Nitrate removal from aqueous solutions by cobalt ferrite nanoparticles synthesized by co-precipitation method: isotherm, kinetic and thermodynamic studies

Abstract

The purpose of this study was to examine the nitrate adsorption by cobalt ferrite (CFO) nanoparticles. The adsorbent was synthesized by co-precipitation method and its structure was characterized using Scanning Electron Microscopy (SEM), Transmission Electron Microscopy (TEM), Fourier Transform Infrared Spectroscopy (FTIR), X-ray diffraction (XRD) and Vibrating-Sample Magnetometer (VSM). In batch adsorption studies, the effects of various parameters like pH (3–11), adsorbent dose (0.2–0.8 g/L), contact time (5–120 min), initial nitrate concentration (50–200 mg/L), and temperature (283–313 K) on the adsorption process were examined. The results of this study indicated that the maximum adsorption capacity was 107.8 mg/g (optimum condition pH = 3, adsorbent dosage: 0.2 g/L, nitrate concentration: 200 mg/L, contact time: 20 min and temperature 313 K). The adsorption isotherm had a proper match with Langmuir (R2 = 0.99) and Freundlich (R2 = 0.99) models. The adsorption of nitrate by CFO has followed pseudo second-order kinetics. The results of the thermodynamics of the nitrate adsorption process by CFO showed that all the values of ΔG, ΔH and ΔS were positive. Therefore, this process was endothermic and non-spontaneous.

Nitrate Uptake from Water Using Amine‐Functionalized Meso‐ and Macroporous Carbons

“…here, K (L ⋅ mg −1 ) is the equilibrium constant for NO 3 − uptake and q max (mg ⋅ g −1 ) is the maximum NO 3 − uptake capacity. The adsorption between the adsorbent surface and NO 3 − has been reasonably interpreted based on the Langmuir isotherm [25,26,28,30,32,33,35,36,38,39,43,45,51] . Table 3 lists the parameters determined using the Langmuir isotherm model.…”

“…The adsorption between the adsorbent surface and NO 3 À has been reasonably interpreted based on the Langmuir isotherm. [25,26,28,30,32,33,35,36,38,39,43,45,51] Table 3 lists the parameters determined using the Langmuir isotherm model. The isotherms indicate that (i) the NO 3 À uptake capacity depends on the specific surface area, and (ii) the surface modification results in an obvious increase in the NO 3 À uptake capacity.…”

“…Until now, various adsorbents have been applied for aqueous NO 3 − removal. For example, as cited above, carbonaceous materials, [25,26,33,35–39] clays and minerals, [28,29,31,40] nano‐sized metal oxides, [32,43] layered double hydroxides, [42] and chitosan [30,44] have been examined as candidate NO 3 − adsorbents.…”

“…Until now, various adsorbents have been applied for aqueous NO 3 À removal. For example, as cited above, carbonaceous materials, [25,26,33,[35][36][37][38][39] clays and minerals, [28,29,31,40] nano-sized metal oxides, [32,43] layered double hydroxides, [42] and chitosan [30,44] have been examined as candidate NO 3 À adsorbents. Among the adsorbents introduced above, carbonaceous materials have been studied because they have many advantages, such as feedstock availability, chemical stability, and low cost.…”

“…Various methods for purification of water containing NO 3 − have been extensively studied. For example, ion exchange, [3–5] reverse osmosis, [6,7] electrochemical reduction, [8–11] capacitive deionization, [12] catalytic and photocatalytic reduction, [13–19] biological treatment, [20–24] and adsorptive uptake [25–45] are well‐known techniques for the aqueous NO 3 − removal. Among these, adsorption is an industrially promising technique owing to its low cost, simple operation, and low energy consumption.…”