Removal of 2-chlorophenol from water by adsorption combined with TiO2 photocatalysis

The results of a laboratory-scale study of an environmentally friendly water treatment method is presented, where the organic model pollutant 2-chlorophenol (2-CP) was first adsorbed and then removed by a direct photolytic or heterogeneous photocatalytic process. The adsorbent was an organically treated (with hexadecylpyridinium chloride) clay mineral (montmorillonite), and the photocatalyst was Degussa P25. The total organic carbon and total inorganic chloride contents were measured to monitor the mineralization process, while the degradation of 2-CP and the formation of intermediates were followed by HPLC. No negative effect of the suspended adsorbent was observed either in the direct photolytic process or in the heterogeneous photocatalytic degradation process. Although direct photolysis allows the highest degree of 2-CP removal, in this case the degradation of the organic pollutant is accompanied by destruction of the adsorbent. The removal of 2-CP through the combination of adsorption and heterogeneous photocatalysis was achieved in a reasonable acceptable time interval, and can therefore be suggested as an efficient, cost-effective and environment-friendly water treatment facility. (C) 2002 Elsevier Science B.V. All rights reserved.