Enhancing the performance of modified ZnAl LDH as hybrid catalyst-adsorbent on tetracycline removal under solar light irradiation

Abstract

The ZnAl Layer Double Hydroxides-based material was modified to enhance its performance in removing Tetracycline in waters. It was calcined at 500 °C to form ZnAl Layer Double Oxides. The restacking-delaminating method is used to intercalate the Clitoria ternatea flower extract into the two catalysts interlayer, resulting in two modified catalysts. These modified catalysts exhibit FT-IR spectra that show a combination of the catalyst and Clitoria ternatea flower extract. ZnAl Layer Double Oxides, which lost the water molecules and interlayer anions, only demonstrated metal oxide vibration peaks in the FT-IR spectra. The XRD patterns of ZnAl Layer Double Hydroxides and ZnAl Layer Double Oxide, respectively, resemble the XRD pattern of standard materials. The reconstructed ZnAl Layer Double Oxide forms ZnAl Layer Double Oxide-Clitoria ternatea flower extract with a layered structure (the diffractogram peak at 2θ 10–11° reappears). ZnAl Layer Double Hydroxides-Clitoria ternatea flower extract could efficiently capture light in the ultraviolet (UV) and visible regions, as indicated by its energy bandgap value of 2.39. The synthesized material was employed in a batch system as a photocatalyst for the Tetracycline degradation. With a 92.25 % Tetracycline removal percentage, ZnAl Layer Double Oxide exhibited the most excellent performance in its capacity as a hybrid catalyst-adsorbent material. After the fifth regeneration, ZnAl Layer Double Hydroxides-Clitoria ternatea flower extract exhibited catalytic performance to degrade Tetracycline entirely in 90 min.