Magnesium hydroxide coagulation performance and floc properties in treating high pH reactive orange wastewater

2015 ◽  
Vol 71 (9) ◽  
pp. 1310-1316 ◽  
Author(s):  
Meile Liu ◽  
Jingfang Lu ◽  
Lei Wei ◽  
Kang Wang ◽  
Jianhai Zhao
Keyword(s):  
Magnesium Hydroxide ◽  
Ph Value ◽  
Particle Dispersion ◽  
Magnesium Ion ◽  
Feeding Mode ◽  
High Ph ◽  
Coagulation Performance ◽  
Initial Ph ◽  
Floc Properties ◽  
Reactive Orange

Application of magnesium hydroxide as a coagulant for treating high pH reactive orange wastewater was studied. The coagulation performance and magnesium hydroxide-reactive orange floc properties were investigated under different dosages, feeding modes and pH values. Flocculation index (FI) was then discussed with controlled experiments using an intelligent particle dispersion analyzer and optimum coagulant dose of 150 mg/L (magnesium ion) was obtained for pH value 12. The results showed that the optimum magnesium ion dose tended to decrease with the increase of initial pH value. One time addition feeding mode led to relatively large FI value and higher removal efficiency compared with other addition modes. All of the flocs under investigation showed a limited capacity for re-growth when they had been previously broken. Based on the changes of zeta potential and floc properties, charge neutralization and precipitate enmeshment were proposed to be the main coagulation mechanisms.

scholarly journals Effect of kaolin on floc properties for reactive orange removal in continuous coagulation process

2018 ◽  
Vol 78 (3) ◽  
pp. 571-577 ◽  
Author(s):  
Jianhai Zhao ◽  
Anmin Wang ◽  
Lei Wei ◽  
Wenqi Ge ◽  
Yongzhi Chi ◽  
...  
Keyword(s):  
Magnesium Hydroxide ◽  
Continuous Process ◽  
Initial Concentration ◽  
Floc Size ◽  
Coagulation Process ◽  
Coagulation Performance ◽  
Process Effects ◽  
Floc Properties ◽  
Reactive Orange ◽  
Floc Breakage

Abstract Magnesium hydroxide was used as a coagulant for treating reactive orange wastewater in a real continuous process. Effects of kaolin on coagulation performance and floc properties were investigated with controlled experiments through floc size distribution, zeta potential, scanning electron microscopy and Fourier transform infrared spectroscopy. Kaolin had significant influence on magnesium hydroxide-reactive orange floc formation and growth. The results showed that average floc size reached 16.31, 12.88 and 20.50 μm, respectively, in the rapid mixer, flocculation basin and sedimentation tank when kaolin concentration was 10 mg/L and reactive orange initial concentration was 0.25 g/L. The floc size tended to increase with the increase of kaolin suspension to 10 mg/L. All of the flocs under investigation showed that floc breakage led to decreased average floc size and remained stable in the flocculation basin. Reactive orange and kaolin could be removed effectively in the continuous coagulation process. Reactive orange was adsorbed in the surface of magnesium hydroxide through charge neutralization and adsorption.

Coagulation-adsorption of reactive orange from aqueous solution by freshly formed magnesium hydroxide: mixing time and mechanistic study

2017 ◽  
Vol 75 (8) ◽  
pp. 1776-1783 ◽  
Author(s):  
Jianhai Zhao ◽  
Huanhuan Shi ◽  
Meile Liu ◽  
Jingfang Lu ◽  
Wenpu Li
Keyword(s):  
Aqueous Solution ◽  
Removal Efficiency ◽  
Magnesium Hydroxide ◽  
Mixing Time ◽  
Particle Dispersion ◽  
Mechanistic Study ◽  
X Ray Diffraction ◽  
Adsorption Mechanisms ◽  
Ft Ir ◽  
Reactive Orange

The utilization of magnesium hydroxide was successfully carried out to remove reactive orange by coagulation-adsorption from aqueous solution. The coagulation-adsorption mechanisms and magnesium hydroxide-reactive orange floc property were analyzed through zeta potential, scanning electron microscope (SEM), X-ray diffraction and Fourier transform infrared spectroscopy (FT-IR). Flocculation Index was then discussed with controlled experiments using intelligent Particle Dispersion Analyzer (iPDA) and optimum rapid mixing time of 90 s was obtained for pH 12. The results of this study indicate that charge neutralization and adsorption are proposed to be the main coagulation mechanisms. The FT-IR spectra and SEM showed that reactive orange was adsorbed on the magnesium hydroxide surface during coagulation and adsorption. Freshly generated magnesium hydroxide can effectively remove reactive orange and the removal efficiency can reach 96.7% and 46.3% for coagulation and adsorption, respectively. Adsorption process accounts for 48% of the whole coagulation experiment. The removal efficiency decreased significantly with increasing magnesium hydroxide formation time.

scholarly journals Effects of Mixing Conditions on Floc Properties in Magnesium Hydroxide Continuous Coagulation Process

