scholarly journals The Effect of pH on Stability of an Isolation Barrier Made of Dolomite Post-Floatation Waste

Minerals ◽  
2021 ◽  
Vol 11 (12) ◽  
pp. 1384
Author(s):  
Jolanta Sobik-Szołtysek
Keyword(s):  
Chemical Properties ◽  
Filtration Coefficient ◽  
Grain Composition ◽  
Fine Grained ◽  
Column Material ◽  
Initial Ph ◽  
Alternative Material ◽  
Leaching Solution ◽  
The Stability ◽  
Physical And Chemical

Dolomite post-floatation waste has been proposed as an alternative material for the construction of separation barriers. The aim of this study was to determine the effect of the pH of leaching solutions on the stability of such barriers. The present research included the determination of selected physical and chemical properties of waste, i.e., density, grain composition, and filtration coefficient. Column tests of leaching by solutions of different pH values modeling varying environmental conditions were performed. Selected ions were determined in the eluates. Grain analyses were carried out for the column material after leaching to determine the changes in grain composition of dolomite due to washing with leaching solutions. The determined value of the filtration coefficient is 6.52 × 10−9 m∙s−1, which confirms the impermeability of the waste. The material is fine-grained, with a grain diameter of d ≤ 200 µm. During leaching, a decrease in the content of the analyzed ions and the diameter of grains and their movement down the barrier, resulting in its sealing, was observed. The central part of all columns showed more grains with a diameter of 7 μm, which is probably due to secondary precipitation of CaSO4. Irrespective of the initial pH of the leaching solution, the reaction of all eluates obtained was slightly alkaline (pH 7.52–8.20). Dolomite post-floatation waste has properties that ensure the tightness and durability of the separation barrier, which, combined with its ability to alkalize solutions and the sealing process, ensures its effectiveness.

Chitosan-based Magnetic Composites - Efficient Adsorbents for Removal of Pb(II) and Cu(II) from Aqueous Mono and Bicomponent Solutions

2018 ◽  
Vol 69 (9) ◽  
pp. 2323-2330 ◽  
Author(s):  
Daniela C. Culita ◽  
Claudia Maria Simonescu ◽  
Rodica Elena Patescu ◽  
Nicolae Stanica
Keyword(s):  
Aqueous Solutions ◽  
Metal Ions ◽  
Chemical Properties ◽  
Order Kinetic ◽  
Mass Ratio ◽  
Magnetic Adsorbent ◽  
Magnetic Composites ◽  
Initial Ph ◽  
Order Kinetic Model ◽  
Physical And Chemical

A series of three chitosan-based magnetic composites was prepared through a simple coprecipitation method. It was investigated the influence of mass ratio between chitosan and magnetite on the physical and chemical properties of the composites in order to establish the optimum conditions for obtaining a composite with good adsorption capacity for Pb(II) and Cu(II) from mono and bicomponent aqueous solutions. It was found that the microspheres prepared using mass ratio chitosan / magnetite 1.25/1, having a saturation magnetization of 15 emu g--1, are the best to be used as adsorbent for the metal ions. The influence of different parameters such as initial pH values, contact time, initial concentration of metal ions, on the adsorption of Pb(II) and Cu(II) onto the chitosan-based magnetic adsorbent was investigated in details. The adsorption process fits the pseudo-second-order kinetic model in both mono and bicomponent systems, and the maximum adsorption capacities calculated on the basis of the Langmuir model were 79.4 mg g--1 for Pb(II) and 48.5 mg g--1 for Cu(II) in monocomponent systems, while in bicomponent systems were 88.3 and 49.5 mg g--1, respectively. The results revealed that the as prepared chitosan-based magnetic adsorbent can be an effective and promising adsorbent for Pb(II) and Cu(II) from mono and bicomponent aqueous solutions.

Synthesis and Kinetic Investigations for the Isomerization Process of 2–Hydroxy Chalcone Derivatives

2019 ◽  
Vol 41 (6) ◽  
pp. 1046-1046
Author(s):  
Omar A Shareef Omar A Shareef ◽  
Said A Said and Ali Y Abdulrazaq Said A Said and Ali Y Abdulrazaq
Keyword(s):  
Biological Activities ◽  
Chemical Properties ◽  
Physical And Chemical Properties ◽  
Pseudo First Order Reaction ◽  
First Order ◽  
Steric Factors ◽  
Kinetic Investigations ◽  
The Stability ◽  
Physical And Chemical ◽  
And Chemical Properties

The wide biological activities of flavanones are mainly depends on their physical and chemical properties, thus a number of substituted 2-Hydroxy chalcones have been synthesized, and their isomerization to their corresponding flavanones was studied. In order to determine the rate constant, kinetic experiments were performed using HPLC technique in (9:1) (CH3CN:H2O) medium at different temperature (298-318) K. The obtained results were interpreted by four steps mechanism, which considered the existence of phenoxide ion as the key intermediate. This study performed with a pseudo first order ( reaction in which the rate for the studied compounds follow the sequence 5 andgt; 2 andgt; 1 andgt; 4 andgt; 3, the activation energy have the same sequence for these compounds .The effect of substituents on the rate showed that electronic and steric factors play reasonable role on the stability of the product .

