Adsorption of p-hydroxybenzaldehyde onto zeolites for water remediation: evaluation of the competition between contaminant and natural organic substances

Toluene is a hydrocarbon belonging to the BTEX class (Benzene, Toluene, Ethylbenzene, Xylene) which is frequently detected in all environmental compartments due to its wide use as solvent, antiknock agent in gasoline, and for the production of benzene. In this study we tested the efficiency of zeolites as eco-compatible adsorbent material for the removal of the organic contaminant toluene from aqueous matrices containing the natural component p-hydroxybenzaldehyde (p-HBA). p-HBA is one of the monomers of humic acids derived from the biodegradation of lignin, these substances are commonly found in surface and ground waters and, due to their dimensions similar to the zeolites pore size, could interfere in the adsorption of organic pollutants. Regarding the adsorption of the contaminant (TOL) from the aqueous matrix containing the natural humic acids monomer (p-HBA), it resulted that this latter does not show competitive behavior: the adsorption of TOL was slightly affected by the presence of p-HBA.