Removal of reactive blue 19 from aqueous solution by pomegranate residual-based activated carbon: optimization by response surface methodology

Background: in this research, response surface methodology (rsm) was applied to optimize reactive blue 19removal by activated carbon from pomegranate residual. a 24 full factorial central composite design (ccd) wasapplied to evaluate the effects of initial ph, adsorbent dose, initial dye concentration, and contact time on the dyeremoval efficiency.methodology: the activated carbon prepared by 50 wt.% phosphoric acid activation under air condition at 500°c.the range of ph and initial dye concentration were selected in a way that considered a wide range of thosevariables. furthermore, the range of contact time and adsorbent dose were determined based on initial tests. levelsof selected variables and 31 experiments were determined. minitab (version 16.1) was used for the regression andgraphical analyses of the data obtained.results: it was found that the decrease of initial dye concentration and the increase of initial ph, adsorbent dose,and contact time are beneficial for improving the dye removal efficiency. analysis of variance (anova) resultspresented high r2 value of 99.17% for reactive blue 19 dye removal, which indicates the accuracy of thepolynomial model is acceptable.conclusions: initial ph of 11, adsorbent dose of 1.025 g/l, initial dye concentration of 100 mg/l, and contact timeof 6.8 minutes found to be the optimum conditions. dye removal efficiency of 98.7% was observed experimentallyat optimum point which confirmed close to model predicted (98.1%) result.