scholarly journals Investigation on coagulation efficiency of polyaluminium silicate chloride (PASiC) coagulant

2012 ◽  
Vol 10 (10) ◽  
pp. 33-37 ◽  
Author(s):  
G Gyawali ◽  
A Rajbhandari (Nyachhyon)
Keyword(s):  
High Performance ◽  
Molar Ratio ◽  
Turbidity Removal ◽  
Molar Ratios ◽  
Residual Aluminum ◽  
Scientific World ◽  
Alum Treatment ◽  
Ph Range ◽  
Optimum Ph Range ◽  
Flocculation Time

Polyaluminium silicate chloride (PASiC) coagulant was synthesized by co-polymerization technique using aluminium salt and polysilicic acid at different OH/Al and Al/Si molar ratios. A synthetic turbid sample was used to investigate the coagulation efficiency of the prepared coagulant. After the coagulant dosing, flocculation time was set for 15 minutes followed by sedimentation for 20 minutes.  High performance of coagulant was achieved at 2.5 molar ratio of OH/Al and 5 molar ratio of Al/Si at the optimal pH. The optimum pH range was found to be 7±0.5.The effective coagulant dose for the efficient removal of turbidity was set as 2.5 mg/L. As compared to conventional alum, PASiC has been found to be excellent inorganic polymeric coagulant for turbidity removal from water and residual aluminum was found to be minimal in comparison to conventional alum treatment. Hence, PASiC has proven the potentiality for the turbidity removal in water treatment over conventional alum. Scientific World, Vol. 10, No. 10, July 2012 p33-37 DOI: http://dx.doi.org/10.3126/sw.v10i10.6859

Application of PFSC in Seawater Desalination Pretreatment

2014 ◽  
Vol 945-949 ◽  
pp. 3510-3513 ◽  
Author(s):  
Jun Cheng ◽  
Si Cheng ◽  
Xiao Fan Cao
Keyword(s):  
Optimal Condition ◽  
Ferric Chloride ◽  
Reaction Temperature ◽  
Ph Value ◽  
Experimental Results ◽  
Curing Temperature ◽  
Molar Ratio ◽  
Seawater Desalination ◽  
Turbidity Removal ◽  
Molar Ratios

The optimal condition of polysilicon ferric chloride (PFSC) flocculant was established by thinking of the factors , such as Si/Fe molar ratios,the reaction temperature and the pH value of the solution. When the molar ratio of Si and Fe = 1, pH value = 0.6, curing temperature at 30 ~40 °C, poly ferric chloride dosage of 0.75mg/L, the rate of turbidity removal of seawater is up to 96.5%. Experimental results show that poly ferric chloride seawater turbidity removal effect is obvious.

scholarly journals High-Performance Solution-Processed Amorphous InGaZnO Thin Film Transistors with a Metal–Organic Decomposition Method

2018 ◽  
Vol 2018 ◽  
pp. 1-7 ◽  
Author(s):  
Yingtao Xie ◽  
Dongping Wang ◽  
Hon Hang Fong
Keyword(s):  
High Performance ◽  
Annealing Temperature ◽  
Solution Process ◽  
Molar Ratio ◽  
Molar Ratios ◽  
Positive Voltage ◽  
Metal Organic ◽  
The Relationship ◽  
Organic Decomposition ◽  
Igzo Tft

