ABSTRACT

In this research, the potential ofNZVI for efficient removal of aniline yellow as a cationic dye from aqueous solutions was investigated. The NZVI were characterized by XRD, SEM and FTIR techniques. To remove aniline yellow, the surface of the NZVI was modified with sodium dodecyl sulfate (SDS) as an anionic surfactant. Also, the various parameters affecting dye removal were investigated and optimized. Dye adsorption equilibrium data were fitted well to the modified Freundlich isotherm and Dubinin-Radushkevich Isotherm. The adsorption process was highly pH-dependent and the results indicate that the optimum pH for adsorption of and maximum adsorption occurred at pH 8.0 for the modified and pH 6.0 for the unmodified. Fig.4.3-4.4 having maximum removal efficiencies of 95.5 and 82%. The kinetic studies for aniline yellow adsorption showed rapid sorption dynamics by a secondorder kinetic model, suggesting Studies on the effect oftemperature showed that the optimum temperature for adsorption of is 80°C for modified and unmodified. Pseudo first-order, second-order and intra-particle diffusivity kinetic models were applied to the experimental data and results showed that the pseudo second-order provided best fit comparing the correlation coefficient R2 of the pseudo first for the modified 0.4669 and 0.7978 for the unmodified, while for the pseudo second order, the R2 values are 0.998 for the modified and 0.9532 for the unmodified respectively. Kinetic studies also showed that the adsorption transport mechanism was particle-diffusion controlled in which weber and morris gave the best fit. The results show that, SDS-coated NZVI, can be used as a cheap and efficient adsorbent for removal of cationic dyes from aqueous solutions.