to 60 cm is recommended. The fit of all the experimental breakthrough curves by the solution based on second order irreversible reaction was found to be very satisfactory. Thus preliminary design for industrial application can be facilitated by the use of simple equations.