novel low-cost magnetic clinoptilolite powders/granules for the removal of crystal violet in single and binary systems

Novel magnetic adsorbents of clinoptilolite/fe3o4 (clin/fe3o4) nanocomposite powders and alginate/clinoptilolite/fe3o4 (alg/clin/fe3o4) nanocomposite granules were synthesized to efficient removal of the cationic crystal violet (cv) dye in single and cv/methylene blue (mb) binary systems. the prepared adsorbents were characterized by ft-ir, xrd, sem, edx, dot mapping, and bet analysis. adsorption tests showed that clin/fe3o4 and alg/clin/fe3o4 had high affinity toward cv removal at 94.32% and 92.35%, in the single system and 84.19% and 80.23%, in the binary system, respectively. based on the findings, ph was the most effective variable in the elimination process and the highest yield was obtained at ph 8 for both adsorbents. the equilibrium data followed the langmuir model (r2 > 0.9) based on which the maximum adsorption capacity (qmax) using clin/fe3o4 and alg/clin/fe3o4 was determined as 44.662 mg/g and 16.528 mg/g, respectively in the single system and it was computed to be 15.797 mg/g and 11.476 mg/g, respectively in the binary system. the kinetic data fitted well to the pseudo-second-order model in both systems. the adsorption process was exothermic and thermodynamically spontaneous. moreover, clin/fe3o4 and alg/clin/fe3o4 adsorbents showed 91.43% and 82.01% recyclability over the desorption tests, thus leading to promising and green-based adsorbents for the removal of dyes. the electrical conductivity (ec) of mb, cv, and cv/mb solutions and also real wastewater sampled from a dyeing unit were measured before and after treatment and the results showed that the ec of all samples was reduced.