Graphene oxide (GO) crosslinked nanocomposites hydrogels (NCH) of chitosan (CS) and carboxymethyl cellulose (CMC) were synthesized and the feasibility of its application as a versatile adsorbent for ...the remediation of cationic (methylene blue, MB) as well as anionic (methyl orange, MO) dyes contaminated wastewater was explored. Initially, GO was functionalized with vinyltriethoxysilane which was subsequently used as a chemical crosslinker to synthesize the NCH of CS and CMC (CS/CMC-NCH) with the polymeric mixture of diallyldimethylammonium chloride and 2-acrylamido-2-methyl-1-propanesulfonic acid. About 99% dye was adsorbed from 50 mg/L dye solution of MB dye with 0.4 g/L of CS/CMC-NCH at pH 7, whereas, for MO about 82% dye was adsorbed with 0.6 g/L of CS/CMC-NCH at pH 3. The Adsorption of both dyes is well explained using pseudo-second-order and Langmuir models with the maximum adsorption capacities of 655.98 mgdye/gads for MB and 404.52 mgdye/gads for MO. Thermodynamics studies suggested spontaneous and exothermic nature of the adsorption process with values of ΔS < 0 and ΔH > 0. Furthermore, CS/CMC-NCH showed excellent regeneration capacity for continuous twenty cycles of adsorption-desorption. Therefore, the synthesized CS/CMC-NCH is a versatile adsorbent that can treat both anionic and cationic dyes contaminated wastewater.
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•GO-VTES crosslinked NCH of chitosan and carboxymethyl cellulose were synthesized.•CS/CMC-NCH adsorbed methylene blue and methyl orange dyes.•Adsorption process was expressed with Langmuir and pseudo-second-order models.•Thermodynamic parameters showed the spontaneous and exothermic adsorption.•Regeneration studies indicated the high reuse efficiency upto twenty cycles.
Naphthalene diimides: perspectives and promise Bhosale, Sheshanath V; Al Kobaisi, Mohammad; Jadhav, Ratan W ...
Chemical Society reviews,
09/2021, Letnik:
5, Številka:
17
Journal Article
Recenzirano
In this review, we describe the developments in the field of naphthalene diimides (NDIs) from 2016 to the presentday. NDIs are shown to be an increasingly interesting class of molecules due to their ...electronic properties, large electron deficient aromatic cores and tendency to self-assemble into functional structures. Almost all NDIs possess high electron affinity, good charge carrier mobility, and excellent thermal and oxidative stability, making them promising candidates for applications in organic electronics, photovoltaic devices, and flexible displays. NDIs have also been extensively studied due to their potential real-world uses across a wide variety of applications including supramolecular chemistry, sensing, host-guest complexes for molecular switching devices, such as catenanes and rotaxanes, ion-channels, catalysis, and medicine and as non-fullerene accepters in solar cells. In recent years, NDI research with respect to supramolecular assemblies and mechanoluminescent properties has also gained considerable traction. Thus, this review will assist a wide range of readers and researchers including chemists, physicists, biologists, medicinal chemists and materials scientists in understanding the scope for development and applicability of NDI dyes in their respective fields through a discussion of the main properties of NDI derivatives and of the status of emerging applications.
In this review, we describe developments in the field of naphthalene diimides (NDIs) from 2016 to the present day.
The current study focused on the use of gum Arabic grafted polyacrylamide (GA-cl-PAM) hydrogel as a self-template for the in situ synthesize of zinc oxide nanoparticles (ZnO NPs) and the application ...of synthesized nanocomposite as a potential adsorbent to remove synthetic dyes especially malachite green (MG) from aqueous solution. Different characterization techniques supported in situ synthesis of ZnO NPs onto polymer matrix. The gum Arabic-crosslinked-poly(acrylamide)/zinc oxide nanocomposites (i.e., GA-cl-PAM/ZnO nanocomposite) exhibited much better surface properties as compared to the parental hydrogel matrix. The swelling abilities of the GA-cl-PAM/ZnO nanocomposites with different concentrations of acrylamide were also checked and the nanocomposite with 7.03 × 10
–4
mol/L of acrylamide exhibited maximum swelling capacity of 2354%. The nanocomposite adsorbed approximately 99% MG dye with 0.4 g/L adsorbent dose at neutral pH. Adsorption kinetics and isotherm followed pseudo-second-order and Langmuir isotherm models, respectively with the high adsorption capacity of 766.52 mg
d
/g
ads
at 25 °C. It was observed that the dye molecules were adsorbed onto GA-cl-PAM/ZnO nanocomposite mostly via electrostatic interactions, hydrogen-bonding and pore-diffusion mechanisms. Diffusion of dye molecules within the internal structure of GA-cl-PAM/ZnO nanocomposite followed the combination of both liquid film as well as intraparticle diffusion mechanisms. Furthermore, nanocomposite was applied ten times consecutively to adsorb MG dye from aqueous solution. Therefore, GA-cl-PAM hydrogel have capability to be used for the in situ ZnO NPs synthesis and thus synthesized nanocomposite can be used effectively to treat dyes polluted wastewater.
