Freshwater recovery through electroactive biocarbon membrane contactors

ARAOZ, MARÍA E.; TREJO GONZÁLEZ, JOSÉ A.; HERRERA, JUAN P.; AVILA, ADOLFO M.

Buenos Aires

Congreso; 11th World Congress of Chemical Engineering; 2023

World Chemical Engineering Council

Freshwater recovery from large pools of wastewater is required worldwide. Energy related extractive industries like shale gas/oil and lithium extraction require to deal with enormous amounts of water. Also, extensive agriculture needs to manage water storage and recycling for irrigation. Overall, these are waste waters containing contaminants derived from the extractive processes of metals, hydrocarbons, minerals as well as agriculture waste waters with organics and pesticides. Therefore, new products and approaches to recover freshwater for recycling are highly demanded. An innovative solution relies on the integration of biomass derived materials into an emerging separation concept like direct heating membrane distillation. In this work, we demonstrated that tube-shaped renewable carbons can work as electrothermal membrane contactors for freshwater recovery for highly concentrated saline solutions. The freshwater was extracted from brine by using tailor-made tubular carbon materials derived from biomass residues. In this case, the renewable carbon-based materials were prepared using sugar-cane harvest residues as the raw material. The biomass precursors in powder form are shown in Figure 1a. The biomass-based tubes were manufactured following the preparation method reported previously [1]. The resulting carbon-based tubes were 5.5 mm OD (Fig. 1b). The tubes have electrical properties and can be heated directly through Joule effect by applying electric potential between the ends. These tubes were investigated in new applications such as freshwater recovery through direct heat membrane distillation [1]. Figure 1c shows a scheme of the experimental setup. The tubes were tested using NaCl solution of 10 and 100 g/L producing fresh water at 7 kg/m2 h with a solute rejection higher than 99.4%. The carbon tubes are tolerant to corrosive and high salinity waters. The tubular geometry, easy scalability, and the advantage of using cost-effective biomass residues make these renewable membrane contactors relevant as separation agents for freshwater recovery from a variety of highly solute concentrated waste streams.