Thermodynamics and Kinetics of Adsorption of the Acid Red by Na-bentonite

The dyestuff waste water is China's currently one of the main harmful and difficult processing industrial waste waters.Na-bentonite was used as an adsorbent to adsorb Acid Red from aqueous solution at various contact time,initial pH and temperature,and the results showed that in the conditions of pH6 and reaction time 50 min,the adsorption capacity was 256.41mg·g-1 at the room temperature,and it became much bigger with the temperature hoisted.The adsorption process was spontaneous and endothermic by calculating thermodynamic parameters ΔG0,ΔH0 and ΔS0 in the different temperatures.The adsorption isotherms fit for the Langmuir model accurately.The adsorption reaction was found to obey a second-order rate.