Simultaneous Removal of Methylene Blue and Crystal Violet Dyes from Aqueous Solutions Using Magnetic Granular Adsorbent Based on Clinoptilolite/Alginate

Simultaneous removal of methylene blue and crystal violet was investigated. Adsorbents made of clinoptilolite/Fe3O4 (Clin/Fe3O4) nanocomposites and alginate/clinoptilolite/Fe3O4 (Alg/Clin/Fe3O4) nanocomposite beads were used. The effects of effective environmental parameters such as pH, adsorbent amount, temperature, contact time, and dye concentration were examined in the adsorption process. The results showed that the highest amount of dye adsorption using both adsorbents was obtained under pH = 8, adsorbent dose of 2 g/l, contact time of 60 minutes, temperature of 25 ºC, and dye concentration of 10 ppm. Under optimal conditions, the adsorption percentage of methylene blue dye was obtained as 80.36 and 74.51 %, and the adsorption percentage of crystal violet dye was obtained as 75.83 and 70.19 %, using Clin/Fe3O4 and Alg/Clin/Fe3O4 adsorbents, respectively. Investigating isothermal models showed that both dyes' adsorption process was mainly physical and desirable. Experimental data on dye adsorption using both adsorbents was most consistent with the Langmuir isotherm and the pseudo-second-order kinetic models. The thermodynamic study showed that the adsorption process was exothermic and spontaneous.