Feed Molar Ratio Research Articles

Synthesis and characterization of alkylated caseinate, and its structure-curcumin loading property relationship in water

Alkylated caseinates (Cn-caseinates) containing selected C8–C16 alkyl groups were successfully synthesized through a two-step reaction between the protein and fatty acids. The substitution degree (SD) of the alkyl groups was 5.2–72.9%, which depended on the feed molar ratio of reagents and fatty acid chain length. The SD value was positively associated with the surface hydrophobicity index (S0) of the Cn-caseinate. Among the tested Cn-caseinates (n = 0, 8, 12, 14 and 16), C16-caseinate showed the best self-assembly and curcumin-loading properties in water. With increased palmitoyl group SD, the critical micelle concentration (CMC) of C16-caseinate was decreased from 5.15 to 3.77 mg/L and the encapsulation efficiency of curcumin-loaded C16-caseinate self-assemblies was increased from 31.16% to 69.87%. Transmission electron microscopy analysis demonstrated a desirable sphere assembly. In addition, the C16-caseinate self-assemblies had good re-dispersibility and storage stability at 4 °C for 6 weeks.

Facile fabrication of polyaniline with coral-like nanostructure as electrode material for supercapacitors

Polyaniline (PANI) with coral-like nanostructure was prepared via chemical oxidative polymerization in the presence of sunset yellow (SY) as dopant and surfactant. The results showed that in comparison with the microsized bulky structure of PANI undoped with SY, the coral-like nanostructure of PANI doped with SY (PANI/SY) was observed and the diameter of coral branch decreased from 180nm to 100nm with the increase of feeding molar ratio of SY to aniline. Coral-like PANI/SY showed the large specific capacitance of 467F/g and nice electrochemical stability when the feeding molar ratio of SY to aniline was 0.035:1, owning to its special coral-like nanostructure and high conductivity of 15.0S/cm, which was essentially attributed to the synergistic effects of high doping level, ordered arrangement of PANI chain and strong π–π interaction between PANI and SY.

Studies on the steam CO2 reforming of methane over ordered mesoporous nickel–magnesium–alumina catalysts

Ordered mesoporous materials have received much attention because of their high surface area and ordered pore structure. The Mg-promoted ordered mesoporous nickel–alumina catalysts (M-Mg x NA), which were prepared using the evaporation induced self-assembly method, were investigated in the Steam CO2 Reforming (SCR) of methane. The fresh and spent catalysts were characterized by various analytical techniques such as N2 physisorption, small-angle X-ray scattering, X-ray diffraction, temperature-programmed reduction, thermogravimetric analysis, transmission electron microscopy and CO2-temperature programmed desorption analysis. We have found that the M-Mg x NA catalyst has a larger surface area and a narrower pore size distribution than the Ni/Al2O3 catalyst (NA); furthermore, the M-Mg x NA catalyst exhibits high catalytic stability under the tested conditions of 600 °C, 1 bar and feed molar ratio of CH4:CO2:H2O = 1:1:1. We consider that the ordered mesoporosity prevents the nickel particles from sintering because of the confinement effect and decreases the particle size in the SCR reaction. Thus, the Mg-promoted ordered mesoporous nickel-alumina catalyst shows enhanced resistance to carbon formation during the steam CO2 reforming of methane.

Optimized microwave reflux extraction and antioxidant activities of piperine from black and white piper nigrum

<p>In this study, the microwave reflux technique was employed to extract piperine from black and white pepper. This is due to its ability to combine the microwave and the conventional solvent extraction together with a high degree of selectivity and quality extract. The extraction process was optimized using theL<sub>9</sub>-Taguchi experimental design. This investigated the effects of four independent factors (irradiation time (x<sub>1</sub>), microwave power level (x<sub>2</sub>), feed particle size (x<sub>3</sub>) and molar ratio (x<sub>4</sub>)) on piperine yield. Antioxidant activity of the oleoresin extracts were later evaluated using DPPH (1, 1-diphenyl-1-picrylhydrazyl) radical scavenging assay. The optimum extraction condition in black pepper refluxation was attained at 90 min irradiation time (x<sub>1</sub>), 350 W power level (x<sub>2</sub>), 0.105 mm feed particle size (x<sub>3</sub>) and 10 mL/g molar ratio (x<sub>4</sub>) with an extremum ranking in decreasing order of x3> x<sub>4</sub>> x<sub>2</sub>> x<sub>1</sub>.However,from the white pepper refluxation an optimum condition was achieved at 120 min irradiation time (x<sub>1</sub>), 350 W power level (x<sub>2</sub>), 0.300 mm feed particle size (x<sub>3</sub>) and 6 mL/g molar ratio (x<sub>4</sub>) with a corresponding decreasing extremum order of x<sub>1</sub>> x<sub>4</sub>> x<sub>2</sub>> x<sub>3</sub>.From the results obtained from concentration-dependent radicals scavenging activity it was concluded that white oleoresins extract were much higher in inhibitory activity than that of black oleoresin extract.</p><p>Chemical Engineering Research Bulletin 19(2017) 139-144</p>