The Establishment of the 3rd National Reference Standard for Tachypleus Tridentatus Lysate

2017 ◽  
Vol 6 (3) ◽  
pp. 50
Author(s):  
Tong Cai ◽  
Guolai Zhang ◽  
Yusheng Pei ◽  
Hua Gao
Keyword(s):  
Chemical Properties ◽  
Physical And Chemical Properties ◽  
Reference Standard ◽  
Tachypleus Tridentatus ◽  
National Reference ◽  
The Stability ◽  
Physical And Chemical ◽  
And Chemical Properties

<p><strong>Objective</strong>  To establish the 3rd national reference standard for Tachypleus Tridentatus Lysate Reagent. <strong>Method</strong> <strong>and Results</strong>  The candidates of reference standard were studied for the physical and chemical properties, and the stability. To determined its sensitivity by collaboration calibration. <strong>Conclusions</strong>  The sensitivity of the 3rd national reference standard for TAL is 0.06EU / ml, lot number is 150603-201003.</p>

Salting-out and salting-in experiments with lignosulfonates (LSs)

Holzforschung ◽  
2013 ◽  
Vol 67 (5) ◽  
pp. 549-557 ◽  
Author(s):  
Bernt O. Myrvold
Keyword(s):  
Chemical Properties ◽  
Physical And Chemical Properties ◽  
Salting Out ◽  
Practical Applications ◽  
Common Ion ◽  
The Common ◽  
Common Ion Effect ◽  
The Stability ◽  
Physical And Chemical ◽  
And Chemical Properties

Abstract The solubility of lignosulfonates (LSs) in water is strongly dependent on other ions present in the water phase. The differences in the solubility might strongly influence the measurements of the physical and chemical properties of the LS molecules. A reduced solubility of the LS might also affect its utility in many practical applications. The understanding of the interaction between LSs and various salts is important for both practical and theoretical reasons. Therefore, the effect of salt concentrations on the LS has been investigated for 41 different salts with 14 different cations and 16 different anions. The observations cannot be explained by the common ion effect or the screening effects. On the contrary, it was found that the stability of LS solutions follows the Hofmeister series, with the exception of those ions that will chemically interact with the LS molecule. Moreover, the positions of phosphate (HPO42-) and sulfate (SO42-) ions were reversed.

The Fabrication and Progress of Core-Shell Composite Materials

2009 ◽  
Vol 62 (12) ◽  
pp. 1561 ◽  
Author(s):  
Shunsheng Cao ◽  
Juanrong Chen ◽  
Jie Hu
Keyword(s):  
Materials Science ◽  
Chemical Properties ◽  
Core Shell ◽  
Production Methods ◽  
Potential Applicability ◽  
Shell Particles ◽  
The Stability ◽  
Physical And Chemical ◽  
Shell Composite ◽  
Organic Particle

Core-shell materials, in which a layer or multilayer of inorganic or organic material surrounds an inorganic or organic particle core, have been investigated both as a means to improve the stability and surface chemistry of the core particle and as a way of accessing unique physical and chemical properties that are not possible from one material alone. As a result, the fabrication of core-shell particles is attracting a great deal of interest because of their unique properties and potential applicability in catalysis, semiconductors, drug delivery, enzyme immobilization, molecular recognition, chemical sensing, etc. As evidenced by the literature described and discussed in this review, a basic understanding of the mechanism and recent progress in production methods have enabled the fabrication of core-shell particles with unique and tailored properties for various applications in materials science.

scholarly journals Does thermal carbonization (Biochar) of organic material increase more merits for their amendments of sandy soil?

