Flotation Behavior Difference between the Pure Quartz and the Quartz Gangue of a Siliceous-Calcareous Phosphate Ore with Fine Size

2013 ◽  
Vol 448-453 ◽  
pp. 3855-3858
Author(s):  
Fang Guo ◽  
Jun Li
Keyword(s):  
Carbon Chain ◽  
Alkaline Condition ◽  
Acid Condition ◽  
Phosphate Ore ◽  
Alkyl Amine ◽  
Alkaline Conditions ◽  
Fine Size ◽  
Ir Analysis ◽  
Adsorption Intensity ◽  
Flotation Behavior

Flotation behavior of pure quartz is difference from that of the quartz gangue of a siliceous-calcareous phosphate ore with fine size. The flotation of pure quartz can attain satisfactory results at alkaline conditions. The IR analysis shows that adsorption intensity of quaternary ammonium salt is stronger which is likely to explain its preferable flotation performance for pure quartz. However, for quartz gangue of phosphate ore, the results are completely opposite. The acid condition is more favorable for reverse flotation than alkaline condition due to the existence of carbonate mineral. The alkyl amine salt is a more effective collector to remove quartz gangue from siliceous-calcareous phosphate ore, especial with 12 carbon chain. Zeta potential of the ore treated by it is almost higher than that by the other alkyl amine salts (with 10, 14 or 18 carbon chain), which suggests its stronger absorption on ore particles.

Degradation of p-Toluenesulfonic Acid by Ozonation: Performance Optimization and Mechanism

2010 ◽  
Vol 113-116 ◽  
pp. 1551-1554 ◽  
Author(s):  
Qi Zhou Dai ◽  
Shao Qing Cai ◽  
Ming Hua ◽  
Jia De Wang ◽  
Jian Meng Chen
Keyword(s):  
Performance Optimization ◽  
Alkaline Condition ◽  
Direct Oxidation ◽  
Pharmaceutical Wastewater ◽  
Acid Condition ◽  
Sharp Difference ◽  
Toluenesulfonic Acid ◽  
Alkaline Conditions ◽  
Acidic Conditions ◽  
Ozonation Process

This paper explored ozonation for the treatment of pharmaceutical wastewater and p-toluenesulfonic acid (PTSA) was selected as the model pharmaceutical intermediate. The results showed that the ozonation process is efficient for the degradation of PTSA both in concentration and COD removal. The mono factor results showed that 60L/h was a suitable ozone flow rate. There were sharp difference between acid condition and alkaline condition, under acidic conditions, the direct oxidation with molecular ozone is of primary importance, and under alkaline conditions the hydroxyl oxidation starts to dominate, and pH=12 was a suitable value. Further, intermediates of PTSA degradation were analyzed and the reaction mechanism was discussed.

Reaction of S-geranyl-2-thiouracil modified oligonucleotides with alkyl amines leads to the N2-alkyl isocytosine derivatives

2017 ◽  
Vol 15 (25) ◽  
pp. 5332-5336 ◽  
Author(s):  
Grazyna Leszczynska ◽  
Klaudia Sadowska ◽  
Malgorzata Sierant ◽  
Milena Sobczak ◽  
Barbara Nawrot ◽  
...  
Keyword(s):  
Modified Oligonucleotides ◽  
Alkyl Amine ◽  
Alkyl Amines ◽  
Alkaline Conditions

The yield of the synthesis ofS-geranylated oligomers depends on the alkaline conditions of oligomer deprotection; a routinely used alkyl amine protocol deliversN2-alkylisocytosine-modified side products.

scholarly journals A facile and effective method for preparation of 2.5-furandicarboxylic acid via hydrogen peroxide direct oxidation of 5-hydroxymethylfurfural

2017 ◽  
Vol 19 (1) ◽  
pp. 11-16 ◽  
Author(s):  
Shuang Zhang ◽  
Long Zhang
Keyword(s):  
Hydrogen Peroxide ◽  
Reaction Time ◽  
Oxidation Mechanism ◽  
Molar Ratio ◽  
Alkaline Condition ◽  
Optimal Parameters ◽  
Direct Oxidation ◽  
Reaction Parameters ◽  
Alkaline Conditions ◽  
Furandicarboxylic Acid

Abstract In this paper, 2,5-furandicarboxylic acid (FDCA) was efficiently prepared by the direct oxidation of 5-hydroxymethylfurfural (5-HMF) using hydrogen peroxide (H2O2) in alkaline conditions without any catalysts. The effects of reaction parameters on the process were systematically investigated and the optimal parameters were obtained as follows: molar ratio of 5-HMF:KOH:H2O2 was 1:4:8, reaction temperature and reaction time were determined as 70°C and 15 minutes, respectively. Under these conditions, the yield of FDCA was 55.6% and the purity of FDCA could reach 99%. Moreover, we have speculated the detailed oxidation mechanism of 5-HMF assisted by hydrogen peroxide in alkaline condition to synthesize FDCA.

