Optimization of Fluoride Adsorption from Aqueous Solution by Marble Powder Using Taguchi Model

Background and Taguchi method is a powerful design in experimental studies. This method, with the minimum number of test factors affecting the process, will save cost and time. This study was done using the Taguchi method to optimize the adsorption of fluoride from aqueous solutions by an adsorbent prepared from marble powder. Marble powder was supplied from Hamadan workshops stonemason and then grinded and sieved to the desired particle size using standard ASTM (mesh 40). Four parameters affecting the adsorption process (pH, contact time, temperature, and adsorbent dose) were considered in four levels. Residual fluoride concentration was measured by a spectrophotometer. Minitab V.16 (L-16 Orthogonal Array) was used to analyze the data. Taguchi model indicated that optimization conditions for fluoride adsorption by marble powder were adsorbent dose 0.7 mg/L, pH=2, temperature 25◦C, and contact time 5 min. ANOVA results showed that the most and least of influential parameters on adsorption process was associated with adsorbent dosage and solution pH, respectively. Taguchi statistical method as an efficient, effective, and without the need for a large number of experiments indicated that the marble powder as a new adsorbent, no cost, and without secondary pollutant has a high efficiency for fluoride removal from aqueous environments.