ion exchange (iex) processchinaionexchange.com/pic/other/2013-09-04-23-00-561.pdf · ion exchange...
TRANSCRIPT
![Page 1: Ion Exchange (IEX) Processchinaionexchange.com/pic/other/2013-09-04-23-00-561.pdf · Ion Exchange (IEX) Process Mohammad Mahdi Bazri Chemical and Biological Engineering Department](https://reader035.vdocument.in/reader035/viewer/2022081611/5f0531417e708231d411bc65/html5/thumbnails/1.jpg)
Ion Exchange (IEX) Process
Mohammad Mahdi BazriChemical and Biological Engineering Department
University of British ColumbiaVancouver, BC, CANADA
December 2011-Tehran-Iran
![Page 2: Ion Exchange (IEX) Processchinaionexchange.com/pic/other/2013-09-04-23-00-561.pdf · Ion Exchange (IEX) Process Mohammad Mahdi Bazri Chemical and Biological Engineering Department](https://reader035.vdocument.in/reader035/viewer/2022081611/5f0531417e708231d411bc65/html5/thumbnails/2.jpg)
Water analysis
2
2
![Page 3: Ion Exchange (IEX) Processchinaionexchange.com/pic/other/2013-09-04-23-00-561.pdf · Ion Exchange (IEX) Process Mohammad Mahdi Bazri Chemical and Biological Engineering Department](https://reader035.vdocument.in/reader035/viewer/2022081611/5f0531417e708231d411bc65/html5/thumbnails/3.jpg)
Introduction3
Initially developed around 5o’s A powerful technology to soften and demineralise water Industrial and domestic applications Industrial and drinking water treatment applications Chemistry and chromatography
![Page 4: Ion Exchange (IEX) Processchinaionexchange.com/pic/other/2013-09-04-23-00-561.pdf · Ion Exchange (IEX) Process Mohammad Mahdi Bazri Chemical and Biological Engineering Department](https://reader035.vdocument.in/reader035/viewer/2022081611/5f0531417e708231d411bc65/html5/thumbnails/4.jpg)
Applications Water Treatment Food Industry
• Sugar industry• Dairy products
Chemical Industry• Metal recovery• Selective removal of various elements
Pharmaceutical Industry• Extract and purification of drug
Other Applications• Mining • Enzyme immobilization• Analytical chromatography
![Page 5: Ion Exchange (IEX) Processchinaionexchange.com/pic/other/2013-09-04-23-00-561.pdf · Ion Exchange (IEX) Process Mohammad Mahdi Bazri Chemical and Biological Engineering Department](https://reader035.vdocument.in/reader035/viewer/2022081611/5f0531417e708231d411bc65/html5/thumbnails/5.jpg)
Fundamentals5
Exchange of the ions on the resin structure with the ones present in the solution
Schematic cation and anion exchange resin beads
![Page 6: Ion Exchange (IEX) Processchinaionexchange.com/pic/other/2013-09-04-23-00-561.pdf · Ion Exchange (IEX) Process Mohammad Mahdi Bazri Chemical and Biological Engineering Department](https://reader035.vdocument.in/reader035/viewer/2022081611/5f0531417e708231d411bc65/html5/thumbnails/6.jpg)
Fundamentals6
Exchange of the ions on the resin structure with the ones present in the solution
Schematic cation and anion exchange resin beads
![Page 7: Ion Exchange (IEX) Processchinaionexchange.com/pic/other/2013-09-04-23-00-561.pdf · Ion Exchange (IEX) Process Mohammad Mahdi Bazri Chemical and Biological Engineering Department](https://reader035.vdocument.in/reader035/viewer/2022081611/5f0531417e708231d411bc65/html5/thumbnails/7.jpg)
Resin Structure7
Polystyrene
Polyacrylic Weakly anionic
Strongly anionic
DVB
![Page 8: Ion Exchange (IEX) Processchinaionexchange.com/pic/other/2013-09-04-23-00-561.pdf · Ion Exchange (IEX) Process Mohammad Mahdi Bazri Chemical and Biological Engineering Department](https://reader035.vdocument.in/reader035/viewer/2022081611/5f0531417e708231d411bc65/html5/thumbnails/8.jpg)
Resin Types8
Remove hardness/alkalinity and other cations:
• Weakly Acidic Cation Exchange Resins (-COOH)• Strongly Acidic Cation Exchange Resins (-HSO3
- )
Remove anions (NO3, SO4, HCO3) and NOM:
• Weakly Basic Anion Exchange Resins (-N(CH3)2)• Strongly Basic Anion Exchange resins (-N(CH3)3 OH)
o Type I (trimethyl amine)o Type II (dimethyl ethanol amine, lower basicity, better
regenerability)
![Page 9: Ion Exchange (IEX) Processchinaionexchange.com/pic/other/2013-09-04-23-00-561.pdf · Ion Exchange (IEX) Process Mohammad Mahdi Bazri Chemical and Biological Engineering Department](https://reader035.vdocument.in/reader035/viewer/2022081611/5f0531417e708231d411bc65/html5/thumbnails/9.jpg)
Terminologies: capacity
Exchange capacity (eq/L)
The number of ion exchange sites
Operating Capacity (useful capacity)
The number of ion exchange sites where exchange has really taken place during the loading run.
