Fixed bed column study for the removal of reactive red 120(Rr120) dye from aquatic environment by low cost adsorbents

Abstract

This study described adsorption of Reactive Red120 (RR120) by cotton shell and neem bark in batch and fixed-bed column modes at 293 K. The kinetic and equilibrium of adsorption in batch mode were studied. Nonlinear regressive method was used to obtain relative parameters of adsorption models. The kinetic process was better described by a -first-order kinetic model. The equilibrium adsorption was effectively described by Freundlich and Langmuir adsorption isotherm. The value of C1 from the Langmuir model was 34.375, (RR120 by NB), 33.33, (RR120 by CS), mg/g, Langmuir adsorption intensity Kd had value of 0.2909,(RRNB), 0.25, (RRCS) and the value of Freundlich adsorption capacity Kf is 2.664 (1/n)=0.38(RR120 NB), 2.691 (1/n)=0.44(RR120 CS) . In fixed-bed column adsorption, the effects of bed height, feed flow rate, and inlet Reactive Red120(RR120) concentration were studied by assessing breakthrough curve. The column data were fitted by the Thomas, Clark and modified dose-response models. The modified dose-response model was best to fit the breakthrough curves at experimental conditions. Box behnken design was successfully employed for experimental design and analysis of the results. The combined effect of pH, temperature and Dye concentatration on the dye adsorption was investigated and optimized using response surface methodology. The optimum pH, temperature, and dye concentration were found to be 6.46,32.22°C and 12.60 for Reactive Red120(RR120) by cotton Shell and the optimum pH, temperature, and dye concentration were found to be 6.37, 30.82°C and 11.65 for Reactive Red120(RR120) by neem bark.The results were implied that cotton shell and neem bark may be suitable as an adsorbent material for adsorption of Reactive Red(RR120) from an aqueous solution.