Studies on kinetics and thermodynamics of biomachining pure copper

Abstract

The kinetics and thermodynamics of biomachining pure copper by Thiobacillus ferrooxidans were quantitatively analyzed. The kinetic effect of bacteria on the ion-cycle between Fe(2+) and Fe(3+) and the thermodynamic effect of hydrolysis on the changes of pH in biomachining processes were expounded through six series of experiment. Finally a model of ion-cycle in the biomachining processes was proposed, and the measures for maintaining the stable equilibrium of the ion-cycle were also discussed.

A study on copper micromachining using microorganisms

“…10 On the other hand, the number of Cu 2+ ions and hydrolysis naturally increased. 11 This situation would affect the activity and growth of the bacteria. The decreasing ferrous sulfate and increasing Cu 2+ and hydrolysis might cause the activity of the bacteria to reduce, thus affecting the MRR.…”

“…12 Acidithiobacillus ferrooxidans, formerly known as Thiobacillus ferrooxidans, was the species used in the preliminary biomachining work by some researchers. [1][2][3]5,11,12 In this study, A. ferrooxidans was also used. A scanning electron microscope (SEM) micrograph of a colony of these bacteria is shown in Fig.…”

Biomachining-a Review

“…The CuS was precipitated, and the Cu ions were removed from the solution. The results of Zhang and Li [10] also indicate that the rate of biomachining depends directly on bacterial concentration.…”

“…If H+ is not added at all times to adjust the pH to about 2, an increase in hydrolysis is observed, which ultimately decreases the growth of At. Ferrooxidans [10]. The necessary conditions for maintaining the stable equilibrium of the biomachining system are the supply of H+ and the removal of Cu2+.…”

Writing metal on SiO2 by laser through culture supernatant of Acidithiobacillus ferrooxidans 13820

“…Among these Acidithiobacillus ferrooxidans is endowed with a remarkably broad metabolic capacity. This species obtains its energy by the oxidation of reduced sulfur compounds and, in addition, is able to oxidize molecular hydrogen, formic acid, iron (II) ions and other metal ions [16,17].…”