Electrochemical Removal of Copper and Lead from Industrial Wastewater: Mass Transport Enhancement

Abstract

The effects of ultrasonic frequencies on both the mass transport process and diffusion layer were investigated during electrochemical treatment. The rates of mass transfer at a stainless steel cathode were measured for copper and lead in dilute acidified copper sulphate and lead nitrate solutions at different ultrasonic frequencies. Concentrations in bulk solution were determined by atomic absorption spectrophotometer. By increasing frequencies from 40 to 100 kHz, a high value for the mass transfer coefficient and an effective thinning of the diffusion layer were observed. Higher rates of mass transfer reduced energy consumption. Use of ultrasound with electrochemical processes can provide valuable contributions to remove metallic ions from industrial wastewater without using extra chemicals. The process has efficiently reduced the cost of energy consumption and deposition time.

Sonoelectrochemistry in Environmental Applications

“…Unfortunately, the specific values of the ultrasonic power or the cathodic material have not always been reported for all experiments. The results of various studies [52][53][54] dealing with copper removal conclude that an improvement in the deposition rate is observed with an ultrasonically agitated bath. Farooq et al [53] used electrodeposition and ultrasound at 35 kHz to remove copper in wastewater.…”

“…It is in diluted solutions that concentration polarization is high and the application of ultrasound is particularly beneficial. The effects of ultrasonic [54] frequency on both the mass transport process and the diffusion layer were also investigated during electrochemical deposition. By increasing frequencies from 40 to 100 kHz, a high value for the mass transport coefficient was observed.…”

“…The removal of zinc [52] and lead [54] from industrial wastewater has also been studied. There are no significant differences in conclusion: ultrasound was found to have a significant effect on metal recovery under diffusion control, while little, if any, effect was observed on systems in which the deposition was under charge-transfer control.…”

Electrodeposition of copper from a copper sulfate solution using a packed-bed continuous-recirculation flow reactor at high applied electric current

“…Researchers with various cell designs have attempted removal of copper from solutions with varying degrees of achievements and improvements [5][6][7][8][9][10][11][12][13][14][15][16][17][18]. All of these researches were done keeping either the applied potential or the applied current constant during an experimental run and none of them used sodium chloride as supporting electrolyte.…”

“…Basha et al [1] studied the electrodeposition of copper at different initial pH values but they did not follow how the pH changed during electrolysis. Yaqub et al [11] investigated the electrolytic removal of Cu and Pb at different pH conditions and reported that the optimum pH range was 3-3.5 in the presence of ultrasound enhancement.…”