ABSTRACT

In this research, the potential of NZVI 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 second-

order kinetic model, suggesting Studies on the effect of temperature 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 R2of the pseudo first for the modified 0.4669 and 0.7978 for the

unmodified, while for the pseudo second order, the R2values are 0.99 8 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.