2019 ◽  
Author(s):  
Yanmei Ding ◽  
Jianhai Zhao ◽  
Lei Wei ◽  
Wenpu Li ◽  
Yongzhi Chi
Keyword(s):  
Zeta Potential ◽  
Removal Efficiency ◽  
Magnesium Hydroxide ◽  
Retention Time ◽  
Mixing Conditions ◽  
Floc Size ◽  
Mixing Speed ◽  
Coagulation Process ◽  
Floc Properties ◽  
Reactive Orange

Magnesium hydroxide continuous coagulation process was used for treating simulated reactive orange wastewater in this study. Effects of mixing conditions and retention time on the coagulation performance and floc properties of magnesium hydroxide were based on the floc size distribution (FSD), zeta potential and floc morphology analysis. Floc formation and growth in different reactors were also discussed.The results showed that increasing rapid mixing speed led to a decrease in the final floc size. Floc formation process was mainly carried out in rapid mixer, rapid mixing speed of 300rpm was chosen according to zeta potential and removal efficiency. Reducing retention time caused relatively small floc size in all reactors. When influent flow is 30 L/h (retention time of 2min in rapid mixer), the average floc size reached 8.06μm in rapid mixer, through breakage and re-growth, the floc size remained stable in flocculation basin. After growth, the final floc size reached to 11.21μm in sedimentation tank. The removal efficiency of reactive orange is 89% in magnesium hydroxide coagulation process.

scholarly journals Effects of Mixing Conditions on Floc Properties in Magnesium Hydroxide Continuous Coagulation Process

2019 ◽  
Vol 9 (5) ◽  
pp. 973
Author(s):  
Yanmei Ding ◽  
Jianhai Zhao ◽  
Lei Wei ◽  
Wenpu Li ◽  
Yongzhi Chi
Keyword(s):  
Zeta Potential ◽  
Removal Efficiency ◽  
Magnesium Hydroxide ◽  
Retention Time ◽  
Mixing Conditions ◽  
Floc Size ◽  
Mixing Speed ◽  
Coagulation Process ◽  
Floc Properties ◽  
Reactive Orange

Magnesium hydroxide continuous coagulation process was used for treating simulated reactive orange wastewater in this study. Effects of mixing conditions and retention time on the coagulation performance and floc properties of magnesium hydroxide were based on the floc size distribution (FSD), zeta potential, and floc morphology analysis. Floc formation and growth in different reactors were also discussed. The results showed that increasing rapid mixing speed led to a decrease in the final floc size. The floc formation process was mainly carried out in a rapid mixer; a rapid mixing speed of 300 rpm was chosen according to zeta potential and removal efficiency. Reducing retention time caused a relatively small floc size in all reactors. When influent flow was 30 L/h (retention time of 2 min in rapid mixer), the average floc size reached 8.06 μm in a rapid mixer; through breakage and re-growth, the floc size remained stable in the flocculation basin. After growth, the final floc size reached 11.21 μm in a sedimentation tank. The removal efficiency of reactive orange is 89% in the magnesium hydroxide coagulation process.

Removal of Reactive Dyes from Wastewater by Magnesium Hydroxide Coagulation Assisted with Ultrasonic

2013 ◽  
Vol 790 ◽  
pp. 77-80 ◽  
Author(s):  
Shi Yu Liu ◽  
Jian Hai Zhao
Keyword(s):  
Zeta Potential ◽  
Magnesium Hydroxide ◽  
Reactive Dyes ◽  
Particle Dispersion ◽  
Controlled Experiments ◽  
Coagulation Process ◽  
Coagulation Performance ◽  
Ultrasonic Time ◽  
On Line ◽  
The Relationship

The effects of ultrasonic on the reactive dyes wastewater removal during magnesium hydroxide coagulation process were studied. The relationship between Flocculation Index (FI) and removal of chrominance was discussed with controlled experiments using on-line intelligent Particle Dispersion Analyzer (iPDA). The results showed that: Coagulation performance was better when increasing the ultrasonic intensity to 80W with the coagulation dose 144 mg/L and the solutions pH 12.0. The removal efficiency of reactive dyes was higher obviously with ultrasonic time 15s and 25s for dyes X-3B and X-R, respectively. The changes of zeta potential were also measured in coagulation process.

scholarly journals Hydrothermal Synthesis of Various Shape-Controlled Europium Hydroxides

Nanomaterials ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 529
Author(s):  
Hongjuan Zheng ◽  
Kongjun Zhu ◽  
Ayumu Onda ◽  
Kazumichi Yanagisawa
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Ph Value ◽  
Hydrothermal Temperature ◽  
X Ray ◽  
Hydrothermal Reactions ◽  
Starting Solution ◽  
Initial Ph ◽  
Shape Controlled ◽  
Scanning Electron

Eu(OH)3 with various shape-controlled morphologies and size, such as plate, rod, tube, prism and nanoparticles was successfully synthesized through simple hydrothermal reactions. The products were characterized by XRD (X-Ray Powder Diffraction), FE-SEM (Field Emission- Scanning Electron Microscopy) and TG (Thermogravimetry). The influence of the initial pH value of the starting solution and reaction temperature on the crystalline phase and morphology of the hydrothermal products was investigated. A possible formation process to control morphologies and size of europium products by changing the hydrothermal temperature and initial pH value of the starting solution was proposed.

