Treatment of Industrial Wastewater Containing High Levels of Ammonia and Salt Using Vacuum Membrane Distillation

The wastewater containing extreme high levels of ammonia and salt was treated by vacuum membrane distillation (VMD). The effects of feed flow rate, temperature and vacuum degree on ammonia removal efficiency (ARE) were investigated systematically. The ARE can be promoted by increasing feed flow rate, feed temperature and vacuum degree in this study. The theoretical mass transfer model was obtained based on series of theory derivation, and the theoretical released ammonia is consistent with the experimental data at conditions ranged in this study, indicating that the developed model is suitable to evaluate the ammonia removal during VMD process.

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Performance Investigation of O-Ring Vacuum Membrane Distillation Module for Water Desalination

Journal of Chemistry ◽

10.1155/2016/9378460 ◽

2016 ◽

Vol 2016 ◽

pp. 1-11 ◽

Cited By ~ 1

Author(s):

Adnan Alhathal Alanezi ◽

H. Abdallah ◽

E. El-Zanati ◽

Adnan Ahmad ◽

Adel O. Sharif

Keyword(s):

Flow Rate ◽

Membrane Distillation ◽

Membrane Module ◽

Water Desalination ◽

Feed Flow Rate ◽

Permeate Flux ◽

Vacuum Degree ◽

Flat Sheet ◽

Vacuum Membrane Distillation ◽

Feed Temperature

A new O-ring flat sheet membrane module design was used to investigate the performance of Vacuum Membrane Distillation (VMD) for water desalination using two commercial polytetrafluoroethylene (PTFE) and polyvinylidene fluoride (PVDF) flat sheet hydrophobic membranes. The design of the membrane module proved its applicability for achieving a high heat transfer coefficient of the order of 103 (W/m2 K) and a high Reynolds number (Re). VMD experiments were conducted to measure the heat and mass transfer coefficients within the membrane module. The effects of the process parameters, such as the feed temperature, feed flow rate, vacuum degree, and feed concentration, on the permeate flux have been investigated. The feed temperature, feed flow rate, and vacuum degree play an important role in enhancing the performance of the VMD process; therefore, optimizing all of these parameters is the best way to achieve a high permeate flux. The PTFE membrane showed better performance than the PVDF membrane in VMD desalination. The obtained water flux is relatively high compared to that reported in the literature, reaching 43.8 and 52.6 (kg/m2 h) for PVDF and PTFE, respectively. The salt rejection of NaCl was higher than 99% for both membranes.

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A Comparison Study of Brine Desalination using Direct Contact and Air Gap Membrane Distillation

Journal of Engineering ◽

10.31026/j.eng.2019.11.04 ◽

2019 ◽

Vol 25 (11) ◽

pp. 47-54

Author(s):

Ahmed Shamil Khalaf ◽

Asrar Abdullah Hassan

Keyword(s):

Flow Rate ◽

Direct Contact ◽

Polyvinylidene Fluoride ◽

Membrane Distillation ◽

Air Gap ◽

Feed Flow Rate ◽

Permeate Flux ◽

Air Gap Membrane Distillation ◽

Flat Sheet ◽

Feed Temperature

Membrane distillation (MD) is a hopeful desalination technique for brine (salty) water. In this research, Direct Contact Membrane Distillation (DCMD) and Air Gap Membrane Distillation (AGMD) will be used. The sample used is from Shat Al –Arab water (TDS=2430 mg/l). A polyvinylidene fluoride (PVDF) flat sheet membrane was used as a flat sheet form with a plate and frame cell. Several parameters were studied, such as; operation time, feed temperature, permeate temperature, feed flow rate. The results showed that with time, the flux decreases because of the accumulated fouling and scaling on the membrane surface. Feed temperature and feed flow rate had a positive effect on the permeate flux, while permeate temperature had a reverse effect on permeate flux. It is noticeable that the flux in DCMD is greater than AGMD, at the same conditions. The flux in DCMD is 10.95LMH, and that in AGMD is 7.14 LMH. In AGMD, the air gap layer made a high resistance. Here the temperature transport reduces in the permeate side of AGMD due to the air gap resistance. The heat needed for AGMD is lower than DCMD, this leads to low permeate flux because the temperature difference between the two sides is very small, so the driving force (vapor pressure) is low.

