Exploring nicotine adsorption performance of commercial XAD-4 resin: Experimental design, isotherm, kinetic modelling and regeneration

Due to tobacco smoking and production, nicotine has been widely found in natural water environment which causes serious effects on living organisms. Herein, the nicotine adsorption over commercial polystyrene resin (XAD-4) was systematically studied via experimental design technique. Response surface methodology was applied in order to analyse the effect of different factors including pH, adsorbent dosage, and initial concentration. The solution pH predominantly affected the nicotine removal and the increase in pH significantly increased the nicotine adsorption ascribed to the electrostatic attraction and Lewis's acid-base interactions. According to the Box-Behnken design, the maximum nicotine removal of 85.06% was observed at an initial concentration of 5.8 mg/L, pH 8.8 and adsorbent dosage of 1.6 g/L. The pseudo-second order kinetic model displayed the highest correlation coefficient (R-2 = 0.993) while the Langmuir-Freundlich isotherm model fitted best to the experimental data (R-2 = 0.980; chi(2) = 0.064) with a maximum adsorption capacity of 5.949 mg/g. The resin could be easily regenerated by methanol or methanol/amin solutions which further enabled its repeatedly usage until six cycles. The commercial XAD-4 resin can be considered as a sustainable strategy to eliminate the emerging toxic contaminant of nicotine.

Automated summary

The study investigated the adsorption of nicotine by XAD-4 resin, highlighting the importance of pH, adsorbent dosage, and initial concentration. The maximum removal rate of 85.06% was achieved under optimal conditions of 5.8 mg/L initial concentration, pH 8.8, and 1.6 g/L adsorbent dosage.