Sonocatalytic degradation of methylene blue by a novel sno2-fe3o4@mwcnt hybrid nanocatalyst under ultrasonic irradiation

In the present work, SnO2-Fe3O4@MWCNT nanocatalyst was fabricated according to a sonochemical-hydrothermal procedure. The surface morphology and structure analyses of the synthesized SnO2-Fe3O4@MWCNT were investigated by transmission electron microscope (TEM), X-ray diffraction (XRD), Raman spectroscopy, EDS, FTIR and BET analyses. The degradation efficiency of SnO2-Fe3O4@MWCNT nanocatalyst in MB solution was tested by several experimental conditions such as SnO2-Fe3O4@MWCNT dosage (8-20 mg/L), initial MB concentration (20-50 mg/L), initial solution pH (5-9), and ultrasonic output power (37-60 kHz). SnO2-Fe3O4@MWCNT nanocatalyst retained its efficiency as 85% at common experimental conditions of 16 mg/L of SnO2-Fe3O4@MWCNTs, 45 mg/L of MB, pH of 8, H2O2 of 15 mM, and 60 kHz in 60 min under ultrasonic irradiation. In addition, the optimum experiment conditions for SnO2-Fe3O4@MWCNTs in MB degradation were investigated. The experiment result showed that the degradation efficiency of MB was increased by adding H2O2 to the reaction medium due to forming more free radicals. Further, it was detected that OH center dot radicals were determined to be the dominant oxidative species in MB degradation using SnO2-Fe3O4@MWCNT catalyst. The reuse tests showed that SnO2-Fe3O4@MWCNT sonocatalyst preserved its very stable structure after using the same catalyst 5 times. The intermediates and by-products after MB degradation using the catalyst were indicated by GC-MS analysis. Overall the results showed that the SnO2-Fe3O4@MWCNT sonocatalyst has excellent potential for treating organic pollutants in wastewater

Mesoporous Materials in Biofuel Cells

WOS: 000458589000007In biological systems, the conversion of chemical energy into electrical energy exhibited the importance of biological fuel cells. Thus, studies on the use of microbes and enzymes in fuel cell devices have recently increased. Reduced fossil resources and damage to the environment have led to an increase in the search for new energy sources. Electric energy can be obtained by using microbial and enzymes in fuel cells. The efficiency and durability of the material to be used in cathodic and anodic electrodes enable the efficient use of the biofuel cell. It is very important to know the properties of the membrane materials that provide ion transfer between the cathode and the anode. So, the characteristics of the materials used in these fuel cells, which can be expressed as biological fuel cells, affect the energy efficiency. This chapter is aimed to report recent developments in microbial fuel cells, enzymatic fuel cells and carbon-based fuel cells and the materials used in these fuel cells

Textile dyes Maxilon blue 5G and Reactive blue 203 induce acute toxicity and DNA damage during embryonic development of Danio rerio

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

Immobilization kinetics and mechanism of bovine serum albumin on diatomite clay from aqueous solutions

Abstract 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 (ΔG*), E a, ΔH* and ΔS* 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

The dye removal from aqueous solution using polymer composite films

Abstract 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 ΔG: − 70.64 K J mol−1, ΔS: − 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

Investigation of the Oxidative Stress Response of a Green Synthesis Nanoparticle (RP-Ag/ACNPs) in Zebrafish

Silver nanoparticles (AgNPs) are prominent nanomaterials that are efficiently used in different industries including medical products, water treatment, and cosmetics. However, AgNPs are known to cause adverse effects on the ecosystem and human health. In this study, aqueous extract of Rumex patientia (RP) was used as a reducing and stabilizing agent in AgNP biosynthesis. The obtained activated carbon (AC) from Chenopodium album (CA) plant was combined with RP-AgNPs to synthesize RP-Ag/AC NPs. Next, the effects of these green synthesis RP-Ag/AC NPs on zebrafish (Danio rerio) embryos and larvae were investigated. First, we characterized the RP-Ag/AC NPs by using X-ray diffraction (XRD) and transmission electron microscopy (TEM) and determined LC50 value as 217.23 mg/L at 96 h. Next, the alterations in survival rate, hatching rate, and morphology of the larvae at 96 h were monitored. The survival rates decreased in a dose-dependent manner. Morphological defects such as yolk sac edema, pericardial edema, spinal curvature, and tail malformation in the NP-treated larvae were observed. RP-Ag/AC NPs stimulated the production of neuronal NOS (nNOS) and 8-OHdG in zebrafish brain tissues in a dose-dependent manner and enhanced neutrophil degeneration and necrosis at concentrations of 50 and 100 mg/L. Thus, the obtained data suggest that the green synthesis process is not sufficient to reduce the effect of oxidative stress caused by AgNPs on oxidative signaling

