Effective and sequential removal of acid and basic dye wastewater with metallic hybrid mesoporous silica

Abstract

In this work, nickel‐modified mesoporous silica prepared via sol–gel method (Ni‐S) and co‐precipitation method (Ni‐C) as effective adsorbents were successfully employed for the removal of acid fuchsin (AF) and basic fuchsin (BF). The effect of the retained templates on the adsorption of AF in synthetic materials was investigated in detail. The results indicated that retained templates contributed to improve the adsorption of AF and the theoretical maximum adsorption capacity of Ni‐S reached 689.66 mg/g according to Langmuir model. The electrostatic attraction between the anions (‐SO3−) in the dye molecules and the cations (‐NH3+) in the template (HAD) helps to enhance the adsorption effect. The adsorption isotherm and kinetics data fitted perfectly to Langmuir isotherm model and followed the pseudo‐second‐order kinetics. The thermodynamic parameters calculated from temperature‐dependent isotherms suggested that AF adsorption on nickel‐modified hexagonal mesoporous silica (Ni‐HMS) was endothermic and spontaneous process. In addition, the above‐mentioned adsorbents depleted after adsorbing AF could be recovered by simple calcination to apply into the adsorption of BF and exhibited excellent removal performance for basic dyes.