scholarly journals Removal of Sulfate Ions by Precipitation and Flotation

2021 ◽  
Vol 41 (3) ◽  
pp. e90349
Author(s):  
Mario Santander ◽  
Paola Cardozo ◽  
Luis Ivan Valderrama
Keyword(s):  
Natural Waters ◽  
Industrial Effluents ◽  
Ion Concentration ◽  
Sulfate Ion ◽  
Polyaluminum Chloride ◽  
Dissolved Air Flotation ◽  
Sulfate Ions ◽  
Flotation Technique ◽  
Co Precipitation ◽  
Different Origins

The removal of sulfate ions from natural waters, as well as from industrial effluents of different origins, is a problem, considering that most of the proposed processes are inefficient and have a high cost, mainly when reducing the sulfate ion concentration to values below 500 mg.L−1 is required. The flotation technique, combined with precipitation, has proven to be efficient for the removal of heavy metal ions. However, there is not enough research to confirm its efficiency for the removal of sulfate ions. This article presents the results of sulfate ion removal from synthetic solutions prepared in an acidic medium, applying the co-precipitation techniques with polyaluminum chloride (PAC) and solid/liquid separation by dissolved air flotation (DAF). The effect of the pH, the [PAC: sulfate ions] ratio, the effect of saturated water flow with air, and the flocculant and collector doses were studied. The achieved results confirm that it is possible to reduce the concentration of sulfate ions from 1 800 to 350 mg.L−1 (80% removal) from synthetic solutions by applying the flotation technique combined with precipitation.

scholarly journals An Optical Fiber Sensor Based on Fluorescence Lifetime for the Determination of Sulfate Ions

Sensors ◽  
2021 ◽  
Vol 21 (3) ◽  
pp. 954
Author(s):  
Liyun Ding ◽  
Panfeng Gong ◽  
Bing Xu ◽  
Qingjun Ding
Keyword(s):  
Optical Fiber ◽  
Fluorescence Lifetime ◽  
Optical Fiber Sensor ◽  
Phase Delay ◽  
Ion Concentration ◽  
Fiber Sensor ◽  
Precipitation Method ◽  
Cellulose Acetate Membrane ◽  
Sulfate Ion ◽  
Sulfate Ions

A new optical fiber sensor based on the fluorescence lifetime was prepared for specific detection of sulfate ion concentration, where 1,1′-(anthracene-9,10-diylbis(methylene))bis(3-(dodecylcarbamoyl)pyridin-1-ium) acted as the sulfate fluorescent probe. The probe was immobilized in a porous cellulose acetate membrane to form the sensitive membrane by the immersion precipitation method, and polyethylene glycol 400 acted as a porogen. The sensing principle was proven, as a sulfate ion could form a complex with the probe through a hydrogen bond, which led to structural changes and fluorescence for the probe. The signals of the fluorescence lifetime data were collected by the lock-in amplifier and converted into the phase delay to realize the detection of sulfate ions. Based on the phase-modulated fluorometry, the relationship between the phase delay of the probe and the sulfate ion concentration was described in the range from 2 to 10 mM. The specificity and response time of this optical fiber sensor were also researched.

Evolution of the sulfate ion transport-deterioration process in concrete

2016 ◽  
Vol 63 (3) ◽  
pp. 196-204 ◽  
Author(s):  
Hao Tian ◽  
Yingwu Zhou ◽  
Lili Sui ◽  
Feng Xing
Keyword(s):  
Design Methodology ◽  
Ion Concentration ◽  
Sulfate Ion ◽  
Sulfate Ions ◽  
Content Type ◽  
Factors Influencing ◽  
Deterioration Process ◽  
Different Depths ◽  
Microscopic Morphology ◽  
The Relationship

Purpose Sulfate-induced degradation is one of the most important factors influencing the durability of concrete. The paper aims to clarify the transport-deterioration process of sulfates in concrete and thus to explain the mechanism and the deterioration of concrete by sulfates. Design/methodology/approach This paper presents an experimental study into the evolution of the transport-deterioration process of sulfate ions in concrete in a pure soaking environment. Findings The microscopic morphology of individual concrete layers at different depths and the change law of the sulfate ion concentration at the corresponding depths were investigated for different exposure times. Furthermore, the relationship between the changes in microstructure and the transport characteristics of the sulfate ions was studied. Originality/value A method to calculate the cracking level sulfate ion concentration was proposed.

