Assessing the performance of silicon nanoparticles in adsorption of Humic acid in water

Humic substances in drinking water react with chlorine and form carcinogenic compounds. Humic acid is a principal component of humic substances and its separation from surface waters is crucial. Adsorption process is among different methods for separation of humic acid from surface waters and because of its simple and economical nature it has attracted considerable attention. The aim of this research was to examine performance of silicon nanoparticles in adsorption of humic acid in water. Experimental study was conducted on both synthetic and real water samples collected from Zarrineh Rood River, Tabriz before its entrance to water treatment process. We used instantaneous sampling method.The chemical quality of crude sample and its humic acid was determined and then the influence of pH, absorbent amount, and time on the removal of humic acid was evaluated. Therefore, the optimal conditions for each of these parameters were determined. In order to get better insight into the process of adsorption, the adsorption kinetic and equilibrium isotherm were studied. We measured humic acid concentration and TOC using spectrophotometer (Shimadzu /UV-1800, Japan) at a wavelength of 254 nm and TOC analyzer (Shimadzu model TOC-VCSH) measured. SPSS software and regression were used for data analysis. At pH=4, retention time of 10 minutes, adsorbent amount of 0.25 g/L, we found that the highest percentage of humic acid adsorption was 88.4 and 81.8 for synthetic and real solutions respectively. The finding revealed that the removal of humic acid follows Freundlich isotherm (=0.8172) and the second order kinetic model (=0.9936). Removal in both real and synthetic solutions was less due to the reaction of influencing factors. However, considering the high percentage of humic acid removal under optimal conditions and its comparison with other methods, the removal of humic acid using SiO2 can be considered as an efficient method.