Synthesis And Characterization Of Fe3o4 Loaded Calcium Silicate Hydrate Composite For Removal Of Nitrate From Water

Abstract

The presence of an excess nitrate ion in the human body leads to various health problems. The increased nitrate level may be a result of different human activities such as the huge amount of fertilizer in agriculture activities, industrial and household wastewaters. Therefore, the removal of nitrate ions to the lowest concentration in drinking water and wastewater is crucial. Physical and Biological technologies have been used for nitrate removal. However, those treatment technologies have limitations regarding cost and complex operations in achieving the required concentration level. The adsorption process is the best among other technologies due to simple design, versatile, lowest cost for instrumentation, easy operation, sludge free, environmentally friendly, and regeneration. Hence, the aim of this work was synthesis and characterization of Fe3O4 loaded CSH composite for removal of nitrate ion from water. XRD, FTIR, SEM, BET, and TGA were used to characterize the crystalline structure, specific functional groups, morphological properties, specific surface area, and thermal stability. The chemical composition and structure of Fe3O4 loaded CSH and the successful surface loading of hydroxyl functional groups were confirmed. The BET specific surface area of CSH and Fe3O4 loaded CSH composite are determined to be 91m2 /g and 163 m2 /g respectively. Adsorption increase with the increase in the surface area of the adsorbent. Moreover, the optimization effects of adsorption parameters such as contact time, adsorbent dose, pH, and initial nitrate concentration have been carried out. The result confirmed that 92.71% of nitrate ion was removed from wastewater at optimum 150 min, 2.4 g adsorbent dose, the pH level of 6.3, and 85 mg/L of initial nitrate concentration. Furthermore, the adsorption parameters such as equilibrium isotherm, kinetics, and thermodynamic properties were conducted. The adsorption isotherm data were best fitted to the Langmuir with a maximum adsorption capacity of 27.93 mg/g. In addition, the result of the kinetic model proved that pseudo second-order provided a good description of the experimental data with a maximum R2 of 0.999. The result of the thermodynamic parameters demonstrated that the adsorption process is spontaneous and endothermic. The removal efficiency of 68.73% of nitrate ion was found after 4 cycles of desorption/adsorption cycles, which indicates wonderful reusability of the adsorbent. The result illustrates that Fe3O4 loaded CSH is an excellent promising adsorbent for the removal of nitrate ions.