Homogeneous Zr and Ti co-doped SBA-15 with high specific surface area: preparation, characterization and application

Abstract

A facile synthesis procedure is proposed to prepare homogeneous Zr and Ti co-doped SBA-15 (Zr-Ti-SBA-15) with high specific surface area of 876.0 m 2 g − 1 . Based on "masking mechanism" from tanning, lactic acid was used as masking agent to obtain the uniform distribution of Zr and Ti species in the SBA-15 framework. The obtained materials were characterized by powder X-ray diffraction (XRD), nitrogen adsorption-desorption isotherms, scanning electron microscope (SEM), transmission electron microscope (TEM) and X-ray photoelectron (XPS). The results reveal that in mesoporous materials, the presence of lactic acid gives rise to the uniform distribution of Zr and Ti species. The adsorption equilibrium and kinetic studies of Zr-Ti-SBA-15 materials show that the adsorption process conforms to the Langmuir isotherm and pseudo-second-order kinetic model, respectively. Regenerational experiments show that the Zr-Ti-SBA-15 displays a significant adsorption ability for methylene blue (MB) (up to 291.6 mg/g), along with good reusability, indicating promising potentials of commercialization. Methodologically, this work provides a wide range of possibilities for further development of SBA-15 based on bimetallic and sewage disposal.

Catalytic Conversion of Biomass-Derived Levulinic Acid to γ-Valerolactone over Amphoteric Zirconium Hydroxide

“…The different BEs of Zr 3d and Si 2p and their electronic states as well as outermost surface compositions were further verified by XPS, and the results are displayed in Figure and summarized in Supplementary Table S1. The stronger spin orbit double peaks appeared at ∼182.5 and ∼185 eV with an energy interval of 2.5 eV corresponding to the Zr 3d core energy levels from the separate contributions of Zr 3d 5/2 and Zr 3d 3/2 for their characteristic phases of ZrO 2 and Zr­(OH) 4 , which suggests the coexistence of ZrO­(OH) 2 · x H 2 O phases with their typical full oxidation state of Zr 4+ . − The peak positions of Zr 3d 5/2 shifted to a higher BE of ∼183.0 eV on ZrOH (10) and ZrOH (20) from ∼182.5 eV on ZrOH (1) [Figure A], which was possibly attributed to the selective formation of Zr–O–Si structures, due to a higher electronegativity of the Si atom than that the Zr atom . In addition, those shifts also largely changed the BEs of the Si 2p peak position from ∼101.9 eV on ZrOH (1) to ∼103.0 eV on ZrOH (20) as displayed in Figure B.…”

“…39−41 The peak positions of Zr 3d 5/2 shifted to a higher BE of ∼183.0 eV on ZrOH (10) and ZrOH (20) from ∼182.5 eV on ZrOH (1) [Figure 2A], which was possibly attributed to the selective formation of Zr−O−Si structures, due to a higher electronegativity of the Si atom than that the Zr atom. 42 In addition, those shifts also largely changed the BEs of the Si 2p peak position from ∼101.9 eV on ZrOH (1) to ∼103.0 eV on ZrOH (20) 43 Based on the above physicochemical properties of the Zr(OH) 4 catalysts, more interesting findings are typical volcano patterns of total and L acid sites as well as medium basic sites with its maximum amount on ZrOH (7) (0.651 and 0.285 as well as 3.91 mmol/g, respectively) as measured by NH 3 -and CO 2 -TPD and Py-IR. Moreover, we strongly believe that the surface OH contents largely altered the number of B acid sites and the ratio of terminal to bridged OH groups due to the newly formed Zr−O−Si structures.…”

Bahaya Kromium Hexavalen (Cr VI) Pada Kulit Dan Produk Kulit Samak Krom Serta Upaya Pencegahannya

“…Masalah pencemaran kromium yang ada merupakan tantangan bagi para peneliti untuk mengembangkan sistem penyamakan alternatif yang meminimalkan kadar kromium limbah (Li, et al, 2019b;Ashokkumar, et al, 2012). Untuk memecahkan masalah pencemaran kromium secara mendasar, telah dilakukan aplikasi penyamakan bebas krom untuk mencapai proses penyamakan hijau (green tanning process) (Zhu, et al, 2020), seperti penyamakan logam non-krom (Qiang, et al, 2019), penyamakan aldehida (Sun, et al, 2018), penyamakan menggunakan tanin sintetis (Beghetto, et al, 2019;(Ferrero, et al, 2015). Namun, penyamakan kulit bebas krom ini mempunyai kekurangan, seperti stabilitas hidrotermal rendah, terbentuknya formaldehida bebas yang karsinogenik dan berbau menyengat sehingga kulitnya tidak dapat diterima pasar (Zhu, et al, 2020).…”