Fast and efficient removal of Reactive Black 5 from aqueous solution by a combined method of ultrasound and sorption process

Removal of Reactive Black 5 (RB5) from aqueous solutions was carried by the sorption process in the presence and in the absence of ultrasound. Sorption of the dye on the solid phase was investigated in a series of batch sorption experiments to determine the influence of different parameters such as contact time, amount of sorbent and concentration of pollutant on the removal efficiency of RB5 with and without ultrasound. The experimental data were fitted properly to the Freundlich model and the isotherm constants were 28.2 and 7.4 for k(f) and 0.13 and 0.38 for 1/n in the presence and in the absence of ultrasound (20 kHz) respectively. The data were analyzed with different sorption kinetic models and were better fitted with a pseudo-second-order kinetic model. Two ultrasonic generators at 20 and 500 kHz were used for sonication of the system. This investigation also reveals that RB5 can be removed by higher frequency apparatus (500 kHz) without sorbent in about 60 min sonication. The rate of removal was higher at the higher frequency than at the lower one.

Sono-sorption as a new method for the removal of methylene blue from aqueous solution

The sorption of methylene blue as a basic dye onto cellulosic materials such as waste newspaper was examined kinetically in the presence of ultrasound (sono-sorption) and in its absence (conventional method). The effects of various experimental parameters such as the amount of sorbent, type of cellulosic sorbents, initial dye concentration, temperature, and contact time have been investigated using a batch sorption technique. The information obtained can be used for treating effluents from the dye industry which deals with this kind of dye. The results show that as the amount of sorbent is increased, the dye removal in conventional method increases accordingly. In case of sono-sorption, it was stopped at specific amount of sorbent. More than 98% removal of the dye could be achieved in a very short period of time of sonication with respect to the conventional method. This behavior is related to the cavitation process which facilitates the removal of dye from aqueous solution. The method mentioned could be employed as a low cost alternative to the commercial activated carbon currently used in wastewater treatment for the removal of dyes.