Softened water equipment resin articles

Views: 0     Author: Site Editor     Publish Time: 2010-01-02      Origin: Site

Ion exchange resin (ionresin) the matrix (matrix), the main raw materials are styrene and acrylic acid (ester) two categories, which were produced with the crosslinker divinylbenzene polymerization to form a long main chain and cross-linking cross-chain structure of polymer backbone network. Styrene resin is first used, acrylic resin is used later.

Adsorption properties of these two types of resin are good, but have different characteristics. Acrylic resin to the majority of ionic exchange adsorption of pigment, decolorizing capacity, but also adsorbed more easily washed, easy regeneration, the sugar can be used as the main decolorizing resin. Good adsorption of aromatic styrene resin material, good absorption of polyphenols in juice color (including the negatively charged or not charged); but regeneration is more difficult elution. Jiangsu color can match Resin Co., Ltd. order thinking, therefore, the first sugar decolorization of crude acrylic resin, styrene resin fine then bleaching can give full play to the strengths of both.

Resin crosslinking degree of polymerization of the resin matrix that is used when the percentage of divinylbenzene, the nature of the resin has a great influence. Typically, cross-linked polymer resin comparatively high close, fastness and durable, high-density, low internal gap, the stronger the ion selectivity; and low cross-linking resin and porous, and greater ability decolorization , reaction speed, but the expansion of work with greater mechanical strength lower, more brittle and fragile. Industrial applications of ion resin crosslinking degree is generally not less than 4%; for decolorization resin crosslinking generally no more than 8%; pure resin for the adsorption of inorganic ions, the higher its degree of crosslinking can be

Water treatment ion exchange resins in great demand, accounting for ion exchange resins yield of 90%, for the various ions in water removal. Currently, the maximum consumption of ion exchange resin is used in the power plant's water treatment, followed by atomic energy, semiconductors, electronics industries.

Natural water contains various salts, these salts dissolve as cations and anions, mainly Ca 2 +, Mg 2 +, Na + and HCO3-, SO4 2 -, Cl - and so on. Water containing these salts, evaporation in the heating process (such as boiler water), water Ca 2 +, Mg 2 + and other ions constant and some anion binding in water into insoluble material and precipitation, and generate scale (commonly known as rust water), there are other high-priced metal ions such as iron, aluminum, manganese, etc. (because of content very low, although into the scale, is negligible), be removed. Hence the need for water softening treatment. Softening equipment is widely used in industrial and civil softened water preparation, such as boiler water, heating, air-conditioning system to add water, water and other quality of life.

Ion exchange softening is a softening of the simplest methods, the method characterized by: no acidic water, recycling agent for industrial salt, equipment, facilities for simple corrosion.

Softening system is composed of multiple valves (or manually screen), the controller, resin tank, salt box form, multi-valve design in the same valve in the valve more than one pathway. Controller based on pre-set procedures, instructions to the occurrence of multiple valves, multiple valves automatically switch each valve to achieve the operation, backwashing, regeneration, is washed until all processes. Manual operation screen is to use high-quality PVC or UPVC pipe and fitting material formed a user interface, it requires staff for all valves, all processes are subject to manual.

In addition to the styrene and acrylic acid the two series, ion exchange resins can also be made from other organic monomers. Such as phenolic (FP), epoxy (EPA), Department of vinyl pyridine (VP), urea-formaldehyde system (UA) and so on.

Ion resin often divided into gel and macroporous types.

Gel-type polymer resin matrix, in dry conditions is not within the pores. It is when the swelling in water absorption in the macromolecular chain link is formed between the fine pores, often referred to as micro holes (micro-pore) ( The average pore size of wet resin 2 ~ 4nm (2 × 10-6 ~ 4 × 10-6mm).

Such resins are more suitable for the adsorption of inorganic ions, and their smaller diameter, usually 0.3 ~ 0.6nm. Such resins can not be adsorbed molecules of organic substances, the latter due to a larger size, such as protein molecular diameter of 5 ~ 20nm, can not enter the pores in the microstructure of these resins.

Macroporous resin, are added in the polymerization porogen to form a porous sponge-like structure of the skeleton, the inside has a large number of permanent micropores, and then made into the exchange groups. It co-exist with tiny holes and large mesh (macro-pore), wetting resin pore size up to 100 ~ 500nm, the size and number can be controlled at the time of manufacture. Pore surface area can increase to more than 1000m2 / g. Jiangsu color can match Resin Co., Ltd. order thinking, not only for the ion exchange provides a good contact condition, reducing the ion diffusion distance, but also increased the number of active site segment, through van der Waals attraction between molecules (van de Waals force) generated molecular adsorption, to as activated carbon adsorption as a variety of non-ionic substances, and expand its capabilities. Jiangsu color can match thinking of some non-finishing resin Limited exchange functional groups can macroporous resin adsorption, separation of various substances, such as chemical plant wastewater phenols.