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Removal of high concentration Congo red by hydrophobic PVDF hollow fiber composite membrane coated with a loose and porous ZIF-71PVDF layer through vacuum membrane distillation

Journal of Industrial Textiles ◽

10.1177/1528083720967075 ◽

2020 ◽

pp. 152808372096707

Author(s):

Hongbin Li ◽

Wenying Shi ◽

Qiyun Du ◽

Shoufa Huang ◽

Haixia Zhang ◽

...

Keyword(s):

Flow Rate ◽

Hollow Fiber ◽

Congo Red ◽

Fiber Composite ◽

Water Flux ◽

Membrane Distillation ◽

Feed Flow Rate ◽

High Concentration ◽

Operation Conditions ◽

Feed Temperature

Although membrane distillation (MD) technology has the outstanding advantages of almost 100% solute retention and mild operation conditions, its further development is limited by low permeate flux. In order to solve the problem, the improvement of membrane hydrophobicity becomes one of the effective solutions. In this study, a loose and porous hydrophobic zeolitic imidazolate frameworks-71 (ZIF-71)/polyvinylidene fluoride (PVDF) coating layer was composited on the outside surface of PVDF hollow fiber support membrane by the dilute solution coating to enhance membrane hydrophobicity. The prepared hollow fiber composite (HFC) membranes were employed to remove high concentration Congo red (CR) through VMD. The effects of different operation conditions including the dye concentration, feed temperature, vacuum pressure and feed flow rate on CR rejection and permeate water flux were investigated. In the variation range of operating conditions, all the CR rejection of the PVDF HFC membranes shows a slight change and remains above 99.9%. Under the optimal operation conditions including dye concentration 600 mg·L−1, vacuum pressure 31.325 kPa, feed temperature 60°C and feed flow rate 50 L·h−1, HFC membrane exhibit a permeate water flux of 13.15 kg·m−2·h−1. HFC membrane suffers dye fouling during the continuous dye filtration for 100 h. The fouling mechanism was proposed and a combined cleaning way including forward washing, back flushing and chemical desorption has been proved to be effective in recovering membrane water flux.

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A Systematic Framework for Optimizing a Sweeping Gas Membrane Distillation (SGMD)

Membranes ◽

10.3390/membranes10100254 ◽

2020 ◽

Vol 10 (10) ◽

pp. 254

Author(s):

Nawras N. Safi ◽

Salah. S. Ibrahim ◽

Nasser Zouli ◽

Hasan Shaker Majdi ◽

Qusay F. Alsalhy ◽

...

Keyword(s):

Flow Rate ◽

Gas Flow ◽

Membrane Distillation ◽

Feed Flow Rate ◽

Permeate Flux ◽

Gas Flow Rate ◽

Feed Concentration ◽

Sweeping Gas ◽

Feed Temperature ◽

Systematic Framework

The present work has undertaken a meticulous glance on optimizing the performance of an SGMD configuration utilized a porous poly (vinylidene fluoride-co-hexafluoropropylene) (PVDF-co-HFP) membrane. This was carried out by conducting a systematic framework for investigating and optimizing the pertinent parameters such as sweeping gas flow rate, feed temperature, feed concentration and feed flow rate on the permeate flux. For this purpose, the Taguchi method and design of experiment techniques were harnessed to statistically determine optimum operational conditions. Besides that, a comprehensive surface and permeation characterization was conducted against the hand-made membranes. Results showcased that the membrane performance was ultimately controlled by the feed temperature and was nearly (~680) % higher when the temperature raised from 45 to 65 °C. Also, to a lesser extent, the system was dominated by the feed flow rate. As the adopted feed flow rate increases (from 0.2 to 0.6 L/min), around 47.5% increment was bestowed on water permeability characteristics. In contra, 34.5% flux decline was witnessed when higher saline feed concentration (100 g/L) was utilized. In the meantime, with raising the sweeping gas flow rate (from 120 to 300 L/h), the distillate was nearly 129% higher. Based on Taguchi design, the maximum permeate flux (17.3 and 17 kg/m2·h) was secured at 35 g/L, 0.4 L/min, 65 °C and 300 L/h, for both commercial and prepared membranes, respectively.