Tribological Behaviors of Polymer Based Composites under Alkaline Conditions

2012 ◽  
Vol 510 ◽  
pp. 563-568
Author(s):  
Yan Ji Zhu ◽  
Hui Juan Qian ◽  
Gui Ying Wang ◽  
Huai Yuan Wang
Keyword(s):  
Wear Resistance ◽  
Frame Structure ◽  
Alkaline Condition ◽  
Wear Properties ◽  
Friction Coefficients ◽  
Wear Rates ◽  
Transfer Films ◽  
Peek Composite ◽  
Alkaline Conditions ◽  
Ptfe Composites

In this paper, polyetheretherketone (PEEK) and polytetrafluoroethylene (PTFE) based composites reinforced with various amounts of potassium titanate whiskers (PTWs) or short carbon fibers (CF) were designed and fabricated respectively. The friction and wear properties of PEEK and PTFE based composites sliding under rigorous alkaline were comparatively investigated. Also, the morphologies of the worn and counterpart surfaces were studied by scanning electron microscopy (SEM). Because of the stable tunnel crystal structure and frame structure micro-reinforcement capacity, PTWs show outstanding performances in increasing the wear resistance and reducing the friction coefficients of both PEEK and PTFE based composites under alkaline. However, CF leads to the degradation of wear resistance and the increase of friction coefficient of PEEK based composites under alkaline. Furrows and abrasive wear were the main mechanisms for CF/PTFE/PEEK and CF/PTFE composites sliding in alkali. The results show that PTW/PTFE composites exhibit higher wear resistance under lower load, while PTW/PTFE/PEEK composite is more suitable for higher load under alkaline condition. Owing to the primary cooling and boundary lubricating effects of alkali, the wear rates and friction coefficients of PTFE composites and PTW/PTFE/PEEK composites decreased obviously, though the transfer films onto the counterpart steel surface were hindered considerably.

In Vitro Antibacterial Activities and Mechanisms of Action of Fatty Acid Monoglycerides Against Four Foodborne Bacteria

2020 ◽  
Vol 83 (2) ◽  
pp. 331-337
Author(s):  
WENYUE WANG ◽  
RUI WANG ◽  
GUIJU ZHANG ◽  
FANGLI CHEN ◽  
BAOCAI XU
Keyword(s):  
Antibacterial Activity ◽  
Antibacterial Activities ◽  
Carbon Chain ◽  
Antimicrobial Activities ◽  
Inhibitory Effect ◽  
Gram Positive ◽  
Gram Negative ◽  
E Coli ◽  
Alkaline Conditions

ABSTRACT Naturally occurring monoglyceride esters of fatty acids have been associated with a broad spectrum of antimicrobial activities. We used an automated turbidimetric method to measure the MIC and assess the antimicrobial activity of five monoglycerides (monocaprin, monolaurin, monomyristin, monopalmitin, and monostearin) against pathogenic strains of Staphylococcus aureus, Bacillus subtilis, Pseudomonas aeruginosa, and Escherichia coli. The antibacterial activity of monocaprin was highest because its carbon chain is shorter than those of other monoglycerides. The MICs of monocaprin against S. aureus, B. subtilis, P. aeruginosa, and E. coli were 0.32, 0.32, 2.5, and 2.5 mg/mL, respectively. Monocaprin had antibacterial activity under neutral and alkaline conditions (pH 7.0 to 9.0) but had no inhibitory effect on S. aureus, B. subtilis, and E. coli under weakly acidic conditions (pH 6.0). The antibacterial mechanism of monocaprin against gram-positive strains (S. aureus and B. subtilis) resulted from destruction of the cell membrane. In contrast, the antibacterial activity of monocaprin against gram-negative strains (P. aeruginosa and E. coli) was attributed to damage to lipopolysaccharides in the cell walls. Because of its inhibitory effect on both gram-positive and gram-negative bacteria, monocaprin could be used as an antibacterial additive in the food industry. HIGHLIGHTS

scholarly journals Tunable Magnetic Hyperthermia Properties of Pristine and Mildly Reduced Graphene Oxide/Magnetite Nanocomposite Dispersions

