Influence of Pesticide Properties on Adsorption Capacity and Rate on Activated Carbon from Aqueous Solution

The adsorbate structural properties such as the type, number, and position of substituents on benzene ring of organic compound, as well as a length and arrangement of hydrocarbon chain in a space, exert a significant influence on the adsorption process. The measurements of adsorption equilibria and kinetics of several pesticides belonging to the group of halogenated phenoxyacids differentiated in terms of structural and physicochemical properties were studied in order to characterize the adsorption mechanism and correlate it with the pollutant properties. Regarding a complexity of investigations (capacity and rate) comprising 21 structurally closely related active substances showing the carcinogenic activity on living organisms and relatively long half-life time in the environment, the proposed intensive studies on the removal of pollutants by adsorption process are very important in cognitive and practical terms

Investigation of surface structure, electrokinetic and stability properties of highly dispersed Ho₂O₃-Yb₂O₃/SiO₂ nanocomposites

A series of highly dispersed Ho2O3–Yb2O3/SiO2 nanocomposites was synthesized using a liquid-phase method and examined using Fourier transform infrared (FTIR) spectroscopy, X-ray diffraction (XRD), nitrogen adsorption–desorption, transmission electron microscopy (TEM), Scanning Electron Microscopy (SEM), and photon correlation spectroscopy (PCS). X-ray fluorescence spectrometry (XRF) confirmed a similar amount of weight percentage of Ho, Yb and Si oxides in the prepared samples. Samples HoYbSi1 (Ho2O3:Yb2O3:SiO2 = 0.5:10:89.5, wt. %), HoYbSi2 (Ho2O3:Yb2O3:SiO2 = 1:10:89, wt. %) and HoYbSi3 (Ho2O3:Yb2O3:SiO2 = 2:10:88, wt. %) calcined at 550 °C are amorphous. TEM and SEM analysis confirm a sphere-like morphology with a quite homogeneous size and shape. As compared with the initial silica, the agglomerated particles of nanocomposites in the aqueous medium are in the range from 200 to 850 nm according to PCS data. The effect of anionic polyacrylic acid (PAA) adsorption on fumed silica (SiO2) and Ho2O3–Yb2O3/SiO2 nanocomposite surfaces on suspension stability was studied. The turbidymetry method was used to monitor the initial silica and triple nanooxides suspensions stability as a function of time

Physicochemical, structural, and adsorption characteristics of DMSPS-co-DVB nanopolymers

The aim of this work is the synthesis and characterization of the series of S,S′-thiodi-4,1-phenylene bis(thio-methacrylate)-co-divinylbenzene (DMSPS-co-DVB) nanomaterials. The series of new nanopolymers including three mixed systems with different ratios of DMSPS and DVB components, DMSPS-co-DVB = 1:1, DMSPS-co-DVB = 1:2, and DMSPS-co-DVB = 1:3, was synthesized in the polymerization reaction. The research task is to investigate the influence of the reaction mixture composition on morphological, textural, and structural properties of final nanosystems including size, shape, and agglomeration effect. The advanced biphasic nanomaterials enriched with thiol groups were successfully synthesized as potential sorbents for binding organic substances, heavy metals, or biomolecules. To determine the impact of the DMSPS monomer on the final properties of DMSPS-co-DVB nanocomposites, several techniques were applied to reveal the nano-dimensional structure (SAXS), texture (low-temperature nitrogen sorption), general morphology (SEM), acid–base properties (potentiometric titration), and surface chemistry and phase bonding effectiveness (FTIR/ATR spectroscopy). Finally, kinetic studies of aniline sorption on polymeric materials were performed

Immobilization of HRP in Mesoporous Silica and Its Application for the Construction of Polyaniline Modified Hydrogen Peroxide Biosensor

Polyaniline (PANI), an attractive conductive polymer, has been successfully applied in fabricating various types of enzyme-based biosensors. In this study, we have employed mesoporous silica SBA-15 to stably entrap horseradish peroxidase (HRP), and then deposited the loaded SBA-15 on the PANI modified platinum electrode to construct a GA/SBA-15(HRP)/PANI/Pt biosensor. The mesoporous structures and morphologies of SBA-15 with or without HRP were characterized. Enzymatic protein assays were employed to evaluate HRP immobilization efficiency. Our results demonstrated that the constructed biosensor displayed a fine linear correlation between cathodic response and H2O2 concentration in the range of 0.02 to 18.5 mM, with enhanced sensitivity. In particular, the current approach provided the PANI modified biosensor with improved stability for multiple measurements