Pyrolyzed magnetic NiO/carbon-derived nanocomposite from a hierarchical nickel-based metal-organic framework with ultrahigh adsorption capacity

Abstract

Herein, a simple one-pot solvothermal approach is used to create magnetic porous carbon nanocomposites which obtained from a nickel-based metal-organic framework (Ni-MOF) and examined for their ability to uptake methyl orange (MO) dye. Derived carbons with exceptional porosity and magnetic properties were created during the different pyrolysis temperatures of Ni-MOF (700, 800, and 900 °C) under a nitrogen atmosphere. The black powders were given the names CDM-700, CDM-800, and CDM-900 after they were obtained. A variety of analysis methods, including FESEM, EDS, XRD, FTIR, VSM, and N2 adsorption-desorption were used to characterize as-prepared powders. Furthermore, adsorbent dosage, contact time, pH variation, and initial dye concentration effects was investigated. The maximum adsorption capacities were 307.38, 5976.35, 4992.39, and 2636.54 mg/g for Ni-MOF, CDM-700, CDM-800, and CDM-900, respectively, which show the ultrahigh capacity of the resulted nanocomposites compared to newest materials. The results showed that not only the crystallinity turned but also the specific surface area was increased about four times after pyrolyzing. The results showed that the maximum adsorption capacity of MO dye for CDM-700 was obtained at adsorbent dosage of 0.083 g/L, contact time of 60 min, feed pH of 3, and temperature of 45 °C. The Langmuir model has the best match and suggests the adsorption process as a single layer. According to the results of reaction kinetic studies using well-known models, the pseudo-second-order model (R2 = 0.9989) displayed high agreement with the experimental data. The synthesized nanocomposite is introduced as a promising superadsorbent for eliminating dyes from contaminated water due to strong recycling performance up to the fifth cycle.