Ordered Mesoporous Silica Prepared in Different Solvent Conditions: Application for Cu(II) and Pb(II) Adsorption

Abstract

In this work, the synthesis of ordered mesoporous silica of MCM-41 type was investigated aimed at improving its morphology by varying the synthesis conditions in a one-pot process, employing different temperatures and solvent conditions. 2-methoxyethanol was used as co-solvent to ethanol. The co-solvent ratio and the synthesis temperature were varied. The pore morphology of the materials was characterized by nitrogen porosimetry and small angle neutron scattering (SANS), and the particle morphology by transmission electron microscopy (TEM) and ultra-small angle neutron scattering (USANS). The thermal behavior was investigated by simultaneous thermogravimetry-differential scanning calorimetry (TG-DSC) measurements. The SANS and N2 sorption results demonstrated that a well-ordered mesoporous structure was obtained at all conditions in the synthesis at room temperature. Addition of methoxyethanol led to an increase of the pore wall thickness. Simultaneously, an increase of methoxyethanol content led to lowering of the mean particle size from 300 to 230 nm, according to the ultra-small angle scattering data. The ordered porosity and high specific surfaces make these materials suitable for applications such as adsorbents in environmental remediation. Batch adsorption measurements of metal ion removal from aqueous solutions of Cu(II) and Pb(II) showed that the materials exhibit dominantly monolayer surface adsorption characteristics. The adsorption capacities were 9.7 mg/g for Cu(II) and 18.8 mg/g for Pb(II) at pH 5, making these materials competitive in performance to various composite materials.

Hydrothermal Synthesis and Properties of Nanostructured Silica Containing Lanthanide Type Ln–SiO2 (Ln = La, Ce, Pr, Nd, Eu, Gd, Dy, Yb, Lu)

“…1480 cm −1 corresponds to bending vibration of the C–H groups of the CTMA+ template, and consequently they are not observed after calcination. The broad absorption bands in region (iv) centered at 1055–1085 cm −1 , 785–805 cm −1 and 450–455 cm −1 in region (v) were attributed to asymmetric stretching, symmetric stretching and bending vibration of the Si-O-Si network, respectively [ 44 ].…”

Removal of Lead from Wastewater Using Synthesized Polyethyleneimine-Grafted Graphene Oxide

“…The maximum adsorption capacities (q m ) of Pb 2+ by PEI/GO and some other adsorbents are summarized in Table 8 . Compared to other reported adsorbents (commercial activated carbons [ 40 , 41 , 42 , 43 , 44 ], waste-based adsorbents/biosorbents [ 8 , 9 , 10 , 11 , 12 , 13 , 45 , 46 ], clays [ 47 , 48 , 49 ], magnetic nanoparticles [ 50 ], CNT composites [ 51 ], and silica-based sorbents [ 52 , 53 ], PEI/GO showed an excellent Pb 2+ adsorption capacity, and this can be attributed to the distinguished features of PEI/GO and, thus, the variety of possible adsorption mechanisms (eight possible interactions between Pb 2+ and PEI/GO), as mentioned earlier ( Figure 14 ).…”

Ordered Mesoporous Silica Delivering siRNA as Cancer Nanotherapeutics: A Comprehensive Review

“…Yamada et al synthesized small sized silica particles using ethanol . While Putz et al explored cosolvent 2-methoxyethanol to generate monodisperse silica particles of ∼200 nm and demonstrated an increase in pore wall thickness with the use of cosolvent . The solvent characters such as polarity, molecular weight, and viscosity altogether influence the silica hydrolysis and condensation rate.…”