scholarly journals The sorption of inorganic arsenic on modified sepiolite: Effect of hydrated iron(III)-oxide

2014 ◽  
Vol 79 (7) ◽  
pp. 815-828 ◽  
Author(s):  
Nikola Ilic ◽  
Slavica Lazarevic ◽  
Vladana Rajakovic-Ognjanovic ◽  
Ljubinka Rajakovic ◽  
Djordje Janackovic ◽  
...  
Keyword(s):  
Sorption Capacity ◽  
Arsenic Removal ◽  
Ph Value ◽  
Inorganic Arsenic ◽  
Arsenic Species ◽  
Deionized Water ◽  
Order Kinetic ◽  
Initial Ph ◽  
Order Kinetic Model ◽  
Pseudo Second Order

The sorption of inorganic arsenic species, As(III) and As(V), from water by sepiolite modified with hydrated iron(III) oxide was investigated at 25 ?C through batch studies. The influence of the initial pH value, the initial As concentrations, the contact time and types of water on the sorption capacity was investigated. Two types of water were used, deionized and groundwater. The maximal sorption capacity for As(III) from deionized water was observed at initial and final pH value 7.0, while the bonding of As(V) was observed to be almost pH independent for pH value in the range from 2.0 to 7.0, and the significant decrease in the sorption capacity was observed at pH values above 7.0. The sorption capacity at initial pH 7.0 was about 10 mg g?1 for As(III) and 4.2 mg g?1 for As(V) in deionized water. The capacity in groundwater was decreased by 40 % for As(III) and by 20 % for As(V). The Langmuir model and pseudo-second order kinetic model revealed good agreement with the experimental results. The results show that Fe(III)-modified sepiolite exhibits significant affinity for arsenic removal and it has a potential for the application in water purification processes.

scholarly journals The Removal of Methylene Blue Dye from Aqueous Solutions Using Activated and Non-Activated Bentonites

2003 ◽  
Vol 21 (5) ◽  
pp. 451-462 ◽  
Author(s):  
Sameer Al-Asheh ◽  
Fawzi Banat ◽  
Leena Abu-Aitah
Keyword(s):  
Methylene Blue ◽  
Ph Value ◽  
Sodium Dodecyl ◽  
Freundlich Isotherm ◽  
Blue Dye ◽  
Batch Adsorption ◽  
Ionic Surfactant ◽  
Methylene Blue Dye ◽  
X Ray Diffraction ◽  
Initial Ph

An improvement in the adsorption capacity of naturally available bentonite towards water pollutants such as Methylene Blue dye (MBD) is certainly needed. For this purpose, sodium bentonite was activated by two methods: (1) treatment with sodium dodecyl sulphate (SDS) as an ionic surfactant and (2) thermal treatment in an oven operated at 850°C. Batch adsorption tests were carried out on removing MBD from aqueous solution using the above-mentioned bentonites. It was found that the effectiveness of bentonites towards MBD removal was in the following order: thermal-bentonite > SDS-bentonite > natural bentonite. X-Ray diffraction analysis showed that an increase in the microscopic bentonite platelets on treatment with SDS was the reason behind the higher uptake of MBD. An increase in sorbent concentration or initial pH value of the solutions resulted in a greater removal of MBD from the solution. An increase in temperature led to an increase in MBD uptake by the bentonites studied in this work. The Freundlich isotherm model was employed and found to represent the experimental data well.

High Cr(VI) Adsorption Performance of Coal-Based Activated Carbon in Aqueous Solution

2013 ◽  
Vol 798-799 ◽  
pp. 1123-1127
Author(s):  
Hua Lei Zhou ◽  
Qiong Qiong Zhu ◽  
Dong Hua Huang
Keyword(s):  
Aqueous Solution ◽  
Activated Carbon ◽  
Pore Structure ◽  
Ph Value ◽  
High Surface ◽  
High Surface Area ◽  
Koh Activation ◽  
Transmission Electron ◽  
Mesoporous Adsorbent ◽  
Initial Ph

The activated carbon with high surface area was prepared by KOH activation from anthracite and used as adsorbent for removal of Cr (VI) from aqueous solution. The pore structure and surface properties were characterized by N2 adsorption at 77K, transmission electron microscope (TEM) and Fourier transform infrared spectroscopy ( FTIR). Effect of pH and isotherms at different temperature were investigated. Results show that the prepared carbon is a microporous-and mesoporous-adsorbent with developed pore structure and abundant surface oxygen-containing groups. PH value of the solution plays key function on the adsorption. The chemical adsorption dominates the adsorption process. The activated carbon exhibits much higher Cr adsorption capacity than the commercial activated carbon at initial pH of ~3. The equilibrium adsorption data are fitted by both Freundlich model and Langmuir model well.

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