Microwave assisted preparation of activated carbon from pomelo skin for the removal of anionic and cationic dyes

In this work, pomelo skin, an industrial effluent abundantly available from the fruit juice processing plants, was utilized as a feedstock for preparation of activated carbon (PSAC) via microwave induced NaOH activation. The activation process was performed at the input power of 800 W and irradiation time of 5 min. The porosity, functional and surface chemistry were featured by means of low temperature nitrogen adsorption, elemental analysis, scanning electron microscopy, Fourier transform infrared spectroscopy and evaluation of surface acidity/basicity. The adsorptive property of PSAC was tested using methylene blue and acid blue 15 dyes as the model adsorbates. Equilibrium data was examined using a comparison of linear and non-linear isotherm models. The adsorption behavior was well described by the non-linear Langmuir isotherm model, showing a monolayer adsorption capacity for methylene blue and acid blue 15 of 501.10 mg/g and 444.45 mg/g, respectively. The findings revealed the potential use of pomelo skin derived activated carbon for removal of cationic and anionic dyes.

► Highlight the renewable use of pomelo skin. ► Activation time of 5 min at the microwave input power of 800 W. ► High BET and Langmuir surface area of 1335 and 2057 m2/g. ► A comparison of linear and non-linear isotherm models was elucidated. ► High monolayer adsorption capacity for both anionic and cationic dyes.