Removal And Recovery Of Copper From Electroplating Rinse Water Via A Galvanic Cementation System

Loading...
Thumbnail Image
Date
2003-02
Authors
YEAN PHIN, HOR
Journal Title
Journal ISSN
Volume Title
Publisher
Abstract
A galvanic system for the removal of copper from aqueous solutions using a divided flow-through cell is proposed. The present study looks into the feasibility of removing copper from dilute electroplating rinse water and recovering it in metallic form by a galvanic cementation process. This process does not require an external supply of energy due to the spontaneous chemical reaction between the copper/iron couple. Therefore, this operation is attractive in reducing operating costs, especially when dealing with low ion concentrations and serves as an alternative to current wastewater treatments available. Two types of operating modes (single-pass and batchrecycle) have been investigated. Initially, the performance of the proposed single-pass system was evaluated as a function of cathode potential, catholyte flow rates, initial copper (II) concentration and types of electrode materials used. Results have shown that the galvanic flow system can remove copper effectively below the maximum permissible level from simulated copper (II) solutions. However, an outlet copper concentration below 1.0 mg L-I was not achieved with any condition when treating industrial wastewater. Therefore, another mode of operation of electrochemical reactor has been attempted to achieve higher efficiency of copper removal. The second part of this work describes a batch-recycle galvanic reactor that operates at flow rates ranging from 3.8 mL min-I to 500 mL min-I. A three-dimensional cathode, 80 ppi reticulated vitreous carbon, was used for this purpose. Mass transfer studies show that the average mass transfer coefficient was proportional to the Reynolds number, RJ, where f = 0.68. A comparison of the performance between a single-pass and a batch-recycle reactor was also conducted with an initial copper concentration of 10 mg L-I, 100 mg L-I and 500 mg L-I. A 500 mL feed of 74.2 mg L-I of copper in electroplating rinse water with a low conductivity of 1.2 mS cm-I was reduced to less than 1.0 mg L-I in 150 minutes with a batch-recycle reactor operating at a flow rate of 500 mL min-I. Additional work on the treatment of other copper plating baths showed satisfactory results especially with copper (II) fluoborate and copper (II) sulphate solutions. The capacity of the batch-recycle galvanic reactor was also detennined. Parametric studies of the copper deposition on reticulated vitreous carbon were made using the optical microscope. A Scanning Electron Microscopy (SEM) investigation was perfonned to study the microscopic features of the copper deposits and X-ray energy dispersive spectrometry (ED AX) analysis was executed to confinn the presence of copper recovered on the electrode.
Description
Keywords
Removal And Recovery Of Copper From Electroplating Rinse Water , Via A Galvanic Cementation System
Citation