Abstract:
Industries where colors and dyes are being widely used have a liquid colored waste that is directly
sent to water streams without implementing any type of operation that can decrease its colored
load. Such wastewaters have adverse effects on human being and also disturb agricultural
ecosystem through blocking the photosynthesis process. Malachite green dye (MG) has several
uses in industries as well as antifungal agent for aquatic system. The intended research utilized the
waste of boilers and coal power plant i.e. coal fly ash (CFA) to treat such wastewater contaminated
with MG dye through batch adsorption process. CFA was successfully modified to Na-zeolite and
Li-zeolite through fusion treatment followed by hydrothermal treatment and characterized using
thermal gravimetric analysis (TGA), X-ray diffractometer (XRD) analysis and SEM analysis.
Parametric studies were performed by varying adsorbent amount, contact time, initial conc. of dye
solution and temperature to estimate the effect on percent removal of MG dye. Kinetic studies
were performed using pseudo-first order, pseudo-second order, intra-particle diffusion and elovich
model. Elovich model was the best fitted model and the adsorption process was controlled by a
diffusion layer inside the particles. Adsorption isotherm was also analyzed by applying Langmuir
isotherms model and Freundlich isotherm model. Freundlich isotherms model well explained the
adsorption system that was backed-up by elovich model explaining the adsorption was happening
in multi-layers. Thermodynamic parameters were also taken in consideration and evaluated that
covers Gibbs free energy (ΔG0), enthalpy change (ΔH0) and entropy change (ΔS0).
