# Divalent Metal Ion Depletion from Wastewater by RVC Cathodes: A Critical Review

## TL;DR

This paper reviews the use of RVC cathodes for removing harmful metal ions from wastewater and proposes a general equation to describe the process.

## Contribution

A general dimensionless equation (Sh = f(Re)) is derived to describe the electrochemical depletion of divalent metal ions using RVC cathodes.

## Key findings

- A dimensionless equation (Sh = f(Re)) was derived to describe the electrochemical depletion process for various divalent ions.
- A log(Sh) vs. log(Re) map was created, showing a strong correlation among all the analyzed systems.
- The study aims to revive interest in RVC cathodes for metal recovery and water treatment applications.

## Abstract

In this paper, a critical review of results obtained using a reticulated vitreous carbon (RVC) three-dimensional cathode for the electrochemical depletion of various divalent ions, such as Cu+2, Cd+2, Pb+2, Zn+2, Ni+2, and Co+2, often present in wastewater, has been carried out. By analyzing the kinetics and fluid dynamics of the process found in literature, a general dimensionless equation, Sh = f(Re), has been determined, describing a general trend for all the analyzed systems regardless of the geometry, dimensions, and starting conditions. Thus, a map in the log(Sh) vs. log(Re) plane has been reported by characterizing the whole ion electrochemical depletion process and highlighting the existence of a good correlation among all the results. Moreover, because in recent years, the interest in using this three-dimensional cathode material seems to have slowed, the intent is to revive it as a useful tool for metal recovery, recycling processes, and water treatments.