Enhanced Removal of Cr(III), Mn(II), Cd(II), Pb(II) and Cu(II) from Aqueous Solution by N-functionalized Ordered Silica

Removal of Poly- and Perfluoroalkyl Substances from Natural and Wastewater by Tailored Silica-Based Adsorbents

“…Using milder conditions (2 M HCl and sodium silicate solution) compared with our previous studies, 28,29,29,34 we obtained SBA based on metasilicate, with an ordered structure, but a slightly lower specific surface area. This can be observed not only from the TEM images (Figure 2) but also from the isotherm in Figure 5.…”

“…The small particle size and ordered mesoporous structure of SBA-15 are known to provide rapid adsorption and mass exchange. 27,28,33 Previously, SBA-15 was primarily obtained using expensive tetraethyl ortho silicate as the silica precursor; therefore, an inexpensive sodium silicate as a source of silica has become an attractive option. 29,30,34 Using another source of silica than in our previous studies (i.e., solution of sodium silicate instead of solid salt) led to further characteristics of the samples especially of "bare" SBA-15.…”

“…This study aimed to develop highly efficient and regenerable tailored silica-based sorbents for the removal of PFOA as a representative of perfluoroalkylated acids (PFAA) and to reveal the sorption mechanisms of PFOA to the sorbents. Amine-containing materials derived from ordered mesoporous silica developed by the University of California at Santa Barbara, SBA-15 (SBA-NH, SBA-DA, SBA-TAfor detailed description, please, see later) were selected as the sorbent for PFAS removal as it has demonstrated high capacity and selectivity in relation to various types of pollutants. − Different ligands were used because the basic properties of the amino group usually are enhanced by the influence of alkyl radicals so primary amines are stronger bases than ammonia, which could be explained by the electron-donating properties of alkyl radicals (induction effect). The electron-donating methyl group makes the secondary amino groups (SAGs) stronger bases than the primary amino group (PAG).…”

Natural Silicates Encapsulated Enzymes as Green Biocatalysts for Degradation of Pharmaceuticals

“…Appearance of the silica shell was additionally monitored by FTIR analysis on bare adsorbents and core–shell immobilized samples. All three samples had characteristic peaks of SiO 2 around 460, 800, and 1085 cm –1 , corresponding to δ­(Si–O–Si), υ­(Si–O–Si), and υ as (Si–O–Si) vibrations , (Figure a, Figure S5). Another characteristic band for leca and FA samples (Figure S5) appeared at 572 cm –1 and a shoulder peak at 730 cm –1 that could correspond to Fe–O and Al–OH groups. − The latter disappeared after silica shell coverage and instead a new band appeared for all three samples at 960 cm –1 that corresponded to Si–OH vibrations …”

Tailoring Nanoadsorbent Surfaces: Separation of Rare Earths and Late Transition Metals in Recycling of Magnet Materials

“…Several reviews have already been devoted to the discussion of the advantages and challenges in the application of functional solid adsorbents for REE separation [ 22 , 23 ]. Recent works have shown that organic–inorganic functionalized silica nanoparticles possess great adsorption capacity and selectivity towards many metal ions, including heavy metals and REEs [ 24 ]. Functional groups such as iminodiacetic acid (IDA), diethylenetriaminepentaacetic acid (DTPA), ethylenediaminetetraacetic acid (EDTA) and triethylenetetraminehexaacetic acid (TTHA) were grafted on dense SiO 2 nanoparticles as well as SiO 2 core–shell magnetic nanoparticles and tested for different REEs adsorption and separation.…”