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Performance of Air Gap Membrane Distillation Unit for Water Desalination

Volume 6A: Energy ◽

10.1115/imece2014-36031 ◽

2014 ◽

Cited By ~ 3

Author(s):

Atia E. Khalifa ◽

Dahiru U. Lawal ◽

Mohamed A. Antar

Keyword(s):

Flow Rate ◽

Membrane Distillation ◽

Air Gap ◽

Water Desalination ◽

Feed Water ◽

Feed Flow Rate ◽

Permeate Flux ◽

Air Gap Membrane Distillation ◽

Gap Width ◽

Feed Temperature

Due to water scarcity in the Arabic gulf region, water desalination technologies are considered extremely important. The present work represents a fundamental study on the effect of basic operating and design variables on the flux of an air gap membrane distillation (AGMD) unit for water desalination. The flat sheet, channeled air gap membrane distillation module was designed and manufactured locally. The effect of feed flow rate, feed temperature, coolant water temperature, the air gap width, and the water salinity on the module flux are investigated. Analytical model for heat and mass transfer is used to predict the flux and the model results are compared to the experimental ones. Results showed that the technique has good potential to be used for water desalination. The permeate flux is increased by increasing feed flow rate, feed temperature, decreasing the air gap width, decreasing coolant temperature, and decreasing salinity of feed water. For a given feed flow rate, the width of the air gap and the feed water temperature are found to be the most effective parameters in increasing the distillate flux. Predicting the permeate flux with analytical models for heat and mass transfer showed good agreement with experimental results.

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Water Desalination Using Direct Contact Membrane Distillation System

Volume 6A: Energy ◽

10.1115/imece2015-50171 ◽

2015 ◽

Cited By ~ 1

Author(s):

Hafiz M. Ahmad ◽

Atia E. Khalifa ◽

Mohamed A. Antar

Keyword(s):

Flow Rate ◽

Direct Contact ◽

Membrane Distillation ◽

Operating Conditions ◽

Water Desalination ◽

Feed Flow Rate ◽

Direct Contact Membrane Distillation ◽

Rejection Factor ◽

System Output ◽

Feed Temperature

Membrane distillation (MD) is a separation technique used for water desalination, which operates at low feed temperatures and pressures. Direct contact membrane distillation (DCMD) is one of the common MD configurations where both the hot saline feed stream and the cold permeate stream are in direct contact with the two membrane surfaces. An experimental study was performed to investigate the effect of operating conditions such as feed temperature, feed flow rate, permeate temperature, and permeate flow rate on the system output flux. To check the effect of membrane degradation, the MD system was run continuously for 48 hours with raw seawater as feed and the reduction in system flux with time was observed. Results showed that increasing the feed temperature, decreasing the permeate temperature, increasing the feed and permeate flow rate yield an increase in flux. The effects of feed temperature and feed flow rate are the most significant parameters. After 48 hours of system continuous operation flux was reduced by 42.4 % but the quality of permeate (as measured by its TDS) is still very high with salt rejection factor close to 100 %. For the DCMD system under consideration, the GOR values remain between 0.8 and 1.2, for the tested range of operating temperatures.