Operating capacity < Total capacity
![Page 10: Ion Exchange (IEX) Processchinaionexchange.com/pic/other/2013-09-04-23-00-561.pdf · Ion Exchange (IEX) Process Mohammad Mahdi Bazri Chemical and Biological Engineering Department](https://reader035.vdocument.in/reader035/viewer/2022081611/5f0531417e708231d411bc65/html5/thumbnails/10.jpg)
The typical operating capacity of a weak base anion exchange resin is 70 to 90 % of the total capacity.
For weak acid cation resin, operating capacity depends on several parameters, so there is no such simple estimate.
The typical operating capacity of SAC and SBA resins is about 40 to 60 % of their total capacity.
![Page 11: Ion Exchange (IEX) Processchinaionexchange.com/pic/other/2013-09-04-23-00-561.pdf · Ion Exchange (IEX) Process Mohammad Mahdi Bazri Chemical and Biological Engineering Department](https://reader035.vdocument.in/reader035/viewer/2022081611/5f0531417e708231d411bc65/html5/thumbnails/11.jpg)
Operating capacity depends on:
Concentration and type of ions to be adsorbed
Service flow rate
Temperature
Type, concentration and quantity of regenerant
Type of regeneration process (co-flow, reverse flow)
Bed depth (reverse flow regeneration only)
Particle size of the ion exchange resins
Performance data and computer programs
![Page 12: Ion Exchange (IEX) Processchinaionexchange.com/pic/other/2013-09-04-23-00-561.pdf · Ion Exchange (IEX) Process Mohammad Mahdi Bazri Chemical and Biological Engineering Department](https://reader035.vdocument.in/reader035/viewer/2022081611/5f0531417e708231d411bc65/html5/thumbnails/12.jpg)
Terminologies: exchange zoneThe area between fully regenerated and fully exhausted resin is called exchange zone or reaction zone.
Ion leakage endpoint of run
![Page 13: Ion Exchange (IEX) Processchinaionexchange.com/pic/other/2013-09-04-23-00-561.pdf · Ion Exchange (IEX) Process Mohammad Mahdi Bazri Chemical and Biological Engineering Department](https://reader035.vdocument.in/reader035/viewer/2022081611/5f0531417e708231d411bc65/html5/thumbnails/13.jpg)
Weak acid and weak base resins are sensitive to flow rate, higher flow rate longer reaction zones.
SAC and SBA resins are less sensitive to flow rate.
Shorter reaction zone, higher utilization of total capacity , higher achievable operating capacity.
