In order to improve the photocatalytic performance of g-C₃N₄, the g-C₃N₄/Ti₃C₂/Ag₃PO₄ S-type heterojunction catalyst was prepared by electrostatic assembly method, and then the g-C₃N₄/Ti₃C₂/Ag₃PO₄/PAN composite nanofiber membrane was prepared by electrospinning technology. The morphology and chemical properties of the nanofiber membrane were characterized by SEM, FTIR, and XRD, and the photocatalytic degradation of tetracycline hydrochloride (TC) in water by the nanofiber membrane was investigated. The results showed that g-C₃N₄/Ti₃C₂/Ag₃PO₄ could be successfully loaded on PAN and uniformly distributed on the surface of composite nanofiber membrane by electrospinning technology. Increasing the amount of loading and catalyst, lowering the pH value and TC concentration of the system were conducive to the oxidation and degradation of TC. The nano-fiber catalytic membrane had been recycled five times and found to have excellent photocatalytic stability and reusability. The study of catalytic mechanism showed that h⁺, •OH and •O₂⁻ were produced and participated in the oxidation degradation reaction of TC, and •O₂⁻ plays a major role in catalysis. Therefore, this work provides a new insight into the construction of high-performance and high-stability photocatalytic system by electrospinning technology.

Herein, poly (allylamine hydrochloride) (PAH)/ poly (styrene sulfonic acid) sodium salt (PSS) microcapsules of (PAH/PSS)₂PAH (P2P MCs) and (PAH/PSS)₂ (P2 MCs) were obtained by a layer-by-layer method. The P2 MCs show high adsorption capacity for Rhodamine B (642.26 mg/g) and methylene blue (909.25 mg/g), with an extremely low equilibrium adsorption time (~20 min). The P2P MCs exhibited high adsorption capacities of reactive orange K-G (ROKG) and direct yellow 5G (DY5G) which were 404.79 and 451.56 mg/g. Adsorption processes of all dyes onto microcapsules were best described by the Langmuir isotherm model and a pseudo-second-order kinetic model. In addition, the P2P MCs loaded with reactive dyes (P2P–ROKG), could further adsorb rhodamine B (RhB) dye, and P2 MCs that had adsorbed cationic MB dyes could also be used for secondary adsorption treatment of direct dye waste-water, respectively. The present work confirmed that P2P and P2 MCs were expected to become an excellent adsorbent in the water treatment industry.