Zeolitic Imidazolate Framework‑8 for Fast Adsorption and Removal of Benzotriazoles from Aqueous Solution

• Published in: ACS applied materials & interfaces Vol. 5; no. 19; pp. 9837 - 9842
• Main Authors: Jiang, Jun-Qing, Yang, Cheng-Xiong, Yan, Xiu-Ping
• Format: Journal Article
• Language: English
• Published: United States American Chemical Society 09.10.2013
• Subjects: adsorbents; Adsorption; aqueous solutions; aromatic compounds; carbon; Charcoal - chemistry; desorption; endothermy; entropy; Imidazoles - chemistry; ionic strength; ions; Kinetics; Nitrogen - chemistry; organic matter; pollutants; sorption isotherms; Triazoles - chemistry; Triazoles - toxicity; Water - chemistry; Water Pollutants, Chemical - chemistry; Water Pollutants, Chemical - toxicity; Water Purification; zinc; adsorption; water treatment; ZIF-8; benzotriazoles; metal−organic frameworks
• ISSN: 1944-8244; 1944-8252; 1944-8252
• DOI: 10.1021/am403079n

1H-benzotriazole (BTri) and 5-tolyltriazole (5-TTri) are emerging pollutants; the development of novel materials for their efficient adsorption and removal is thus of great significance in environmental sciences. Here, we report the application of zeolitic imidazolate framework-8 (ZIF-8) as a novel adsorbent for fast removal of BTri and 5-TTri in aqueous solution in view of adsorption isotherms, kinetics and thermodynamics, desorption, and adsorbent regeneration. The adsorption of BTri and 5-TTri on ZIF-8 was very fast, and most of BTri and 5-TTri were adsorbed in the first 2 min. The adsorption for BTri and 5-TTri follows a pseudo-second-order kinetics and fits the Langmuir adsorption model with the adsorption capacity of 298.5 and 396.8 mg g–1 for BTri and 5-TTri at 30 °C, respectively. The adsorption was a spontaneous and endothermic process controlled by positive entropy change. No remarkable effects of pH, ionic strength, and dissolved organic matter on the adsorption of BTri and 5-TTri on ZIF-8 were observed. The used ZIF-8 could be regenerated effectively and recycled at least three times without significant loss of adsorption capacity. In addition, ZIF-8 provided much larger adsorption capacity and faster adsorption kinetics than activated carbon and ZIF-7. The hydrophobic and π–π interaction between the aromatic rings of the BTri and 5-TTri and the aromatic imizole rings of the ZIF-8, and the coordination of the nitrogen atoms in BTri and 5-TTri molecules to the Zn2+ ions in the ZIF-8 framework was responsible for the efficient adsorption. The fast adsorption kinetics, large adsorption capacity, excellent reusability as well as the pH, ionic strength, and dissolved organic matter insensitive adsorption create potential for ZIF-8 to be effective at removing benzotriazoles from aqueous solution.