Fine resins have generally higher kinetics: shorter path for the ions to travel inside the resin beads
![Page 14: Ion Exchange (IEX) Processchinaionexchange.com/pic/other/2013-09-04-23-00-561.pdf · Ion Exchange (IEX) Process Mohammad Mahdi Bazri Chemical and Biological Engineering Department](https://reader035.vdocument.in/reader035/viewer/2022081611/5f0531417e708231d411bc65/html5/thumbnails/14.jpg)
Water SofteningRemove hardness mainly Ca+2 and Mg+2
Strongly acidic cation exchange resin in Na+ form
Applications• Domestic and industrial water boilers• Laundries, Dish washer• Soft drink plants
Resins used• Amberlite IR120 Na; SR1L Na , AmberjetTM 1000 Na
Treated water quality• Residual hardness < 0.02 meq/L (1 mg/L as CaCO3)
with reverse flow regeneration Regeneration: brine (NaCl as a 10 % solution)
![Page 15: Ion Exchange (IEX) Processchinaionexchange.com/pic/other/2013-09-04-23-00-561.pdf · Ion Exchange (IEX) Process Mohammad Mahdi Bazri Chemical and Biological Engineering Department](https://reader035.vdocument.in/reader035/viewer/2022081611/5f0531417e708231d411bc65/html5/thumbnails/15.jpg)
Water Softening
SAC (Na+)
![Page 16: Ion Exchange (IEX) Processchinaionexchange.com/pic/other/2013-09-04-23-00-561.pdf · Ion Exchange (IEX) Process Mohammad Mahdi Bazri Chemical and Biological Engineering Department](https://reader035.vdocument.in/reader035/viewer/2022081611/5f0531417e708231d411bc65/html5/thumbnails/16.jpg)
Water Softening
The water salinity is unchanged, only the hardness is replaced by sodium.
Sodium salts have much higher solubility, so they don't form scale or deposits.
A small residual hardness is still there, its value depends on regeneration conditions.
![Page 17: Ion Exchange (IEX) Processchinaionexchange.com/pic/other/2013-09-04-23-00-561.pdf · Ion Exchange (IEX) Process Mohammad Mahdi Bazri Chemical and Biological Engineering Department](https://reader035.vdocument.in/reader035/viewer/2022081611/5f0531417e708231d411bc65/html5/thumbnails/17.jpg)
Water De-alkalizationRemove bicarbonate and temporary associated hardnessWeakly acidic cation exchange resin in H+ form
Applications• Beverages, Soft drink plants, municipal water
Resins used• Amberlite IRC86 (industrial), Amberlite PWC13
(municipal), ImacTM HP333 and HP335 (household filter cartridges)
Treated water quality• Endpoint at 10 % of the raw water alkalinity• Contains CO2 which requires degasifier
Regeneration: Acid (preferably HCl at 5 % concentration)
![Page 18: Ion Exchange (IEX) Processchinaionexchange.com/pic/other/2013-09-04-23-00-561.pdf · Ion Exchange (IEX) Process Mohammad Mahdi Bazri Chemical and Biological Engineering Department](https://reader035.vdocument.in/reader035/viewer/2022081611/5f0531417e708231d411bc65/html5/thumbnails/18.jpg)
Degasification2 R-H + Ca (HCO3)2 R2-Ca+2 H+ + 2 HCO3
-
H+ + HCO3CO2 + H2O (CO2 solubility @ 25 : 1.5 g/L)
• Reduce the ionic load thus regenerant• CO2 residual 10 mg/L
![Page 19: Ion Exchange (IEX) Processchinaionexchange.com/pic/other/2013-09-04-23-00-561.pdf · Ion Exchange (IEX) Process Mohammad Mahdi Bazri Chemical and Biological Engineering Department](https://reader035.vdocument.in/reader035/viewer/2022081611/5f0531417e708231d411bc65/html5/thumbnails/19.jpg)
Degasifier
![Page 20: Ion Exchange (IEX) Processchinaionexchange.com/pic/other/2013-09-04-23-00-561.pdf · Ion Exchange (IEX) Process Mohammad Mahdi Bazri Chemical and Biological Engineering Department](https://reader035.vdocument.in/reader035/viewer/2022081611/5f0531417e708231d411bc65/html5/thumbnails/20.jpg)
Degasifier• Atmospheric degasser (bicarbonate + CO2 < 0.6
meq/L)
• Forced draft degasser
• Thermal degasser, (O2-CO2)
• Vacuum degasser, (1-5 kPa, O2-CO2)
• Membrane degasser
Small size, for RO permeates with low pH and high
free CO2, small demineralization systems
