Effect of Concentration of Aminopropyl Groups on the Surface of MCM-41 on Adsorption of Cu²⁺

Abstract

MCM-41 synthesized at room temperature was functionalized with aminopropyltrimethoxysilane (APTMS). The functionalized MCM-41 were characterized by powder X-ray diffraction, scanning electron micrography (SEM), transmission electron-microscopy (TEM), nitrogen adsorptionÀdesorption, and carbon, nitrogen, and hydrogen (CHN) analysis. X-ray diffraction patterns indicate that the modified materials retain the structure of MCM-41. An increase in surface concentration of aminopropyl groups (0.7 to 1.9 mmol/g) resulted in a decrease in the surface area, BJH pore size, and total pore volume. Studies on the adsorption of Cu 2+ on these samples showed the Langmuir type adsorption isotherms. The value of the Langmuir monolayer capacity of Cu 2+ adsorption increased linearly with an increase in the surface concentration of the amino group. The NH 2 /Cu 2+ mole ratio increased from ∼1.5 to ∼2 when the concentration of the amino group increased from 0.71 to 1.42 mmol/g and remained almost the same for higher concentrations.

Study of the controlled assembly of DNA gated PEI/Chitosan/SiO2 fluorescent sensor

“…After doping into SiO 2 nanoparticles, the positive shift of the Zeta potential of SiO 2 nanoparticles was affected. When PEI was doped into SiO 2 nanoparticles, a large number of amine groups of PEI bound to protons under neutral conditions, so the Zeta potential on the surface of SiO 2 nanoparticles was greatly shifted positively . Moreover, the amount of positive charge on the surface of composite nanoparticles can be adjusted by the amount of PEI added in the PEI/Chitosan/SiO 2 nanoparticles.…”

“…At present, the most commonly used method is the addition of aminated reagents in the synthesis process, such as APTES, and the introduction of amino groups into nanomaterials . Moreover, the aminated reagent is chemically bonded on the surface of the synthesized nanomaterials by a two‐step reaction, leading to the introduction of amino groups onto the surface of nanomaterials . However the two‐step reaction method has the disadvantage of complicating the experimental process, poor nanoparticle dispersion and low degree of amination.…”

Adsorption of Pb(II) and Cu(II) metal ions on functionalized large-pore mesoporous silica

“…6Ab than that of SH-SBA-15 materials. Under the same pH and initial solute concentration, pore size, the quantity, and nature of the functional group are the main factors affecting the metal adsorptions (Lam et al 2006;Walcarius et al 2003;Vasudevan et al 2011;Blitz et al 2007;Aguado et al 2009;Xia et al 2010). Aguado et al (2009) studied adsorption of heavy metal ions by SBA-15 materials functionalized with various amino-containing groups prepared by both one-pot condensation and grafting methods.…”

“…Several methods have been developed to remove heavy metal ions from aqueous solutions, and adsorption is one of the most frequently used techniques. The adsorbents adopted in the literature include waste dust (Wang and Lin 2008;Amarasinghe and Williams 2007;Sharaf and Hassan 2014;Singh et al 2014), clays (Ö zcan et al 2009), polymer fibers (Deng et al 2003), and porous silica (Feng et al 1997;Liu et al 2000;Lam et al 2006;Walcarius et al 2003;Vasudevan et al 2011;Blitz et al 2007;Aguado et al 2009Aguado et al , 2008Xia et al 2010;Da'na and Sayari 2011;Shahbazi et al 2011;Liang et al 2009;Kao et al 2008;Chandra et al 2010). Still, researches toward the development of efficient adsorbents for the removal of heavy metals from wastewater are of great concern.…”

“…Many works show that the adsorption capacity of mesoporous silica is related to the density of active sites and their textural properties (Lam et al 2006;Xia et al 2010;Agnado et al 2008). So far, the literature considering the influence of morphology of mesoporous organosilica on the adsorption of metal ions is limited on the silica gels (Vasudevan et al 2011;Blitz et al 2007;Xia et al 2010). Well-ordered thiol-functionalized SBA-1 with isotropic or spherical-shaped morphology has been synthesized by Kao et al (2008) using co-condensation method, but the different morphology materials have not been used in the adsorption of metal ions yet.…”