Removal of hazardous reactive blue19 dye from aqueous solutions by agricultural waste

Low-cost grapefruit peel (Agricultural Waste) was used for removal of reactive blue19 dye from aqueous solutions. The process was studied as a function of contact time, initial dye concentration and pH. Adsorption process was attained to the equilibrium within 45 min for initial dye concentrations of 50, 75, and 100 mg L-1. An acidic medium was the optimum condition for adsorption of dye at room temperature. The maximum dye removal of 83.56 % could be achieved at initial pH 2 using adsorbent dosage of 0.5 mg in 150 ml (50 mg L-1 dye concentration) and agitation rate of 180 rpm. The adsorption capacity was found to be about 12.534 mg g-1. The isotherm data could be well described via Langmuir equation with the correlation coefficient of 0.986 in dye concentration range of 50-100 mg L-1 at 25 ◦C. Kinetic studies revealed that the experimental data correlated well with pseudo second-order model possessing regression coefficient of R2 ≥ 0.999. Scanning Electron Micrographs provided a supporting evidence for efficient dye sorption onto grapefruit peel.