![Page 21: Ion Exchange (IEX) Processchinaionexchange.com/pic/other/2013-09-04-23-00-561.pdf · Ion Exchange (IEX) Process Mohammad Mahdi Bazri Chemical and Biological Engineering Department](https://reader035.vdocument.in/reader035/viewer/2022081611/5f0531417e708231d411bc65/html5/thumbnails/21.jpg)
Water DemineralizationRemove all the ions from water CIX (H+) - AIX (OH-)Treated water contains only traces of sodium and silica
Applications• Beverages, soft drink plants, municipal water
Resins used• Amberlite IRC86 (WAC), Amberlite IR120 or Amberjet
1000 or 1200 (SBA), Amberlite IRA96 or IRA67 (WBA), Amberlite IRA402 or Amberjet 4200 or 4600 (SBA)
Treated water quality (lower than RO or Distillation)• Conductivity: 0.2 to 1 µS/cm • Residual silica 5 to 50 µg/L
Regeneration: strong acid and caustic soda
![Page 22: Ion Exchange (IEX) Processchinaionexchange.com/pic/other/2013-09-04-23-00-561.pdf · Ion Exchange (IEX) Process Mohammad Mahdi Bazri Chemical and Biological Engineering Department](https://reader035.vdocument.in/reader035/viewer/2022081611/5f0531417e708231d411bc65/html5/thumbnails/22.jpg)
Operational aspect Column Operation
• Co-flow regeneration• Counter flow regeneration
Batch (well-mixed)• MIEX, other IEX resins
Fluidized or Suspended • MIEX or any other IEX resin
![Page 23: Ion Exchange (IEX) Processchinaionexchange.com/pic/other/2013-09-04-23-00-561.pdf · Ion Exchange (IEX) Process Mohammad Mahdi Bazri Chemical and Biological Engineering Department](https://reader035.vdocument.in/reader035/viewer/2022081611/5f0531417e708231d411bc65/html5/thumbnails/23.jpg)
Column Operation
23
23
![Page 24: Ion Exchange (IEX) Processchinaionexchange.com/pic/other/2013-09-04-23-00-561.pdf · Ion Exchange (IEX) Process Mohammad Mahdi Bazri Chemical and Biological Engineering Department](https://reader035.vdocument.in/reader035/viewer/2022081611/5f0531417e708231d411bc65/html5/thumbnails/24.jpg)
Column operationFreeboard columns
• Air or water hold down vessels (requires inert resin)• Stratified (weak/strong mix) vessels• Split flow regeneration unit (avoid disturb, hard to adjust)
Packed bed columns• Very little extra space, Smaller and cheaper• Usually higher depth• Floating bed with almost not fluidization • WAC/SAC and WBA/SBA are separated via a plate with
nozzlesMix beds
• Hard to regenerate • Not very efficient due to shallow depth
![Page 25: Ion Exchange (IEX) Processchinaionexchange.com/pic/other/2013-09-04-23-00-561.pdf · Ion Exchange (IEX) Process Mohammad Mahdi Bazri Chemical and Biological Engineering Department](https://reader035.vdocument.in/reader035/viewer/2022081611/5f0531417e708231d411bc65/html5/thumbnails/25.jpg)
25
Practical limitations
Affinity difference
Effective for low concentrations (brackish or sea water )
Only ionized targets can be eliminated
Regeneration (cost, environmental burden)
![Page 26: Ion Exchange (IEX) Processchinaionexchange.com/pic/other/2013-09-04-23-00-561.pdf · Ion Exchange (IEX) Process Mohammad Mahdi Bazri Chemical and Biological Engineering Department](https://reader035.vdocument.in/reader035/viewer/2022081611/5f0531417e708231d411bc65/html5/thumbnails/26.jpg)
26
Practical limitations
Affinity difference
Effective for low concentrations (brackish or sea water )
Only ionized targets can be eliminated
Regeneration (cost, environmental burden)
![Page 27: Ion Exchange (IEX) Processchinaionexchange.com/pic/other/2013-09-04-23-00-561.pdf · Ion Exchange (IEX) Process Mohammad Mahdi Bazri Chemical and Biological Engineering Department](https://reader035.vdocument.in/reader035/viewer/2022081611/5f0531417e708231d411bc65/html5/thumbnails/27.jpg)
Regenerant
27
27
• NaCl or KCl (10% ) for SAC and SBA• HCl for nitrate removal• Demineralization (SAC)
o HCl (5%), efficient no precipitationo H2SO4 (0.7-6%), cheaper and easier to store , less
efficient, potential for precipitationo HNO3, exothermic reaction, dangerous, not
recommended
• De-alkalization WAC , HCl, H2SO4 (0.7%)• SBA , NaOH (4%)• WBA, NaOH, NH3, bicarbonate