Aromatic Modification of Low Molecular Weight PEI for Enhanced Gene Delivery.

Low molecular weight polyethylenimine (1800 Da, also referred to as oligoethylenimines, OEI) was modified with amino acids, including two aromatic amino acids (tryptophan, phenylalanine) and an aliphatic amino acid (leucine). The substitution degree of amino acids could be controlled by adjusting the feeding mole ratio of the reactants. Fluorescence spectroscopy and circular dichroism experiments demonstrated that the indole ring of tryptophan may intercalate into the DNA base pairs and contribute to efficient DNA condensation. In vitro gene expression results revealed that the modified OEIs (OEI-AAs) may provide higher transfection efficiency even than high molecular weight polyethylenimine (25 kDa, PEI), especially the aromatic tryptophan substituted OEI. Moreover, OEI-AAs exhibited excellent serum tolerance, and up to 137 times higher transfection efficiency than PEI 25 kDa that was obtained in the presence of serum. The cytotoxicity of OEI-AAs is much lower than PEI 25 kDa. This study may afford a new method for the development of low molecular weight oligomeric non-viral gene vectors with both high efficiency and biocompatibility.

Techno-economic modeling and optimization of solar-driven high-temperature electrolysis systems

We present a techno-economic analysis of solar-driven hightemperature electrolysis systems used for the production of hydrogen and synthesis gas. We consider different strategies for the incorporation of solar energy, distinguished by the use of differing technologies to provide solar power and heat: i) thermal approaches (system 1) using concentrated solar technologies to provide heat and to generate electricity through thermodynamic cycles, ii) electrical approaches (system 2) using photovoltaic technologies to provide electricity and to generate heat through electrical heaters, and iii) hybrid approaches (system 3) utilizing concentrated solar technologies and photovoltaics to provide heat and electricity. We find that system 3 generates hydrogen at a high efficiency (ηSTF = 9.9%, slightly lower than the best performing system 1 with 10.6%) and at a low cost (Cfuel = $4.9/kg, lowest cost of all three systems) at reference conditions, providing evidence for the competitiveness of this hybrid approach for scaled solar hydrogen generation. Sensitivity analysis indicates an optimal working temperature for system 3 of 1350 K, which balances the increased thermal receiver losses with the reduced electrolysis cell potential when increasing the temperature. Lower working pressure always favors high system efficiency and low cost. The working current densities for thermoneutral voltage were determined for various temperature and pressure combinations, and trends for efficient and cost-effective thermoneutral operation were identified. The water conversion extent was optimized to avoid mass transport limitations in the electrodes while ensuring large fuel generation rates. For synthesis gas production, a H2/CO molar ratio of 2 can be achieved by tuning the inlet feeding molar ratio of CO2/H2O, temperature, and pressure. This study introduces a flexible simulation framework of solar-driven high-temperature electrolysis systems allowing for the assessment of competing solar integration approaches and for the guidance of the operational conditions maximizing efficiency and minimizing cost, providing pathways for scalable solar fuel processing.

Extraction, radical scavenging activities and physicochemical fingerprints of black pepper (Piper nigrum) extract

Black pepper (Piper nigrum) is an essential tropical crop which doubled as spice in food industries and medicine in the treatment of free radical related disorders. For this study, microwave reflux method was employed in the extraction of bioactive oleoresin from black peppercorns. Extraction parameters such as irradiation time, microwave power, feed particle size and molar ratio were optimized. The effects of these parameters on the oleoresin yield and antiradical activities were investigated using a multi-level Taguchi methodology. The results obtained placed the optimum extraction condition at 120 min irradiation time, 350 W microwave power, 0.105 mm feed particle size and 12 g/ml molar ratio. Under this optimal condition, the oleoresin yield was obtained as 5.64% (w/w). However, the optimum percentage inhibitions of the extracted spice oleoresins on the stable DPPH and hydrogen peroxide radicals were estimated to be 88.75 and 90.31%, respectively. Moreover, the Fourier transform infrared (FTIR) analysis confirmed the presence of unsaturated amide groups, which validated the antioxidant potential of the black pepper extract. The scanning electronic microscopy (SEM) further elucidated the structural transformation of black pepper from the pulsed microwave heating effect.

