Boron removal from seawater by combined system of seawater reverse osmosis membranes and ion exchange process: a pilot-scale study

2010 ◽  
Vol 15 (1-3) ◽  
pp. 178-182 ◽  
Author(s):  
Byeong-Cheol Kim ◽  
Phan Vu Xuan Hung ◽  
Seung-Hyeon Moon
Keyword(s):  
Ion Exchange ◽  
Reverse Osmosis ◽  
Exchange Process ◽  
Pilot Scale ◽  
Boron Removal ◽  
Combined System ◽  
Ion Exchange Process ◽  
Seawater Reverse Osmosis ◽  
Reverse Osmosis Membranes

Further treatment of ion exchange brine with dynamic vapour recompression

2012 ◽  
Vol 7 (4) ◽  
Author(s):  
E. Vaudevire ◽  
E. Koreman ◽  
G. Galjaard ◽  
R. Trommel ◽  
M. Visser
Keyword(s):  
Sodium Chloride ◽  
Ion Exchange ◽  
Exchange Process ◽  
Nitrate Removal ◽  
Pilot Scale ◽  
Selective Precipitation ◽  
Ion Separation ◽  
Ion Exchange Process ◽  
Pre Treatment ◽  
Controlled Precipitation

In the context of the development of the SIX© Ion exchange process, the Dutch water company (PWN) decided to investigate options for treatment of the brine arising from the regeneration of the resin. Main goals for the brine treatment are volume reduction and product recovery (water + NaCl). In this regard a biological denitrification (DNF) aiming at total nitrate removal followed by a nanofiltration (NF) aiming at ion separation (monovalent/bivalent) focused on NaCl re-use were implemented on a pilot scale recovering 80% of the total SIX brine (implying 80%recovery of NaCl). Further NF concentrate minimization and Sodium Chloride reclamation would allow a reduction of the disposal fees and chemical uses and therefore largely increase the overall process sustainability. During operation on a pilot scale with a capacity of 250l/h, the Dynamic Vapour Recompression (DVR) technology has proved itself to be capable to reduce the raw regenerate another 6 to 10 times reaching meanwhile the solubility limits of NaCl and other salts making their recovery on a solid stream possible. The condensate that resides after DVR treatment is low contaminated and is therefore suitable for re-injection upstream the SIX pre-treatment process. Laboratory scale evaporation tests showed that salts would precipitate according to the following order: BaSO4 >BaCO3 > MgSO4 > MgCO3 >CaCO3 > CaSO4 > Na2CO3 > Na2SO4 and NaCl. A sequenced thickening by DVR treatment leads to selective precipitation of BaSO4, BaCO3, MgCO3, CaCO3 and CaSO4 at concentration factor around 8 but beyond a CF of 10 it leads to a more or less simultaneous precipitation of NaCl, Na2CO3 and Na2SO4 without fouling/clogging problems of the DVR. A reuse of a heterogeneous (co)precipitate solid fraction is difficult; however this problem could be countered by further investigation on a temperature controlled precipitation of Na2CO3 and Na2SO4. Cooling down the DVR brine saturated in dissolved sodium chloride, sulphate and bicarbonate to a temperature of 5 °C increases solubility differences between sodium chloride and its two contaminants, making their separation possible.

Removal of Toxic Dyestuffs from Aqueous Solution by Amphoteric Bioadsorbent

2020 ◽  
Vol 16 ◽  
Author(s):  
Reda M. El-Shishtawy ◽  
Abdullah M. Asiri ◽  
Nahed S. E. Ahmed
Keyword(s):  
Aqueous Solution ◽  
Ion Exchange ◽  
Dye Removal ◽  
Exchange Process ◽  
Cationic Dyes ◽  
Carboxyl Groups ◽  
Maximum Adsorption Capacity ◽  
Equilibrium Isotherm ◽  
Ion Exchange Process ◽  
Dyes And Pigments

