Simultaneous Removal of Organic Dyes from Environmental Samples by Using Sistan Sand as an Effective Sorbent

Organic dyes are compounds with complex chemical structures, mostly of high hazard to humanhealth. Moreover, they are one of the major pollutants, especially when entering environmentalwaters [1]. Many of dyes are not bio-degradable and must be removed from watersby physico-chemical processes. One of the most economical, easy and rapid methods toachieve this purpose is using an adsorbent [2]. In this work, Sistan sand was successfully usedas a free and available sorbent for simultaneous removal of Malachite Green (MG), RhodamineB (RhB) and Cresol Red (CR) dyes from environmental water samples. This sand canbe found everywhere in Sistan area. We could show that each gram of this sand can effectivelyadsorb and remove high amount of 0.132 mg of CR, 0.109 mg of RhB and 0.120 mg ofMG very rapidly. When these three dyes are in a mixture, Sistan sand can remove up to 83%of the dyes from the solution. In this regards, Sistan sand can be compared with some veryhigh-priced nano-sorbents. Parameters affecting adsorption were optimized using both experimentaldesign methods (Taguchi and Plackett-Burman) and experimentally. According to ourkinetic studies, the pseudo-first-order equation was the best model for all three dyes. To thebest of our knowledge, no other report can be found for the simultaneous removal of organicdyes by a natural sorbents.