Mechanisms and Remediation Technologies of Sulfate Removal from Acid Mine Drainage

2012 ◽  
Vol 610-613 ◽  
pp. 3252-3256
Author(s):  
Mei Qin Chen ◽  
Feng Ji Wu
Keyword(s):  
Heavy Metals ◽  
Acid Mine Drainage ◽  
Mine Drainage ◽  
Metal Corrosion ◽  
Sulfate Ion ◽  
High Concentration ◽  
Biological Reduction ◽  
Acid Mine ◽  
Sulfate Removal ◽  
Co Precipitation

Acid mine drainage (AMD) has properties of extreme acidification, quantities of sulfate and elevated levels of soluble heavy metals. It was a widespread environmental problem that caused adverse effects to the qualities of ground water and surface water. In the past decades, most of investigations were focused on the heavy metals as their toxicities for human and animals. As another main constitution of AMD, sulfate ion is nontoxic, yet high concentration of sulfate ion can cause many problems such as soil acidification, metal corrosion and health problems. More attention should be paid on the sulfate ion when people focus on the AMD. In the paper, sulfate removal mechanisms include adsorption, precipitation, co-precipitation and biological reduction were analyzed and summarized. Meanwhile, the remediation technologies, especially the applications of them in China were also presented and discussed.

scholarly journals Influence of sulfate ion concentration and pH on the corrosion of Mg-Al-Zn-Mn (GA9) magnesium alloy

2015 ◽  
Vol 3 (3) ◽  
pp. 258-270 ◽  
Author(s):  
Sudarshana Shetty ◽  
Jagannath Nayak ◽  
A. Nityananda Shetty
Keyword(s):  
Magnesium Alloy ◽  
Ion Concentration ◽  
Sulfate Ion

Cryptosporidium removal during water treatment using dissolved air flotation

1995 ◽  
Vol 31 (3-4) ◽  
pp. 125-135 ◽  
Author(s):  
T. Hall ◽  
J. Pressdee ◽  
R. Gregory ◽  
K. Murray
Keyword(s):  
Water Treatment ◽  
Metal Ion ◽  
Ion Concentration ◽  
Sudden Increase ◽  
Water Turbidity ◽  
Dissolved Air Flotation ◽  
Treatment Processes ◽  
Air Flotation ◽  
The Uk ◽  
Dissolved Air

The occurrence of the protozoan parasite Cryptosporidium parvum in water supplies, and the resultant outbreaks of cryptosporidiosis in the UK and USA, have led to concern over the ability of conventional water treatment processes to remove Cryptosporidia from water sources. Large scale pilot plant trials of water treatment have been carried out in the UK to establish the degree of removal that can be achieved by a range of treatment processes, including dissolved air flotation, and to compare the performance of different treatment options. Results from part of these trials are presented in this paper. These results suggest that well operated chemical coagulation based treatment, using either dissolved air flotation or floc blanket clarification, should be capable of achieving removal of Cryptosporidium oocysts of over 99%. There was no evidence of differences in performance between the different types of filter media investigated. The risk of increased Cryptosporidium concentration in the filtered water will increase as filtrate turbidity increases. However, other factors such as high coagulant metal-ion concentration in the filtered water, or a sudden increase in clarified water turbidity, without any increase in filtered water turbidity, may also indicate treatment problems and associated risk from Cryptosporidia. Recycling of backwash waters may also increase the risk.

Supramolecular architectures in cytosinium 6-chloronicotinate monohydrate and 5-bromo-6-methylisocytosinium hydrogen sulfate

2018 ◽  
Vol 74 (3) ◽  
pp. 325-331
Author(s):  
Robert Swinton Darious ◽  
Nithianantham Jeeva Jasmine ◽  
Ammasai Karthikeyan ◽  
Packianathan Thomas Muthiah ◽  
Franc Perdih
Keyword(s):  
Hydrogen Bonds ◽  
Pyrimidine Ring ◽  
Hydrogen Sulfate ◽  
X Ray Diffraction ◽  
Sulfate Ion ◽  
Sulfate Ions ◽  
Supramolecular Architectures ◽  
Hydrated Salt ◽  
Sheet Structure ◽  
Hydrogen Bonded

Aminopyrimidine derivatives are biologically important as they are components of nucleic acids and drugs. The crystals of two new salts, namely cytosinium 6-chloronicotinate monohydrate, C4H6N3O+·C6H3ClNO2−·H2O, (I), and 5-bromo-6-methylisocytosinium hydrogen sulfate (or 2-amino-5-bromo-4-oxo-6-methylpyrimidinium hydrogen sulfate), C5H7BrN3O+·HSO4−, (II), have been prepared and characterized by single-crystal X-ray diffraction. The pyrimidine ring of both compounds is protonated at the imine N atom. In hydrated salt (I), the primaryR22(8) ring motif (supramolecular heterosynthon) is formedviaa pair of N—H...O(carboxylate) hydrogen bonds. The cations, anions and water molecule are hydrogen bonded through N—H...O, N—H...N, O—H...O and C—H...O hydrogen bonds, formingR22(8),R32(7) andR55(21) motifs, leading to a hydrogen-bonded supramolecular sheet structure. The supramolecular double sheet structure is formedviawater–carboxylate O—H...O hydrogen bonds and π–π interactions between the anions and the cations. In salt (II), the hydrogen sulfate ions are linkedviaO—H...O hydrogen bonds to generate zigzag chains. The aminopyrimidinium cations are embedded between these zigzag chains. Each hydrogen sulfate ion bridges two cationsviapairs of N—H...O hydrogen bonds andvice versa, generating twoR22(8) ring motifs (supramolecular heterosynthon). The cations also interact with one anotherviahalogen–halogen (Br...Br) and halogen–oxygen (Br...O) interactions.

