The collaborative incentive effect in adsorption-photocatalysis: A special perspective on phosphorus recovery and reuse

Achieving efficient recovery and direct utilization of phosphorus as one of the important components of the green economy is a huge challenge. Herein, we innovatively constructed a coupling adsorption-photocatalytic (CAP) process using synthetic dual-functional Mg-modified carbon nitride (CN-MgO). The CAP could utilize the recovered phosphorus from wastewater to promote the in-situ degradation of refractory organic pollutants via CN-MgO, where its phosphorus adsorption capacity and photocatalytic activity were significantly and synergistically increased. It was specifically reflected in the high phosphorus adsorption capacity of CN-MgO (218 mg/g), which was 153.5 times that of carbon nitride (1.42 mg/g), and its theoretical maximum adsorption capacity could reach 332 mg P/g. Subsequently, the phosphorus-enriched sample (CN-MgO-P) was employed as a photocatalyst to remove tetracycline with a reaction rate (k = 0.07177 min-1) 2.33 times higher than that of carbon nitride (k = 0.0327 min-1). Notably, the coordinated incentive mechanism present in this CAP between adsorption and photocatalysis may be attributed to the more adsorption sites of CN-MgO and the facilitation of hydroxyl production through adsorbed phosphorus, which ensured the feasibility of creating environmental value from the phosphorus in wastewater by means of CAP. This study provides a new perspective on the recovery and reuse of phosphorus resources in wastewater and the integration of environmental technologies in multiple fields.