Coupled Adsorption and Electrochemical Process for Copper Recovery from Wastewater Using Grapefruit Peel

Abstract

The recovery of copper by-products from wastewater was achieved by carrying out an adsorption process coupled with an electrochemical system using modified grapefruit peels for metal recovery in a continuous flow. The adsorption capacity of grapefruit peels was 52.48 mg g−1, and it was possible to reuse it in repeated adsorption–desorption cycles (more than 17). The recovery of copper from the saturated adsorbent was possible by means of a two-step process: first, desorption was carried out using 0.1 M HCl, achieving 90% of Cu(II) eluted in a concentrated solution, and then, an electrolytic process was carried out, achieving up to 65% of metal recovery as electrolyzed copper with high purity. The adsorbent material and eluted solution could be reused. In a final step, the exhausted adsorbent was processed through thermal degradation; copper adhered to the material acted as a catalyst, which reduced the energy consumption and finally resulted in the formation of copper oxide with 54% weight for weight (w/w) copper purity.