Direct-Air-Capture Technique of Cellulose for Mineralizing Pb2+ from Wastewater: Synchronous Accomplishment of CO2 Capture and Water Treatment

Lead pollution has caused serious environmental concerns because of its wide range of applications. How to remove and recover lead via a low-cost and green approach has posed great challenges. In this work, Pb²⁺ has been recovered via a direct-air-capture technique. Bioresource cellulose was used as a substrate to enrich superlow-concentration CO₂ from air and immobilize the resultant Pb²⁺ salts. Being simply operated at modest conditions, PbCO₃ and Pb₃(CO₃)₂(OH)₂ have been identified and immobilized onto cellulose. Their intimate interfacial interaction, as supported by X-ray diffraction, scanning electron microscopy, and Fourier transform infrared, makes the recovery and storage feasible, rapid, and complete. Entire elimination of Pb²⁺ from water is achieved with an adsorption capacity of 320 mg·g^–1. Simultaneously, CO₂ capture capacity gets to 54.5 mg_CO2·g^–1. Thus, two wastes, Pb²⁺-containing effluent and CO₂, are exploited for resource conservation and recycling. Our treatment strategy also helps to decrease/remedy environmental pollution and benefits carbon negativity.