A facile solution process was introduced for the preparation of IGZO thin films via a metal–organic decomposition (MOD) method. The IGZO ink was synthesized by mixing the solutions of gallium acetylacetonate [Ga(C5H7O2)3], zinc acetylacetonate hydrate [Zn(C5H7O2)2·xH2O] dissolved in ethanol, and indium acetylacetonate [In(C5H7O2)3] dissolved in tetrahydrofuran (THF). The deposited films by spin-coating were annealed at moderate process temperature (≤500°C). The relationship between device performance and postannealing temperature was studied. The result demonstrated that mobility of IGZO TFT increased as the annealing temperature increased. Based on the analysis of O 1s statement, the annealing temperature can influence the number of oxygen vacancy to further affect the carrier centration. In addition, the IGZO TFT devices with various Ga molar ratios were compared to demonstrate the influence of the Ga addition. The result demonstrated that the saturated mobilities (μe) decreased and VTH shifted to positive voltage as the Ga molar ratio was increased. It is likely that Ga can offer stronger chemical bonds between metal and oxygen that reduced the concentration of free carriers and thus help reducing VTH. As a result, the optimized performance of IGZO TFT with the mobility of 3.4 cm2V−1s−1 showed the MOD process was a promising approach.

The Roles of Polyvinyl Alcohol (PVA) as the Capping Agent on the Polyol Method for Synthesizing Silver Nanowires

2017 ◽  
Vol 49 ◽  
pp. 174-180 ◽  
Author(s):  
Junaidi ◽  
Kuwat Triyana ◽  
Edi Suharyadi ◽  
Harsojo ◽  
Linda Y.L. Wu
Keyword(s):  
Electron Microscopy ◽  
Polyvinyl Alcohol ◽  
High Performance ◽  
Silver Nanowires ◽  
Polyol Method ◽  
Molar Ratio ◽  
Face Centered Cubic ◽  
Capping Agent ◽  
Molar Ratios ◽  
Xrd Patterns

We report our investigation of roles of polyvinyl alcohol (PVA) as a high-performance capping agent in synthesizing silver nanowires (AgNWs) using polyol method. For this purpose, we varied the concentration of silver nitrate (AgNO3), from 0.3 M to 1.0 M, and molar ratios of [PVA:AgNO3] from 2 to 6. The UV-vis spectra show the AgNWs growth optimally at a molar ratio of 4.5 with the absorbance peaks of 378 nm and 380 nm. Meanwhile, from XRD patterns, it was found that the crystal structure of the AgNWs can be identified as a face-centered cubic (fcc) with a lattice constant according to the spacing distance between the {111} planes of 4.087 Å. Finally, scanning electron microscopy (SEM) and transmission electron microscopy TEM images show the diameter and length of the AgNRs are 150 to 230 nm and 50 to 120 µm, respectively. These results show that the AgNWs synthesized using PVA having a long size.

High Performance Ag/AgBr/TiO2 Photocatalyst-Coated Silica Beads

2016 ◽  
Vol 690 ◽  
pp. 156-161
Author(s):  
Jate Panichpakdee ◽  
Nobuaki Negishi ◽  
Siriporn Larpkiattaworn
Keyword(s):  
Formic Acid ◽  
High Performance ◽  
Sol Gel ◽  
Molar Ratio ◽  
Photocatalytic Efficiency ◽  
Gel Method ◽  
Acid Degradation ◽  
Molar Ratios ◽  
Study Results ◽  
Silica Beads

A series of three-component photocatalyst consisting of Ag, AgBr, and TiO2 were synthesized and successfully coated on PSB-01 beads (TiO2-coated silica beads). Different Ag to Ti molar ratios of 0.07, 0.10, and 0.20 in ethanol were prepared and coated on PSB-01 beads by sol-gel method. The morphologies and elemental compositions of these photocatalysts were characterized by SEM, EDS, and XRD, respectively. The performance of the photocatalyst coated on PSB-01 beads was evaluated in aspects of efficiency and stability. As for the photocatalytic efficiency, formic acid was used as the chemical model in this study. Results showed that the deposition of Ag/AgBr/TiO2 at Ag/Ti molar ratio of 0.07 on PSB-01 beads had the best performance in terms of formic acid degradation when compared to other ratios of Ag/AgBr/TiO2-coated PSB-01, Ag-coated PSB-01, and PSB-01 beads. In addition, for the study of stability, the release of silver from a series of Ag/AgBr/TiO2-coated PSB-01 was also evaluated.