A novel one-dimensional CoIIcoordination polymer:catena-poly[[hexaaquacobalt(II)] [[diaquabis(sulfato-κO)cobalt(II)]-μ-4,4′-bipyridine-κ2N:N′] [[triaqua(sulfato-κO)cobalt(II)]-μ-4,4′-bipyridine-κ2N:N′]]

2012 ◽  
Vol 68 (9) ◽  
pp. m265-m268 ◽  
Author(s):  
Kai-Long Zhong ◽  
Ming-Yi Qian
Keyword(s):  
Crystal Structure ◽  
Three Dimensional ◽  
The Other ◽  
Water Molecules ◽  
Supramolecular Network ◽  
Sulfate Ion ◽  
Sulfate Ions ◽  
One Dimensional ◽  
The Third ◽  
Hydrogen Bonding Interactions

The title compound, {[Co(H2O)6][Co(SO4)(C10H8N2)(H2O)3][Co(SO4)2(C10H8N2)(H2O)2]}n, contains three crystallographically unique CoIIcentres, all of which are in six-coordinated environments. One CoIIcentre is coordinated by two bridging 4,4′-bipyridine (4,4′-bipy) ligands, one sulfate ion and three aqua ligands. The second CoIIcentre is surrounded by two N atoms of two 4,4′-bipy ligands and four O atoms,i.e.two O atoms from two monodentate sulfate ions and two from water molecules. The third CoIIcentre forms part of a hexaaquacobalt(II) ion. In the crystal structure, there are two different one-dimensional chains, one being anionic and the other neutral, and adjacent chains are arranged in a cross-like fashion around the mid-point of the 4,4′-bipy ligands. The structure features O—H...O hydrogen-bonding interactions between sulfate anions and water molecules, resulting in a three-dimensional supramolecular network.

scholarly journals Deterioration Regularity of Sodium Sulfate Solution Attack on Cemented Coal Gangue-Fly Ash Backfill under Drying-Wetting Cycles

2020 ◽  
Vol 2020 ◽  
pp. 1-13
Author(s):  
Shaojie Chen ◽  
Zhen Zhang ◽  
Dawei Yin ◽  
Junbiao Ma
Keyword(s):  
Fly Ash ◽  
Sodium Sulfate ◽  
Sulfate Solution ◽  
Coal Gangue ◽  
Salt Crystallization ◽  
Sodium Sulfate Solution ◽  
Sulfate Ion ◽  
Sulfate Ions ◽  
Ion Contents ◽  
The Masses

To research the properties of cemented coal gangue-fly ash backfill (CGFB) exposed to different concentrations of sodium sulfate solutions under drying-wetting cycles, the mass changes, uniaxial compressive strengths, sulfate ion contents at different depths, and microstructures of CGFB samples were measured in this study. The results show that the CGFB samples were damaged by salt crystallization in the dry state and attacked by the expansive products in the wet state. The sulfate ion contents in CGFB samples increased with the sulfate concentrations and drying-wetting cycles and decreased from the surface to the inside of the samples. The damage process of CGFB samples evolved from the surface to the inside. In the early stage of corrosion, sulfate ions adsorbed to the surface of CGFB samples and consumed nonhydrated particles to form acicular ettringite and other products that filled the material pores. For this stage, the driving force of sulfate ions to enter into the CGFB samples was the highest for the samples immersed in 15% sodium sulfate solution, and the masses and strengths increased the fastest. As the drying-wetting cycles continued, the nonhydrated particles inside the samples were nearly completely hydrated, and the samples were constantly damaged by salt crystallization and dissolution. The corrosion ions entered into the samples and consumed portlandite to produce a large amount of prismatic ettringite and aggravated the internal corrosion of CGFB samples. At the fifteenth drying-wetting cycle, the higher the salt concentration of the immersion solution was, the faster the masses and the strengths of CGFB samples decreased. Moreover, the surface spalling and failure of CGFB samples were more severe.

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