Simultaneous removal of benzene polycarboxylic acids from water by polypyrrole composite filled with a cellulosic agricultural waste

The polypyrrole composite filled with a cellulosic agricultural waste (Nut-shells of Argan) was prepared by chemical oxidative polymerization. PPy/Nut-shells of Argan (PPy/NA) composite was used as an eco-friendly adsorbent for the removal of three polycarboxy-benzoic acids (hemimellitic, trimellitic, and pyromellitic acids) from single, binary, and ternary systems. The effects of parameters influencing the adsorption process including initial pH, adsorbent dose, contact time, initial concentration of polycarboxy-benzoic acids, and temperature were investigated. The kinetics studies indicated that the pseudo-second-order kinetic model well better described the adsorption kinetics for single systems. The adsorption equilibrium data from single, binary, and ternary systems were successfully described by the Langmuir isotherm model. The comparison of equilibrium adsorbed amounts in single and multi-component systems shows an antagonism effect. The obtained results indicate that the affinity of studied polycarboxy-benzoic acids on the surface of PPy/NA composite followed the order pyromellitic acid > trimellitic acid > hemimellitic acid. The thermodynamic parameters show that the nature of adsorption is spontaneous and endothermic.