Facile synthesis of MgAl-LDH/g-C3N4 composites for the photocatalytic degradation toward ciprofloxacin

2D/2D MgAl-LDH/g-C3N4 composites were synthesized via electrostatic self-assembly method in aqueous solution. The MgAl-LDH nanosheets were uniformly anchored on the surface of g-C3N4 nanosheets, which constructed a MgAl-LDH/g-C3N4 heterojunction, thus facilitated the separation and transport of photogenerated electron and hole pairs and improved the photocatalytic degradation performance. The photocatalytic activity of the MgAl-LDH/g-C3N4 composites strengthened with the increasing of MgAl-LDH content, reached the optimum for the sample 30 %MACN (containing 30 wt% of MgAl-LDH), and then gradually decreased. Under the visible light irradiation for 150 min, 30 %MACN composite degraded 80.1 % of ciprofloxacin (CIP), and its first-order reaction rate constant was 2.04 times that of pure g-C3N4 nanosheets. Additionally, the effects of the catalyst dosage, pH value and the initial concentration of CIP on the degradation efficiency of CIP were investigated. Moreover, 30 %MACN exhibited outstanding stability and recyclability, as well as good universality for degrading organic pollutants, including norfloxacin, methylene blue, tetracycline and crystal violet. The degradation pathway and the mechanism of CIP were proposed. This work provided a feasible green way to synthesis MgAl-LDH/g-C3N4 composite photocatalyst with high performance for removing pollutants in wastewater.