Polyhydroxyl gemini surfactant-modified montmorillonite for efficient removal of methyl orange

Abstract Two types of organoclays including dioctadecyl tetrahydroxyethyl dibromopropane diammonium (DTDD) and octadecylmethyldihydroxyethyl ammonium bromide (OMDAB) modified montmorillonites (DMt and OMt) were fabricated by microwave synthesis for the first time, of which structure, morphology and surface properties were explored by different techniques. This study revealed that the amount of adsorbent, pH, and the initial concentration of methyl orange (MO) solution had significant effects on the adsorption capacity of DMt. The adsorption mechanisms of DMt and OMt to MO were proposed based on the characterizations, adsorption kinetic models and adsorption isotherms, which proved that DMt could adsorb MO in the faster manner with higher affinity. (The estimated maximum adsorption capacities of DMt-1.0 and OMt predicted by the Langmuir isotherm model was 250.63 and 91.11 mg g −1 , respectively.) Compared with the pristine Na-Mt, OMt, and C 43 H 92 N 2 Cl 2 -modified montmorillonite (18-3-18-Mt), DMt-1.0 containing hydroxyls in the alkyl chain of gemini surfactant molecule had the best adsorption capacity for MO removal from aqueous media.