Preparation of Calcium Sulfate Anhydrate Whisker and a Primary Investigation of its Arsenic Removal Performance

2013 ◽  
Vol 690-693 ◽  
pp. 1013-1019
Author(s):  
Xiao Juan Chen ◽  
Liu Chun Yang ◽  
Jun Feng Zhang ◽  
Yan Huang
Keyword(s):  
Calcium Sulfate ◽  
Arsenic Removal ◽  
Removal Rate ◽  
Optical Microscope ◽  
Alkaline Condition ◽  
Crystal Water ◽  
Arsenic Uptake ◽  
Ft Ir ◽  
High Removal Rate ◽  
Calcium Sulfate Whisker

Calcium sulfate whisker (CSW) was prepared through the method of cooling recrystallization. In an attempt to develop its new application in environmental protection, we investigated the effect of calcination on the material properties and arsenic uptake performance of calcium sulfate whisker anhydrate (CSAW), which was obtained from CSW calcined at 600 °C for 2 h. Moreover, XRD, SEM, optical microscope, and FT-IR were used to characterize CSW samples. It was found that calcination played an important role in the whisker structure through changing the content of crystal water and the morphology. The CSAW material exhibited a high removal rate of As3+/As5+under strongly alkaline condition.

The Effect of Solvent Polarity on Phase Transformation of Citrogypsum via Hydrothermal Process

2019 ◽  
Vol 803 ◽  
pp. 351-355 ◽  
Author(s):  
Thanakit Sirimahasal ◽  
Yutthana Kalhong ◽  
Lida Simasatitkul ◽  
Siriporn Pranee ◽  
Samitthichai Seeyangnok
Keyword(s):  
Physical Properties ◽  
Calcium Sulfate ◽  
Hydrothermal Process ◽  
Solvent Polarity ◽  
Sem Images ◽  
Crystal Water ◽  
Calcium Sulfate Dihydrate ◽  
Hexagonal Shape ◽  
Ft Ir ◽  
Hexane Solution

Calcium sulfate dihydrate (CaSO4•2H2O, CSD), gypsum is a by-product in the production of citric acid (citryogypsum). This by-product could neither be exploited nor distributed as a reactant because of its physical properties including those that are not equivalent to natural gypsum. Moreover, the mentioned citrogypsum has been continually increasing environmental problems. Therefore, this research aims at how to recycle gypsum that is synthesized by hydrothermal method at 95oC for 7 hrs under the atmospheric pressure via different solutions (MeOH, EtOH, PrOH, BuOH and Hexane). In order to produce alpha-calcium sulfate hemihydrate (α-CaSO4•0.5H2O, α-CSH) with improved physical properties that will be used for different industries. FT-IR reveals the chemical composition of crystal and the adsorption of methyl group on the surface. Besides, TGA thermogram shows the theoretical crystal water content of CSD and α-CSH 20.9 wt% and 6.2 wt% respectively. The DSC thermogram, shows that endothermic peaks at 151.2 oC and 168.5 oC. There were two steps of loss at 1.5 and 0.5 water molecule respectively. With SEM images of crystal shows the plate-like shape of citrogypsum, while α-CSH shows the hexagonal shape excluding hexane solution. Of all the results, the polarity of solution has an impact on the transition of CSD to α-CSH under this condition.

Alkaline refining of crude lead: a method of arsenic removal and the behavior of arsenic in the process

2022 ◽  
Vol 119 (1) ◽  
pp. 105
Author(s):  
Rong Zhu ◽  
Hailin Long ◽  
Haoyu Li ◽  
Huimin Xie ◽  
Shaohua Yin ◽  
...  
Keyword(s):  
Reaction Temperature ◽  
Lead Oxide ◽  
Arsenic Removal ◽  
Removal Rate ◽  
Holding Time ◽  
Sodium Arsenate ◽  
Experimental Conditions ◽  
Lead Arsenate ◽  
Ft Ir ◽  
Refining Agent