Macroporous resin inside the pores are many and great, great surface area, active sites and more fast-ion diffusion, ion exchange speed is much faster than the gel-type resin is about about ten times faster. The role of speed when used with high efficiency, the required processing time. Macroporous resin, there are many advantages: anti-swelling, hard fragmentation, resistance to oxidation, wear, heat, and resistant to temperature changes, as well as easier on the adsorption of organic macromolecules and exchange, and therefore strong anti-pollution, and more easily regeneration.

Ion exchange resin ion exchange performance, reflected in its "ion exchange capacity", that is, dry resin per gram or per ml of wet resin can exchange the number of ions meq, meq / g (dry) or meq / mL (wet); when the ion is a price, that is, the number of mg mg equivalent number of molecules (of the divalent or multivalent ions, the former for the latter by ion valence). It has "total exchange capacity", "exchange capacity" and "renewable exchange capacity" and three kinds of representation.

1, the total exchange capacity, expressed per unit volume (weight or volume) resin ion exchange reaction can be carried out chemical groups of the total.

2, the exchange capacity, said that under certain conditions in a resin ion exchange capacity, and resin type and the total exchange capacity, as well as specific working conditions such as solution composition, flow rate, temperature and other factors.

3, regeneration exchange capacity, expressed in some regeneration dose achieved under the conditions of regeneration of the resin exchange capacity, indicating that the original chemical groups in the resin regeneration of the extent of recovery.

Typically, the regeneration of the total exchange capacity of the exchange capacity of 50 ~ 90% (normal control 70 ~ 80%), while the exchange capacity for the regeneration of the exchange capacity of 30 to 90% (in terms of recycled resin), the latter ratio is also known as resin utilization.

In actual use, the exchange capacity of ion exchange resins include adsorption capacity, but the proportion of the latter varies by resin structure. Are not yet calculated, respectively, in the specific design, the need to empirically modify the data and the actual run-time cross-checking.

Determination of ion exchange capacity generally inorganic ion. Small size of these ions can freely spread to resin body, and all within it the exchange group to react. In practical applications, the solution can often contain high molecular organic compounds, their larger size, poor access to micro holes in the resin, so the actual exchange capacity will be lower than the inorganic ions measured values. This type of resin, pore size and structure of the substances handled.

Ion exchange resins of different ions in solution have different affinity for their selective adsorption. Variety of ion exchange resin adsorption by the intensity level of a general law, but different resins may be slightly different. Main rule is as follows:

(1) of the cation adsorption.

Ions is usually preferential adsorption, and low adsorption is weak. Ions with similar price, the diameter of the larger ions are adsorbed stronger. Some cations can be adsorbed Jiangsu color resin Forsythe Co., finishing in the following order:

Fe3 +> Al3 +> Pb2 +> Ca2 +> Mg2 +> K +> Na +> H +

(2) anion adsorption

Strongly basic anion resin adsorption of inorganic acid radical general order:

SO42-> NO3-> Cl-> HCO3-> OH-

Weak base anion resin anion adsorption general sequence is as follows:

OH-> citrate 3 -> SO42-> tartrate 2 -> oxalate 2 -> PO43-> NO2-> Cl-> acetate -> HCO3-

(3) the adsorption of colored material

Sugar decolorization often use strong base anion resin, it intended to melanin (reaction products of reducing sugars and amino acids) and alkaline decomposition products of sugar absorption is stronger than the weak adsorption of the caramel. This is considered as the first two are usually negatively charged, while the caramel is very weak charge.

Typically, cross-linked resin with high selectivity on the ion strong selective macroporous resin is less than gel-type resin. This greater selectivity in dilute solution, in less concentrated solution.

Ion exchange resin particle size and the physical nature of the performance of its work and has great influence.

(1) resin particle size

Ion exchange resins are usually made of beads shaped small particles, its size is also important. Resin particles are smaller, higher speed of response, but fine particles of liquid through the resistance of larger, require higher work pressure; particularly high concentration of sugar solution viscosity, the impact more significant. Therefore, the resin particle size should be chosen appropriately. If the resin particle size of 0.2mm (about 70 mesh) below, will significantly increase the flow through the resistance, reducing flow and productivity.

Resin particle size measurement is usually wet sieve method, the resin swelling in full after the screening, the cumulative in 20,30,40,50 ... ... mesh stay online stock to 90% of the particles through their corresponding the sieve diameter, known as resin "effective size." Most general-purpose resin products, effective particle size between 0.4 ~ 0.6mm.

Resin particles that are uniform to uniform coefficient. It is the resin in the determination of "effective size" get the map coordinates of the stock of accumulated leave 40% of particles, corresponding to the sieve diameter and effective diameter ratio. Jiangsu color can match Resin Co., Ltd. order thinking, such as a resin (IR-120) of the effective diameter of 0.4 ~ 0.6mm, it is in the 20 mesh sieve, 30 mesh and 40 mesh sieve retained particles were: 18.3%, 41.1 %, and 31.3%, the calculated uniformity coefficient of 2.0.

