Effect of rise distance on droplets generated from bubble bursting on the surface of chromic acid solutions.
In the processes of chromium electroplating, bursting bubbles are the major sources of chromium droplets that may lead to nasal septum disorders among workers. The gas bubbles form as a result of electrochemical reactions on the surfaces of pieces being plated, rise through the liquid, and then burst into droplets at liquid surfaces. The dimensions of the pieces being plated differ from piece to piece, and therefore the rise distance of the bubbles varies. This study is aimed at evaluating the effect of rise distance on the characteristics of droplets generated from bubbles bursting on the surface of chromic acid solutions by an experimental bubbling system. Two rise distances, 15 and 30 cm, were tested. An aerodynamic particle sizer was used to determine the droplet size distribution over the range of 0.8-30 microm. A Marple personal impactor was employed to collect droplet samples on polyvinyl chloride filters for Cr(VI) analysis. It was found that the Cr(VI) concentrations in droplets increased when the bubble rise distance increased. The result suggests that soluble ions such as Cr(VI) are scavenged by rising bubbles.
Kuo
Yu-Mei
YM
Department of Industrial Safety and Hygiene, Chung Hwa College of Medical Technology, Jen-Te Hsiang, Tainan, Taiwan.
Wang
Chiu-Sen
CS
D000336:Aerosols; D002840:Chromates / Q000737:chemistry*; D004595:Electroplating / Q000379:methods*; D004781:Environmental Exposure / Q000517:prevention & control; D010316:Particle Size; D012996:Solutions; D013499:Surface Properties
D000336:Aerosols; D002840:Chromates; D012996:Solutions; C034944:chromic acid