Recent advances and future applications in electro-adsorption technology: An updated review

Electrochemistry aimed at improving the adsorptive capacity of materials has been studied and applied in several industrial fields, such as protein purification, electrocatalysts synthesis, effluent treatment, antibiotic removal and degradation, heavy metals, and waste by-products. Electro-adsorption stands out as an alternative technology to the conventional adsorptive method due to the production of increasingly complex electrodes with better surface properties, porosity, electronic affinity, selectivity, and the ability to perform electrochemical reactions. Other electrochemical processes such as electro-oxidation, electrocoagulation, and electrospinning can be introduced in a concurrent, consequential, or sequential manner for a large-scale process to improve electro-adsorption. The approach allows a lower energy impact during the process by increasing the adsorbent regenerative capacity and increasing the application's stability and cycle number. Most studies present an intrinsic relationship between the working variables with an improvement in the electrochemical adsorption efficiency. The main variables are voltage, current density, pH, and ion concentration in solution. They can be analyzed separately. However, their associated study is more significant in the search for complete answers. In this way, the review presents the main studies, applications, and trends, between 2015 and 2021 regarding electro-adsorption as a technique that aims to replace or improve conventional methods of adsorption, removal, or degradation of compounds.