In this study, we report a facile and effective production process of palladium nanoparticles supported on polypyrrole/reduced graphene oxide (rGO/Pd@PPy NPs). A novel electrochemical sensor was ...fabricated by incorporation of the prepared NPs onto glassy carbon electrode (GCE) for the simultaneous detection of ascorbic acid (AA), dopamine (DA) and uric acid (UA). The electrodes modified with rGO/Pd@PPy NPs were well decorated on the GCE and exhibited superior catalytic activity and conductivity for the detection of these molecules with higher current and oxidation peak intensities. Simultaneous detection of these molecules was achieved due to the high selectivity and sensitivity of rGO/Pd@PPy NPs. For each biomolecule, well-separated voltammetric peaks were obtained at the modified electrode in cyclic voltammetry (CV) and differential pulse voltammetry (DPV) measurements. Additionally, the detection of these molecules was performed in blood serum samples with satisfying results. The detection limits and calibration curves for AA, DA, and UA were found to be 4.9 × 10
, 5.6 × 10
, 4.7 × 10
M (S/N = 3) and ranging from 1 × 10
to 1.5 × 10
M (in 0.1 M PBS, pH 3.0), respectively. Hereby, the fabricated rGO/Pd@PPy NPs can be used with high reproducibility, selectivity, and catalytic activity for the development of electrochemical applications for the simultaneous detection of these biomolecules.
In this work, we report the synthesis, characterization and application of graphene oxide stabilized PdCo nanoparticles (PdCo@GO) for the dehydrocoupling of dimethylamine borane (DMAB) as a model ...reaction. Bimetallic graphene oxide stabilized PdCo nanoparticles were readily synthesized using an ultrasonic reduction technique, in which both metals of Pd and Co were reduced with GO. The dispersion of PdCo nanoparticles on the surface of GO was enhanced with the help of the ultrasonic reduction method which result in the enhancing of dispersion of both metals without any agglomeration problem. The characterization studies revealed that graphene oxide stabilized PdCo nanoparticles have a uniform, homogeneous distribution on graphene oxide and an average particle size of 3.48 ± 0.22 nm. After fully characterization of graphene oxide stabilized PdCo nanoparticles, they have been tried in model reaction as a catalyst and exhibited a high catalytic performance compared the previous catalysts in literature with a TOF value of 226.80 h−1. The investigation of kinetic parameters showed that graphene oxide stabilized PdCo nanoparticles have very high negative entropy (ΔS: −170.85 J mol−1 K−1) value and a low activation energy value (Ea: 17.53 ± 2 kJ mol−1) for the model reaction.
•Monodisperse PdCo@GO was prepared by the ultrasonic reduction method.•Monodisperse PdCo NPs were decorated on graphene oxide as efficient and stable catalysts.•PdCo@GO NPs exhibited a high catalytic activity with a 226.80 h−1 TOF value.•The detailed kinetic study of the dehydrocoupling reaction of DMAB catalyzed by PdCo@GO NPs was studied.
Common textile dyes used in various industrial sectors are organic compounds and considered for the aquatic environment as pollutants. The textile dye industry is one of the main sectors that have ...serious impacts on the environment due to a large amount of wastewater released into the ecosystem. Maxilon blue 5G (MB-5G) and Reactive Blue 203 (RB-203) are widely used textile dyes. However, their potential toxicity on living organisms remains to be elucidated. Here, we investigate the acute toxicity and genotoxicity of MB-5G and RB-203 dyes using the zebrafish embryos/larvae. Embryos treated with each dye for 96 h revealed LC50 values of acute toxicity as 166.04 mg L−1 and 278.32 mg L−1 for MB-5G and RB 203, respectively. When exposed to MB-5G and RB-203 at different concentrations (1, 10, and 100 mg L−1) for 96 h, the expression of 8-hydroxy-2′-deoxyguanosine (8-OHdG), a marker of oxidative DNA damage, significantly increased in brain tissues as compared to control. MB-5G and RB-203 resulted in common developmental abnormalities including tail malformation, microphthalmia, pericardial edema, curved body axis, and yolk sac/pericardial edemas. Moreover, at its highest dose (100 mg L−1), RB-203 caused premature hatching after 48 h, while MG-5G did not. Our results collectively reveal that the textile dyes MB-5G and RB-203 cause genotoxicity and teratogenicity during embryonic and larval development of zebrafish. Thus, it is necessary to eliminate these compounds from wastewater or reduce their concentrations to safe levels before discharging the textile industry wastewater into the environment.
Display omitted
•Maxilon Blue 5G (MB-5G) and Reactive Blue 203 (RB-203) exert acute toxicity on zebrafish embryos/larvae.•MB-5G exhibits no changes in the hatching rate, but RB-203 may lead to premature hatching.•MB-5G and RB-203 induce dose-related oxidative DNA damage in the larval zebrafish brain.
