Effect Of Feed Ratio Research Articles

Rapid degradation of formaldehyde using Fe coupled with walnut shell biochar with high surface defect in Fenton-like reaction

The Fenton technology used for treating formaldehyde-containing wastewater (HCHO) has limitations in terms of pH, efficiency, and cost. To address these issues, a Fex-HT Fenton-like catalyst was developed in this study. This catalyst combines active Fe with walnut shell biochar (HT) that contains surface defects, resulting in a highly effective solution for the rapid purification of formaldehyde wastewater in complex environments. The carbon defects on the HT surface play a crucial role in stabilizing the active Fe binding, while the appropriate loading of Fe further enhances the specific surface area of HT. Additionally, the porous structure of HT provides ample contact sites for formaldehyde. Furthermore, the Fe3-HT catalyst exhibits superparamagnetism, allowing for convenient recovery of the catalyst after use. Experimental results demonstrate that Fe3-HT achieves an impressive 90% degradation rate for systems containing HCHO concentrations ranging from 200 to 800 mg/L. The effects of feed ratio, pH, and formaldehyde concentration on the performance of Fe3-HT were thoroughly investigated. Moreover, a possible mechanism for the degradation of HCHO by the Fe3-HT Fenton-like catalyst was proposed. The environmentally friendly catalyst developed in this study boasts numerous advantages, including low cost, high treatment capacity for wastewater, and strong adaptability to complex wastewater environments.

Application of waterborne epoxy acrylic photosensitive resin in coating and wet-end addition during pulping and papermaking

Light curing coating has many advantages and it has the potential prospect in chemical engineering. It could be popularized as a new paper-reinforcing agent. In this paper, the waterborne epoxy acrylic photosensitive resin was prepared with the raw materials of epoxy resin, acrylic acid, and maleic anhydride. Its applications were studied in coating and wet-end addition during pulping and papermaking. At the same time, the effects of feed ratio (Solid content), pH value, and UV (Ultraviolet) curing sequence on the strength of the resin were discussed. The results showed that the physical strength of papers was significantly improved when the resin was used in coating and wet-end addition. In addition, the photosensitive resin had the characteristics of being fast and environmental-friendly. It indicated that the waterborne epoxy acrylic photosensitive resin met the requirements of being a paper-wet strength agent.

Effects of feeding ratio on growth and food conversion rate of common carp Cyprinus carpio reared in floating cages

Effects of feeding ratios (3%, 5% and 7%) on growth and food conversion rate (FCR) of common carp Cyprinus carpio reared in floating cages at Shatt Al-Arab River, Hartha district were studied during a period of 27-4-2010 to 28-6-2010. Statically analysis of results proved that there were significant differences between final weight and length reached by fishes fed on 3% of fish weight and fished fed on 5% and 7% of fish weight. Final weights of fishes were (188, 275.8 and 252.6) g and final lengths were (216.6, 234.6 and 227.2) mm for (3, 5 and 7)% feeding ratio respectively. Better results of growth and FCR obtained from fishes fed 5% of fish weight. Results appeared that FCR values were 4.82, 2.63 and 3.98, daily growth rates were (1.07, 3.16 and 2.78) g/day and specific growth rates were (0.7, 1.85 and 1.71) %/day for fishes fed 3, 5 and 7% of fish weight respectively.

Functionalizing of Waste Tire Rubber with Active Functional Groups

In this study the waste tire rubber was converted to carboxylated rubber without needed to reclaimed the rubber. An active carboxylate moieties were incorporated to the rubber chains of the wasted tire directly. Three types of active materials were used for the reaction with the wasted rubber; maleic anhydride, N-(3,5-dimethoxyphenyl) maleimic acid and N-(3-carboxyphenyl) maleimic acid. The reaction was carried out by mixing the materials in closed system. The effect of feed ratio, time and the temperature of the reaction have been studied.

Well-designed 2D/2D Ti3C2TA/R MXene coupled g-C3N4 heterojunction with in-situ growth of anatase/rutile TiO2 nucleates to boost photocatalytic dry-reforming of methane (DRM) for syngas production under visible light

Well-designed fabrication of 2D/2D g-C3N4/Ti3C2TA/R (CN/TCT) MXene heterojunction with in-situ growth of TiO2-nucleates for boosting photocatalytic dry reforming of methane (DRM) has been investigated. Samples were synthesized through controlled chemical etching process to construct a TiO2 (anatase/rutile) embedded Ti3C2 (TCT) with layer by layer construction of g-C3N4, resulting in higher visible light absorption and proficient charges separation. Etching Ti3AlC2 with HF (49 vol. %) produces more TiO2 compared with HF (39 vol. %), whereas, amount of TiO2 produced was dependent on reaction time. The CN/TCT composite exhibited H2 and CO rate of 51.24 and 73.31 μmole g-1 h-1, much higher than using CN and TCT. This reveals layered Ti3C2 sheets embedded anatase/rutile TiO2, enabling proficient charge carrier separation with light absorption. The effect of feed ratio (CO2/CH4) further confirmed efficient sorption process with good recyclability and would be beneficial to promote the conversion of CO2 and CH4 to syngas under visible light.