In this work, the alkaline refining of arsenic in crude lead was studied with a mixture of sodium hydroxide and sodium carbonate as alkaline refining agents. Taking the arsenic removal rate as the research object, the effects of reaction temperature, holding time, Na2CO3:NaOH, the dosage of refining agent were investigated. The arsenic removal rate is 79.09% under the optimum experimental conditions as follows: reaction temperature 823 K, holding time 60 min, Na2CO3:NaOH 1:4, refining agent dosage 10%. The oxidation purification mechanism of arsenic was studied by XPS, SEM-EDS, XRD and FT-IR. The results show that arsenic in the crude lead is gradually oxidized by oxygen and lead oxide during arsenic removal process, and the arsenic trioxide is eventually converted into sodium arsenate (Na3AsO4) and lead arsenate (Pb2As2O7) in the slag.

A Study on the Preparation and Flocculation Properties of Boracic Poly-Aluminum-Ferric-Silicate

2013 ◽  
Vol 726-731 ◽  
pp. 3025-3029 ◽  
Author(s):  
Xiao Wei Tian ◽  
Chun Ying Han ◽  
Li Dan Zhang ◽  
Wei Zhao Du ◽  
Zeng He Li
Keyword(s):  
Removal Rate ◽  
Water Solution ◽  
Molar Ratio ◽  
Sodium Borate ◽  
Rapid Coagulation ◽  
Ft Ir ◽  
High Removal Rate ◽  
Micro Morphology ◽  
Polymerization Method ◽  
Electronic Microscope

The boracic poly-aluminum-ferric-silicate (B-PSAF) coagulant was prepared by water solution co-polymerization method, which was synthesized from sodium silicate, aluminum sulfate, ferric chloride and sodium borate. In addition, the best molar ratio of boron and silicon was determined by single factor process. The micro-morphology and structure of B-PSAF were studied by scanning electronic microscope (SEM) and Fourier transform infrared spectrum (FT-IR). It has been studied the operation of B-PSAF as the flocculating agent, the dosage and its effects on the flocculability. Experiments show that B-PSAF is a good effective flocculant, which can be used to treat alkaline dyeing wastewater and it has the features of less consumption, rapid coagulation and high removal rate of CODCr.

scholarly journals Synthesis of Novel Phenyl Porous Organic Polymers and Their Excellent Visible Light Photocatalytic Performance on Antibiotics

Materials ◽  
2019 ◽  
Vol 12 (20) ◽  
pp. 3296 ◽  
Author(s):  
Xiang Gao ◽  
Jiao Liu ◽  
Zhaopeng Liu ◽  
Yuehua Deng ◽  
Wenjie Nie ◽  
...  
Keyword(s):  
Photocatalytic Performance ◽  
Removal Rate ◽  
Photocatalytic Property ◽  
Nitrogen Adsorption ◽  
Organic Polymers ◽  
Reaction Conditions ◽  
Porous Organic Polymers ◽  
Ft Ir ◽  
High Removal Rate ◽  
Considerable Loss

The efficient and green removal of residual antibiotics in the environment is an attractive topic. In this work, four different phenyl porous organic polymers (P-POPs) photocatalysts were successfully synthesized, and a series of techniques, such as Fourier transform infrared spectroscopy (FT-IR), scanning electron microscopy (SEM), nitrogen adsorption and desorption experimentation, and solid ultraviolet visible spectroscopy (UV-vis) were conducted to characterize the obtained P-POPs. Moreover, the photocatalytic property of P-POPs in the removal of tetracycline was studied, and the reaction conditions were optimized. Further study indicated that the P-POPs were also efficient for removing other antibiotics, such as chloramphenicol, in a high removal rate of 77%. Furthermore, the separation of the photocatalysts from the solution was easy, and the photocatalysts could be reused at least four times without a considerable loss in catalytic activity.

scholarly journals Efficient activation of persulfate by calcium sulfate whisker supported nanoscale zero-valent iron for methyl orange removal