In recent years, substantial progress has been made towards developing effective catalysts for the hydrogenation of CO2 into fuels. However, the quest for a robust catalyst with high activity and ...stability still remains challenging. In this study, we present a cost-effective catalyst composed of MoS2 nanosheets and functionalized porous date seed-derived activated carbon (f-DSAC) for hydrogenation of CO2 into formic acid (FA). As-fabricated MoS2/f-DSAC catalysts were characterized by FE-SEM, XRD, Raman, FT-IR, BET, and CO2-TPD analyses. At first, bicarbonate (HCO3–) was successfully converted into FA with a high yield of 88% at 200 °C for 180 min under 10 bar H2 atmosphere. A possible reaction pathway for the conversion of HCO3– into FA is postulated. The catalyst has demonstrated high activity and long-term stability over five consecutive cycles. Additionally, MoS2/f-DSAC catalyst was effectively used for the conversion of gaseous CO2 into FA at 200 °C under 20 bar (CO2/H2 = 1:1) over 15 h. The catalyst exhibited a remarkable TOF of 510 h–1 with very low activation energy of 12 kJ mol−1, thus enhancing the catalytic conversion rate of CO2 into FA. Thus, this work demonstrates the MoS2/f-DSAC nanohybrid system as an efficient non-noble catalyst for converting CO2 into fuels.
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•CO2 conversion to valuable products is a promising way for climate change control.•Novel MoS2/f-DSAC nanocatalyst was developed for CO2 hydrogenation to formic acid.•HCO3– was successfully converted into formic acid over MoS2/f-DSAC catalyst.•Gaseous CO2 was hydrogenated into formic acid with TOF of 510 h–1 and Ea of 12 kJ mol−1.•MoS2/f-DSAC catalyst is more assuring for CO2 abatement and mitigation.
The low surface area of TiO2 (50 m2g-1 - Degussa P25) due to randomly oriented, agglomerated nanostructures and charge carrier recombination tendency, has till date been its major limitation for ...photocatalytic remediation of polluted wastewater. This study presents an innovative process to design super porous TiO2 nanostructures with high effective surface area (238 m2g-1), robust, structurally ordered mesoporosity via a simple sol-gel assisted reflux method. Detailed material characterization studies suggest that the higher degree of intermolecular ligation in novel templates such as butanetetracarboxylic or tricarballylic acid modified titanium hydroxide gels resulted in retainment of the porous structure during the urea assisted combustion synthesis. The induction of robust structural porosity is accompanied by a reduction in pore size distribution, an increase in pore volume leading to significantly higher total surface area of the synthesized TiO2. Detailed investigation of dye adsorption kinetics and photocatalytic degradation kinetics, complemented by kinetic modeling analysis confirmed that the super porous TiO2 with robust mesoporous structure outperforms the rest of synthesized TiO2 catalyst (having only agglomerate porosity) in terms of its superior adsorption capacity, faster diffusion kinetics and photocatalytic activity for degradation of Amaranth dye. Thus, the super porous TiO2 shows promising potential for application in sustainable photocatalytic technology for remediation of wastewater contaminated with azo dyes.
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•Super porous TiO2 with robust structural mesoporosity, enhanced surface area has been synthesized.•Ti(OH)4 gels have been innovatively modified with butanetetracarboxylic acid and urea to transform agglomerate porosity in to robust, structural mesoporosity.•Significant improvements in the Amaranth dye adsorptive separation capacity and photocatalytic degradation efficiency have been measured.•Detailed kinetic modeling analysis, signify the potential of super porous TiO2 for application in self-sustainable photocatalytic water purification technology.
•The transmission of toxic trace metals from fuels to soot generated from them is investigated.•ICPMS for metals and HRTEM, XRD, and Raman analyses for soot nanostructures are used.•Cu and Fe were ...dominant metals in diesel and soot, though with transmission of only 0.09%.•The addition of 20% Karanja-biodiesel to diesel enhances transmission of toxic metals to soot.•Biodiesel addition induces disorder in soot to enhance reactivity and metal trapping efficiency.
Despite benefits of biodiesel such as reduced soot emissions and enhanced combustion efficiency, it enhances NOx emissions and may emit toxic trace metals that are present in biomass. This investigation focuses on the transmission of trace metals from fuels (diesel, Karanja biodiesel, and diesel/biodiesel blend) to soots generated from them. The study finds that the addition of 20% Karanja-biodiesel to diesel enhances the transmission of toxic metals such as Zn, Sr, Cs, and Pb to soot by normalized factors, defined as the ratio of the transmission rate from diesel to its soot (%) and the transmission rate from blended fuel to its soot (%), of 17, 7, 58 and 3, respectively, as compared to diesel. Although Cu and Fe were dominant metals in diesel and its soot, their transmission from fuel to soot was only 0.09%, suggesting a preferential selectivity of some metals such as Zn, Sr, Cs, and Pb or the catalytic effects of some metals such as Fe and Cu on soot surface. The nanostructural investigation of soot using HRTEM, XRD, and Raman analyses confirm that the addition of Karanja biodiesel to diesel induces structural disorders in soot such as higher fringe tortuosity, shorter fringe length, and smaller primary particle diameter than diesel soot that enhance its reactivity and possibly the trapping efficiency of metals. A combination of greater degree of metal transmission from Karanja biodiesel-blended diesel fuel to soot and the increased nanostructural disorder and reactivity makes soot from such blend potentially more hazardous than diesel soot.