Assessment of oxidative DNA damage, apoptosis and histopathological alterations on zebrafish exposed with green silver nanoparticle

The effect of green synthesis approaches in NP synthesis and their possible toxicity in aquatic environments has been very limitedly studied. In this study, VA-Ag / AC NPs were synthesised using Viscum album plant as a reducing agent and Chenopodium album (CA) plant as an active carbon source. TEM (Transmission Electron Microscope) and XRD (X-ray crystallography) analysis of the synthesised VA-Ag / AC NPs were performed to detect their morphological and chemical properties. The inducing of oxidative stress and the effectiveness of VA-Ag/AC NPs in neurotoxic pathways and teratogenic changes in aquatic organisms have been investigated. In addition, a modelling was created to elucidate the toxicity mechanism. The results revealed that green synthesised VA-Ag/AC NPs nanoparticles are approximately 1600 times less toxic than nanoparticles synthesised by different methods. It had been determined that only high doses of VA-Ag/AC NPs nanoparticles cause neurological, histopathological and morphological changes. The findings in this study for VA-Ag/AC NPs, which are the evidence of the complexity of their mode of action at the cellular level, are a first in the aquatic ecosystem and require different findings regarding the stability and safety of such synthesis products

Novel Chitosan-Based Nanocomposites for Dye Removal Applications

WOS: 000446408700003Monodisperse Pd nanoparticles (Pd NPs@CGO) decorated Chitosan-graphene oxide (CGO) are produced to get a nanoadsorbent material to remove methylene blue (MB) from aqueous solutions. X-ray diffraction (XRD), transmission electron microscopy (TEM), high-resolution transmission electron microscopy (HR-TEM) and X-ray photoelectron spectroscopy (XPS) were used to characterize the Pd NPs@CGO. The spectroscopic results showed that Pd NPs@CGO has highly crystalline, monodisperse and colloidal structures. Furthermore, Pd NPs@CGO was highly efficient and stable for methylene blue removal. They provide a high adsorption capacity of 186.42 mg/g and its MB adsorption equilibrium is obtained in similar to 60 min. Nonetheless, Pd NPs@CGO are reusable and promising nanocomposites for methylene blue removal, keeping 43.05 % of the first efficacy after six adsorption-desorption cycles

Graphene Oxide-Chitosan Furnished Monodisperse Platinum Nanoparticles as Importantly Competent and Reusable Nanosorbents for Methylene Blue Removal

WOS: 000446408700011In this study, the microwave assisted methodology was employed to produce uniformly distributed platinum nanoparticles decorated with graphane oxide-chitosan. The capacity of methylene blue removal of these nanohybrids at room temperature was examined via adsorption. Characterizations of these novel nanoadsorbents were accomplished using X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), transmission electron microscopy (TEM) and high-resolution transmission electron microscopy (HRTEM). The X-ray diffractogram of the Pt NPs@CSGO displayed an ordinary structure of face-centered cubic (FCC). Adsorbance measurement results represented significant performance increases for all these novel nanohybrids for methylene blue removal. However, Pt NPs@CSGO hybrid was one of the best nanoadsorbent compared to others produced in this study. Our results presented that the one of highest methylene blue adsorption capacity belongs to the Pt NPs@CSGO, which was 194.6 mg/g, can be considered as an outstanding capacity. Its equilibrium was accomplished in 55 min. Furthermore, all these Pt NPs are reusable materials for the methylene blue removal application because they sustained 74.02 % of the initial efficiency after six successive adsorptions-desorption cycles