2014 ◽  
Vol 6 (1) ◽  
pp. 535-558 ◽  
Author(s):  
Y. Wu ◽  
G. Xu ◽  
J. N. Sun ◽  
H. B. Shao
Keyword(s):  
Soil Ph ◽  
Saline Soil ◽  
Chemical Properties ◽  
Exchange Capacity ◽  
Low Fertility ◽  
Available P ◽  
Available Phosphorus ◽  
Furfural Residue ◽  
Leaching Solution ◽  
Physical And Chemical

Abstract. Organic materials (e.g. furfural residue) are generally believed to improve the physical and chemical properties of the soils with low fertility. Recently, biochar have been received more attention as a possible measure to improve the carbon balance and improve soil quality in some degraded soils. However, little is known about their different amelioration of a sandy saline soil. In this study, 56d incubation experiment was conducted to evaluate the influence of furfural and its biochar on the properties of saline soil. The results showed that both furfural and biochar greatly reduced pH, increased soil organic carbon (SOC) content and cation exchange capacity (CEC), and enhanced the available phosphorus (P) in the soil. Furfural is more efficient than biochar in reducing pH: 5% furfural lowered the soil pH by 0.5–0.8 (soil pH: 8.3–8.6), while 5% biochar decreased by 0.25–0.4 due to the loss of acidity in pyrolysis process. With respect to available P, 5% of the furfural addition increased available P content by 4–6 times in comparison to 2–5 times with biochar application. In reducing soil exchangeable sodium percentage (ESP), biochar is slightly superior to furfural because soil ESP reduced by 51% and 43% with 5% furfural and 5% biochar addition at the end of incubation. In addition, no significant differences were observed between furfural and biochar about their capacity to retain N, P in leaching solution and to increase CEC in soil. These facts may be caused by the relatively short incubation time. In general, furfural and biochar have different amendments depending on soil properties: furfural was more effectively to decrease pH and to increase available P, whereas biochar played a more important role in increasing SOC and reducing ESP of saline soil.

scholarly journals COMPLEXATION OF APPLE PECTIN, MODIFIED TO PHARMACOPHORE, WITH THE CATIONS MANGANESE (II) IN AQUEOUS SOLUTIONS

2020 ◽  
pp. 25-32
Author(s):  
Roza Khanifovna Mudarisova ◽  
Alina Failovna Sagitova ◽  
Ol'ga Sergeyevna Kukovinets
Keyword(s):  
Metal Complexes ◽  
Chemical Properties ◽  
Thermodynamic Characteristics ◽  
Standard Thermodynamic Characteristics ◽  
Anthranilic Acids ◽  
Drug Compound ◽  
The Stability ◽  
Physical And Chemical ◽  
And Chemical Properties ◽  
Polymer Ligand

Complex formation in systems containing manganese (II), natural pectin and/or pectin modified by organic pharmacophores (nicotine, salicylic, 5-aminosalicylic, anthranilic acids) was studied by spectral (UV-, IR-, NMR 13C spectroscopy), potentiometric and viscometric methods. Method isomolar series and the molar relationship defined by the molar composition and the range of stability of metal complexes: pectin + nicotinic acid > pectin + acid 5-aminosalicylic > pectin + anthranilic acid > pectin + salicylic acid > native pectin. It is shown that the stability constant of metal complexes is significantly influenced by the reaction temperature and the structure of the pharmacophore. The presence of an amino group in the structure of an aromatic molecule increases the stability of metal complexes by 1.5–2 orders of magnitude. The standard thermodynamic characteristics (∆Hº; ∆Gº; ∆Sº) are calculated, which indicate that the processes of complexation in all cases are enthalpy-entropy favorable (∆Hº<0, ∆Sº>0) and proceed spontaneously (∆Gº<0). The influence of the structure of the drug compound in the polymer ligand on a number of physical and chemical properties of metal complexes was revealed. The data of NMR 13C and IR-spectra allow us to conclude that not only carboxyl groups but also hydroxyl functions of polymer matrices participate in the coordination interaction of pectin and/or pharmacophore-containing pectin with manganese (II) cations.

scholarly journals Self-assembly of biopolymer films for UV protection of wood

2021 ◽  
Author(s):  
Kristina Ivana Fabijanic ◽  
Aída Ninfa Salinas López ◽  
Long Pan ◽  
Chi-Yuan Cheng ◽  
Yu Wang ◽  
...  
Keyword(s):  
Free Radical ◽  
Self Assembly ◽  
Three Dimensional ◽  
Chemical Properties ◽  
Free Radical Scavenger ◽  
Radical Scavenger ◽  
Ionic Surfactant ◽  
Reducing Ability ◽  
Alternative Material ◽  
Physical And Chemical

