Superior long service life of a porous Ti-foam/TiOxHy-NTs/SnO2-Sb anode for highly efficient degradation of the pretreatment polyacrylamide-containing fracturing flowback fluid

Abstract

Doped-SnO2 electrodes have shown outstanding performances in electrochemical oxidation (EO), but limitations in long service life and high durability have necessitated further advances in electrode design. Herein, this study proposes a porous Ti-foam/TiOxHy-NTs/SnO2-Sb anode with superior long service life for efficient degradation of polyacrylamide (PAM) - containing fracturing flowback fluid. The Ti-foam/TiOxHy-NTs/SnO2-Sb anode was designed by preferably choosing reduced TiO2 nanotube arrays grown in situ on porous Ti foam (Ti-foam/TiOxHy-NTs) as substrate coated with SnO2-Sb coating through the sol-gel method. The superiority of the design concept is verified by achieving a superior long service life of 735.2 h (0.5 M H2SO4) and 53.2 h (0.5 M HCl) at a current density of 1.0 A cm−2 by the tests of accelerated service life. The superior long service life originates from multidimensional and hierarchical architecture for lowering electrical resistance by shorting the transport path of electrolyte ions and electrons, and loading more active material without aggregation. Furthermore, the Ti-foam/TiOxHy-NTs/SnO2-Sb electrode displays excellent ability in efficiently degrading the real and simulated PAM-containing fracturing flowback fluid, achieving a chemical oxygen demand decomposition of above 90.0 % after 120 min of EO process. Therefore, the synthesized Ti-foam/TiOxHy-NTs/SnO2-Sb electrode exhibits great potential industrial application for efficient decomposition of PAM-containing fracturing flowback fluid using in EO process.