Adsorption and Recognition Property of Tyrosine Molecularly Imprinted Polymer Prepared via Electron Beam Irradiation

Application Progress of Electron Beam Radiation in Adsorption Functional Materials Preparation

To solve the problems of water and air pollution, adsorption functional materials (ASFMs) have been extensively investigated and applied. Among the preparation methods of ASFM, electron beam radiation (EBR) has attracted much attention for its high efficiency, environmental friendliness, and wide applicability. Based on the introduction of the application of EBR technology, the EBR preparation of ASFM is summarized by grafting and cross-linking. Secondly, the application of corresponding ASFM for the adsorption of metal ions, inorganic anions, dyes, drugs and chemical raw materials, and carbon dioxide is summarized systematically. Then, the adsorption mechanisms of ASFM are illustrated, according to the different pollutants. Finally, the progress, issues, and prospects of EBR technology for ASFM preparation are discussed.

A new di-recognition and di-functional nanosurface aptamer molecularly imprinted polymer probe for trace glyphosate with SERS/RRS/Abs trimode technique

A new di-recognition nitrogen-doped carbon dot nanosurface aptamer molecularly imprinted polymer (CDNAg@MIPApt) nanocatalytic di-functional probe was prepared by microwave irradiation. The probe was utilized nitrogen-doped silver carbon dots (CDNAg) as the matrix, glyphosate (Gly) as the template molecule, α-methyl acrylate as the monomer, ethylene glycol dimethacrylate as the cross-linker, and aptamer as the biorecognition element. It could not only recognize Gly but also exhibits catalytic amplification function. It was found that CDNAg@MIPApt catalyzed the redox reaction of polyethylene glycol 400 (PEG400)-AgNO3 to generate silver nanoparticles (AgNPs). The AgNPs indicator component exhibit the effects of surface-enhanced Raman scattering (SERS), resonance Rayleigh scattering (RRS) and surface plasmon resonance absorption (Abs). In the presence of Gly, it binds to the surface imprinted site of CDNAg@MIPApt, to reduce AgNPs generation due to the catalytic activity of CDNAg@MIPApt decreasing. Thus, the SERS/RRS/Abs signal values decreased linearly. The linear ranges of SERS/RRS/Abs assay were 0.1-2.5 nM, 0.25-2.75 nM and 0.5-5 nM respectively. The detection limits were 0.034 nM, 0.071 nM and 0.18 nM Gly.

Label-Free Mode Based on Ferrocene/PEDOT:PSS-PPy for Molecularly Imprinted Electrochemically Ultrasensitive Detection of Amino Acids

Generally, molecularly imprinted (MIP) electrochemical sensors for amino acids operate in a "label-like" mode. That is, after an amino acid is specifically recognized by an imprinted cavity at the sensing interface, the amino acid itself provides the sensing signal for quantitative detection. However, poorly electroactive amino acids impede electron transfer at the sensing interface and require high potentials to drive the reaction; thus, more interfering reactions tend to be triggered in practical applications, causing enhanced background noise in the detection. To address these issues, a "label-free" mode of the MIP sensor based on the ferrocene (Fc)/PEDOT:PSS-polypyrrole (PPy) composite was designed for the first time. The Fc/PEDOT:PSS-PPy is drop coated on the electrode surface as a substrate, and MIP polymers with specific recognition ability are immobilized on the substrate via electrostatic adsorption. As a proof of concept, l-tyrosine (l-Tyr) was selected as a model analyte and the "label-free" mode MIP/Fc/PEDOT:PSS-PPy sensor was constructed. The limit of detection (LOD) and linearity range of the MIP/Fc/PEDOT:PSS-PPy sensor were 2.31 × 10-11 M and from 100 pM to 5 mM, respectively. Compared with the label-like mode, the LOD was three orders of magnitude lower, the linear range was increased by three orders of magnitude, and the sensitivity was improved by more than four times. This work provides a universal and effective concept for MIP electrochemical sensing of amino acids.

Adsorption of Levofloxacin onto Graphene Oxide/Chitosan Composite Aerogel Microspheres

The removal of pharmaceutical residues from water resources using bio-based materials is very important for human safety and health. Bio-based graphene oxide/chitosan (GO/CS) aerogel microspheres were fabricated with emulsification and cross-linking, followed by freeze drying, and were used for the adsorption of levofloxacin (LOF). The obtained GO/CS aerogel microspheres were characterized with scanning electron microscopy (SEM), Fourier-transform infrared (FTIR), and thermogravimetry (TG). The effects of GO content, pH value, and temperature on their adsorption capacity were investigated. With the incorporation of 40 wt% GO, the adsorption capacity increased from 9.9 to 45.6 mg/g, and the highest adsorption capacity, 51.5 mg/g, was obtained at pH = 8 and T = 25 °C. In addition, to obtain deeper insight into the adsorption process, the thermodynamics and kinetics of the process were also investigated with four different models of LOF adsorption. The thermodynamic modeling results revealed that LOF adsorption is exothermic, and the kinetic investigation demonstrated that LOF adsorption is generally consistent with a pseudo-first-order rate law.

Optimization Conditions of Malachite Green Adsorption onto Almond Shell Carbon Waste Using Process Design

Almond shell-based biocarbon is a cheap adsorbent for the removal of malachite green, which has been investigated in this work. FT-IR, DRX, and BET were used to characterize almond shell-based biocarbon. The nitrogen adsorption-desorption isotherms analysis results showed a surface area of 120.21 m2/g and a type H4 adsorption isotherm. The parameters of initial dye concentration (5-600 mg.L-1), adsorbent mass (0.1-0.6 mg), and temperature (298-373 K) of adsorption were investigated. The experiments showed that the almond shell could be used in a wide concentration and temperature range. The adsorption study was fitted to the Langmuir isotherm and the pseudo-second-order kinetic model. The results of the FT-IR analysis demonstrated strong agreement with the pseudo-second-order chemisorption process description. The maximum adsorption capacity was calculated from the Langmuir isotherm and evaluated to be 166.66 mg.g-1. The positive ∆H (12.19 J.mol-1) indicates that the adsorption process is endothermic. Almond shell was found to be a stable adsorbent. Three different statistical design sets of experiments were taken out to determine the best conditions for the batch adsorption process. The optimal conditions for MG uptake were found to be adsorbent mass (m = 0.1 g), initial dye concentration (C0 = 600 mg.L-1), and temperature (T = 25 °C). The analysis using the D-optimal design showed that the model obtained was important and significant, with an R2 of 0.998.

Effect of Carbon Nanoparticles Morphology on the Properties of Poly(styrene-b-isoprene-b-styrene) Elastomer Composites

Though nanomaterials based on carbon have been widely used for the preparation of high-performance polymeric nanocomposites, there are few works focused on the effect of carbon nanoparticle morphology on the performance of corresponding polymer nanocomposites. Therefore, four representative carbon nanoparticles, including fullerene, carbon nanotubes, graphene, and carbon black incorporated poly(styrene-b-isoprene-b-styrene) (SIS) elastomer nanocomposites were fabricated using the solvent casting method. In addition, the effect of carbon nanoparticle morphology on the rheological, mechanical, electrical, and thermal properties of the obtained polymeric nanocomposites was systematically investigated. The results showed that the shape of carbon nanoparticles has a different effect on the properties of the obtained elastomer nanocomposites, which lays the foundation of carbon nanoparticle screening for high-performance polymer nanocomposite construction.