The composite consisted of clay and polymers like polyethylene (GCP) was used to remove methylene blue (MB) from the water. The most effective pH, temperature and initial dye concentration in ...adsorption process were found to be 9, 55 °C and 5 × 10
−6
M, respectively. The results of the experiment showed that the adsorption process was compatible with the pseudo-second-order model. Activation parameters of Δ
G
: − 70.64 K J mol
−1
, Δ
S
: − 70.64 J mol
−1
K
−1
,
E
a
: 12.37 K J mol
−1
at 308 °C were calculated and showed that adsorption process was exothermic and spontaneous. The results revealed that adsorption of MB on composite GCP was spontaneous and the composite of GCP
f
could be used for removing of MB from the water.
In this paper, we present the synthesis, characterization, catalytic and computational studies of Composites of Platinum-Iridium Alloy Nanoparticles and Graphene Oxide (PtIr@GO) for dimethylamine ...borane (DMAB) dehydrogenation. The prepared PtIr@GO nanocatalysts were synthesized using an ethanol super-hydride method, and the characterization procedures for PtIr@GO alloy nanoparticles were carried out by various advanced spectroscopic methods like X-ray Diffraction (XRD), X-ray photoelectron spectroscopy (XPS), Transmission Electron Microscopy(TEM) and high-resolution transmission electron microscopy (HRTEM). Additionally, catalytic activity, reusability, substrate concentration, and catalyst concentration experiments were performed for DMAB dehydrogenation catalyzed by PtIr@GO alloy nanomaterials. According to the results obtained in this study, PtIr@GO NPs catalyst was found to be active and reusable for the DMAB even at ambient conditions. Besides, DFT-B3LYP calculations have been utilized on PtIr@GO cluster to reveal the prepared catalyst activity. The calculated findings based on DFT was found to be a good agreement with experimental results.
In this research, adsorption properties of bovine serum albumin (BSA) on diatomite clay, which is an oxide mineral, were studied as a function of BSA, sodium phosphate buffer and protein ...concentration and pH and the thermodynamic parameters of adsorption process were investigated. The BSA adsorption experiment onto diatomite clay indicated that the BSA solution reached the maximum adsorption value at pH 5.5. It was observed that the maximum adsorption capacity (qm) of the data obtained from the adsorption studies showed a great dependence on pH. The maximum amount of adsorption in adsorption experiments can be considered as points where the electrostatic interaction for pH is appropriate. Both structural and electrostatic interaction in regions outside of the isoelectric point may have caused a decrease in BSA absorbance. The structural influences were associated with different conformational states that while BSA molecules accept changes with pH, electrostatic effects can be observed in BSA molecules behaved like soft particles. In this case, it is not possible to explain the independence of the qm–pH curves of the amount of adsorption. The protein molecules at this point are very stable. Because this value is close to the isoelectric point of serum albumin. The surface structural change of BSA and diatomite clay was studied. For this, Fourier transform infrared spectroscopy (FTIR) spectroscopy values were compared before and after the experiment. The diatomite samples used as support material were characterized by FTIR, scanning electron microscopy, thermogravimetric analysis and Brunauer Emmett–Teller surface area analysis. The thermodynamic functions such as enthalpy, entropy, Gibbs free energy and activation energy were investigated in their experimental work. The thermodynamic parameters such as Gibbs free energy (Δ
G
*),
E
a
, Δ
H
* and Δ
S
* were calculated as − 67.45, 15.41, − 12.84 kJ mol
−1
and − 183.28 J mol
−1
K
−1
for BSA adsorption, respectively. We can deduce that the adsorption process from the data obtained from the thermodynamic parameters is spontaneous and exothermic. The adsorption of the process was investigated using Eyring and Arrhenius equations, and its adsorption kinetic found to be coherent with the pseudo-second-order model. As a result, we reached that the diatomite clay is a suitable adsorbent for the BSA. Experimental results showed that diatomite clay has the potency to be used for rapid pretreatment in the process of identifying proteins.
In this study, adsorption of catalase enzyme onto activated carbon obtained from apple shell, kinetic parameters, and activation data of adsorption process was investigated. Temperature (15, 25, ...36.5, and 45 °C), solution pH (5.5, 7, and 9), initial catalase enzyme concentration (1.10
−1
, 2.10
−1
, and 2.5.10
−1
g l
−1
), and ionic strength (1.10
−2
, 5.10
−2
, and 7.5.10
−2
M) have taken as kinetic parameters for the adsorption of catalase enzyme on activated carbon. In all runs, common parameters of temperature, pH, initial enzyme concentration, and ionic strength were taken as 298 K, pH 7, 0.2 g l
−1
, and 5.10
−2
M, respectively. The results of experiments revealed that the adsorption of catalase enzyme onto activated carbon increased with increasing temperature (15–45 °C), ionic strength, and initial catalase enzyme concentration. However, the adsorption process of catalase on activated carbon was affected negatively by increased pH. The thermodynamic functions such as enthalpy (Δ
H
), activation energy (
E
a
), entropy (Δ
S
), and Gibbs energy (Δ
G
) were investigated. Δ
G
,
E
a
, Δ
H
, and Δ
S
were found to be − 70.61, 4.19, − 1.69 kJ mol
−1
, and 231 J mol
−1
K
−1
for catalase enzyme adsorption, respectively. The adsorption of the process was investigated using Eyring and Arrhenius equations, and the findings showed that the adsorption kinetic is coherent with the pseudo-second-order model. Eventually, activated carbon can be used as an effective adsorbent for the adsorption of catalase.