Enhancing stability and coaromatization of n-hexane and methanol over [Zn,Cr]/HZSM-5

The catalytic performance and properties of [Zn,Cr]/HZSM-5 were determined using XRD, py-FTIR, ICP, TG, and XPS and compared with those of Zn/HZSM-5 and HZSM-5 for the aromatization of n-hexane. A distinct role of Cr in enhancing n-hexane conversion, aromatic yield, and stability was observed. The catalytic performance of [Zn,Cr]/HZSM-5 and the effects of feed ratio, reaction temperature, and contact time on the coaromatization of n-hexane and methanol were investigated. Methanol addition increased the xylene yield due to methylation. Cofeeding provided high stability arising from the slow carbon deposition rate. At a feed ratio (n-hexane/methanol) of 3:7, reaction temperature 450 °C, and WHSV 2 h-1, the aromatic yield was 40.1%, with xylene selectivity of 40.4%.

Staggered spinning of thin-walled Hastelloy C-276 cylindrical parts: Numerical simulation and experimental investigation

Staggered spinning is a cost-effective method to manufacture axisymmetric components, especially for the ultrathin cylindrical parts. However, due to the complex material flow behavior during staggered spinning of Ni-based thin-walled cylindrical parts, the accurate control of geometric precision is still a great challenge. In this work, a three-dimensional (3D) finite element model (FEM) is developed to investigate the effects of staggered spinning parameters on the dimensional accuracy of a thin-walled Hastelloy C-276 cylindrical part. It is found that the deviations of wall thickness and inner diameter are sensitive to spinning parameters. Based on the results from the finite element analysis, the optimized spinning parameters are obtained for the studied thin-walled cylindrical part, i.e., an appropriate wall thickness reduction range is 30%–40% during the single pass spinning. Meanwhile, the effects of feed ratio on the uniformities of wall thickness and inner diameter are significant, and a suitable feed ratio is 0.8 mm/r. Finally, the industrial three-roller staggered spinning experiments are carried out to verify a fact that the developed FEM, as well as the optimized spinning parameters, can be effectively used for the staggered spinning of thin-walled Hastelloy C-276 cylindrical parts.

Sulfur Doped Lead Monoxide Superfine Powder Materials: Solid-State Synthesis, Characterization, Adsorption and Photocatalytic Property of Methylene Blue

Sulfur doped lead monoxide (S–PbO) superfine powder materials with high visible light-driven activity were successfully prepared by a simple solid-state reaction method at low temperature using sodium dodecyl benzene sulfonate (SDBS) as a template. The samples were characterized by X-ray powder diffraction, high resolution transmission electron microscopy/energy-dispersive X-ray spectroscopy, UV–Vis absorption spectra, infrared spectroscopy, X-ray photoelectron spectroscopy and N2 adsorption–desorption. The effect of feed ratio on the microstructure of materials, the doping mechanism of sulfur and the adsorption mechanism of methylene blue (MB) on the material surface were discussed. In addition, the intrinsic relationships among the material structure parameters, the photocatalytic degradation of MB under visible light irradiation and the stability of materials were investigated. The results show that the S element is successfully incorporated into the (111) crystal plane of the orthorhombic β-PbO lattice as a S(IV) and S(VI) at the assistance of SDBS. The content of sulfur has a certain regulatory effect on the energy gap of the orthorhombic PbO, and there is a positive correlation among the photocatalytic property of MB, the content of sulfur, and the lattice spacing of (111) and (310) crystal plane. The adsorption of MB mainly depends on the interaction between the surface active sites (S–O bond) and hydroxyl groups, and the adsorption relaxation time under different sulfur content. Under visible-light irradiation at room temperature within 60 min, the photocatalytic degradation (wt%) rate of MB (C0 = 50 mg/L) follows an order of S–PbO(S:Pb = 0.05:0.95) (97.8%) > S–PbO(S:Pb = 0.10:0.90) (90.6%) > S–PbO(S:Pb = 0.15:0.85) (83.5%) > S–PbO(S:Pb = 0.20:0.80) (72.3%) > PbO (48.2%). The holes (h+) and hydroxyl radicals (·OH) are the main active species during the photodegradation of MB solution for the S-doped PbO materials. The S-doped PbO materials are of a p-type indirect semiconductor, and the loss of lead is very little in the MB solution, it is feasible to the S-doped PbO powder materials as photocatalysts.