Nanomaterials ◽  
2020 ◽  
Vol 10 (12) ◽  
pp. 2426
Author(s):  
Erzsébet Illés ◽  
Etelka Tombácz ◽  
Zsófia Hegedűs ◽  
Tamás Szabó
Keyword(s):  
Graphene Oxide ◽  
Heat Production ◽  
Colloidal Stability ◽  
Magnetic Hyperthermia ◽  
Magnetic Core ◽  
Alkaline Condition ◽  
Graphene Oxides ◽  
Alkaline Conditions ◽  
Improved Stability ◽  
Co Precipitation

We present a study on the magnetic hyperthermia properties of graphene oxide/magnetite (GO/MNP) nanocomposites to investigate their heat production behavior upon the modification of the oxidation degree of the carbonaceous host. Avoiding the harsh chemical conditions of the regular in situ co-precipitation-based routes, the oppositely charged MNPs and GO nanosheets were combined by the heterocoagulation process at pH ~ 5.5, which is a mild way to synthesize composite nanostructures at room temperature. Nanocomposites prepared at 1/5 and 1/10 GO/MNP mass ratios were reduced by NaBH4 and L-ascorbic acid (LAA) under acidic (pH ~ 3.5) and alkaline conditions (pH ~ 9.3). We demonstrate that the pH has a crucial effect on the LAA-assisted conversion of graphene oxide to reduced GO (rGO): alkaline reduction at higher GO loadings leads to doubled heat production of the composite. Spectrophotometry proved that neither the moderately acidic nor alkaline conditions promote the iron dissolution of the magnetic core. Although the treatment with NaBH4 also increased the hyperthermic efficiency of aqueous GO/MNP nanocomposite suspensions, it caused a drastic decline in their colloidal stability. However, considering the enhanced heat production and the slightly improved stability of the rGO/MNP samples, the reduction with LAA under alkaline condition is a more feasible way to improve the hyperthermic efficiency of magnetically modified graphene oxides.

scholarly journals A Comparison Study on Fluorescence Properties of Formononetin and Ononin

2021 ◽  
Author(s):  
Jinjin Cao ◽  
Fang Lv ◽  
Ting Liu ◽  
Luchen Niu ◽  
Bocong Han ◽  
...  
Keyword(s):  
Fluorescence Enhancement ◽  
Alkaline Condition ◽  
Excitation Wavelength ◽  
Comparison Study ◽  
Spectral Difference ◽  
Experimental Conditions ◽  
Pyrone Ring ◽  
Wide Ph Range ◽  
Alkaline Conditions ◽  
Ph Range

Abstract In this work, reasons for the spectral difference between two isoflavones, Formononetin (F) and ononin (FG), are explained in the viewpoint of molecular structure through a comparison study of the fluorescence features of the two. The fluorescence enhancement of FG in hot alkaline condition is reported for the first time. For F, there was almost no fluorescence under acidic conditions, but when pH>5, its fluorescence began to increase with increasing pH due to the proton ionization of 7-OH. In the range of pH 9.3-12.0, the anion form of F produced a fairly strong and stable fluorescence with maximum excitation wavelength (λex) of 334 nm and emission wavelength (λem) of 464 nm, its fluorescence quantum yield (Yf) was measured to be 0.042. And for FG, its aqueous solution fluoresced weakly in a wide pH range until it was placed under hot alkaline conditions, which was presumed to the cleavage reaction of the γ-pyrone ring in FG by observing a significant fluorescence at λex / λem =288 / 388nm, and Yf was determined to be 0.020. The fluorescence sensitization methods of F and FG both exhibit low limits of detection (2.60 ng·mL-1, 9.30 ng·mL-1) and wide linear ranges (0.0117-1.86 μg·mL-1, 0.0146-2.92μg·mL-1). Although the structural relationship between F and FG is glycoside and aglycone, FG cannot be translated to F by glucoside hydrolysis under hot alkaline condition, the fluorescence enhancement mechanisms of the two are essentially different. The fluorescence difference between the two under different experimental conditions lays the foundation for future fluorescence quantitative analysis.

