Preparation of CPB-modified FAU zeolite for the removal of tannery wastewater contaminants

The preparation of organomodified zeolites with different framework structures (FAU, LTA and MOR) using N-cetylpyridinium bromide (CPB) as tailoring agent was studied. The sorption properties of CPB-modified zeolites were evaluated in the removal of tannery contaminants from aqueous solution. The CPB-modified FAU-type zeolite presented the highest Cr(VI) retention capacity (37 mmol/kg) due to the higher Cr(VI) retention of its unmodified form (larger pore opening) and its high CPB sorption capacity. CPB-modified FAU zeolite also exhibited high thermal stability as consequence of special interactions between the CPB molecules and the zeolite surface. In addition, the intrinsic Cr(III) exchange capacity of FAU zeolite increased with CPB loading (162-527 mmol/kg), which appear to be due to an additional retention mechanism provided by the sorbed cetylpyridinium surfactant layer. On other hand, CPB-modified FAU zeolite also exhibited high toluene retention capacity (62 mmol/kg) due to of the hydrophobic character of its surfactant-modified surface and toluene adsorption on internal sorption sites of FAU zeolite. Thus, CPB-modified FAU zeolite appears as a promising adsorbent for simultaneous removal of Cr(III), Cr(VI) and toluene contaminants from aqueous solution.