Background: Color effluents generated from the production industry of dyes and pigments and their use in different applications such as textile, paper, leather tanning, and food industries, are high in color and contaminants that damage the aquatic life. It is estimated that about 105 of various commercial dyes and pigments amounted to 7×105 tons are produced annually worldwide. Ultimately, about 10–15% is wasted into the effluents of the textile industry. Chitin is abundant in nature, and it is a linear biopolymer containing acetamido and hydroxyl groups amenable to render it atmospheric by introducing amino and carboxyl groups, hence able to remove different classes of toxic organic dyes from colored effluents. Methods: Chitin was chemically modified to render it amphoteric via the introduction of carboxyl and amino groups. The amphoteric chitin has been fully characterized by FTIR, TGA-DTG, elemental analysis, SEM, and point of zero charge. Adsorption optimization for both anionic and cationic dyes was made by batch adsorption method, and the conditions obtained were used for studying the kinetics and thermodynamics of adsorption. Results: The results of dye removal proved that the adsorbent was proven effective in removing both anionic and cationic dyes (Acid Red 1 and methylene blue (MB)), at their respective optimum pHs (2 for acid and 8 for cationic dye). The equilibrium isotherm at room temperature fitted the Freundlich model for MB, and the maximum adsorption capacity was 98.2 mg/g using 50 mg/l of MB, whereas the equilibrium isotherm fitted the Freundlich and Langmuir model for AR1 and the maximum adsorption capacity was 128.2 mg/g. Kinetic results indicate that the adsorption is a two-step diffusion process for both dyes as indicated by the values of the initial adsorption factor (Ri) and follows the pseudo-second-order kinetics. Also, thermodynamic calculations suggest that the adsorption of AR1 on the amphoteric chitin is an endothermic process from 294 to 303 K. The result indicated that the mechanism of adsorption is chemisorption via an ion-exchange process. Also, recycling of the adsorbent was easy, and its reuse for dye removal was effective. Conclusion: New amphoteric chitin has been successfully synthesized and characterized. This resin material, which contains amino and carboxyl groups, is novel as such chemical modification of chitin hasn’t been reported. The amphoteric chitin has proven effective in decolorizing aqueous solution from anionic and cationic dyes. The adsorption behavior of amphoteric chitin is believed to follow chemical adsorption with an ion-exchange process. The recycling process for few cycles indicated that the loaded adsorbent could be regenerated by simple treatment and retested for removing anionic and cationic dyes without any loss in the adsorbability. Therefore, the study introduces a new and easy approach for the development of amphoteric adsorbent for application in the removal of different dyes from aqueous solutions.

Chromate ion-exchange process at alkaline pH

1986 ◽  
Vol 20 (9) ◽  
pp. 1177-1184 ◽  
Author(s):  
Arup K. Sengupta ◽  
Dennis Clifford ◽  
Suresh Subramonian
Keyword(s):  
Ion Exchange ◽  
Exchange Process ◽  
Alkaline Ph ◽  
Ion Exchange Process ◽  
Chromate Ion

The Application of ß“-Alumina As A Solid State Laser Host

1985 ◽  
Vol 60 ◽  
Author(s):  
J. D. Barrie ◽  
D. L. Yang ◽  
B. Dunn ◽  
O. M. Stafsudd
Keyword(s):  
Optical Properties ◽  
Solid State ◽  
Ion Exchange ◽  
Exchange Process ◽  
Laser Action ◽  
Solid State Laser ◽  
Host Crystal ◽  
State Laser ◽  
Ion Exchange Process ◽  
Single Host

AbstractIon exchanged ß“-aluminas display a number of interesting optical properties which suggest that the material is well suited for application as a solid state laser host. Small platelets of Nd3+ Ion exchanged β“-alumina exhibit laser action with gain coefficients many times greater than YAG. The versatility of the ion exchange process enables one to form a wide variety of compounds with different active ions and concentrations, thereby allowing the study of many different effects within a single host crystal.

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