Production of a carbonaceous sorbent from the CO2 pyrolysis of hydraulic fracturing flowback and produced water solids

Abstract

Hydraulic fracturing produces wastewater, referred to as flowback and produced water, which can be saline or brackish, and contain residual additives (e.g.: friction reducers, biocides) and chemicals from the formation water (brines) that may pose risks to the environment, if not properly managed and handled according to existing regulations. Here, we created a pyrolyzed product from flowback water and characterize the resulting material for the purpose of using it for contaminant sorption. The produced pyrolyzed flowback water solids were compositionally comparable to biochar and activated carbon samples, had a high pH value (9.6), surface area (92 m2/g), and sorption capacity (120 mg/g methylene blue), and showed relatively low concentrations of most metals and metalloids as compared to other charcoal materials. The new material was shown to perform better than activated carbon and biochar to remove metals from flowback water, demonstrating its potential use in flowback water treatment operations.