![Page 28: Ion Exchange (IEX) Processchinaionexchange.com/pic/other/2013-09-04-23-00-561.pdf · Ion Exchange (IEX) Process Mohammad Mahdi Bazri Chemical and Biological Engineering Department](https://reader035.vdocument.in/reader035/viewer/2022081611/5f0531417e708231d411bc65/html5/thumbnails/28.jpg)
Regeneration
28
28
Co-flow regenerationReverse exchange (displacement of low affinity with high affinity ions)Requires large excess of solution to fully regenerateLeakage in the next run
Counter-flow regenerationHigher reg. Efficiency, lower reg. quantityLower elution leakageLower resin inventoryImproved water qualityHard to keep the resin bed consolidatedResin mixingPurity of the regenerant
![Page 29: Ion Exchange (IEX) Processchinaionexchange.com/pic/other/2013-09-04-23-00-561.pdf · Ion Exchange (IEX) Process Mohammad Mahdi Bazri Chemical and Biological Engineering Department](https://reader035.vdocument.in/reader035/viewer/2022081611/5f0531417e708231d411bc65/html5/thumbnails/29.jpg)
Regeneration steps
29
29
• Backwash the bed to remove the suspended solids (co-flow)• Regenerant injection at low flow-rate (20-40 minutes)• Rinsing • Washing with service water
Regeneration ratioAmberjet 1200 regenerated with 55 g HCl per litreoperating capacity : 1.20 eq/L 55 g/L HCl = 55/36.5 = 1.507 eq/L Regenerant ratio = 1.507/1.20 = 1.26 = 126 %
![Page 30: Ion Exchange (IEX) Processchinaionexchange.com/pic/other/2013-09-04-23-00-561.pdf · Ion Exchange (IEX) Process Mohammad Mahdi Bazri Chemical and Biological Engineering Department](https://reader035.vdocument.in/reader035/viewer/2022081611/5f0531417e708231d411bc65/html5/thumbnails/30.jpg)
Regeneration ratio
30
30
• WAC resins: A safe number is 105 to 110 %.
• WBA resins: 115 to 140 %, due to presence of some strongly basic functional groups.
• SAC resins: Regenerated with sulphuric acid, larger excess (at least 40%) than those regenerated with HCl.
• SBA resins: Depends on the type of SBA resin (styrenictype I, type II or acrylic resins). Not economical to regenerate the resin totally.
• SAC and SBA resins: Larger excess than their weak counterparts.
![Page 31: Ion Exchange (IEX) Processchinaionexchange.com/pic/other/2013-09-04-23-00-561.pdf · Ion Exchange (IEX) Process Mohammad Mahdi Bazri Chemical and Biological Engineering Department](https://reader035.vdocument.in/reader035/viewer/2022081611/5f0531417e708231d411bc65/html5/thumbnails/31.jpg)
Thoroughfare regeneration
31
31
![Page 32: Ion Exchange (IEX) Processchinaionexchange.com/pic/other/2013-09-04-23-00-561.pdf · Ion Exchange (IEX) Process Mohammad Mahdi Bazri Chemical and Biological Engineering Department](https://reader035.vdocument.in/reader035/viewer/2022081611/5f0531417e708231d411bc65/html5/thumbnails/32.jpg)
Throughput32
Volume produced until the cartridge has to be replaced
• Salinity of the feed water • Volume of resin in the cartridge (throughput is
approximately proportional to resin volume) • Type of resin used • Quality and efficiency of the off-site regeneration process • Endpoint (conductivity at which the unit is considered
exhausted)
With good resins and good regeneration, the throughput can be approximately calculated as:
Throughput [L] = 500 × (Resin volume [L]) / (Salinity [meq/L])
![Page 33: Ion Exchange (IEX) Processchinaionexchange.com/pic/other/2013-09-04-23-00-561.pdf · Ion Exchange (IEX) Process Mohammad Mahdi Bazri Chemical and Biological Engineering Department](https://reader035.vdocument.in/reader035/viewer/2022081611/5f0531417e708231d411bc65/html5/thumbnails/33.jpg)
Kinetics33
![Page 34: Ion Exchange (IEX) Processchinaionexchange.com/pic/other/2013-09-04-23-00-561.pdf · Ion Exchange (IEX) Process Mohammad Mahdi Bazri Chemical and Biological Engineering Department](https://reader035.vdocument.in/reader035/viewer/2022081611/5f0531417e708231d411bc65/html5/thumbnails/34.jpg)
Kinetics34
In normal practice, solution is withdrawn at the outlet of the column so the equilibrium is permanently shifted to the right.
