Lanthanum ions decorated 2-dimensional g-C3N4 for ciprofloxacin photodegradation

• Published in: Chemosphere (Oxford) 2021-04, Vol.268, p.128780-128780, Article 128780
• Main Authors: Kuila, Saikat Kumar, Gorai, Deepak Kumar, Gupta, Bramha, Gupta, Ashok Kumar, Tiwary, Chandra Sekhar, Kundu, Tarun Kumar
• Format: Article
• Language: English
• Subjects: Chemisorption; Ciprofloxacin; Defect engineering; Density functional theory; Scavengers; UV photodegradation
• ISSN: 0045-6535; 1879-1298
• DOI: 10.1016/j.chemosphere.2020.128780

The low band gap energy and high surface area two-dimensional materials allow it to tune its basic properties using surface decoration. Here, La3+ are decorated on two-dimensional graphitic carbon nitride using a simple and easily scalable chemisorption process with an adsorption capacity of 657.32 mg g−1. In the X-ray diffraction (XRD) study, the positive slope of the W–H plot elucidates the tensile strain generation (0.103) in La3+ ions decorated 2D-g-C3N4 (La3+-2D-g-C3N4). The high-resolution transmission electron microscope (HR-TEM) study and the higher ID/IG ratio (0.82) in the Raman spectroscopy study confirm the more defects intensification in La3+-2D-g-C3N4. The reduction in band gap energy for La3+-2D-g-C3N4 (from 2.83 eV to 2.21 eV) has shown a good correspondence with the band structures study as obtained from the DFT study. In the DFT study, the significant contributions of N atoms in charge transfer validate the N 1s findings from the X-ray photoelectron spectroscopy (XPS) study for La3+-2D-g-C3N4. La3+-2D-g-C3N4 shows the photodegradation efficiency (93%) of ciprofloxacin under UV irradiation, which is superior to pristine 2D-g-C3N4 (82%) as well as other g-C3N4 based nanocatalysts. Also, La3+ decoration results in enhancement (32.3%) in photodegradation kinetics rate. The degradation and kinetics studies in the presence of different scavengers ensure that the O2ˉ and OH− radicals are mostly responsible for the ciprofloxacin photodegradation. The Liquid chromatographic-mass spectroscopy and the high-performance liquid chromatography studies confirm the photodegradation. The reusability of La3+-2D-g-C3N4 is tested up to the fifth cycle. FTIR and UV–visible absorption spectroscopy confirm the stability of the used photocatalyst. [Display omitted] •Spectroscopic and microscopic studies assure the defects in La3+-2D-g-C3N4.•Band gap energy and N 1s findings have good correspondence with DFT study.•Optoelectronics properties (from the DFT study) predict the photocatalytic effects.•˙OH and ˙O2ˉ are the key radicals as confirmed from the scavengers’ kinetics study.•HPLC and LC-MS studies validate the UV-photodegradation (93%) of ciprofloxacin.