Magnetite activated carbon/chitosan composite from biomass for removal of diclofenac in aqueous solution

<jats:title>Abstract</jats:title>
<jats:p>Diclofenac (DCF) is a type of micropollutant from pharmaceutical waste which brings adverse effect to the aquatic environment if the wastewater is not well-treated. The impregnation of biopolymer on activated carbon has recently gained increasing attention to improve the removal efficiency of micropollutant from wastewater. Magnetite rice husk activated carbon/chitosan composite (MACCS) with high adsorption capacity was developed in this study by modifying rice husk activated carbon (RHAC) with iron oxide (Fe<jats:sub>3</jats:sub>O<jats:sub>4</jats:sub>) nanoparticles and cross-linked with chitosan. The adsorption performance of the synthesized MACCS was compared with rice husk activated carbon (RHAC) and magnetite chitosan (MCS) for DCF removal from aqueous solution. The physical and chemical properties of the synthesized biosorbents were investigated via scanning electron microscopy (SEM) and Fourier-transform infrared spectroscopy (FTIR). MACCS was identified as the best performing biosorbent and its DCF removal ability was further tested in batch with different parameters. The parameters reported in this study were solution pH and the synthesis ratio of activated carbon and chitosan. The most effective adsorption of DCF with MACCS was achieved at solution pH of 2.5 and activated carbon to chitosan ratio of 1:2. In acidic condition, the perfect coating of chitosan which contained abundance of amine group attached on the RHAC with high porosity had achieved 94% removal of DCF with maximum adsorption capacity of 270 mg/g. Besides, the MACCS could easily be separated from the aqueous solution due to its magnetic property. From the results, the MACCS biosorbent showed its potential to be an excellent alternative adsorbent for the removal of micropollutant from wastewater.</jats:p>