The effects of feeding ratio on final properties of vinyl acetate-based latexes via semi-continuous emulsion copolymerization

Semi-continuous emulsion polymerization of vinyl acetate and dioctyl maleate (VAc/DOM) (60/40, w/w) was carried out with pre-emulsion feeding using potassium persulfate as an initiator. The influence of emulsifier type and its initial ratio were studied and the mixture of non-ionic emulsifiers; 30 and 10 mol ethoxylated nonylphenol (NP30 and NP10) at a ratio of 50/50 (w/w) provided better pre-emulsion and polymerization stability, and also final latex stability. In addition, two series of experiments were conducted to determine the effect of initiator and reactive surfactant, oligomeric N-methylol acrylamide (o-NMA) amount in the initial reactor charge on the latex properties. By increasing the initial initiator amount from 10 to 50 wt%, the average particle size of the latexes decreased from 203 to 143 nm. As expected, the amount of initiator strongly affected the particle charge and the highest zeta potential value was obtained when 50 wt% of the initiator was initially present in the reactor, showing the increased latex stability. On the other hand, it was detected that the colloidal properties of the copolymer latexes were significantly affected by the change of initial charge of o-NMA. The o-NMA amount exceeding 50 wt% caused coagulation. When all o-NMA was initially fed, the highest viscosity value, 9878 cP; lowest zeta potential value, − 5 mV; and the highest surface tension value, 37.5 mN m−1, were obtained. Consequently, the change in the initial charge of emulsifier, initiator, and reactive surfactant has played an important role on the colloidal stability of VAc/DOM latexes.

Synthesis gas production over highly active and stable nanostructured Ni[sbnd]MgO[sbnd]Al2O3 catalysts in dry reforming of methane: Effects of Ni contents

In this paper, CH4 reforming with CO2 was studied over NiMgOAl2O3 catalysts with various Ni contents for the production of syngas (a mixture of H2 and CO). Mesoporous nanocrystalline NiMgOAl2O3 catalysts with the high specific surface area were prepared using a simple co-precipitation method. The samples were characterized by N2 adsorption/desorption (BET), X-ray diffraction (XRD), temperature-programmed reduction and oxidation (TPR and TPO), and scanning electron microscopy (SEM) techniques. The prepared catalysts exhibited high catalytic performance (activity and stability) in dry reforming reaction. The obtained results indicated that the increase in nickel content increased both the reactant conversions and the amount of deposited carbon (whisker type carbon) on nickel catalysts. In addition, the effect of feed ratio was examined and the results showed that the increase in CO2/CH4 molar ratio from 0.5 to 3.0 increased the methane conversion and decreased the carbon dioxide conversion. With the increase of gas hourly space velocity (GHSV), the methane and carbon dioxide conversions decreased.

Non-injection and one-pot approach to CdSe: Eu3+ hybrid nanocrystals with tunable photoluminescence from green to red

Europium ion-doped CdSe hybrid nanocrystals (CdSe:Eu3+ NCs) as a class of new luminescent materials have drawn increasing attention in recent years owing to their remarkable optical properties. In this paper, we report a facile method to prepare CdSe:Eu3+ NCs using oleic acid (OA) as the capping agent. With this non-injection and one-pot synthesized approach, the formation and surface passivation of CdSe:Eu3+ NCs are performed simultaneously and result in intrinsic luminescence. The as-prepared CdSe:Eu3+ NCs are characterized by transmission electron microscopy, X-ray diffraction, and energy-dispersive X-ray spectroscopy (EDX). Their optical properties are also studied by UV–vis and photoluminescence spectra. Moreover, the effects of feed ratios and reaction temperatures on the optical properties are further investigated. The results show that the luminescent spectra of CdSe:Eu3+ NCs are tunable from green (490 nm) to red (630 nm) and gradually redshift with the increase of the nanoparticle size from 2.5 to 4.4 nm. Upon decoration with 2-thenoyltrifluoroacetone (TTA), the luminescence of europium ion drastically increases and efficient energy transfer from CdSe host to the europium ion is proposed. In addition, an MTT and apoptosis assay show CdSe:Eu3+ NCs have low cellular toxicity and could be used as fluorescence imaging for human epithelial type 2 (Hep-2) cells. These properties make CdSe:Eu3+ NCs a potential candidate for biological labeling, immunoassays, and optical sensing.