R-A+ + B+ R-B+ + A+
Na+-form SAC resins initially remove divalent cations fromwater, but not other monovalent cations (selectivity)
2 R-Na + Ca+2 (HCO3–)2 R2-Ca + 2 Na+ HCO3
–
![Page 35: Ion Exchange (IEX) Processchinaionexchange.com/pic/other/2013-09-04-23-00-561.pdf · Ion Exchange (IEX) Process Mohammad Mahdi Bazri Chemical and Biological Engineering Department](https://reader035.vdocument.in/reader035/viewer/2022081611/5f0531417e708231d411bc65/html5/thumbnails/35.jpg)
Selectivity35
WAC (H-form) resin removes only hardness, and only when alkalinity is present.
For softening WAC resin must first be converted to the Na-form with an alkali.
OH– form resins are not used to remove bicarbonate or carbonate from neutral water when it contains hardness (precipitation risk)
![Page 36: Ion Exchange (IEX) Processchinaionexchange.com/pic/other/2013-09-04-23-00-561.pdf · Ion Exchange (IEX) Process Mohammad Mahdi Bazri Chemical and Biological Engineering Department](https://reader035.vdocument.in/reader035/viewer/2022081611/5f0531417e708231d411bc65/html5/thumbnails/36.jpg)
Selectivity36
OH-form resin reacts with very weak acids, such as silica (SiO2) or boric acid (H3BO3).
Special SBA resins with different functional groups are used with an increased nitrate, sulphate, perchlorateselectivity.
R-OH + H+HSiO3– R-HSiO3 + H+OH–
![Page 37: Ion Exchange (IEX) Processchinaionexchange.com/pic/other/2013-09-04-23-00-561.pdf · Ion Exchange (IEX) Process Mohammad Mahdi Bazri Chemical and Biological Engineering Department](https://reader035.vdocument.in/reader035/viewer/2022081611/5f0531417e708231d411bc65/html5/thumbnails/37.jpg)
Selectivity37
![Page 38: Ion Exchange (IEX) Processchinaionexchange.com/pic/other/2013-09-04-23-00-561.pdf · Ion Exchange (IEX) Process Mohammad Mahdi Bazri Chemical and Biological Engineering Department](https://reader035.vdocument.in/reader035/viewer/2022081611/5f0531417e708231d411bc65/html5/thumbnails/38.jpg)
Selectivity38
![Page 39: Ion Exchange (IEX) Processchinaionexchange.com/pic/other/2013-09-04-23-00-561.pdf · Ion Exchange (IEX) Process Mohammad Mahdi Bazri Chemical and Biological Engineering Department](https://reader035.vdocument.in/reader035/viewer/2022081611/5f0531417e708231d411bc65/html5/thumbnails/39.jpg)
Selectivity39
![Page 40: Ion Exchange (IEX) Processchinaionexchange.com/pic/other/2013-09-04-23-00-561.pdf · Ion Exchange (IEX) Process Mohammad Mahdi Bazri Chemical and Biological Engineering Department](https://reader035.vdocument.in/reader035/viewer/2022081611/5f0531417e708231d411bc65/html5/thumbnails/40.jpg)
Selectivity40
![Page 41: Ion Exchange (IEX) Processchinaionexchange.com/pic/other/2013-09-04-23-00-561.pdf · Ion Exchange (IEX) Process Mohammad Mahdi Bazri Chemical and Biological Engineering Department](https://reader035.vdocument.in/reader035/viewer/2022081611/5f0531417e708231d411bc65/html5/thumbnails/41.jpg)
Selectivity41
![Page 42: Ion Exchange (IEX) Processchinaionexchange.com/pic/other/2013-09-04-23-00-561.pdf · Ion Exchange (IEX) Process Mohammad Mahdi Bazri Chemical and Biological Engineering Department](https://reader035.vdocument.in/reader035/viewer/2022081611/5f0531417e708231d411bc65/html5/thumbnails/42.jpg)
Selectivity42
![Page 43: Ion Exchange (IEX) Processchinaionexchange.com/pic/other/2013-09-04-23-00-561.pdf · Ion Exchange (IEX) Process Mohammad Mahdi Bazri Chemical and Biological Engineering Department](https://reader035.vdocument.in/reader035/viewer/2022081611/5f0531417e708231d411bc65/html5/thumbnails/43.jpg)
