Solution systems model dissolution application

An additional study on the same system has been reported, including a comparison of direct electrochemical and conventional chemical dissolution of metallic copper in TMTD solutions in various solvents under conditions of simultaneous ultrasonic treatment of the reaction system [133,620]. It has been shown that the system TMTD-copper-solvent could serve as a perfect model to study the influence of simultaneous application of ultrasonic treatment (see Sec. 3.5) on the syntheses of complexes of the transition metals in different nonaqueous solutions, by using and testing several techniques [620]. Several other studies on the interaction of copper and iron species with thiruam sulfides have also been reviewed [621]. 

The application of equilibrium speciation models in aquatic systems works best when the oxidation state remains relatively constant and when complexes formed from solution or absorption are reversible (Tipping et al., 1998). For example, the application of such models to changing oxidation states, dissolution and/or formation of oxide precipitates, or formation of organometallic complexes will not prove useful because many of these... 

White, A. F., and Claassen, H. C. Dissolution kinetics of silicate rocks, application to solute modeling, JjL Jenne, E.A., ed., Chemical Modeling—Speciation, Sorption, Solubility, and Kinetics in Aqueous Systems, Am. Chem. Soc., 1978 (this volume). 

Macpherson and Unwin (43) developed the theory for dissolution processes at the substrate induced by depleting of electroactive species at the SECM tip. The UME tip can oxidize or reduce the species of interest in solution at the crystal surface. If this species is one of the crystal components, the depletion of its concentration in the solution gap between the tip and substrate induces crystal dissolution. This process produces additional flux of electroactive species to the tip similarly to positive feedback situation discussed in previous sections. Unlike the desorption reaction, where only a small amount of adsorbed species can contribute to the tip current, the dissolution of a macroscopic crystal is not limited by surface diffusion. Accordingly, the developed theory is somewhat similar to that for finite heterogeneous kinetics at the substrate. Several models developed in Ref. 43a-d use different forms of the dissolution rate law applicable to different experimental systems. In general, the rate of the substrate process is (43a) ... 

---