Comparison of adsorption process by GAC with novel formulation of coagulation-flocculation for color removal of textile wastewater

ABSTRACT

This study evaluates the effectiveness of adsorption process by Granular Activated Carbon [GAC] compared with a novel formulation of coagulation - flocculation process for dye removal from textile wastewater. In this regard, acidic, reactive, disperse and direct red dye are used to prepare the synthetic dye. Dominant wave length for each dye is determined by spectrophotometeric method. Using GAC as adsorbent, equilibrium time and adsorption isotherm of each dye are determined with aid of spectrophotometric method. The results show that GAC can not remove dispersed red dye. Acidic red, direct red and reactive red of 5 mg/L concentration are removed by GAC up to 90%, 88% and 43% in 30, 60 and 120 min. [equilibrium time] respectively. Dyes of 50 mg/L concentration are removed up to 93%, 30% and 51% in 15, 90 and 150 min. respectively. Adsorption obeys Freundlich isotherm for acidic red, BET isotherm for direct red and Langmuir isotherm for reactive red. This investigation presents a novel formulation of coagulation - flocculation for color removal from textile dye solutions and illustrates its efficiency. Novel formulation of coagulation - flocculation remove direct red, reactive red and disperse red of 5 mg/L concentration respectively up to 93%, 91.3% and 57.1%. Also the mentioned dyes of 50 mg/L are removed respectively up to 90.8%, 91.9% and 70.1%