Formation of iron (III) trimesate xerogel by ultrasonic irradiation

Fe-BTC materials have attracted vast attention owing to their high chemical stability, adaptable synthesis, and potential applications. Herein, we describe, for the first time, the preparation of iron trimesate gels by ultrasonic (US) irradiation of an aqueous solution of Iron (III) nitrate and trimesic acid. Two different procedures were used: (1) sonication for 10 or 20 minutes, (2) 3 minutes sonication under controlled pH (pH 3-5). After drying, stable Fe-BTC xerogels were obtained from both procedures. The xerogels consisted of interconnected spherical nanoparticles with similar microstructure when analyzed by FT-IR and PXRD and similar thermal behavior under oxygen in the range of 25-900°C. When analyzed by Nitrogen adsorption-desorption at 77K, all samples showed a permanent porosity with a narrow micropore distribution below 10 Å. Different textural properties were found among samples obtained with the same procedure. The product of 10 minutes sonication had a specific surface area (SSA) of 1042 m2/g.