Mixing and osmosis

2018 ◽  
Author(s):  
Dennis Sherwood ◽  
Paul Dalby
Keyword(s):  
Osmotic Pressure ◽  
Reverse Osmosis ◽  
Industrial Process ◽  
Colligative Properties

Building on the results of the previous chapter, this chapter extends the analysis of colligative properties to mixing and osmosis, with an analysis of osmotic pressure and also the important industrial process of reverse osmosis.

scholarly journals Using Reverse Osmosis Membrane at High Temperature for Water Recovery and Regeneration from Thermo-Responsive Ionic Liquid-Based Draw Solution for Efficient Forward Osmosis

Membranes ◽  
2021 ◽  
Vol 11 (8) ◽  
pp. 588
Author(s):  
Eiji Kamio ◽  
Hiroki Kurisu ◽  
Tomoki Takahashi ◽  
Atsushi Matsuoka ◽  
Tomohisa Yoshioka ◽  
...  
Keyword(s):  
Ionic Liquid ◽  
High Temperature ◽  
Energy Saving ◽  
Osmotic Pressure ◽  
Reverse Osmosis ◽  
Forward Osmosis ◽  
Solution Temperature ◽  
Water Recovery ◽  
Temperature Dependent ◽  
Draw Solution

Forward osmosis (FO) membrane process is expected to realize energy-saving seawater desalination. To this end, energy-saving water recovery from a draw solution (DS) and effective DS regeneration are essential. Recently, thermo-responsive DSs have been developed to realize energy-saving water recovery and DS regeneration. We previously reported that high-temperature reverse osmosis (RO) treatment was effective in recovering water from a thermo-responsive ionic liquid (IL)-based DS. In this study, to confirm the advantages of the high-temperature RO operation, thermo-sensitive IL-based DS was treated by an RO membrane at temperatures higher than the lower critical solution temperature (LCST) of the DS. Tetrabutylammonium 2,4,6-trimethylbenznenesulfonate ([N4444][TMBS]) with an LCST of 58 °C was used as the DS. The high-temperature RO treatment was conducted at 60 °C above the LCST using the [N4444][TMBS]-based DS-lean phase after phase separation. Because the [N4444][TMBS]-based DS has a significantly temperature-dependent osmotic pressure, the DS-lean phase can be concentrated to an osmotic pressure higher than that of seawater at room temperature (20 °C). In addition, water can be effectively recovered from the DS-lean phase until the DS concentration increased to 40 wt%, and the final DS concentration reached 70 wt%. From the results, the advantages of RO treatment of the thermo-responsive DS at temperatures higher than the LCST were confirmed.

scholarly journals Flux Optimization in Reverse Osmosis via the Solution-Diffusion Model

2019 ◽  
Vol 4 (5) ◽  
pp. 39-44
Author(s):  
Hisham A. Maddah
Keyword(s):  
Osmotic Pressure ◽  
Reverse Osmosis ◽  
Diffusion Model ◽  
Water Flux ◽  
Applied Pressure ◽  
Arabian Gulf ◽  
Water Sources ◽  
Operating Conditions ◽  
Membrane Thickness ◽  
Membrane Type

This paper suggests a new method of predicting flux values at reverse osmosis (RO) desalination plants.  The study is initiated by using the solution-diffusion model that is applied to the groundwater source at Abqaiq plant (500 RO plant) at Saudi Aramco, Dhahran, Saudi Arabia in order to calculate the osmotic pressure of the treated water for Shedgum/Abqaiq groundwater. For modelling purposes, the same technique is used to determine the osmotic pressure drops at the same plant configuration and operating conditions when using seawater sources such that of Arabian Gulf and the Red Sea waters. High rejection brackish water RO (BWRO) element Toray TM720D-400 with 8" is the RO membrane type that is used at Abqaiq plant. The calculated osmotic pressures of the three water sources, assuming that they are all treated at Abqaiq plant, are utilized to determine the appropriate flux values as well as membrane resistances of different BWRO Toray membranes. Values of numerous parameters such as water permeability constant, applied pressure, gas constant, water temperature, water molar volume and membrane thickness, water salinity/TDS are taken into account to develop our calculations through the solution-diffusion model. A comparison between low-pressure, standard and high-pressure BWRO Toray membranes performance have been established to select the ideal membrane type for the treatment of water from various sources at Abqaiq plant. The model results confirm an inverse relationship between the membrane thickness and the water flux rate. Also, a proportional linear relation between the overall water flux and the applied pressure across the membrane is identified. Higher flux rates and lower salinity indicate lower membrane resistance which yields to the higher water production. Modelled data predict that BWRO Toray TM720D-440 with 8" membrane is the optimal BWRO membrane choice for the three water sources at Abqaiq plant.

Toward the conceptual and quantitative understanding of biosolids conditioning: the gel approach

2009 ◽  
Vol 59 (9) ◽  
pp. 1679-1685 ◽  
Author(s):  
Derya Dursun ◽  
Steven K. Dentel
Keyword(s):  
Osmotic Pressure ◽  
Conceptual Model ◽  
Chemical Potential ◽  
Satisfactory Description ◽  
Colloidal Gel ◽  
Quantitative Understanding ◽  
Fundamental Value ◽  
Limited Diffusion ◽  
Gel Network ◽  
Colligative Properties

Proper chemical conditioning of wastewater solids is crucial for both operational and economic reasons, but the process has defied satisfactory description to date, in either conceptual or quantitative terms. In this research, a new conceptual model of biosolids structure—likening it to a colloidal gel—was assessed as a means of interpreting conditioning mechanisms. The basis of the gel approach lies in the colligative properties that are altered by lowering of the solvent chemical potential by introducing a solute. Results indicate that inorganic conditioners form precipitates and complexes thus collapsing the gel network and forming particulates, whereas organic polymers lead to heterogeneous collapse with limited diffusion inside the gel. A gel model, based on the osmotic pressure, was found reasonably successful in defining the conditioning efficacy of biosolids. Beyond the model's fundamental value, these results validate a new way of understanding how conditioning and dewatering operate, which should help to improve the selection and optimization of these processes.

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