In this research, the adsorption of bovine serum albümin (BSA) onto activated carbon (AC) obtained from apple bark was carried out and the thermodynamic parameters of adsorption process were ...investigated. Besides, the functions involved in BSA attachment were examined by adsorption experiments on retention capacities for BSA at 298 K, pH of 7, ionic strength of 5.10
−2
M, and initial concentration of 5.10
−2
g L
−1
, respectively. The bovine serum albumin (BSA) adsorption experiment onto activated carbon (AC) indicated that the highest adsorption yield was achieved at pH 5.5. The BSA molecules at pH 5.5 are very stable and that pH value is close to isoelectronic point of BSA. The surface structural change of BSA and activated carbon was studied before and after the experiment using scanning electron microscopy (SEM) analysis and Fourier Transform Infrared Spectroscopy (FTIR). By the way, the thermodynamic functions such as Gibbs free energy (ΔG
∗
), activation energy (Ea), activation entalphy (ΔH
∗
), and activation entropy (ΔS
∗
) were calculated as − 66.17, 37.73, − 29.09 kJ mol
−1
, and + 124.42 J mol
−1
K
−1
for bovine serum albumin (BSA) adsorption, respectively. The adsorption of the process was investigated using Eyring and Arrhenius equations and the adsorption kinetic of BSA on AC was found to be coherent with the pseudo-second-order model.
Graphical Abstract
In this research, adsorption of
Candida rugosa
lipase enzyme (CRLE) onto activated carbon obtained from apple bark was carried out, and the thermodynamic parameters of adsorption process were ...investigated. The surface structural change of lipase enzyme and activated carbon was studied. The thermodynamic functions such as enthalpy, entropy, Gibbs free energy, and activation energy were investigated in their experimental work. The thermodynamic parameters of ΔG
∗
, Ea, ΔH
∗
, and ΔS
∗
were calculated as − 75.56, 13.42, − 15.29 kJ mol
−1
, and 202.2 J mol
−1
K
−1
for CRLE adsorption, respectively. The experiment results showed that the adsorption process of CRLE on activated carbon is spontaneous and exothermic. The maximum adsorption capacity according to CRLE was 5.5 pH. The maximum adsorption capacity of active carbon was found to be 96.2 mg/g at pH 5.5, 309.5 K, and initial enzyme concentration of 5.0 × 10
−3
M. The protein molecules at this point are very stable that is close to the isoelectric point of lipase enzyme. As a result, we can say that the activated carbon can be used as an effective adsorbent for the adsorption of CRLE.
May PdCu@f‐MWCNT NPs be an ecotoxicologic risk? Alak, Gonca; Yeltekin, Aslı Çilingir; Köktürk, Mine ...
Applied organometallic chemistry,
March 2023, 2023-03-00, 20230301, Letnik:
37, Številka:
3
Journal Article
Recenzirano
The mechanisms of various metal nanoparticles (NPs) are still a matter of debate in aquatic toxicology. In order to close this gap, the number of studies on this subject is increasing. The aims of ...this study are to explore the interactions of PdCu@f‐MWCNT NPs with zebrafish and get to know if it has an ecotoxicological risk. In this study, we synthesized, characterized PdCu@f‐MWCNT NPs, and investigated its ecotoxicological effects. The chemical and morphological structures of PdCu@f‐MWCNT nanomaterials were elucidated with advanced analysis techniques such as scanning electron microscope (SEM), X‐ray spectrophotometer (EDX), transmission electron microscope (TEM), and X‐ray diffraction (XRD) analyses. The ecotoxicological risks were investigated by conducting biochemical analyses and malformation defects in zebrafish. The results were obtained using multiple marker applications including oxidative stress parameters, proinflammatory cytokine expressions, DNA damage, and apoptosis markers. The obtained findings showed embryonic development, survival rate, and incidence of malformation increasing in parallel with the dose increase in zebrafish exposed to PdCu@f‐MWCNT NPs at 10–1000 μg/L levels. Despite the observed decreases in antioxidant enzyme activities, GSH level, AChE activity, and NRF‐2 level, inductions in malondialdehyde (MDA) level, IL‐6, TNF‐α, NF‐kB, DNA damage, and apoptosis levels were observed with increasing dose. Considering these findings, it has been determined that there are toxic effects in zebrafish at all levels above the concentration that we examine as a safe dose (10 μg/L). The effects of all studied concentrations of this NP above the safe dosage, especially on oxidative stress, malformation, and immune system, were found to be quite significant. The more widespread use of nanotechnology in the future will mean more contact of aquatic organisms with NPs. As a result, it is clearly seen that these organisms, which form the important link of the food chain, and the aquatic environment are living at risk conditions.
PDF
