Removal of hexavalent chromium and sulfamethazine by green zero valent iron nanoparticles (NZVI)
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A green and low-cost method for nZVI fabrication was developed in this thesis using FeCl3 as the source of iron and yerba mate (Ilex paraguariensis) extract as the reductant. The extract showed an impressive high content of polyphenols, up to 28.14 GAE (gallic acid equivalent), which is much higher than that in most of reported plants extract. We investigated the effect of iron to GAE ratio on nZVI, as well as optimize iron particles as a benchmark of zeta-potential and Cr(VI) reduction capacity. nZVI fabricated from molar ratio of 0.89 Fe(III)/GAE showed the best performance and was selected for further exploration of Cr(VI) and sulfamethazine removal. The optimized nZVI was studied with a series of characterizations, indicating that nZVI particles were amorphous, with high colloidal stability and spherical shape of 7.8 ± 2.1 nm diameter. Several functional groups on iron particles surface were related to the phenol ligands cap of the iron particles. In this second part, several influential factors were explored. We concluded that there is higher efficiency for Cr(VI) removal at acidic solution, and the reaction was easily happed due to the low activation energy of 35.01 kJ/mol. The product was immobilized on the particles surface. In the third part of the thesis, nZVI was applied to catalyze H2O2 for degrading sulfamethazine. A series of experiments were conducted to find the optimal experimental condition, and the results indicated an excellent sulfamethazine removal efficiency for Fenton treatment process with minute H2O2 concentration.