Preparation of MIL-101-NH2 MOF/triazine based covalent organic framework hybrid and its application in acid blue 9 removals

Abstract

Due to the increasing environmental pollution from the textile industry, synthesizing efficient adsorbents to remove coloring agents from waste streams is of practical interest and importance to chemists and material scientists. Metal-organic framework (MOF) and covalent organic framework (COF) are multidimensional, porous, and crystalline. Owing to their high BET surface area, they are both right choices for dye adsorption. A superior feature of COF materials compared to MOFs is their stability in organic solvents and acidic environments. Herein, considering the importance of the complete removal of acid blue 9 and economic aspects, a new hybrid of aminated chromium-based MOF and triazine-based COF (MIL-101-NH2@COF) was synthesized and used for the removal of the dye from textile wastewater. These materials were characterized by FT-IR spectra, PXRD, elemental analysis, and BET. Since the hybrid adsorbent had a mesoporous structure of a large surface area for nitrogen adsorption, it would be the right candidate for solving the coloring agent pollution problem. Some essential parameters, such as pH, contact time, temperature, and adsorbent dosage, were optimized. The optimum condition was pH = 2, absorbent dosage 0.01 g, contact time 90 min, and temperature 35 °C. The obtained maximum adsorption capacity was 256 mg g−1. The experimental results, in general, agree with those of the Langmuir model and the pseudo-second-order kinetics, suggesting that acid blue 9 was adsorbed to the hybrid adsorbent in monolayers due to its chemical affinity.