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.

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 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.

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.

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.

Optimization of the Coagulation Process for Kaolin and Humic Acid Removal Using Polymeric Aluminum Ferric Sulfate

2015 ◽  
Vol 1088 ◽  
pp. 353-357 ◽  
Author(s):  
Zhen Zhen Jiang ◽  
Yang Chen ◽  
Jun Ren Zhu
Keyword(s):  
Humic Acid ◽  
Removal Efficiency ◽  
Mixing Time ◽  
Ferric Sulfate ◽  
Single Factor ◽  
Mixing Speed ◽  
Rapid Mixing ◽  
Coagulation Process ◽  
Coagulation Performance ◽  
Slow Mixing

In the paper, the optimization of the coagulation process for Kaolin and humic acid removal using polymeric aluminum ferric sulfate (PAFS) was studied. In order to obtain the maximum turbidity and humic acid removal efficiency of Kaolin and humic acid simulated wastewater, the optimum coagulation conditions was investigated with the factors of mixing speed and time. Furthermore, mixing speed and time including parameters affecting the coagulation performance such as rapid mixing speed, rapid mixing time, slow mixing speed and slow mixing time using single factor and orthogonal array L9 (34) analysis were examined. The results showed that the optimum single factor of mixing speed and time indicated rapid mixing speed of 350 rpm, rapid mixing time of 1.0 min, slow mixing speed of 60 rpm and slow mixing time of 20 min. Then the orthogonal optimization experiment of mixing speed and time indicated maximum HA removal efficiency was 97.5% at rapid mixing speed of 350 rpm, rapid mixing time of 1.25 min, slow mixing speed of 60 rpm, and slow mixing time of 20 min.

scholarly journals Investigation of Electro-coagulation Process for Phosphate and Nitrate Removal From Sugarcane Wastewaters

2021 ◽  
Vol 15 (1) ◽  
pp. 19-26
Author(s):  
Majid Ebadi ◽  
◽  
Ali Asareh ◽  
Reza Jalilzadeh Yengejeh ◽  
Najaf Hedayat ◽  
...  
Keyword(s):  
Removal Efficiency ◽  
Retention Time ◽  
Nitrate Removal ◽  
Phosphate Removal ◽  
Septic Tank ◽  
Industrial Complex ◽  
Khuzestan Province ◽  
Coagulation Process ◽  
Aluminum Electrodes ◽  
Electro Coagulation

Background: Highly-concentrated phosphate and nitrate anions from sugarcane wastewater are often discharged into public waters without standardized treatments. This study assessed the effects of electrical coagulation, initial pH and reaction time in the removal of phosphate and nitrate pollutants. Methods: We used aluminum electrodes to remove the pollutants at Hakhim Farabi Agricultural and Industrial complex, Khuzestan Province, Iran. A septic tank was used for collecting water samples followed by measuring the pH, and the concentrations of phosphate and nitrate in the samples. The pH was set at 5, 7, 9 or 11. Six aluminum electrodes were placed perpendicular to the water flow and were connected to power in a single-polar method. They were used to assess the effects of pH changes, electrical power at 10 and 30 volts and the water retention time at 15, 30, 45 or 60 min. on the efficiency of the pollutants’ removal. Results: The results indicated that under equal retention time and varying pH values, as voltage increased from 10 to 30, the phosphate and nitrate removal increased progressively. It was further demonstrated that the maximum phosphate removal efficiency was achieved at pH7, while it declined at higher pH levels. The highest possible nitrate removal efficiency was achieved under alkaline pH levels. The overall results showed that at every pH and voltage, the percentage of phosphate and nitrate removal increased over time. Conclusion: This study demonstrated that electro-coagulation process is an appropriate and efficient method to remove phosphate and nitrate pollutants from sugarcane wastewaters.

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.

Zeta potential measurement on the surface of blue-green algae particles for micro-bubble process

2008 ◽  
Vol 57 (1) ◽  
pp. 19-25 ◽  
Author(s):  
Kazuo Taki ◽  
Tatsuhiro Seki ◽  
Sakiyori Mononobe ◽  
Kohichi Kato
Keyword(s):  
Zeta Potential ◽  
Chlorophyll A ◽  
Green Algae ◽  
Removal Efficiency ◽  
Magnesium Hydroxide ◽  
Hybrid Technique ◽  
Eutrophic Lakes ◽  
Potential Measurement ◽  
Blue Green Algae ◽  
Maximum Removal

Any kind of blue-green alga produces metabolites of musty substances and toxins. Therefore, it is necessary to remove the blue-green algae, and processing also including nutrient removal is desired for the water quality improvement of eutrophic lakes. The purpose of this study has been to investigate the possibility of a flotation system using a hybrid technique (chemical compounds and electrostatic bridge) applied to raw water containing phytoplankton with high pH of water, and to examine the zeta potential value of phytoplankton surface and the removal efficiency for phytoplankton, ammonia, nitrogen, and phosphoric acid. The results were as follows: firstly, zeta potential of M. aeruginosa particles was observed to achieve charge neutralization on their surface by adhesion of magnesium hydroxide precipitation with increasing pH. Secondly, maximum removal efficiency concerning chlorophyll-a was observed as 84%, and this efficiency was obtained in the condition of pH > 10, and magnesium hydroxide precipitation was observed. Thirdly, in the pH condition that the maximum removal efficiency of chlorophyll-a was obtained, the removal efficiency and the amount of decrease of NH4-N and PO4-P before and after the change of pH values were observed as 6.7% (0.04 mg-P/L) and 63.6% (0.07 mg-N/L), respectively.

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