Study on morphology, thermal, mechanical and Cd(II) adsorption properties of PVC/α-MnO2-stearic acid nanocomposites: production and application

Electrochemical aptasensor based on the target-induced strand displacement strategy-driven for T-2 toxin detection

Herein, an aptasensor based on target-induced strand displacement (TISD) strategy was developed for sensitive detection of T-2 toxin. Gold nanoparticles@ aminated manganese dioxide (AuNPs@NH₂-MnO₂) exhibited excellent electrical conductivity and provided more binding sites for aptamer (Apt). Besides, polyethyleneimine-reduced graphene oxide/gold‑platinum core-shell nanorods composites (PEI-rGO/Pt@Au NRs) were used to be carriers for signaling tags, as their sufficiently large specific surface area improved the loading capacity for signal molecules. In the presence of T-2, the Apt sequence was more inclined to form an Apt-T-2 complex, and the cDNA was displaced from the Apt-cDNA duplex, while the signal tag was released, resulting in a weakened MB signal, differential pulse voltammetry (DPV) was used to record the signal change. Under optimal conditions, the signal response of the constructed electrochemical aptasensor exhibited a good linear relationship with the concentration of T-2. The detection limit was 8.74 × 10^-7 ng mL^-1over a wide range of concentration from 5 × 10^-6 ng mL^-1 to 5 ng mL^-1. Furthermore, the proposed aptasensor had excellent specificity, good stability and can be well applied to the detection of real samples. It provided a new avenue for the research and development of sensitive aptasensors in food detection and analysis.

Enhanced removal of oxytetracycline antibiotics from water using manganese dioxide impregnated hydrogel composite: Adsorption behavior and oxidative degradation pathways

The present work provides the first attempt of using manganese dioxide loaded poly(sodium acrylate) hydrogel (MnO₂@PSA) to address potential threats posed by oxytetracycline (OTC) antibiotics in aqueous environment. The MnO₂@PSA was prepared via a facile approach and demonstrated enhanced removal performance even under extremely high concentrations of OTC. The outstanding performance exhibited by MnO₂@PSA was attributed to synergetic effects of adsorption oxidative degradation. The synthesized composite was characterized evaluated under varying conditions. The adsorption pH was optimized at pH 5, at which the removal efficiency OTC was reached 91.46%. According to the kinetics study, the pseudo-second-order kinetic model was the best to explain the adsorption data, implying the interaction mechanisms were dominated by chemisorption. The Langmuir isotherm model was the best to explain the isotherm data, and the corresponding maximum adsorbed amount of OTC was 1150.4 mg g^-1. The MnO₂@PSA was highly selective for OTC adsorption and degradation under the presence of natural organic matter and common environmental metal ions. The oxidative degradation study indicated that OTC molecules were structurally degraded into 15 intermediate products via six reaction pathways. Both the theoretical models and spectroscopic methods demonstrated the removal mechanism of OTC onto MnO₂@PSA was governed by ion exchange, cation-π bonding, hydrogen-bonding, and π-π electron donor-acceptor. Overall, MnO₂@PSA is an excellent and environmentally sustainable material to remove OTC from water and wastewater via the combined effects of adsorption and oxidative degradation.

Design and identification of poly(vinyl chloride)/layered double hydroxide@MnO2 nanocomposite films and evaluation of the methyl orange uptake: linear and non-linear isotherm and kinetic adsorption models

In this work, an adsorbent based on poly(vinyl chloride) (PVC) for the removal of methyl orange (MO) dye is proposed.

Simple construction of core–shell MnO2@TiO2 with highly enhanced U(vi) adsorption performance and evaluated adsorption mechanism

Simple construction of core–shell MnO₂@TiO₂ with highly enhanced U(vi) adsorption performance and evaluation of its adsorption mechanism.

