Characterization of reverse osmosis and nanofiltration membranes by an automated system

The objective of this work is to study the ageing state of a used reverse osmosis (RO) membrane taken in Algeria from the Benisaf Water Company seawater desalination unit. The study consists of an autopsy procedure used to perform a chain of analyses on a membrane sheet. Wear of the membrane is characterized by a degradation of its performance due to a significant increase in hydraulic permeability (25%) and pressure drop as well as a decrease in salt retention (10% to 30%). In most cases the effects of ageing are little or poorly known at the local level and global measurements such as (flux, transmembrane pressure, permeate flow, retention rate, etc.) do not allow characterization. Therefore, a used RO (reverse osmosis) membrane was selected at the site to perform the membrane autopsy tests. These tests make it possible to analyze and identify the cause as well as to understand the links between performance degradation observed at the macroscopic scale and at the scale at which ageing takes place. External and internal visual observations allow seeing the state of degradation. Microscopic analysis of the used membranes surface shows the importance of fouling. In addition, quantification and identification analyses determine a high fouling rate in the used membrane whose foulants is of inorganic and organic nature. Moreover, the analyses proved the presence of a biofilm composed of protein.

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Innovative concepts of regeneration of decolorization ion exchange resins in sugar refineries

Sugar Industry ◽

10.36961/si17497 ◽

2016 ◽

pp. 377-380

Author(s):

Marc André Théoleyre ◽

Anne Gonin ◽

Dominique Paillat

Keyword(s):

Ion Exchange ◽

Reverse Osmosis ◽

Energy Supply ◽

Ion Exchange Resins ◽

Salt Solutions ◽

Nanofiltration Membranes ◽

Local Conditions ◽

Salt Consumption ◽

Multiple Effect ◽

Exchange Resins

Regeneration of resins used for decolorization of sugar solutions is done with concentrated salt solutions. Nanofiltration membranes have been proven effective, in terms of industrial efficiency in decreasing salt consumption. More than 90% of the salt that is necessary for regeneration can be recycled through a combination of direct recycling of intermediate eluates, the separation of colored compounds by use of very selective nanofiltration membranes and a system to concentrate salty permeates. According to specific local conditions on energy supply and cost, the concentration of salty permeates can be either a multiple effect evaporator or a combination of electrodialysis and reverse osmosis. The desalted color compound solution is sent to the molasses, limiting considerably the effluent to be treated. Starting from a liquor of 800 IU, the water requirement is limited to less than 100 L/t of sugar and the amount of wastewater can be reduced to less than 40 L/t of sugar.

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Effect of the structure of cellulose acetate membranes on their permeability, electrical conductivity and rejection

Collection of Czechoslovak Chemical Communications ◽

10.1135/cccc19902933 ◽

1990 ◽

Vol 55 (12) ◽

pp. 2933-2939 ◽

Cited By ~ 1

Author(s):

Hans-Hartmut Schwarz ◽

Vlastimil Kůdela ◽

Klaus Richau

Keyword(s):

Electrical Conductivity ◽

Electrical Properties ◽

Cellulose Acetate ◽

Reverse Osmosis ◽

Water Flux ◽

Cellulose Acetate Membrane ◽

Structure Parameters ◽

Dc Electrical Conductivity ◽

Cellulose Acetate Membranes

Ultrafiltration cellulose acetate membrane can be transformed by annealing into reverse osmosis membranes (RO type). Annealing brings about changes in structural properties of the membranes, accompanied by changes in their permeability behaviour and electrical properties. Correlations between structure parameters and electrochemical properties are shown for the temperature range 20-90 °C. Relations have been derived which explain the role played by the dc electrical conductivity in the characterization of rejection ability of the membranes in the reverse osmosis, i.e. rRO = (1 + exp (A-B))-1, where exp A and exp B are statistically significant correlation functions of electrical conductivity and salt permeation, or of electrical conductivity and water flux through the membrane, respectively.

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Comparison of Reverse Osmosis and Nanofiltration Membranes in Water Purification Process

SSRN Electronic Journal ◽

10.2139/ssrn.3982137 ◽

2021 ◽

Author(s):

Ahmet Bora Yavuz ◽

Osman Nuri Ata

Keyword(s):

Reverse Osmosis ◽

Water Purification ◽

Purification Process ◽

Nanofiltration Membranes

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Influence of Drying in Hyptis pectinata Essential Oil

Journal of Agricultural Science ◽

10.5539/jas.v10n4p96 ◽

2018 ◽

Vol 10 (4) ◽

pp. 96

Author(s):

Núbia Angélica de Ávila Branquinho ◽

Fabiano Guimarães Silva ◽

Osvaldo Resende ◽

Luiz Cláudio Almeida Barbosa ◽

Daniel Emanuel Cabral de Oliveira ◽

...

Keyword(s):

Essential Oil ◽

Anhydrous Sodium Sulfate ◽

Fixed Bed ◽

Chemical Characterization ◽

Automated System ◽

Caryophyllene Oxide ◽

System A ◽

Different Temperatures ◽

Drying Conditions

The present study assessed the effects of drying at different temperatures (35, 45 and 55 °C) and air velocities (1 and 2 m s-1) on the content and chemical characteristics of Hyptis pectinata essential oil. Drying was conducted in a fixed-bed dryer, and the temperatures and air velocities were controlled and recorded by an automated system. A 350±0.12 g quantity of fresh leaves was used for each of the four repetitions in each dryer. From the material obtained after drying, 60 g of each repetition was used to extract essential oil by the hydrodistillation method. Dichloromethane was used as the solvent, and anhydrous sodium sulfate was used as the desiccating agent. Gas chromatography in the forms of GC-MS and GC-FID were used for the chemical characterization of the essential oil compounds. Decreasing drying times and decreasing concentrations of essential oils were observed with increasing temperatures. A GC-MS analysis of the essential oil from H. pectinata leaves led to the identification of 19 compounds. A sesquiterpene called caryophyllene oxide was the most abundant compound under all drying conditions, with the highest concentration at a temperature of 55 °C, ranging from approximately 42 to 53%.

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