Effect of oxidative modification of activated carbon for the adsorption behavior of nicotine

The adsorption of nicotine onto activated (AC) and AC modified (MAC, by contact with ammonium persulfate) can be described well using the Langmuir model with maximum adsorption capacities of 552 and 640 mg g−1, respectively. Nicotine has high ‘hardness’ and appears to adsorb most readily on the increased concentration of ‘hard’ MAC edge functional groups. Adsorption is shown to be exothermic; with enthalpy of −10 and −16 kJ mol−1 for AC and MAC, respectively. The negative free energy and positive entropy of adsorption indicate a spontaneous process and a strong affinity between aqueous nicotine and AC or MAC.

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