Efficient Removal of Both Anionic and Cationic Dyes by Activated Carbon/NiFe-layered Double Oxide

The magnetic composite of activated carbon and NiFe-layered double oxide was carried out by mechanical method. The activated carbon was obtained by using Hanguana malayana as a carbon source. NiFe-layered double oxide was prepared by the calcination of NiFe-layered double hydroxide at 400 degrees C for 2 h. The characteristics of the products were verified by XRD, FT-IR, VSM, BET and SEM. The elemental mapping images of the composite revealed the corresponding carbon, iron, nickel and oxygen, indicating the presence of the activated carbon and NiFe-layered double oxide. The saturation magnetization and specific surface area of the composite were improved of 3.7 emu/g and 225 m(2)/g relative to the activated carbon and NiFe-layered double oxide, respectively. The adsorption efficiency of the composite adsorbent was evaluated by the removal of both cationic and anionic dyes from aqueous solution with the help of external magnet on the adsorbent separation. The maximum adsorption capacity of Congo red and methylene blue on the composite surface was estimated at 250 and 227 mg/g, and the capacity dropped only 9% and 7% after the 5th reusing cycles, respectively. The composite showed the high selective adsorption performance for both Congo red and methylene blue due to the combined interaction of NiFe-layered double oxide and activated carbon that contained the functional groups on capturing anionic and cationic dyes, respectively.