Synthesis of magnetic metal-organic framework nanocomposite (ZIF-8@SiO2@MnFe2O4) as a novel adsorbent for selective dye removal from multicomponent systems

Herein, magnetic metal-organic framework nanocomposite (ZIF-8@SiO2@MnFe2O4) was synthesized. The ultrasound-assisted simultaneous adsorption of Malachite Green (MG) and Methyl Orange (MO) as cationic and anionic dyes onto ZIF-8@SiO2@MnFe2O4 magnetic microporous nanocomposite (MMNC) as a novel adsorbent was investigated. The FTIR, FESEM, TEM, XRD, BET and VSM were used to characterize the prepared adsorbent. The analysis of dyes concentration in a binary mixture was investigated using zero-order and first order derivative spectrophotometry. The individual effects and possible interactions between the various parameters were investigated by response surface methodology (RSM). The optimized values of sonication time, adsorbent mass, MG and MO concentrations were found to be 15 min, 0.005 g, 13 and 10 mg L−1, respectively. The removal percentages for MG and MO were predicted to be 92.5% and 5.9%, respectively. The data matched well with pseudo-second order kinetic model and Langmuir isotherm models. The maximum adsorption capacities were obtained 1010.2 and 78.12 mg g−1 for MG and MO dyes, respectively. Moreover, the magnetic nanocomposite showed that it could selectively adsorbed cationic MG dye from the MG/MO mixture. After reaction, the magnetic adsorbent can be easily separated from the mixture via an external magnetic field and can be effectively regenerated.