3D NiCo-LDH hollow nanocages for rapid and efficient removal of tetracycline hydrochloride from water

Abstract

Tetracycline hydrochloride (TC) water pollution poses a serious threat to human health. Preparation of a high-efficiency TC treatment agent is one of the key tasks in TC wastewater treatment. The present work innovatively designed and successfully prepared a three-dimensional layered double hydroxide nanocage (H-NiCo-LDH) to efficiently remove TC through synergistic adsorption and non-photocatalytic degradation. The nanocage structure, derived from Co-ZIF through the Kirkendall effect, featured ultrathin nanosheets with a high specific surface area of 659 m² g⁻¹ and abundant oxygen vacancies (Ovs). The material showed excellent TC removal performance in a wide pH (5–11) and temperature (5–45 °C) range, and the removal rate of 20 mg L⁻¹ of TC reached 99.6% in 5 min. In addition, the maximum removal amount reached 630 mg g⁻¹, which was higher than that of most reported LDHs. The removal mechanism was confirmed to be the combined effect of adsorption and ¹O₂ driven degradation. Remarkably, the degradation pathway, independent of light, relied on Ov-mediated dissolved oxygen. Liquid chromatography-mass spectrometry (LC-MS) gave the primary intermediates of TC degradation, and toxicity assessment showed that the degradation process decreased the environmental risks of TC. The work provides a paradigm for designing self-sustaining catalysts for antibiotic removal in complex aquatic environments.