scholarly journals Cyanide Removal and Recovery by Electrochemical Crystallization Process

Water ◽  
2021 ◽  
Vol 13 (19) ◽  
pp. 2704
Author(s):  
Natacha Martin ◽  
Vinh Ya ◽  
Vincenzo Naddeo ◽  
Kwang-Ho Choo ◽  
Chi-Wang Li
Keyword(s):  
Cost Effective ◽  
Molar Ratio ◽  
Mechanical Mixing ◽  
Molar Ratios ◽  
Dissolved Iron ◽  
Iron Salts ◽  
H2o2 Oxidation ◽  
Ph Range ◽  
Fe Ions ◽  
Removal And Recovery

Alkaline chlorination, an efficient but high chemical cost process, is commonly employed for cyanide (CN−) removal from CN-rich wastewater streams. CN− removal and recovery through the precipitation of Prussian Blue (Fe4III[FeII(CN)6]3, PB) or Turnbull’s Blue (Fe3II[FeIII(CN)6]2, TB) were realized using iron salts, leading to a cost-effective and sustainable process producing a valuable recovery product. However, the precipitation of PB and TB is highly affected by pH and dissolved oxygen (DO). CN− removal and recovery from CN-containing water by crystallization of PB and/or TB were investigated using dissolved iron that was electrochemically generated from a sacrificial iron anode under various pH values, initial CN− levels (10 to100 mg/L) and DO levels (aeration, mechanical mixing, and N2 purging). It was shown that the complexation of CN− with Fe ions prevented the vaporization of HCN under acidic pH. At pH of 7 and initial CN− concentration of 10 mg/L, CN− removal efficiency increases linearly with increasing Fe:CN− molar ratios, reaching 80% at the Fe:CN− molar ratio of 5. A clear blue precipitate was observed between the pH range of 5–7. CN− removal increases with increasing initial CN− concentration, resulting in residual CN− concentrations of 8, 7.5 and 12 mg/L in the effluent with the Fe:CN− molar ratio of 0.8 for initial concentrations of 10, 50 and 100 mg CN−/L, respectively. A polishing treatment with H2O2 oxidation was employed to lower the residual CN− concentration to meet the discharge limit of <1 mg CN−/L.

scholarly journals Novel approach to synthesize NiCo2S4 composite for high-performance supercapacitor application with different molar ratio of Ni and Co

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
S. K. Shinde ◽  
Sivalingam Ramesh ◽  
C. Bathula ◽  
G. S. Ghodake ◽  
D.-Y. Kim ◽  
...  
Keyword(s):  
Thin Films ◽  
High Performance ◽  
Molar Ratio ◽  
Silar Method ◽  
New Approach ◽  
Supercapacitor Application ◽  
Molar Ratios ◽  
Novel Approach ◽  
Layer Adsorption ◽  
Binary Metal Oxides

Abstract Here, we developed a new approach to synthesize NiCo2S4 thin films for supercapacitor application using the successive ionic layer adsorption and reaction (SILAR) method on Ni mesh with different molar ratios of Ni and Co precursors. The five different NiCo2S4 electrodes affect the electrochemical performance of the supercapacitor. The NiCo2S4 thin films demonstrate superior supercapacitance performance with a significantly higher specific capacitance of 1427 F g−1 at a scan rate of 20 mV s−1. These results indicate that ternary NiCo2S4 thin films are more effective electrodes compared to binary metal oxides and metal sulfides.

scholarly journals Stabilization of horseradish peroxidase by covalent conjugation with dextran aldehyde against temperature and pH changes

2009 ◽  
Vol 7 (3) ◽  
pp. 423-428 ◽  
Author(s):  
Melda Altikatoglu ◽  
Candan Arioz ◽  
Yeliz Basaran ◽  
Huriye Kuzu
Keyword(s):  
Horseradish Peroxidase ◽  
Room Temperature ◽  
Gel Permeation Chromatography ◽  
Molar Ratio ◽  
Thermal Stabilities ◽  
Molar Ratios ◽  
Covalently Bonded ◽  
Different Temperatures ◽  
Ph Range ◽  
Long Storage

