Removal of Methyl Orange from Aqueous Solution Using Zeolitic Imidazolate Framework-11: Adsorption Isotherms, Kinetics and Error Analysis

Dyes, which are increasingly harmful to human health and ecology, are an environmental concern and their removal from wastewater is extremely required. It is also important for researchers to find relevant techniques to process these types of pollutants. This study examines the use of the synthesized imidazolate zeolite frameworks-11 (ZIF-11) by stirring method for the Methyl Orange (MO) dye removal from an aqueous solution. Scanning electron microscopy, thermogravimetry, X-ray diffraction, and Fourier transform infrared spectroscopy, were used for the analysis of ZIF-11 particles, which exhibited highly porous, irregular, and heterogeneous shapes and variable sizes. The MO removal was assessed by batch adsorption with ZIF-11 particles as adsorbent, whose efficiency was achieved at pH=8, stirring speed of 600 rpm, for a contact time of 40min, and a dosage of 800mg/L of MO solution. The thermodynamic and kinetic analysis of the MO adsorption process was achieved successfully with the pseudo-second-order kinetic model as well as Langmuir and Temkin isotherms, indicating the feasibility and spontaneity of the uniform distribution of MO molecules on the active sites of ZIF-11 particles. The calculated maximum adsorption capacity of MO on ZIF-11 particles was 178.57 mg/g, which is indicative of the potential adsorptive properties of the synthesized ZIF-11 for MO dyes.