Novel mesoporous silica nanocomposites for adsorption of Cu(ii) from aqueous solution were prepared by in situ polymerization of MMA and modified KIT-6 as filler.

Well-ordered KIT-6 mesoporous silica was synthesized via a sol-gel process and functionalized with sulfonic acid groups. The catalyst was characterized using XRD, BET, TGA, SEM, TEM and pyridine FTIR spectroscopy techniques. The prepared catalyst was used to catalyze the conversion of fructose to 5-hydroxymethylfurfural (HMF) in DMSO. Various reaction parameters such as effect of reaction temperature, reaction time, catalyst loading, and solvent on HMF yield were investigated. A fructose conversion of 100% and 84.1% yield of HMF was obtained at 165 ºC after 30 min in DMSO. The reaction is quite selective toward HMF. The catalyst was used several times without significantly losing its catalytic effect.

It is no longer news that the world is in the midst of a freshwater crisis, with the future health of both humans and the environment being threatened by heavy metal pollution. Accordingly, attempts at removing the toxic heavy metals from water are attracting considerable attention around the world. As a result, for the first time, amine-modified MCM-41/polymer matrix nanocomposites (m-MCM-41/ PMNCs) have been applied to remove hexavalent chromium species (Cr VI ) from aqueous solution. Poly(methyl methacrylate), poly(vinyl alcohol), nylon-6, and polystyrene, which are environmentally benign and economically accessible polymer matrices, were used for fabricating four different types of m-MCM-41/PMNCs. Owing to the abundance of chemically active functional groups on the surface of these m-MCM-41/PMNCs, excellent adsorption performance was observed. Maximum metal removal was observed at low pH (2−3) and with the efficiency of Cr VI removal being in the range of 61.78−85.71%. The kinetic modeling and equilibrium isotherm data were analyzed, and the results showed that various adsorption mechanisms, depending on the type of polymers, may occur. Also, the computed thermodynamic parameters, i.e., ΔG°, ΔH°, and ΔS°, suggested that the adsorption of Cr VI onto the m-MCM-41/PMNCs is an endothermic, spontaneous, and physical adsorption process.

The addition of nanoboehmite as a nanofiller into the polymer matrix led to the improvement of the thermal properties and increased the active sites of nanocomposites for Cu(ii) removal.