Cold-cathode X-ray irradiation pre-treatment for fouling control of reverse osmosis (RO) in shale gas produced water (SGPW) treatment

•Cold-cathode X-ray irradiation was newly applied to control fouling prior to RO process in SGPW treatment.•The feasibility of this novel X-ray technology was improved by developing CNT film emitter.•Its advantages include better energy efficiency, less heat generation, and easy dose control.•Aliphatic hydrocarbon (oil) caused severe fouling in the RO process during SGPW treatment.•New X-ray irradiation effectively reduced fouling with a low dose and energy consumption.