Catalytic Ozonation of Nitrobenzene by Manganese-Based Y Zeolites

Abstract

Catalytic ozonation process (COP) is considered as a cost-efficient technology for the treatment of refractory chemical wastewaters. The catalyst performance plays an important role for the treatment efficiency. The present study investigated efficiencies and mechanisms of manganese (Mn)-based Y zeolites in COPs for removing nitrobenzene from water. The catalysts of Mn/NaY and Mn/USY were prepared by incipient wetness impregnation, while Mn-USY was obtained by hydrothermal synthesis. Mn-USY contained a greater ratio of Mn 2+ than Mn/NaY, and Mn/USY. Mn oxides loaded on Y zeolites promoted the COP efficiencies. Mn/NaY increased total organic carbon removal in COP by 7.3% compared to NaY, while Mn/USY and Mn-USY increased 11.5 and 15.8%, respectively, relative to USY in COP. Multivalent Mn oxides (Mn 2+ , Mn 3+ , and Mn 4+ ) were highly dispersed on the surface of NaY or USY, and function as catalytic active sites, increasing mineralization. Mn-USY showed the highest total organic carbon removal (44.3%) in COP among the three catalysts, because Mn-USY had a higher ratio of Mn 2+ to the total Mn oxides on the surface than Mn/NaY and Mn/USY and the catalytic effects from intercorrelations between Mn oxides and mesoporous surface structures. The hydroxyl radicals and superoxide radicals governed oxidations in COP using Mn-USY. Nitrobenzene was oxidized to polyhydroxy phenol, polyhydroxy nitrophenol, and p-benzoquinone. The intermediates were then oxidized to small organic acids and ultimately carbon dioxide and water. This study demonstrates the potential of Y zeolites used in COP for the treatment of refractory chemical wastewaters.

Materials engineering strategies for cancer vaccine adjuvant development

“…Moreover, apart from conventional vaccine components, the diverse physicochemical properties of antigens and adjuvants also raises technical concerns over the sterilization method, bioavailability, and stability. 77 Recently, some synthetic polymer-and lipid-based nanomaterials have emerged as vaccine adjuvants that exhibit self-adjuvant properties for cancer immunotherapy. These self-adjuvanting materials exhibit immune activity to effectively trigger innate immune responses.…”

New opportunities for immunomodulation of the tumour microenvironment using chemical tools

“…Other PRRs have also been explored for their ability to activate APCs. 91,92 For example, Bertozzi et al employed ligands for C-type lectin receptors (CLRs) that were composed of glycopolypeptides containing mono-, di-, and trisaccharides for APC activation. 93 This finding suggests that polysaccharides have potential as adjuvants for immunotherapy and their further applications are worthy of exploration.…”

Overcoming STING Agonists Barriers: Peptide, Protein, and Biomembrane‐based Biocompatible Delivery Strategies

“…Agonist‐induced STING activation in antigen‐presenting cells (APCs) not only generates IFN‐β and other pro‐inflammatory cytokines, but also upregulates the costimulatory signals (CD86, CD80 and CD40) and major histocompatibility complex (MHC) class I/II. These characteristics are exactly what is required for the efficient presentation of vaccine antigens and T cell immunity induction [17–19] . Currently, the adjuvant application of STING agonists focuses on cancer vaccine (tumor‐associated antigen and neoantigen), influenza vaccine and SARS‐CoV‐2 vaccine.…”

“…These characteristics are exactly what is required for the efficient presentation of vaccine antigens and T cell immunity induction. [17][18][19] Currently, the adjuvant application of STING agonists focuses on cancer vaccine (tumor-associated antigen and neoantigen), influenza vaccine and SARS-CoV-2 vaccine. Tumor-associated antigen (TAA) is a self-antigen abnormally expressed or overexpressed on tumor cell, but also has a lower level on normal cell.…”