RSC Advances ◽  
2021 ◽  
Vol 11 (1) ◽  
pp. 452-461
Author(s):  
Yi Han ◽  
Xian Zhou ◽  
Li Lei ◽  
Huiqun Sun ◽  
Zhiyuan Niu ◽  
...  
Keyword(s):  
Composite Material ◽  
Methyl Orange ◽  
Calcium Sulfate ◽  
Zero Valent Iron ◽  
Nanoscale Zero Valent Iron ◽  
Calcium Sulfate Whiskers ◽  
Calcium Sulfate Whisker

In order to improve the utilization of nanoscale zero-valent iron (nZVI) in activating persulfate (PS), a composite material of nZVI/CSW with nZVI supported on calcium sulfate whiskers (CSWs) was synthesized in this study.

scholarly journals Hydrothermal Synthesis of Sodalite-Type N-A-S-H from Fly Ash to Remove Ammonium and Phosphorus from Water

Materials ◽  
2021 ◽  
Vol 14 (11) ◽  
pp. 2741
Author(s):  
Pengcheng Lv ◽  
Ruihong Meng ◽  
Zhongyang Mao ◽  
Min Deng
Keyword(s):  
Fly Ash ◽  
Adsorption Capacity ◽  
Removal Rate ◽  
Kinetic Studies ◽  
Solute Concentration ◽  
Raw Material ◽  
Sodium Aluminosilicate ◽  
Equilibrium Data ◽  
One Step ◽  
Ft Ir

In this study, the hydrated sodium aluminosilicate material was synthesized by one-step hydrothermal alkaline desilication using fly ash (FA) as raw material. The synthesized materials were characterized by XRD, XRF, FT-IR and SEM. The characterization results showed that the alkali-soluble desilication successfully had synthesized the sodium aluminosilicate crystalline (N-A-S-H) phase of sodalite-type (SOD), and the modified material had good ionic affinity and adsorption capacity. In order to figure out the suitability of SOD as an adsorbent for the removal of ammonium and phosphorus from wastewater, the effects of material dosing, contact time, ambient pH and initial solute concentration on the simultaneous removal of ammonium and phosphorus are investigated by intermittent adsorption tests. Under the optimal adsorption conditions, the removal rate of ammonium was 73.3%, the removal rate of phosphate was 85.8% and the unit adsorption capacity reached 9.15 mg/L and 2.14 mg/L, respectively. Adsorption kinetic studies showed that the adsorption of ammonium and phosphorus by SOD was consistent with a quasi-secondary kinetic model. The adsorption isotherm analysis showed that the equilibrium data were in good agreement with the Langmuir and Freundlich model. According to thermodynamic calculations, the adsorption of ammonium and phosphorus was found to be a heat-absorbing and spontaneous process. Therefore, the preparation of SOD by modified FA has good adsorption properties as adsorbent and has excellent potential for application in the removal of contaminants from wastewater.

Preparation of xanthated bentonite and its removal behavior for Pb(II) ions

2010 ◽  
Vol 61 (5) ◽  
pp. 1235-1243 ◽  
Author(s):  
Y. F. He ◽  
F. R. Li ◽  
R. M. Wang ◽  
F. Y. Li ◽  
Y. Wang ◽  
...  
Keyword(s):  
Adsorption Mechanism ◽  
Removal Rate ◽  
Freundlich Isotherm ◽  
Particle Size Analysis ◽  
Lead Ions ◽  
Size Analysis ◽  
Optimum Conditions ◽  
X Ray Diffraction ◽  
X Ray ◽  
Ft Ir

Xanthate was successfully grafted onto bentonite by a relatively simple solution reaction. The obtained xanthated bentonite (XBent) was characterized by FT-IR spectrophotometer, thermogravimetric analysis (TG), particle size analysis, x-ray diffraction (XRD) and scanning electron microscopy (SEM). XBent acting as a type of environmentally friendly adsorbent was applied to remove lead ions from aqueous solutions. The optimum conditions were as follows: [Pb2 + ] = 500 mg L−1, [XBent] = 2 g L−1, pH = 5.0; oscillating 60 min under 200 rpm at 25°C. The removal rate of lead was up to 99.9%. It was found that the lead(II) ions—XBent adsorption isotherm model fitted well to the Freundlich isotherm. The adsorption mechanism was also investigated by SEM and XRD, which concluded that lead ions were complexed or chelated with XBent. XBent appears to have potential to be used later in water treatment as a type of inorganic polymer reagent.

