Browsing by Author "TAN, H"

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CHROMIC-ACID RECOVERY FROM CHROME PLATING RINSE WATER BY ION-EXCHANGE
(1995-07-01)
TAN, H
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交大名義發表
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應用化學系
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National Chiao Tung University
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Department of Applied Chemistry
The regeneration of an anion bed saturated with dichromate ions by treatment with NaOH solution was studied in connection with the treatment of chrome plating rinse water by ion exchange. Column experiments were conducted to obtain an Cr(VI) elution curve and OH- breakthrough curve. The parametric effects of bed height, NaOH feed concentrations, and flow rate on the performance of regeneration were investigated. It was found that for a bed height of 70 cm and NaOH feed concentration of 1.5 to 2 mol/L with a flow rate of 100-150 mL/hr, up to a maximum concentration of 100 g/L of CrO3 could be obtained. Under the above operating conditions, the regenerant consumption is about 1.65 mole of OH- per mole of Cr(VI) recovered and the resin utilization is about 80%. An attempt is made to employ a simple analytic equation to correlate the OH- breakthrough and Cr(VI) elution data. The results of this work may be useful in the design and operation of systems for recovery and reuse of chromic acid by ion exchange in the chrome electroplating process.
TREATMENT OF CHROMIUM PLATING RINSE WATER BY ION-EXCHANGE
(1994-03-01)
TAN, H
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交大名義發表
;
應用化學系
;
National Chiao Tung University
;
Department of Applied Chemistry
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.