Application of magnetic peanut husk for methylene blue adsorption in batch mode.

Magnetic peanut husk (PN-Fe₃O₄) was prepared by co-precipitation and applied for the removal of methylene blue (MB) from the solution. The results from the characterization of PN-Fe₃O₄ showed that Fe₃O₄ was successfully loaded onto peanut husk. The effect of factors such as pH, temperature, salt, and contact time on the adsorption process were carried out using the batch method. The adsorption isotherm was well-described by the Langmuir isotherm whereas the pseudo-second kinetic-order was observed to be the best fitted kinetic model. The maximum equilibrium capacity of PN-Fe₃O₄ according to the Langmuir model was 32.5 mg g^−1 at 303 K. After three adsorption cycles, PN-Fe₃O₄ had significant adsorption capacities as well as its magnetic properties which ensures its easy separation from the aqueous solution by the use of a magnet. A single-stage batch design for MB adsorption was also presented based on the Langmuir isotherm model. PN-Fe₃O₄ is promising as an adsorbent to remove dyes from the solution. [ABSTRACT FROM AUTHOR]