Acid-labile poly(amino alcohol ortho ester) based on low molecular weight polyethyleneimine for gene delivery.

A series of acid-labile poly(amino alcohol ortho ester) (POEeis) were synthesized through ring-opening polymerization between diglycidyl ethers with ortho ester bonded and low molecular weight polyethyleneimine by various feed molar ratios. The obtain POEei 1 and POEei 2 exhibited clear kinetic of degradation and condensed plasmid DNA into nanoparticles of suitable sizes (250-300 nm) and positive zeta potentials (+20-30 mV) while protecting DNA from enzymatic digestion. Further, these polymers have uniform distribution of abundant hydroxyl groups, which could improve their water solubility, biocompatibility, and lower protein adsorption. Significantly, ortho ester groups in POEeis main-chains could hydrolyze rapidly at acidic endosomal pH, resulting in intracellular DNA release and diminished material toxicity. MTT assay revealed that all the polymers exhibited much lower cytotoxicity than 25 kDa PEI in the human neuroblastoma SH-SY5Y cells. Moreover, the transfection efficiency of POEei 1 was higher than 25 kDa PEI in serum-free medium or 10% serum medium.

Abstract 3099: pH-regulated hydrophilicity/hydrophobicity-, surface charge-reversible and redox sensitive nanogels for anticancer drug delivery

Abstract Long circulation in blood, enhanced tumor accumulation and penetration, efficient cellular internalization and intracellular drug release are major challenges in the development of ideal anticancer drug delivery systems. Although several strategies have been reported to improve therapeutic efficacy, they mainly meet one or a few features which can not circumvent all the barriers. Here the stimuli-responsive zwitterionic nanogels were developed to overcome the sequential physiological barriers in cancer chemotherapy. The nanogels were constructed via a simple precipitation polymerization method by using temperature-sensitive monomer N-isopropylacrylamide (NIPAM) pH-responsive monomer methylallyl amine (MAA) and betaine-based zwitterionic monomer sulfobetaine methacrylate (SBMA) with in vivo anti-protein adsorption property as comonomers, and disulfide bonds-containing N, N'-bis(acryloyl) cystamine (BAC) as crosslinker. Volume phase transition temperature (VPTT) and surface charge of the prepared nanogels were precisely controlled by altering the feeding molar ratio of these comonomers. Remarkably, The nanogels possess ultra-pH sensitive hydrophilicity/hydrophobicity reversible property, in which the nanogels were hydrophilic in the blood (pH 7.4, 37 °C) for prolonged circulation, while they were rapidly switched to hydrophobic with similar size and surface charge at acidic tumor pH, resulting in enhanced tumor accumulation and penetration and strong internalization by normal cancer cells and CSCs. For efficient lysosomal escape and intracellular drug release, the nanogels were positively charged at lysosome pH, which allowed them to be transported into the cytosol where the loaded cargo DOX was released from the nanogels with the introduction of intracellular high GSH concentration to exert cytotoxicity. This study indicated that pH-dependent hydrophilicity/hydrophobicity-, surface charge-reversible and redox sensitive nanogels might be used as potential carriers for anticancer drugs, which provided a foundation for designing an effective drug delivery system for cancer therapy. Note: This abstract was not presented at the meeting. Citation Format: Hao Yang, Qin Wang, Fuying Li, Yanhong Zhu, Lu Gan, Xiangliang Yang. pH-regulated hydrophilicity/hydrophobicity-, surface charge-reversible and redox sensitive nanogels for anticancer drug delivery [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 3099. doi:10.1158/1538-7445.AM2017-3099

Effects of monomer compatibility on sizing properties of feather keratin-g-P(AA-co-MA)

In order to endow feather keratin with good sizing properties for all-polyester or high-polyester yarns, methyl acrylate (MA) and acrylic acid (AA) monomers with a variation in feed molar ratio from 10/90 to 30/70 were grafted onto the molecular chains of native feather keratin under equal monomer concentration. Effects of monomer compatibility of MA/AA on sizing properties of the feather keratin-g-P(AA-co-MA) were studied in terms of apparent viscosity, contact angle of sizing paste on polyester fibers, mechanical properties of sizing film, and adhesion to polyester fibers. It was found that grafting MA & AA monomers with rational compatibility onto the molecular chains of feather keratin was an effective method to improve sizing properties of grafted feather keratin, such as adhesion to polyester fibers and toughness of sizing film. In view of overall performance of the grafted feather keratin sizes, the appropriate feed molar ratio of MA/AA should be 20/80.

