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

Abstract

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 particularly attractive because it results in prospects of zero sludge discharge. This work reports on NOM degradation and adsorption via the heterogeneous Fenton process using phytogenic zero-valent iron nanoparticles (nZVI) synthesised from green tea extract (Camellia sinensis) and supported on kaolin (fK-nZVI). The synthesised material was characterised using scanning electron microscopy (SEM), Fourier-transform infrared spectroscopy (FTIR) and Brunauer-Emmett-Teller (BET) analysis. Morphological analysis of SEM images and BET values revealed an increase in the surface area from 11.64 m2 · g−1 for kaolin to 27.07 m2 · 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 mg · g−1, a value higher than reported in other adsorption systems at equivalent adsorbent dosage and NOM concentration. The promising results obtained in this study indicate heterogeneous Fenton degradation and adsorption can be a viable and effective method for NOM removal from aqueous media. HIGHLIGHTS The Brunauer–Emmett–Teller surface area of kaolin-supported nZVI increased by 57%.; Maximum removal of bovine serum albumin (BSA) was achieved when the pH was set at 4.5 and H2O2 concentration at 5 mM.; Fenton processes increased the chemisorption capacity and subsequent oxidation of BSA by 44%.;

Keywords

• camellia sinensis
• fenton process
• kaolin
• natural organic matter
• zero-valent iron