Heavy Metal Ion Removal and Wastewater Treatment by Combined Magnetic Particle and 3-D Electrochemical Technology

Abstract

Abstract : A cost effective method was proposed for the removal of heavy metal ions from small plating operations. Beltran developed a combined technique that includes 3-D (three-dimensional) electrochemical technology (ET) and electrochemical coagulation (EC), as a result of which iron hydroxide with a reproduced structure of magnetite is generated. Theoretical and experimental investigations performed in Phase I showed the feasibility of purification of wastewaters from Cr, Ni, and Cd by means of 3-D electrolysis with a cathode of carbon felt and with current density equal to 4-8 mA/sq cm. The possibility of applying the EC method for purification of electroplating rinse waters was proved experimentally. It was determined that Cd, Ni, and Cr removal to maximum permissible concentrations (MPC) occurs with a pH of 2-9, current density of 0.5-0.7 A/sq dm. The result of a complex of electrochemical investigations that we conducted was to allow anodic reaction speed to be controlled during water purification by the EC method. It was determined that the EC process must be provided with current density of 0.1-1.0 A/sq dm. A concentration of 4-5 moles/sq m of chlorine ions is enough for active iron dissolution in waters of the given composition (current efficiency is equal to 98.5-99.4%).