removal of acid red 14 by pumice stone as a low cost adsorbent: kinetic and equilibrium study

in this work, removal of c. i. acid red 14 was investigated by pumice stone as a low cost adsorbent. various parameters such as initial dye solution, contact time and ph were studied. removal of dye were increased by increasing of contact time and initial dye solution and deceased by increasing of ph. three isotherm models were studied. linear and non-linear regression analyses were used for determination of best isotherm model. in addition, chi-square test parameter (χ2) was used for the comparison of experimental and calculated data that was obtained from equilibrium studies. the results of linear and non-linear regression analysis shows the removal of acid red 14 follows the frundlich isotherm model (r2>0.987, x2=11.1). fitting of obtained data onto kinetic models show the pseudo second order kinetic model best describe kinetic sorption of acid red 14 onto pumice. mass transfer coefficient was determined at various initial dye solutions and was compared with the same work. the order of external mass transfer coefficient was 10-3-10-4. de-sorption studies demonstrate low regeneration of pumice for acid red 14 (9.4%).