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Separation of HCl/water mixture using air gap membrane distillation, Taguchi optimization and artificial neural network

Chemical Product and Process Modeling ◽

10.1515/cppm-2020-0078 ◽

2020 ◽

Vol 0 (0) ◽

Author(s):

Sarita Kalla ◽

Rakesh Baghel ◽

Sushant Upadhyaya ◽

Kailash Singh

Keyword(s):

Water Temperature ◽

Flow Rate ◽

Cooling Water ◽

Membrane Distillation ◽

Air Gap ◽

Water Mixture ◽

Feed Flow Rate ◽

Ann Model ◽

Cooling Water Temperature ◽

Feed Temperature

AbstractThe aim of this paper is to analyze the performance of the air gap membrane distillation (AGMD) process for the separation of HCl/Water mixture first by applying Taguchi optimization approach and second by developing an artificial neural network (ANN) model. The experimental data which are fed as input to the above approaches are collected from the fabricated AGMD lab-scale setup using poly-tetra-fluoro-ethylene membrane of 0.22 µm pore size. The process input variables considered are bulk feed temperature, feed flow rate, air gap thickness, cooling water temperature and cooing water flow rate and AGMD performance index is the total permeate flux. The optimum operating condition is found to be at feed temperature 50 °C, air gap thickness 7 mm, cooling water temperature 5 °C and feed flow rate 10 lpm. Analysis of variance test is carried out for both Taguchi and ANN models. Regression model has also been developed for the comparison between experimental and model predicted data. The developed ANN model has been found well fitted with experimental data having R2 value of 0.998. Based on the calculated percentage of contribution of each input parameter on the AGMD permeate flux, it can be concluded that feed temperature and air gap thickness have highest weightage whereas feed flow rate and cooling water temperature have moderate effects. Predictive ability of the developed ANN model is further checked with 2D contour plot. The distinctive feature of the paper is the development of the Taguchi experimental design and ANN model and then consequently integration of both Taguchi and ANN has been carried out to optimized the developed ANN model parameters.

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Numerical Simulation of Cross-Flow Vacuum Membrane Distillation and Characteristics Analysis

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.396-398.1846 ◽

2011 ◽

Vol 396-398 ◽

pp. 1846-1850

Author(s):

Chang Li ◽

Bao An Li ◽

Shi Chang Wang

Keyword(s):

Numerical Simulation ◽

Cross Flow ◽

Membrane Distillation ◽

Inlet Temperature ◽

Coefficient Distribution ◽

Vacuum Degree ◽

Membrane Flux ◽

Characteristics Analysis ◽

Vacuum Membrane Distillation ◽

Feed Inlet

The mechanism of cross-flow vacuum membrane distillation (VMD) was discussed in this paper, and the coupled process of heat and mass transfer in numerical simulation was realized by writing user defined function (UDF). The numerical simulation results of membrane flux were well agree with experimental data. The membrane flux in various conditions of feed velocity, feed inlet temperature and vacuum degree was obtained in numerical simulation. Around the cross-section of a single hollow fiber, velocity distribution was approximately symmetrical; TPC and heat transfer coefficient distribution are consistent.

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Preparation of Hydrophobic Microporous Polypropylene/Isotactic Polypropylene Blending Membranes via Thermally Induced Phase Separation for Vacuum Membrane Distillation

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.790.81 ◽

2013 ◽

Vol 790 ◽

pp. 81-84 ◽

Cited By ~ 1

Author(s):

Na Tang ◽

Shuang Zhang ◽

Lei Zhang ◽

Peng Gao Cheng ◽

Jin Jin Li

Keyword(s):

Phase Separation ◽

Isotactic Polypropylene ◽

Membrane Distillation ◽

Mass Ratio ◽

Thermally Induced Phase Separation ◽

Nacl Solution ◽

Optimum Conditions ◽

Thermally Induced ◽

Vacuum Membrane Distillation ◽

Feed Temperature

The hydrophobic microporous membranes were prepared from a blend system by thermally induced phase separation (TIPS) process. The polymer blend system was isotactic polypropylene (iPP)/ high-density polyethylene (HDPE) and the diluent was soybean oil. The effects of the mass ratio of iPP and HDPE and the initial concentration of blending on the membranes structure were both investigated. Additionally, the influence of the feed temperature and the feed rate on the VMD performance of iPP/HDPE blend membranes was also investigated. For 0.5M aqueous NaCl solution, the VMD flux and reject ratio of the membranes reached 8.7kg/(m2·h) and nearly 100% under the optimum conditions (mass ration of iPP/HDPE was 6:1, and intial blend concentration was 38%), respectively.

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