AbstractStabilization of Horseradish Peroxidase (HRP; EC 1.11.1.7) against temperature and pH via the formation of the conjugates obtained by multipoint covalent bonding of dextran aldehyde (DA) to the enzyme were studied. Hence, three different molar weighted dextrans (17.5 kD, 75 kD, 188 kD) were covalently bonded to purified enzyme with different molar ratios (nHRP/nDA 20/1, 10/1, 1/1, 1/5, 1/10, 1/15, 1/20). The thermal stabilities of the obtained conjugates were evaluated with the activities determined at different temperatures (25, 30, 35, 40, 50, 60, 70, 80°C) applying 60 minutes incubation time. Conjugates formed were characterized by gel-permeation chromatography (GPC) and fluorescence techniques. The conjugate synthesized using dextran 75 kDa with nHRP/nDA 1/10 molar ratio showed better thermal stability than other conjugates and purified enzyme at pH 7. This conjugate also has wider activity pH range than purified enzyme. In addition, mentioned conjugate at pH 7 had very long storage lifetime compared to purified enzyme at +4°C and room temperature; which is considered a favorable feature for usage in practice.

Application of a fractionation technique for better understanding of the removal of natural organic matter by alum coagulation

2002 ◽  
Vol 2 (5-6) ◽  
pp. 427-433 ◽  
Author(s):  
J. van Leeuwen ◽  
C. Chow ◽  
R. Fabris ◽  
N. Withers ◽  
D. Page ◽  
...  
Keyword(s):  
Organic Matter ◽  
Natural Organic Matter ◽  
High Performance ◽  
Relative Proportion ◽  
Water Source ◽  
Size Exclusion ◽  
Gas Chromatography Mass Spectrometry ◽  
Pyrolysis Gas ◽  
Alum Treatment ◽  
Hydrophobic Acids

To gain an improved understanding of the types of organic compounds that are recalcitrant to water treatment, natural organic matter (NOM) isolates from two drinking water sources (Mt. Zero and Moorabool reservoirs, Victoria, Australia) were separated into fractions of distinct chemical behaviour using resins. Four fractions were obtained from each water source and were organics absorbed to: (1) XAD-8 (very hydrophobic acids, VHA); (2) DAX-4 (slightly hydrophobic acids, SHA); (3) bound to an anion exchange resin (charged organics, CHAR); and (4) not absorbed or bound to resins (neutrals, NEUT). These fractions were then tested to determine the capacity of alum to remove them from water and to correlate this with the character of each isolate. The fractions were characterised by the application of high performance size exclusion chromatography (HPSEC), bacterial regrowth potential (BRP), trihalomethane formation potential (THMFP), pyrolysis gas-chromatography mass spectrometry (Py-GC-MS) and thermochemolysis. The highest removals of dissolved organic carbon (DOC) by alum treatment were in waters spiked with the CHAR fractions while the NEUT fractions were the most recalcitrant. The number average molecular weights (Mn) of DOC of the CHAR fractions before treatment were the highest, whilst those of the NEUT fractions were the lowest. After alum treatment, the Mn of the NEUT fractions were only slightly reduced. Results from Py-GC-MS and thermochemolysis indicate that the NEUT fractions had the highest relative proportion of saccharide derived organic material. Nonetheless, the BRP of waters spiked with the NEUT fractions differed markedly, indicating that organics recalcitrant to alum treatment can vary substantially in their chemical composition and capacity to support microbial growth.

scholarly journals Photocatalytic Reduction of CO2 to Methanol Using a Copper-Zirconia Imidazolate Framework

