Solar-driven integrated system: a synergistical solution of both water treatment and hydrogen source availability

Efficient treatment of oilfield wastewater, typically enriched in polyacrylamide, surfactant, and oil, remains a major impediment to sustainable oilfield operations. Conventional alkaline electrolysis systems for hydrogen generation are constrained by the sluggish oxygen evolution reaction (OER). Substituting the OER with a more thermodynamically and kinetically favorable oxidation process can substantially lower energy requirements. The intrinsic elevated alkalinity and organic content of oilfield wastewater make it an attractive candidate. Herein, an integrated strategy of solar driven oilfield wastewater treatment and hydrogen production is innovatively proposed to address the intersection of energy utilization, water management and hydrogen source availability. The concept feasibility of the solar-driven integrated oilfield produced water treatment-hydrogen production system is validated via thermodynamic calculations and experiments. Experimental data illustrate that the hydrogen produced by oilfield wastewater is more than the one by fresh water, especially by polymer flooding and alkali surfactant polymer flooding. The alkali surfactant polymer flooding system exhibits high Coulombic efficiency of 93 %, coupled with chemical oxygen demand removal rate of 65 % within 1 h. Furthermore, the conversion from solar to heat can markedly enhance the hydrogen production rate and Coulombic efficiency while lowering the required cell potential. The integrated system not only improves the overall efficiency of solar energy utilization but also transforms industrial waste into valuable energy resource, exemplifying a genuine “waste-to-value” paradigm. • Solar-thermal-electro system enables oilfield wastewater treatment and H 2 production. • Organic in oilfield wastewater act as alternative anodic reactions replacing traditional OER. • Coulombic efficiency of ASP flooding wastewater is 1.2 times that of fresh water. • H 2 production of the solar-driven system at 60 °C reaches 1.35 times that at 25 °C.