AbstractThere is an increasing need for materials with tunable physical and chemical properties that are relatively non-toxic and efficacious for their intended application. Many wood stains and finishes emit toxic chemicals which may have serious implications to one’s health. A novel alternative material is realized between xanthan gum and Neodol, a non-ionic surfactant. The resulting three-dimensional film is evaluated as a free-radical scavenger for the protection of wood at different ratios. Atomic force microscopy visualizes the topography and quantifies the local nanomechanics, while rheological measurements showcase a shift from viscoelastic material to gel. Electron plasmon resonance confirms the free-radical reducing ability (3.5 times), while liquid chromatography mass spectroscopy quantifies the UV degradation of sinapyl alcohol. This material has potential, not only in coating industries as a safer option, but also in those industries requiring flexibility and tenability, namely for biosensors and anti-inflammatory therapeutics. Graphic abstract

scholarly journals DEVELOPMENT OF EFFERVESCENT GRANULE OF CORN MILK, SUPPLEMENTED WITH PROBIOTICS LACTOBACILLUS STRAIN SHIROTA

2018 ◽  
Vol 10 (5) ◽  
pp. 71
Author(s):  
Reni Hiola ◽  
Robert Tungadi
Keyword(s):  
Citric Acid ◽  
Tartaric Acid ◽  
Milk Powder ◽  
Chemical Properties ◽  
Lactobacillus Strain ◽  
Dissolution Time ◽  
Wet Granulation ◽  
Nutrient Contents ◽  
The Stability ◽  
Physical And Chemical

Objective: One of the materials which can be formulated into probiotics drink is corn milk. It has nutrient contents such as vitamin A, B, C, minerals, and fibres. The objective of this study was to develop and evaluate the probiotic drink of corn milk which was formulated into an effervescent granule.Methods: The first step was carried out to make corn extract with the addition of Lactobacillus strain Shirota and incubated 24 h at 40 °C to gain corn milk. After that, corn milk was centrifuged to get filtrate and dried by oven 40 °C for 2 d to gain dry powder. Then corn milk powder was formulated into effervescent granule (3 formulas) using different ratio of acids. The method which used in making effervescent granule of corn milk was wet granulation. All formulas were done evaluations including physical and chemical properties of granule and hedonic test.Results: The results showed that formula 1 (only citric acid 23.84%) gave unsatisfactory results particularly on the evaluation tests such as LOD 9.64%, dissolution time 3.25 min, moisture content 10.67% and hedonic test which did not meet the requirements. Otherwise, formula 2 (only tartaric acid 23.84%) and formula 3 (citric acid 7.94% and tartaric acid 15.9% combination) showed satisfactory results for all evaluation tests of granules. Particularly formula 3 gave pH 5 on pH test which was the same as pH lactic acid for fermentation and LOD 4.34%, MC 4.53%, ρb 0.53 g/ml, ρt 0.62 g/ml and hedonic test around 80%.Conclusion: Formula 3 was the best formulation based on the evaluation and the stability of corn milk effervescent granule.

Adsorption of Cr6+ and Pb2+ on soy sauce residue biochar from aqueous solution

BioResources ◽  
2019 ◽  
Vol 14 (2) ◽  
pp. 4653-4669 ◽  
Author(s):  
Xiaoxun Xu ◽  
Chenying Zhou ◽  
Shirong Zhang ◽  
Zhang Cheng ◽  
Zhanbiao Yang ◽  
...  
Keyword(s):  
Heavy Metals ◽  
Pyrolysis Temperature ◽  
Chemical Properties ◽  
Soy Sauce ◽  
Order Kinetic ◽  
Metals Removal ◽  
Initial Ph ◽  
Pseudo Second Order ◽  
Pyrolysis Of Biomass ◽  
Physical And Chemical

Biochar produced by the pyrolysis of biomass can be used to counter water pollution from heavy metals. The purpose of this work was to develop a biosorbent based on soy sauce residue (SSR) for the removal of Cr6+ and Pb2+. The SSR biochar (SBC) from oxygen-limited pyrolysis under the temperatures of 300 to 700 °C were obtained, and their adsorption capability was evaluated. After determining the optimum pyrolysis temperature, the effects of initial pH values, contact times, and initial metal concentrations on the Cr6+ and Pb2+ adsorption by SBC prepared at 600 °C (SBC600) were investigated. With the increase of pyrolysis temperature, the physical and chemical properties of SBC developed in a direction favorable to heavy metal adsorption. The SBC600 reached the adsorption equilibrium at the time of 2 (Cr6+) and 24 h (Pb2+), and the maximum adsorption amounts of Cr6+ and Pb2+ were 25.80 and 135.3 mg/g, respectively. The adsorption kinetics followed the pseudo-second-order kinetic equation, and the adsorption isotherms was best described by the Langmuir isotherms. The SBC was an adsorbent with certain potential for heavy metals removal in wastewater.

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