Derivation of Optimum Study Factors for Samples Contaminated with Cd Using Electric/Magnetic Field and ORP

2013 ◽  
Vol 813 ◽  
pp. 519-524
Author(s):  
Sang An Ha ◽  
Jei Pil Wang
Keyword(s):  
Magnetic Field ◽  
Heavy Metals ◽  
Removal Rate ◽  
Underground Water ◽  
Liquid Electrode ◽  
Oxidation Reduction ◽  
Oxidation Reduction Potential ◽  
Removal Of Heavy Metals ◽  
High Removal Rate ◽  
Membrane Treatment

A purpose of the present study is to derive optimum study factors for removal of heavy metals using combined alternating current electric/magnetic field and electric membranes for the area contaminated with heavy metals in soil or underground water. ORP (Oxidation Reduction Potential) analysis was conducted to determine an intensity of tendency for oxidation or reduction of the samples contaminated with heavy metals, and electrical membrane treatment was used with adjustment of concentrations and voltages of liquid electrode (Na2SO4) to derive a high removal rate. Removal constants were analyzed to be 0.0417, 0.119, 0.1594 when the voltages were 5V, 10V, 15V, respectively, and treatment efficiency was shown to increase as the liquid electrode concentration was increased. Keywords: heavy metals, electric/magnetic field, ORP, electrical membrane

Numerical Prediction of Contaminant Removal from Cavity in Horizontal Channel by Constrained Interpolated Profile Method

2014 ◽  
Vol 695 ◽  
pp. 384-388
Author(s):  
Nor Azwadi Che Sidik ◽  
A.S. Ahmad Sofianuddin ◽  
K.Y. Ahmat Rajab
Keyword(s):  
Reynolds Number ◽  
Aspect Ratio ◽  
Removal Rate ◽  
Contaminant Removal ◽  
Square Cavity ◽  
Profile Method ◽  
Aspect Ratios ◽  
Contaminants Removal ◽  
Parabolic Flow ◽  
High Removal Rate

In this paper, Constrained Interpolated Profile Method (CIP) was used to simulate contaminants removal from square cavity in channel flow. Predictions were conducted for the range of aspect ratios from 0.25 to 4.0. The inlet parabolic flow with various Reynolds number from 50 to 1000 was used for the whole presentation with the same properties of contaminants and fluid. The obtained results indicated that the percentage of removal increased at high aspect ratio of cavity and higher Reynolds number of flow but it shows more significant changes as increasing aspect ratio rather than increasing Reynolds number. High removal rate was found at the beginning of the removal process.

Arsenic Removal from Wastewater Using Adsorptive Mediums

2011 ◽  
Vol 189-193 ◽  
pp. 404-409
Author(s):  
Fu Quan Peng ◽  
Zhen Cheng Xu ◽  
Jian Hong Huang ◽  
Qing Wei Guo ◽  
Feng Nie
Keyword(s):  
Arsenic Removal ◽  
Removal Rate ◽  
National Standards ◽  
Ferrous Oxide ◽  
Anion Resin ◽  
Quartz Sands ◽  
Long Time ◽  
Removal Of Arsenic ◽  
Adsorptive Properties

Different adsorptive mediums and adsorbents’ compounds were chosen to remove arsenic from Yangzonghai Lake wastewater. Results showed that Ca(OH)2, attapulgite, bentonite, LDHs these adsorptive mediums had adsorptive capacities of less than 2.5 mg/g of As removal and it took long time for sediment before monitoring; adsorbents compounds’ results showed Fe2O3 and quartz sands had best removal rate and quartz sands had little removal of arsenic. Both strong anion resin and hydrated ferrous oxide-loaded on polystyrene diethanolamine resin(designated as PDR-HFO) can decrease As concentration to less than 0.01 mg/L reaching national standards for arsenic; anions such as SO42- can not be removed when strong anion resin was regenerated causing its loss of exchange ions; PDR-HFO exhibited excellent adsorptive properties and recyclability.

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