Development of an adsorption-enhanced heterogeneous Fenton process for abatement of natural organic matter by kaolin-supported phytogenic nanoscale zero-valent iron

Natural organic matter (NOM) serves as a precursor for the formation of carcinogenic disinfection by-products when not adequately removed by conventional water treatment processes. The degradation of NOM by heterogeneous Fenton processes is attractive because it results in zero sludge discharge, and the process can operate irrespective of the operating pH. This work reports on NOM degradation and adsorption via the heterogeneous Fenton process using phytogenic zero-valent iron nanoparticles (nZVIs) synthesised from green tea extract (Camellia sinensis) and supported on kaolin (fK-nZVI). Charactersisation using scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR), and Brunauer-Emmett-Teller (BET) analysis. SEM analysis and BET values revealed an increase in the surface area from 11.64 m(2).g(-1) for kaolin to 27.07 m(2).g(-1) for the kaolin-supported nZVI (K-nZVI), thus presenting an ideal modification for effective adsorption. Fenton process parameters were optimised, that is, H2O2 concentration (5 mM) and pH (4.5). At equilibrium, the adsorption by the fK-nZVI system was 0.127 mgg(-1), a value higher than those reported in other adsorption systems at equivalent adsorbent dosage and NOM concentration. The promising results obtained in this study indicate that heterogeneous Fenton degradation, and adsorption can be a viable and effective method for NOM removal from aqueous media.