Indium doped BiOI nanosheets: Preparation, characterization and photocatalytic degradation activity

Semiconductor photocatalysis is a promising method to remove the harmful compounds into harmless molecules. Herein, In-doped BiOI (In-BiOI) photocatalysts with highly exposed dominant {001} facets were synthesized through a facile hydrothermal method. The XRD, SEM and TEM determinations revealed the high crystallinity structure of the samples, and the XPS results confirmed the doping of In. The In-BiOI nanosheets exhibited a higher activity in the photodegradation of p-chloroaniline (PCA) than that of pristine BiOI, among which the In-2 BiOI sample (feed mole ratio of In:Bi=2%) possessed the best performance. Doping with In didn’t alter the structure, morphology, specific surface area or light absorption capacity of BiOI, but significantly improved its charge separation efficiency and transport capability, which were verified by the results of the lower PL emission, larger photocurrent intensity and smaller arc radius of EIS plots. More importantly, the mechanism of photocatalytic degradation is studied systematically, revealing that O2− and h+ were the major reactive species during the photodegradation process. Finally, the possible role of In-doping in enhancing the photocatalytic performance of BiOI is proposed.

Comparative modeling study of catalytic membrane reactor configurations for syngas production by CO2 reforming of methane

Modeling based analysis of catalytic CO2 reforming of methane in fixed bed (FBR) and membrane reactors (MR) has been carried out for the production of syngas. Four Ni-based catalysts have been studied separately in FBR to identify suitable catalyst on the basis of carbon formation tendency at the reactor operating conditions of temperature (973–1073K), and CO2/CH4 molar feed ratio (CMR=1, 2, and 3). The simulation has resulted in Ni/La2O3 as most suitable catalyst at 1073K and CMR=1. Addition of 10% H2 to the feed further reduces the carbon formation tendencies. Two fixed bed reactor configurations [FBR1 (Ni/La2O3), and FBR2 (Rh/γ-Al2O3)], and two membrane reactor configurations [MR1 (FBR1+dense membrane), and MR2 (FBR2+porous membrane)] have been evaluated by simulation to identify the favorable configuration at operating conditions for syngas production. The yields of H2 and CO are found maximum as 94.5% and 98% respectively at CMR=1 in reactor MR1. Also the H2/CO ratio has been found close to unity at 1073K and CMR=1 in reactor MR1 with no significant effect of sweep gas. Hence, the membrane reactor MR1 is the best reformer configuration to produce syngas by dry reforming of methane.

Heavy water decontamination tests through a Pd-Ag membrane reactor: Water Gas Shift and Isotopic Swamping performances

A Pd-Ag membrane reactor has been studied to assess its ability in heavy water decontamination through Isotopic Swamping (IS) and Water Gas Shift (WGS) reactions under different operating conditions (i.e. reactor temperature, lumen pressure, feeding molar ratio and isotopic swamping). The reactor has been installed in a new facility of the ENEA Membrane Laboratory called HyFraMe, by testing two catalysts. The results are reported in terms of decontamination factor or DF (the amount of gaseous deuterium recovered from heavy water). Both catalysts demonstrate, in the WGS reactions, low methane production (1.72mol% in the worst case) and high DF, almost 80%, at pressure of 400–500kPa at 623K. The IS reaction tests exhibited a lower performance (DF=67% at the best).