Food adulteration occurs globally, in many facets, and affects almost all food commodities. Adulteration is not just a crucial economic problem, but it may also lead to serious health problems for ...consumers. Turmeric (Curcuma longa) is a world-class spice commonly contaminated with various chemicals and colors. It has also been used extensively in many Asian curries, sauces, and medications. Different traditional approaches, such as chemical and physical methods, are available for detecting adulterants in turmeric. These approaches are rather time-consuming and inaccurate methods. Therefore, it is of utmost importance to identify the adulterants in turmeric accurately and instantly. A cloud-based system was developed to detect adulteration in adulterated turmeric. The dataset consists of spectral images of turmeric with tartrazine-colored rice flour adulterant. Adulterants in weight percentages of 0%, 5%, 10%, and 15% were mixed with turmeric. A convolutional neural network (CNN) was implemented to detect adulteration, which achieved 100% accuracy for training and 94.35% accuracy for validation. The deep CNN (DCNN) models, namely, VGG16, DenseNet201, and MobileNet, were implemented to detect adulteration. The proposed CNN model outperforms DCNN models in terms of accuracy and layers. The CNN model is deployed to the platform as a service (PaaS) cloud. The deployed model link can be accessed using a smartphone. Uploading the adulterated turmeric image to a cloud link can analyze and detect adulteration.
Soot is a major anthropogenic air pollutant that affects human health and contributes to global warming. To understand its formation pathways and reduce emission, several flame and engine studies ...exist in the literature, though the fundamental differences in the characteristics of engine and flame soots are not well understood. This study presents a detailed comparative investigation of soot nanostructural properties and their relationship with the oxidative reactivity of soots from an engine and a diffusion flame using diesel and 20% Jatropha biodiesel/diesel blend fuels. X-ray diffraction, Raman spectroscopy, high-resolution transmission electron microscopy, electron energy loss spectroscopy, and thermogravimetric analyses confirm that engine soot has greater primary particle diameter, higher concentration of loosely held aliphatics, greater degree of graphitized nanocrystallites with lower interplanar separation, longer fringe lengths, lower tortuosity, and greater resistance for oxidation than the flame soot, though the differences in several properties were minor. The effects of biodiesel addition to diesel on soot properties and sooting tendency were predicted very well with both flame and engine setup. Moreover, the enhanced soot oxidation in the combustor catalyzed by fuel-bound oxygen in biodiesel further reduces the nanostructural and reactivity differences between engine and flame soots. Though engine soot properties have more relevance to anthropogenic particulate matter, flame setups appear to be suitable for screening and studying the effect of fuel additives on the sooting propensity and physicochemical properties of soot prior to their testing and utilization in engines.
Turmeric is widely used as a health supplement and foodstuff in South East Asian countries because of its medicinal benefits. Like several other plants and peppers, turmeric is prone to exploitation ...because of its economic value, rising consumer need, and essential food element that adds colour and flavour. Due to this, quick and comprehensive testing processes are needed to detect adulterants in turmeric. In this study, pure turmeric powders were mixed with starch in proportions ranging from 0 to 50% with a 1% variation to obtain different combinations. Reflectance spectra of pure turmeric and starch mixed samples were recorded using a JASCO-V770 spectrometer from 400 to 2050 nm. The recorded spectra were pre-processed using a Multiplicative Scatter Correction (MSC) and Standard Normal Variate (SNV). The Savitzky-Golay (SG) filter was initially applied to these original (X), MSC, and SNV-corrected spectra. Secondly, the Extra Tree Regressor (ETR) feature selection method was employed to select the best features. Finally, principal component analysis (PCA) was used to reduce the dimension of the selected features. The stacked generalization method was applied to improve the performance of this work. Both regressors and classifier stacking techniques have been tested with different classification and regression methods. The K-Nearest Neighbours (KNN), Decision Tree (DT), and Random Forest (RF) models were used as base learners, and Logistic Regression (LRC) was used as a meta-model for classification and Linear Regression (LR) for regression analysis. The proposed method achieved the best regression performance with r
2
of 0.999, Root Mean Square Error (RMSE) of 0.206, Ratio of Performance to Deviation (RPD) of 73.73, and Range Error Ratio (RER) of 480.58, whereas 100% F1 score and Matthew's Correlation Coefficient (MCC) classification performance.
