Decoration of mesoporous hydroxyapatite nanorods by CdSe and PtO nanoparticles for enhanced photocatalytic oxidation of antibiotic pollutant in water

Background

A large variety of antibiotic pollutants in water sources has been detected being a worldwide concern. The photocatalytic process is promising to degrade the organic compound under illumination in the presence of semiconductor photocatalysts

Method

Design and synthesis of innovative of mesoporous hydroxyapatite (HAP) nanorods with a high surface area was achieved through the dual surfactant-assisted sol-gel approach. Then, HAP nanorods were decorated by CdSe and PtO nanocrystals as active visible-photocatalyst to degrade Ciprofloxacin (CPF) as a pollutant model

Significant Findings

The novel photocatalyst exhibited an absorption edge at 712 nm with estimated bandgap energy of 1.77 eV The PtOCdSe/HAP nanocomposite highly improved the photocatalytic ability towards degradation CPF by suppressing the recombination of electrons and holes and boosting the absorption in wide visible spectra. The photocatalytic ability of optimal PtOCdSe/HAP photocatalyst demonstrated a maximum degradation of 100 % after 30 min of illumination time, much larger than those of CdSe (44 %) and CdSe/HAP (82 %). The PtOCdSe/HAP photocatalyst showed an enhanced rate constant of 0.0359 min^–1 which is larger 4.488 and 1.768 times compared to pure CdSe (0.008 min^–1) and CdSe/HAP (0.0203 min^–1). This enhanced photocatalytic ability of PtOCdSe/HAP nanocomposite is interpreted by the synergetic effect between PtO and CdSe, large surface area with pores structure and efficient charge separation of the photocharge carriers. The reused nanocomposite showed a slight reduction in the photocatalytic ability (98.5 %) within five consecutive cycles, demonstrating its quite stability. This work opens the gate for the design of HAP-based photocatalysts for antibiotic removal under solar energy.