Selectivity43
![Page 44: Ion Exchange (IEX) Processchinaionexchange.com/pic/other/2013-09-04-23-00-561.pdf · Ion Exchange (IEX) Process Mohammad Mahdi Bazri Chemical and Biological Engineering Department](https://reader035.vdocument.in/reader035/viewer/2022081611/5f0531417e708231d411bc65/html5/thumbnails/44.jpg)
Nitrate removal
44
44
RSBA-Cl + NO3- RSBA-NO3 + Cl-
SAB (Cl-)
Amberlite PWA5 –PWA15Purolite A520E
SIR-100-HP
Methemoglobinemia, also known as “blue baby syndrome
![Page 45: Ion Exchange (IEX) Processchinaionexchange.com/pic/other/2013-09-04-23-00-561.pdf · Ion Exchange (IEX) Process Mohammad Mahdi Bazri Chemical and Biological Engineering Department](https://reader035.vdocument.in/reader035/viewer/2022081611/5f0531417e708231d411bc65/html5/thumbnails/45.jpg)
Nitrate removal
45
45
Anion resins are less dense and require a backwash flow rate about 1/3 that of softening resin.
salt concentrations are typically applied at 4 percent to 8 percent.
Regenerant levels must be high enough in nitrate removal to ensure that nitrate leakages are kept to acceptably low levels.
![Page 46: Ion Exchange (IEX) Processchinaionexchange.com/pic/other/2013-09-04-23-00-561.pdf · Ion Exchange (IEX) Process Mohammad Mahdi Bazri Chemical and Biological Engineering Department](https://reader035.vdocument.in/reader035/viewer/2022081611/5f0531417e708231d411bc65/html5/thumbnails/46.jpg)
Natural Organic Matter
46
46
Removal Mechanisms by IEX resins :• Adsorption (blocking exchange sites)• Size Exclusion (blocking exchange sites)• Ion exchange (favourable)
Easier regeneration (lower conc., lower flow rate/contact time)
Hydrophobic Hydrophilic
Neutral
Very Complex Mixture
![Page 47: Ion Exchange (IEX) Processchinaionexchange.com/pic/other/2013-09-04-23-00-561.pdf · Ion Exchange (IEX) Process Mohammad Mahdi Bazri Chemical and Biological Engineering Department](https://reader035.vdocument.in/reader035/viewer/2022081611/5f0531417e708231d411bc65/html5/thumbnails/47.jpg)
IEX for NOM removal47
• A relatively recent concept
• Polystyrene resins are more hydrophobic /selective thanPolyacrylic resins.
• Polystyrene resins have shown stronger affinity witharomatic moieties.
• Competition kinetics exist between NOM and inorganicIons
SO4 > NO3 > NOM > Cl > HCO3 > OH > F
![Page 48: Ion Exchange (IEX) Processchinaionexchange.com/pic/other/2013-09-04-23-00-561.pdf · Ion Exchange (IEX) Process Mohammad Mahdi Bazri Chemical and Biological Engineering Department](https://reader035.vdocument.in/reader035/viewer/2022081611/5f0531417e708231d411bc65/html5/thumbnails/48.jpg)
Important characteristics of resin48
• Functional group (strong or weak basic)
• Backbone structure (acrylic or styrene)
• Resin water content
• Physical form (gel or macroporous)
• Bead size
• Treatment process
![Page 49: Ion Exchange (IEX) Processchinaionexchange.com/pic/other/2013-09-04-23-00-561.pdf · Ion Exchange (IEX) Process Mohammad Mahdi Bazri Chemical and Biological Engineering Department](https://reader035.vdocument.in/reader035/viewer/2022081611/5f0531417e708231d411bc65/html5/thumbnails/49.jpg)
IEX for NOM removal49
• Efficient reactor design
• Enforce IEX as the dominant removal mechanism• Shorter contact time
• Combined different IEX resins
• Enhance the NOM removal• Combination of weakly-strongly basic IEX resin• Combination of Polystyrene-Polyacrylic IEX resins
• Microbial growth on IEX resins
• Disinfection• set-up configuration