Biosorption of Direct red 81 dye from aqueous solution on prepared sonchus fruit plant, as a low cost biosorbent: Thermodynamic and Kinetic study

The biosorption of reactive azo dyes (Direct red 81) found in textile wastewaters by activated carbon prepared from sonchus fruit plant has been investigated. Batch experiments were carried out for the biosorption of dyes molecules onto biosorbent at different temperature. The biosorption kinetics was found to follow pseudo- second order kinetic model with high degree of correlation coefficient (R2>0. 99). The equilibrium isotherms of biosorption and kinetics were studied. The biosorption equilibrium data were analyzed by using Langmuir and freundlich isotherm models and the results have shown that biosorption behavior of this dye could be follow to Langmuir isotherm model. Various parameters such as contact time، initial dyes concentrations، temperature، stirring speed and does of biosorbent were taken into account، and promising results were obtained. Furthermore، it was also found that the sonchus fruit plant can using as a low cost material for azo dye biosorbtion.