Applicability of a TSA/ZrO2 catalytic membrane for the production of ethyl levulinate as raw material of gamma-valerolactone

The aim of this study is to synthesize of ethyl levulinate as raw material by the green catalytic membrane process for the produce of gamma-valerolactone by hydrogenation. Production of zirconium oxide supported tungstosilicic acid loaded hydroxyethyl cellulose catalytic membrane was done by solution casting method. Zirconium oxide supported tungstosilicic acid, which used as the catalyst, was prepared by the wet impregnation method in the laboratory. Catalyst and catalytic membrane were characterized by XRD and SEM. The reaction was carried out in the batch reactor by using catalytic membrane pieces as the catalyst. Optimum conditions were determined as the reaction temperature of 75 °C, molar feed ratio of 6:1, catalyst concentration of 2 wt.% and catalytic membrane amount of 4 wt.%. The conversion value of levulinic acid to ethyl levulinate was obtained as 86% under these conditions and catalytic membrane was used for five times without losing catalytic activity. As a result of the study, catalytic membrane was found as an efficient catalyst for the synthesis of ethyl levulinate.

Carbon nanofiber-supported PdNi alloy nanoparticles as highly efficient bifunctional catalysts for hydrogen and oxygen evolution reactions

Efficient bifunctional electrocatalysts for the hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) must be developed to realize an inexpensive water-splitting system for large-scale applications. Herein, a novel PdNi carbon nanofiber (PdNi/CNF) catalyst was synthesized by facile electrospinning and carbonization processes. The size and homogeneity of the Pd−Ni alloy nanoparticles (NPs) could be effectively tuned by controlling the molar feed ratio of metal precursors .The morphology and structure of the PdNi/CNFs were characterized, and the working electrodes fabricated from the prepared catalyst mats were directly employed in the HER and OER. The PdNi/CNFs-1:2 catalyst exhibits high catalytic activity in the HER with a low overpotential of 55mV at a current density of 10mAcm−2 in an acidic solution. Moreover, under 1M KOH electrolyte, an overpotential of 187mV is required in the HER over the catalyst to arrive 10mAcm−2 and an overpotential of 289mV is achieved in the OER at the same current density. The superior HER and OER activities of the PdNi/CNFs are attributed to the synergistic effects of the PdNi alloy nanoparticles (NPs) assembled on the CNFs. This work provides a simple route for synthesizing highly efficient bifunctional electrocatalysts from 3d transition metals and a small amount of noble metals for hydrogen and oxygen evolution reactions.

Thermal analysis and melt spinnability of poly(acrylonitrile-co-methyl acrylate) and poly(acrylonitrile-co-dimethyl itaconate) copolymers

This work investigated the cyclization possibility and melt spinnability of carbon fiber precursors, poly(acrylonitrile-co-methyl acrylate) (AN/MA) and poly(acrylonitrile-co-dimethyl itaconate) (AN/DMI). The onset temperature of cyclization of the AN/DMI copolymer is lower than that of the AN/MA copolymer and also the polyacrylonitrile (PAN) homopolymer. The enthalpy ( ΔH) of the AN/DMI copolymer is about 3–4 times that of the PAN homopolymer and about 1.8 times that of the AN/MA copolymer, indicating that the degree of cyclization of the AN/DMI copolymer is relatively higher. The melt dwell time of the AN/DMI copolymer is increased to about 3–5 times that of the AN/MA copolymer, especially when synthesized with a feed molar ratio of AN/DMI = 85/15. The AN/DMI copolymer (AN/DMI = 85/15) has the longest melt dwell time, 24.8 min, at the lowest melting temperature, 190oC, among all the PAN-related copolymers synthesized herein. Furthermore, the AN/DMI copolymer (AN/DMI = 85/15) can be rapidly cyclized at the cyclization temperature of 260℃, which is 25℃ lower than that of the AN/MA copolymer (AN/MA = 85/15). In short, this work demonstrates that the carbon fiber precursor made by the AN/DMI copolymer (AN/DMI = 85/15) will be superior to that of the AN/MA copolymer (AN/MA = 85/15) with respect to the melt spinnability and cyclization at low temperature.

Intensification of carboxylic acid esterification using a solid catalyst in a mesoscale oscillatory baffled reactor platform