Production of CO-rich Hydrogen Gas from Methane Dry Reforming over Co/CeO2 Catalyst

Production of CO-rich hydrogen gas from methane dry reforming was investigated over CeO2-supported Co catalyst. The catalyst was synthesized by wet impregnation and subsequently characterized by field emission scanning electron microscope (FESEM), energy dispersion X-ray spectroscopy (EDX), liquid N2 adsorption-desorption, X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR) and thermogravimetric analysis (TGA) for the structure, surface and thermal properties. The catalytic activity test of the Co/CeO2 was investigated between 923-1023 K under reaction conditions in a stainless steel fixed bed reactor. The composition of the products (CO2 and H2) from the methane dry reforming reaction was measured by gas chromatography (GC) coupled with thermal conductivity detector (TCD). The effects of feed ratios and reaction temperatures were investigated on the catalytic activity toward product selectivity, yield, and syngas ratio. Significantly, the selectivity and yield of both H2 and CO increases with feed ratio and temperature. However, the catalyst shows higher activity towards CO selectivity. The highest H2 and CO selectivity of 19.56% and 20.95% respectively were obtained at 1023 K while the highest yield of 41.98% and 38.05% were recorded for H2 and CO under the same condition.

Biocompatible Glutathione Capped Functionalized Carbon Dots as Nanosensors for the Detection of Silver Nanoparticles in Aqueous Solution and Human Cells as well as Bacterial Cells

AbstractFunctional carbon materials have aroused much attention owing to their applications in cellular imaging and sensing. In this paper, we use a hydrothermal approach to prepare luminescent sodium citrate carbon dots (CDs) using glutathione (GSH) as the surface capping reagent. The effects of feed ratio, reaction temperature and reaction time on the luminescent behavior of CDs are investigated. Subsequently, as‐prepared CDs are characterized by UV‐vis, photoluminescence, X‐ray photoelectron spectroscopy (XPS), Fourier transform infrared spectroscopy (FTIR) and transmission electron microscope (TEM). The luminescent CDs exhibit good stability in the presence of various ions or photo irradiation. Furthermore, the luminescence of the CDs is reversible upon the pH cycling between pH=4 and 6. In addition, the emission intensity of CDs decreases gradually with increasing the concentration of silver nanoparticles (AgNPs) and a linear relationship between the logarithm of emission intensity and the concentration of AgNPs is observed within the investigated concentration ranging from 0 to 40 μmol•L−1. The detection limit is 0.9 μmol•L−1 in terms of signal‐to‐noise ratio of 3. More importantly, the sensor can be successfully applied to the detection of AgNPs in real lake water, urine of human, Hep‐2 cells, E. Coli and Salmonella bacteria, which offers a promising platform for environmental and biological sensing applications.

Syngas production from CO2 reforming of methane over neodymium sesquioxide supported cobalt catalyst

This paper reports for the first time the catalytic dry (CO2) reforming of methane over 20 wt%Co/80 wt%Nd2O3 catalyst. The catalyst was synthesized by wet-impregnation procedure and its physicochemical properties were characterized by TGA, XRD, FESEM, EDX, FTIR, H2-TPR and TPD followed by activity testing in a fixed-bed reactor. The effects of feed ratios (CH4: CO2) ranged 0.1–1.0, reactant (CH4 and CO2) partial pressure (0–50 kPa) and temperature ranged 923–1023 K on the activity of the catalyst were investigated. The conversion of both reactants increased with the feed ratio and reaction temperature reaching maximum values of 62.7% and 82% for CH4 and CO2, respectively. The CO2 reforming of methane resulted into the formation of syngas with maximum yields of 59.91% and 62.02% for H2 and CO, respectively, leading to formation of syngas ratio of 0.97. The mechanistic proposition includes the CH4 and CO2 adsorption, activation of CH4 by methane cracking and gasification of carbon deposited on the catalyst surface. The experimental data were fitted by Langmuir Hinshelwood kinetic models. Activation energy values of 21.89 and 62.04 kJ mol−1 were obtained for the consumption of CO2 and CH4 respectively from Langmuir-Hinshelwood models. The lower values of activation energy obtained for CO2 compared to that of CH4 shows that the rate of consumption of CO2 was faster than that of CH4 leading to higher conversion of CO2.

