Optimization of Important Factors on the Adsorption of Methyl Violet by Modified Palm Fiber Using Experimental Design Method

Via Box-Behnken method, we evaluated the influence of various factors on adsorption, including the amount of adsorbent, the speed of stirring the solution and adsorbent, pH of solution, time of contact, and various concentrations of violet methyl colour, to obtain optimum conditions. The maximum extent of violet methyl removal was found at 100 mg/L concentration, pH=4.6, contact time=50 minutes, 120 rotation speed, and adsorbent dose = 1.488 g/L (0.0744 gram in 50 millilitre). In order to determine the reaction mechanism, two kinetic models were used, namely pseudo-first-order and pseudo-second kinetics models. The adsorption kinetics followed pseudo-second order model, and the mechanism of chemical reaction was the rate-limiting step. Furthermore, the Langmuir and Freundlich Isotherms were considered for adsorbing the violet methyl on the palm fiber adsorbent. The adsorption isotherms showed a balanced relationship between the materials adsorbed on the adsorbent (qe) and a balanced concentration in the solution (Ce) at a constant temperature. This method was used to remove the violet methyl colour from real samples such as industrial sewage, tap and river water.