Effect of Mechanical Refining Treatment on Fiber Grafting Modification

2014 ◽  
Vol 496-500 ◽  
pp. 436-439
Author(s):  
Wei Liu ◽  
Fan Gong Kong ◽  
Shou Juan Wang ◽  
Qin Wu
Keyword(s):  
Aqueous Solution ◽  
Isopropyl Alcohol ◽  
Alcohol Solution ◽  
Alkaline Condition ◽  
Hydroxyl Groups ◽  
Cellulosic Fibers ◽  
Ion Removal ◽  
Mechanical Refining ◽  
Grafting Modification ◽  
Ir Analysis

Cellulosic fibers, as the most abundant biopolymer on earth, are attracting more and more interesting to be absorbent for ion removal from aqueous solution due to its biodegradability and renewability. In this paper, 3-chloro-2-hydroxypropyl trimethyl ammonium chloride was used as functional agent to modify the cellulosic fibers to be absorbent for Cr (VI) in aqueous solution. Our attention in this work was aimed at the influence of mechanical refining treatment before graft on the modification as well as the absorption capability of modified fibers. The modification was carried out using refined fibers and raw fibers. The modified fibers were verified by IR analysis. The results showed that in isopropyl alcohol solution and under alkaline condition, the functional agent can be grafted onto fibers. The mechanical refining treatment of cellulosic fibers before modification can improve the grafting efficiency. The absorption capability of modified treated-fibers for Cr (VI) from aqueous solution is higher than that of modified untreated-fibers. More hydroxyl groups on the surface of fibers after mechanical refining treatment is the reason for higher absorption capability of modified treated-fibers and higher grafting efficency.

scholarly journals Liquid organic fertilizer from seaweed (Sargassum sp.)and fish waste hydrolysate

2010 ◽  
Vol 5 (2) ◽  
pp. 59 ◽  
Author(s):  
Jamal Basmal
Keyword(s):  
Growth Hormone ◽  
Solid Waste ◽  
Alginic Acid ◽  
Organic Fertilizer ◽  
Fruit Production ◽  
Alkaline Condition ◽  
Acid Condition ◽  
Fish Waste

The combination of seaweed Sargassum sp. and fish waste hydrolysate can be used as anorganic fertilizer, both in liquid or solid forms. The organic fertilizer has a complete macro andmicro nutrients. It contains growth hormone factor such as auxin, cytokinine (zeatin and kinetin)and giberelin. The function of growth hormone factor in plants is to enhance the roots, stems, andleaves expansion, as well as to increase fruit production. To produce liquid organic fertilizer,seaweed has to be hydrolyzed in alkaline condition, meanwhile solid waste of fish has to behydrolyzed in acid condition. The liquid organic fertilizer had protein value of 0.08% or equal to0.012% N, 0.13% P, 1.22% K, 0.06% Ca, 0.17% Mg, 55.04% Fe, 122.75 ppm Mn, 1.95 ppm Cu,24.59 ppm Zn, 13 ppm B, and 18% alginic acid. It had auxin (IAA) of 91.48 ppm, cytokinine of84.71 ppm kinetin and of 70.27 ppm zeatin and giberellin (GA3) of 107.72 ppm.

scholarly journals Evaluation of residual antimicrobial activity and acute toxicity during the degradation of gatifloxacin by ozonation

2021 ◽  
Author(s):  
Marlon Caianelo ◽  
Caio Rodrigues-Silva ◽  
Milena Guedes Maniero ◽  
Vinicius Diniz ◽  
Mylena Spina ◽  
...  
Keyword(s):  
Antimicrobial Activity ◽  
Wastewater Treatment Plants ◽  
Degradation Products ◽  
Aqueous Media ◽  
Residual Activity ◽  
Fourth Generation ◽  
Alkaline Condition ◽  
Residual Toxicity ◽  
Test Organisms ◽  
Alkaline Conditions

Abstract The concerns regarding the occurrence of pharmaceuticals in wastewater treatment plants have been increased in the last decades. Gatifloxacin (GAT), the fourth generation of fluoroquinolones, has been widely used to treat both Gram-positive and Gram-negative bacteria and has a limited metabolization. The present study aimed to evaluate the ozonation as a technique to degrade GAT. A UHPLC-MS/MS method was used to quantify the residual of GAT and to assess its degradation products. The removal efficiency was higher at alkaline condition (pH = 10), reaching up to 99% of GAT after 4 min. It was also observed that the first ozone attack on the GAT molecule was through the carboxylic group. In contrast, at acid conditions (pH = 3), the ozone attack was first to the piperazinyl ring. The antimicrobial activity was evaluated using Escherichia coli and Bacillus subtilis as test organisms, and it was observed that the residual activity reduced most at the alkaline conditions. In contrast, the best condition to remove the residual toxicity evaluated for the marine bacteria V. fischeri was the acidic one. Due to this, the ozonation seemed to be an exciting process to remove GAT at aqueous media.

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