Catalysts ◽  
2021 ◽  
Vol 11 (3) ◽  
pp. 346
Author(s):  
Sonam Goyal ◽  
Maizatul Shima Shaharun ◽  
Ganaga Suriya Jayabal ◽  
Chong Fai Kait ◽  
Bawadi Abdullah ◽  
...  
Keyword(s):  
Photoelectron Spectroscopy ◽  
Catalyst Support ◽  
Oxidation Potential ◽  
Molar Ratio ◽  
X Ray Diffraction ◽  
X Ray ◽  
Molar Ratios ◽  
Optimum Parameters ◽  
Reduction Of Co2 ◽  
Enhanced Yield

A set of novel photocatalysts, i.e., copper-zirconia imidazolate (CuZrIm) frameworks, were synthesized using different zirconia molar ratios (i.e., 0.5, 1, and 1.5 mmol). The photoreduction process of CO2 to methanol in a continuous-flow stirred photoreactor at pressure and temperature of 1 atm and 25 °C, respectively, was studied. The physicochemical properties of the synthesized catalysts were studied using X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), and photoluminescence (PL) spectroscopy. The highest methanol activity of 818.59 µmol/L.g was recorded when the CuZrIm1 catalyst with Cu/Zr/Im/NH4OH molar ratio of 2:1:4:2 (mmol/mmol/mmol/M) was employed. The enhanced yield is attributed to the presence of Cu2+ oxidation state and the uniformly dispersed active metals. The response surface methodology (RSM) was used to optimize the reaction parameters. The predicted results agreed well with the experimental ones with the correlation coefficient (R2) of 0.99. The optimization results showed that the highest methanol activity of 1054 µmol/L.g was recorded when the optimum parameters were employed, i.e., stirring rate (540 rpm), intensity of light (275 W/m2) and photocatalyst loading (1.3 g/L). The redox potential value for the CuZrIm1 shows that the reduction potential is −1.70 V and the oxidation potential is +1.28 V for the photoreduction of CO2 to methanol. The current work has established the potential utilization of the imidazolate framework as catalyst support for the photoreduction of CO2 to methanol.

scholarly journals Lipozyme 435-Mediated Synthesis of Xylose Oleate in Methyl Ethyl Ketone

Molecules ◽  
2021 ◽  
Vol 26 (11) ◽  
pp. 3317
Author(s):  
Maria Carolina Pereira Gonçalves ◽  
Jéssica Cristina Amaral ◽  
Roberto Fernandez-Lafuente ◽  
Ruy de Sousa Junior ◽  
Paulo Waldir Tardioli
Keyword(s):  
Oleic Acid ◽  
Methyl Ethyl Ketone ◽  
Molar Ratio ◽  
Methyl Ethyl ◽  
Sugar Ester ◽  
Molar Ratios ◽  
Emulsion Capacity ◽  
Ping Pong ◽  
Commercial Sugar ◽  
Repeated Use

In this paper, we have performed the Lipozyme 435-catalyzed synthesis of xylose oleate in methyl ethyl ketone (MEK) from xylose and oleic acid. The effects of substrates’ molar ratios, reaction temperature, reaction time on esterification rates, and Lipozyme 435 reuse were studied. Results showed that an excess of oleic acid (xylose: oleic acid molar ratio of 1:5) significantly favored the reaction, yielding 98% of xylose conversion and 31% oleic acid conversion after 24 h-reaction (mainly to xylose mono- and dioleate, as confirmed by mass spectrometry). The highest Lipozyme 435 activities occurred between 55 and 70 °C. The predicted Ping Pong Bi Bi kinetic model fitted very well to the experimental data and there was no evidence of inhibitions in the range assessed. The reaction product was purified and presented an emulsion capacity close to that of a commercial sugar ester detergent. Finally, the repeated use of Lipozyme 435 showed a reduction in the reaction yields (by 48 and 19% in the xylose and oleic acid conversions, respectively), after ten 12 h-cycles.

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