Synthesis and Characterization of Bone char/Aluminum Loaded Zeolite Y Composite for Removal of Fluoride from aqueous solution

Abstract

Millions of people throughout the world suffer from health problems caused by high fluoride levels in water supplies. Fluoride has an intense stimulation and corrosion effect on the skin mucosa and dental fluorosis. Developing efficient and eco-friendly methods for water treatments are a very crucial activity due to the wide-scale concentration of fluoride ion. The adsorption process is the best among other technologies due to simple design, versatile, lowest cost for instrumentation. Hence, this work focus on synthesis and characterization of bone char and aluminum loaded zeolite Y for enhancing the removal efficiency of fluoride from water. Bone char (BC) and Aluminum loaded zeolite Y (AZ) were uniformly grinded, sieved and mixed in three different ratio (1:1, 1:3, 3:1) (BC to AZ) and pure bone char, zeolite Y and Aluminum loaded zeolite Y was compared. BC and AZ have high adsorption efficiency next to 3:1 Bone char and Aluminum loaded zeolite Y (BAZ) composite. The composite is confirmed successfully using XRD, FTIR, SEM and TGA. The BET specific surface area of BC, ZY and BAZ are determined to be 406.25 m 2 /g, 523.120 m2 /g and 540 m 2 /g respectively. Adsorption increase with the increase in the surface area of the adsorbent. The experiments have been designed by Central Composite Design (CCD) with three factors such as pH of the solution, contact time and adsorbent dosage. The result confirmed that 98.1% of fluoride ion was removed from water at optimum 60 min contact time, 0.5 g adsorbent dose, the pH level of 7.5. 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 R 2 of 0.999 and a maximum adsorption capacity of 19.23 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 fluoride ion was found after 3 cycles following 90.4%, 85.8%, and 74.98% removal efficiency for the first, second and third desorption/adsorption cycles respectively. The recycle continue until the removal efficiency below 50%, which indicates wonderful reusability of the adsorbent. The result illustrates that BAZ is an excellent promising adsorbent for the removal of fluoride ions.