Experimental design and modeling of removal of Acid Green 25 dye by nanoscale zero-valent iron

Abstract

We have used nanoscale zero-valent iron particles to remove Acid Green 25 (AG-25) dye from aqueous solution and have studied the effects of important variables, such as dye concentration, catalyst amount, pH and time, on the dye removal process, optimized by the Taguchi approach. Sixteen experiments were required to study the effect of all four parameters on removal of the dye. Each experiment was repeated three times to calculate the signal/ noise (S/N) ratio. Based on the S/N ratio, optimum values of 4, 0.6 g, 120 s, 20 mg L -1 were obtained for pH, catalyst amount, time and dye concentration, respectively. At the optimized condition, the removal percentages of AG-25 dye was found to be 96.82%.

Simultaneous optimization of parameters influencing organic mulch test using response surface methodology

“…By measuring the signal-to-noise ratio, the accuracy of the model can be shown, which should be greater than 4. In this study, this ratio is 21.521 and 30.514 for the values of permeability and wind erosion, respectively which indicates a high degree of accuracy 24 . Fig.…”

“…We used Design-Expert to design and analyze the experiment and the results are given to the software. It calculates one-way analysis of variance to check the preciseness of the experiment 24 . Then, the model and formulation are carried out.…”

“…where: In this relation, Z i is the value of the encoded independent variable, x i and x 0 are the actual values of the independent variables, x 0 is the central point, and Δx i is amount of variation. The best method for assessing the fitness quality of the model is to use ANOVA analysis for test results 24 . After entering the results into Design-Expert software, the quadratic model was considered as the ideal model for resistance to penetration and wind erosion among different mathematical models.…”

Effect of Kaolin particle size on the removal of Pb(II) from aqueous solutions by Kaolin-supported nanoscale zero-valent iron

“…The main reason for this phenomenon is that, the removal rate decreases with the increasing of concentrations of Pb(II), due to there is no sufficient surface in adsorbent to remove all Pb(II). Oppositely, in low concentrations of the Pb(II), all of the molecules stick to the adsorbent surface, and then remove from the solution [5,22,25]. That being said, since the iron particles contain a finite number of adsorption sites, excess Pb(II) will saturate these sites before being fully adsorbed [48,49].…”

“…Various synthetic methods have been exploited to prepare iron nanoparticles [11][12][13][14][15][16][17]. Due to its considerable specific surface area, nZVI has a high surface energy and high reactivity [18], and therefore it is suitable for the removal of different environmental pollutants [19][20][21][22][23][24][25][26]. However, its efficiency is reduced by a strong propensity for aggregation [27].…”