Nickel catalyst supported on mesoporous MgAl2O4 nanopowders synthesized via a homogenous precipitation method for dry reforming reaction

Mesoporous MgAl2O4 nanopowders were synthesized via the homogenous precipitation method and employed as a support for Ni catalysts in the dry reforming reaction. The prepared samples were characterized by XRD, BET, TPR, TPO, NH3-TPD, and SEM techniques. The XRD and BET results revealed that the prepared MgAl2O4 powder exhibited a nanocrystalline structure with high surface area (175 m2g−1). The catalytic tests, including activity and stability tests, showed that the prepared catalysts with various nickel loadings possessed high activity and stability in reaction. The Ni/MgAl2O4 with the highest amount of Ni had an acceptable performance in a long-term stability test. Increasing nickel loading increased the methane conversion and the amount of deposited carbon. The effects of feed ratio and GHSV on the catalytic activity of the Ni/MgAl2O4 catalyst were investigated in detail.

Theoretical prediction of flange wrinkling in first-pass conventional spinning of hemispherical part

Flange wrinkling is one of the most common defects in conventional spinning. A lot of work has been done to find the reason for the flange wrinkling and the way to avoid it. However, the theoretical prediction of flange wrinkling is limited for the non-uniformly distributed stresses and complicated boundary conditions of the flange. In this paper, a FE (Finite element) model is established to study the deformation characteristic of the material in conventional spinning, two stable compressive stress rings distributed at the middle surface of the formed part are found, and the outer stress ring distributed at the flange is considered to be the key factor of flange wrinkling. A theoretical flange wrinkling prediction method is proposed based on the plastic buckling theory and the energy method with the boundary conditions extracted from the FE simulation results. Experiments are designed to research the flange wrinkling phenomenon and verify the proposed theoretical flange wrinkling prediction method. At last, effects of feed ratio on flange wrinkling are analyzed by this method, it is concluded that the decrease of the circumferential compressive stresses distributed in the flange caused by low feed ratio reduces the risk of flange wrinkling.

Facile preparation of chitin nanowhisker–gold nanocluster hybrids: effect of feeding ratio and surface amino group contents on gold absorption amount

Chitin nanowhiskers (ChNWs) hybridized with the densely adsorbed gold nanoclusters (AuNCs) were facilely prepared by a simple mixing of aqueous suspensions of ChNWs and AuNCs. Adsorption of AuNCs on the ChNW surface was confirmed by transmission electron microscopy and scanning electron microscopy with energy dispersive X‐ray spectroscopy. The amounts of adsorbed AuNCs measured by thermogravimetry and combustion using a muffle furnace were in good agreement. While the amount of adsorbed AuNCs increased with AuNCs/ChNWs feeding ratio, we found only a weak dependence of adsorbed AuNC amount on the surface amino group content of ChNWs controlled by pre‐deacetylation of the starting chitin. Copyright © 2016 John Wiley & Sons, Ltd.

Preparation of nanocrystalline Ni/Al2O3 catalysts with the microemulsion method for dry reforming of methane

AbstractMesoporous nanocrystalline nickel‐alumina catalysts with high surface area were prepared by a microemulsion (ME) method and were employed in methane reforming with carbon dioxide for syngas production. The catalysts were characterized by X‐ray diffraction (XRD), Brunauer‐Emmett‐Teller surface area analysis (BET), temperature‐programmed reduction (TPR), temperature‐programmed oxidation (TPO), and scanning electron microscopy (SEM) techniques. The results showed that the catalysts possessed mesoporous structure with high surface area (> 250 m2 · g−1) and small crystallite size (∼5 nm). The catalytic results revealed high activity and stability for the prepared catalysts. In addition, the effect of feed ratio and GHSV on catalytic performance was investigated.

Effects of feeding ratio on growth and food conversion rate of common carp Cyprinus carpio reared in floating cages

Effects of feeding ratio on growth and food conversion rate of common carp Cyprinus carpio reared in floating cages

Synthesis and Characteristics of Thermo-and pH-Sensitive PNIPAAm/PVP Hydrogels

Poly (N-isopropylacrylamide)(PNIPAAm)/Poly (N-vinylpyrrolidone)(PVP) hydrogels were prepared by irradiating the aqueous solution mixture of NIPAAm and PVP with electron beam. The effects of feed ratio, pH, and temperature on the swelling ratio of the hydrogels were investigated. It appeared that the hydrogels possessed both pH and temperature sensitivity, the lower critical solution temperature (LCST) of PNIPAAm/PVP hydrogels increased with the increasing of PVP content in the copolymers. The experimental results also showed that the hydrogels were ionic strength sensitivity, the swelling ratio decreased sharply when the ionic strength of the solution arrived to a certain critical value.