Intensified production of carboxylic acid esters has been investigated using a mesoscale oscillatory baffled reactor (meso-OBR), operated in continuous multi-steady states, dynamic and multi-dimensional modes. This study was performed to investigate the suitability of the reactor for solid-liquid reactions, capacity for quality steady states and rapid process development. A heterogeneously catalysed hexanoic acid esterification with methanol was studied in a meso-OBR packed with Amberlyst™ 70 resin as an acid catalyst. The esterification conditions investigated were feed molar ratios in the range of 1.5:1–30:1 and residence times in the range of 1min–20min. The meso-OBR was operated at oscillatory conditions of 4.5Hz frequency and 8mm amplitude (centre-to-peak) and reaction temperature of 60°C. Clear steady states were achieved at all the residence times used, with maximum hexanoic acid to methyl hexanoate conversion of 95.4±1.0% obtained at 20min residence time and 30:1 methanol to acid molar ratio. Methyl ester conversions were 98.5±1.5% at 20min residence time and 30:1 methanol to acid molar ratio for dynamic screening, and 98.2±1.1% at 14min residence time and 21:1 methanol to acid molar ratio for the multi-dimensional mode. Use of dynamic screening required 16% less time and reactant compared to the multi-steady states approach. A more significant reduction in the process development time and reactants requirement, approximately 30% compared to the multi-steady states approach, was achieved using the multi-dimensional approach. This demonstrates a substantial reduction in process development time, another major advantage of the meso-OBR platform as the choice reactor in process development for multiphase reactions. The Amberlyst™ 70 entirely regained its catalytic activity after water spiking, and was not permanently deactivated by water.

Ethanol Steam Reforming for Renewable Hydrogen Production over La-modified Tio2 Catalyst

In recent years, ethanol steam reforming (ESR) has received considerable attention as a promising route for cleaner H2 production. This process could be industrially advantageous, ideally yielding 6 moles of H2 per mole of ethanol reacted. The major drawbacks of the process are the endothermic nature of the reaction and presence of CO2 in the product. At low temperatures (below 500 °C), side reactions that yield alternative products such as acetic acid, acetaldehyde and ethylene are favoured. Besides promoting ESR, higher temperatures make the process costly for an industrial development while promoting CO, CO2 and coke formation, which is the main cause of catalyst deactivation. In this study, a series of La-loaded TiO2 catalysts were prepared by an impregnation-co-precipitation method, La being a well-known inhibitor of CO and CO2 formation. Catalytic ethanol steam reforming was conducted in a tubular fixed bed reactor operated at 1 atm, 500 °C and an ethanol/water molar feed ratio of 10:1. The influence of La-loading on inhibiting coke formation and selectivity towards hydrogen formation by ethanol steam reforming has been investigated. The catalytic performance of La-loaded TiO2 catalyst was found to be considerably higher when compared to the pure TiO2. At 10 % La loading, ethanol conversion of ~27.5 % was achieved with a H2 mole fraction of 0.53. Significant amounts of valuable products such as CH4 and C2H4 were also detected in the product mixture. More importantly, CO was not detected over La-loaded TiO2 catalyst, which confirmed its ability for minimizing coke formation. This development has confirmed improved efficiency of La/TiO2 catalyst toward renewable hydrogen production.

Batch Preparation of High Basicity Polyferric Sulfate by Hydroxide Substitution from Bipolar Membrane Electrodialysis

An experimental study was carried out on the batch preparation of high basicity polyferric sulfate (PFS) by hydroxide substitution from bipolar membrane electrodialysis (BMED) with BP-A configuration. Effects of operation time, current density, and molar feed ratio of FeSO4 to H2SO4 on PFS properties were investigated. Results show that increasing operation time and molar feed ratio may increase the PFS basicity, turbidity removal ratio, and energy consumption simultaneously; meanwhile, increasing current density could increase the basicity and turbidity removal ratio but decrease the energy consumption. When the current density is 20 mA/cm2, the basicity attains to 14.72%, turbidity removal ratio increases to 93.43%, and energy consumption decreases to 2.72 kW·h/(kg H2SO4). Moreover, X-ray diffraction (XRD), scanning electron microscopy (SEM), and Fourier transform infrared (FT-IR) were conducted to determine the structure and morphology analysis of solid PFS.

Size-dependent dual emission of Cu,Mn:ZnSe QDs: Controlling both emission wavelength and intensity.

Cu,Mn:ZnSe quantum dots (QDs) of tunable size, controllable photoluminescence (PL) intensity ratio and PL range were prepared. A study of the experimental conditions confirmed that the size of Cu,Mn:ZnSe QDs is affected by the pH of the solution, the speed at which the Zn solution is injected and the reaction temperature. In general, high pH, low injection speed and high reaction temperature are optimal for preparing large QDs. Based on this knowledge, different sizes of Cu,Mn:ZnSe QDs were synthesized. Moreover, white emission Cu,Mn:ZnSe QDs were designed by controlling the experimental conditions and the feeding mole ratio of Mn:Cu.