Ultrasound-assisted surface treatment of ZrO2 with BSA and incorporating in PVC to improve the properties of the obtained nanocomposites: Fabrication and characterization

This paper describes the preparation of poly(vinyl chloride) (PVC) nanocomposites (NCs) reinforced with modified zirconia (ZrO₂) nanoparticles (NPs). The ZrO₂ NPs were defined as efficient filler for PVC NCs. For achieving the best dispersion and improvement of properties, the surface of ZrO₂ NPs was modified by Bovine Serum Albumin (BSA). Carboxylic acids and amines are important functional groups of BSA which handle the grafting BSA on the surface of ZrO₂ NPs. The PVC/ZrO₂-BSA NCs were fabricated by incorporation of various amounts of the ZrO₂-BSA NPs (3, 6 and 9wt%) into PVC matrix. All the above processes were accomplished by ultrasonication asa green and environmentally-friendly method. Also, the magnetic and mechanical stirrer was used for the preparation of samples but the results are not suitable and the aggregation was observed which indicated the use of ultrasonic irradiation is the best method for the preparation of NC. The products were characterized by Fourier transform infrared spectroscopy, Transmission electron microscopy, Field emission scanning electron microscopy, X-ray diffraction, Thermogravimetric analysis, Ultraviolet-visible spectroscopy, photoluminescence spectroscopy, energy dispersive X-ray spectroscopy, wettability, and mechanical tests. The achieved PVC/ZrO₂-BSA NCs showed high thermal stability, good mechanical, optical and wettability properties compared to the pure PVC. In addition, among the obtained NCs, the PVC/ZrO₂-BSA NC 6wt% showed the best improvement.

Employment of ultrasonic irradiation for production of poly(vinyl pyrrolidone)/modified alpha manganese dioxide nanocomposites: Morphology, thermal and optical characterization

This work explains the production, morphology, and features of novel nanocomposite (NC) established on poly(vinyl pyrrolidone) (PVP) as polymer background and modified alpha manganese dioxide (α-MnO₂) nanorod (NR) asan efficient filler. At first, one-dimensional α-MnO₂ nanorods (NRs) were produced by a hydrothermal technique and then they were amended with stearic acid (SA) by a solvothermal process. In following, the NCs were made by adding different volumes of α-MnO₂-SA NR (1, 3 and 5wt%) in the PVP matrix through ultrasonic irradiation as a green, low-cost, fast, and useful technique. Structural and morphological descriptions confirm crystallinity of α-MnO₂-SA NRs and showed that NRs have been separately dispersed in PVP matrix with rod-like morphology and diameter of about 40-60nm. The use of modifier and ultrasonic waves is accountable for good homogeneities of NRs. Thermogravimetric analysis revealed that thermal permanency of the obtained NCs has grown with increasing the α-MnO₂-SA content. Also, the UV-vis absorption of NCs was enhanced with the incorporation of the modified α-MnO₂ NR in PVP matrix. The substantial perfections in NCs properties are associated to compatible intermolecular relations between the surface modifying groups of the α-MnO₂-SA and PVP chain.

Use of PVA/α-MnO2-stearic acid nanocomposite films prepared by sonochemical method as a potential sorbent for adsorption of Cd (II) ion from aqueous solution

Alpha manganese dioxide (α-MnO₂) nanorods have been covalently functionalized with stearic acid by solvothermal method. The α-MnO₂-stearic acid nanorods were characterized by Fourier transform infrared spectroscopy, X-ray diffraction, field emission scanning electron microscopy and transmission electron microscopy. The amount of stearic acid grafted onto α-MnO₂ surface was determined about 41wt% by thermogravimetric analysis. The α-MnO₂-stearic acid nanorods was used as nanofiller for the preparation of poly(vinyl alcohol) (PVA) nanocomposites (NCs). The NCs with 1, 3, and 5wt% of nanofiller were prepared through ultrasound assisted technique as an economical, fast, eco-friendly, and effective method. The PVA/α-MnO₂-stearic acid NCs were characterized by different techniques. The results showed that with increasing the α-MnO₂-stearic acid content, the thermal stability and tensile properties were improved. Besides, the NC 5wt% was used as adsorbent for sorption of Cd (II) ion. The adsorption efficiency of NC 5wt% in different initial concentrations of Cd (II) ion (20-100mgL^-1) was 58-95%. All the isotherm data were well fitted by both Langmuir and Freundlich equations. The adsorption kinetics study demonstrated that pseudo-second-order model was the best fit with the experimental data. The results indicated that prepared NCs are promising adsorbents for the removal of Cd (II) ion from the aqueous solution.