Metals and Antibiotics as Aqueous Sequestration Targets for Magnetic Polyamidoamine-Grafted SBA-15

Abstract

In this study, a magnetic generation-5 polyamidoamine (G-5 PAMAM) dendrimer-functionalized SBA-15 (mPSBA) composite was synthesized by coupling amine-functionalized silica (SBA-15-NH 2 ) and amine-functionalized magnetic nanoparticles (MNP-NH 2 ) with the G-5 PAMAM, before characterization and aqueous sorption of As(III), Cd(II), tetracycline, and ciprofloxacin using the composite. The mPSBA characterization data exhibited the typical Si−O−Si infrared peaks from the SBA-15 backbone in addition to the acquired characteristic infrared Fe−O and amide-I/II peaks from the MNP and G-5 PAMAM dendrimers, respectively. Postsorption infrared spectra showing shifts for the amide-linked groups indicated the likely points of contaminant attachment on the composite. Its thermal stability was lower than that of SBA-15 but higher than that of SBA-15-NH, while the XRD diffractograms of the backbone SBA-15-NH and MNP were unchanged in the final composite. The mPSBA composite was a better As(III) and Cd(II) adsorbent than SBA-15 by ≈400 and 140%, respectively, with rapid uptake in the first 60 min and equilibrium achieved at 120 min. Sorption was enhanced with increasing pH (until pHpzc) and initial contaminant concentration. The process was spontaneous and endothermic; thus, increasing ambient temperature enhanced Cd(II) sorption. The sorption data fitted better to the homogeneous fractal pseudo-second-order (FPSO) kinetics model and the Brouers−Sotolongo fractal adsorption isotherm models, indicating complex sorption interactions and pore-filling/contaminant trapping within mPSBA. Further experiments using mPSBA for the uptake of tetracycline and ciprofloxacin showed 679% and 325% higher sorption, respectively, compared with that for SBA-15-NH. In addition to the added advantage of easy removal from solution/treated water after the adsorption process, mPSBA sorption capacities for these studied contaminants [As(III): 23.3 mg/g; Cd(II): 74.5 mg/g; tetracycline: 38.4 mg/g; ciprofloxacin: 23.0 mg/g] are better than those of several advanced adsorbents reported in the literature.

Facile synthesis of pyrazolopyridine pharmaceuticals under mild conditions using an algin-functionalized silica-based magnetic nanocatalyst (Alg@SBA-15/Fe3O4)

“…3a, the diffractograms of SBA-15 shows a broad distinctive peak in the range of 2 θ : 20°–30° attributed to the amorphous SiO 2 character. 47,48 The XRD pattern of SBA-15/Fe 3 O 4 shows peaks at 2 θ = 30.35°(2 2 0), 35.98°(3 1 1), 43.56°(4 0 0), 57.70°(3 3 3) (Fig. 3b) that are also present in the diffractograms of the prepared Fe 3 O 4 nanoparticles.…”

Development of Regular Hydrophobic Silica Aerogel Microspheres for Efficient Oil Adsorption

“…The bands at 1269 and 1257 cm –1 are C–H symmetrically deformed vibrations from the Si–OR group. Antisymmetric stretching vibrations of Si–O–Si are classified as transverse optical and longitudinal optical bands at 1136, 1016, and 1056 cm –1 , respectively. , The band at 951 cm –1 originates from the Si–O in-plane stretching vibration of the Si–O group. The Si–O stretching vibrations caused by the Si–O–Si group can be accounted for by the bands at 793, 781, and 755 cm –1 .…”

Mesoporous Silica-Confined MOF-525 for Stable Adsorption of Tetracycline over a Wide pH Application Range

“…This finding can be explained by the formation of MOF-525 crystals on the outer surface of SBA-15. 22 The porous structure of SBA-15 was maintained in the TEM image of the composites (Figure 3d), but dark spots appeared in the ordered hexagonal pores. Hence, the MOF-525 crystals likely nucleated inside the mesopore channels of SBA-15.…”

“…One way to circumvent the instability is to combine MOFs with other highly robust supporting materials. Ordered mesoporous silica materials stand out owing to their high hydrothermal stability and mechanical strength, modifiable surface properties, and adjustable pore size. − More recently, the MOF and mesoporous silica composites have emerged and subsequently aroused research interest. For example, Furtado et al .…”