(2) the density of resin

Resin in the dry density as true density. Wet resin per unit volume (with gaps between the particles) is called as the density of the weight. Resin cross-linking density and its degree and nature of the exchange group's. Typically, cross-linked high density and high resin, strongly acidic or strongly basic resin, the density higher than the weak acid or weak alkaline persons, while the macroporous resin density is lower. Jiangsu color can order such Forsythe Resin Co., Ltd., styrene gel-type strong acid cation resin, the true density 1.26g/mL, as the density of 0.85g/mL; and acrylic acid gel-type weak acid cation resin in the true density To 1.19g/mL, as the density of 0.75g/mL.

(3) the solubility of resin

Ion exchange resin should be insoluble. However, the process of resin in the synthesis of a mixture of relatively low degree of polymerization of the material, and resin decomposed substance dissolved in the work of running out of time. Crosslinked and more active groups containing resin, dissolved tend to be larger.

(4) swelling

Ion exchange resin contains a large number of hydrophilic groups, contact with water that is swelling. When the resin in the ion change, if cation resin from the H + to Na +, Cl-anion resin to the OH-, is due to the increase of ion diameter was expanded, increasing the volume of resin. Typically, low cross-linking degree of a larger expansion of the resin. Ion-exchange unit in the design must be considered when the swelling resin to meet the production run in the ion exchange resin, the resin volume change occurred.

(5) durability

Resin particles used are transferred, friction, expansion and contraction changes, there will be little long-term use after the loss and fragmentation, so resin should have high mechanical strength and wear resistance. Typically, a low degree of resin crosslinking easier to fragmentation, but more durable resin mainly determined by the uniformity of cross-linked structure and strength. Such as resin, has a high degree of crosslinking are, structural stability, the ability of repeated regeneration.

On the mechanism of ion exchange process, among other things, the most suitable water treatment technology, is a colloidal ion exchange resins as the material structure, which on the view that the ion exchange resin in the polymer surface, there are many and colloid similar double layer. Means that there are two ions, close to the surface layer of polymer as the inner ion-ion, in its opposite sign outside is a layer of ion layer. And colloidal nomenclature similar, we used the same symbols and the inner ion ion ion is called with the symbol opposite said counter-ion. So is the ion exchange resin in the solution of the original counter-ions and it kind of counter-ion exchange positions.

Colloidal structure under the concept of electric double layer of counter ion size of their activity can be divided into the fixed layer and diffusion layer. Poor performance of those activities, are tightly adsorbed on the surface of the plasma polymer layer, called the fixed layer, in the outside, those activities of a larger, gradually spread to the solution of the anti-ion layer, called the diffusion layer, because These anti-ion, like the atmosphere, like Earth, enveloped in a polymer surface, it is also known as the ionic atmosphere.

Rely on chemical bonding, the inner ion polymer backbone in a fixed layer of ions depend on different charges against the appeal is fixed with. In the diffusion layer, the counter ion, due to different charge less attractive, more significant thermal motion, so these anti-ions from the polymer surface, gradually spread to the solution of the phenomenon.

When the ion exchanger in aqueous solution containing electrolytes encountered when the electrolyte layer of its double role of the following:

⑴ exchange interaction. Anti-diffusion layer in the activities of ions in solution than the free, ion exchange, mainly in such counter-ions and counter ions in solution between the other, but not limited to this. By balancing the relationship between the counter ion in solution will first exchange to the diffusion layer, and then layer with a fixed position in the counter-ion exchange.

Diffusion layer in the ion energy at different locations are not equal, those and the inner layer farthest away from the biggest anti-ion energy, so they are the most lively, most likely, and other anti-ion exchange; and get closer to the inner layer from the counter-ion energy minimum, activity is poor. This multi-multi-acid or alkali similar to the multi-level ionization.

⑵ compression. When the salt concentration in solution increases, the diffusion layer can be compressed, so that part of the counter ion diffusion layer into a fixed counter-ion layer, diffusion layer smaller range of activities. This explains why when the concentration of regeneration solution is too large, not only can not improve the regeneration, the regeneration effects are sometimes reduced.

Ion exchange reaction is reversible, and other equivalent manner. From the experimental results, in dilute solution at room temperature with the ion exchange potential cation of higher charge, the radius increases; high molecular weight organic ions and metal complex anion has a high exchange potential. High polarization of ions, such as Ag +, Tl +, also has a high exchange potential. Ion exchange rate increases with increasing degree of crosslinking of resin decreases with the particle decreases. Temperature increased, the concentration increased, the exchange reaction rate is also faster.

Since ion exchange is reversible, so the general ion exchange resins used with the appropriate concentration of inorganic acid or alkali washing, restore the original state and re-use, this process is called regeneration. Cation exchange resin can be diluted hydrochloric acid, sulfuric acid leaching solution, etc.; anion exchange resin such as sodium hydroxide solution was used to carry out regeneration.

Ion exchange process is often carried out in the ion exchanger. Similar pressure ion exchange filter, a steel tank shell; ion exchange method commonly used filters, filter bed constituted by the exchange agent, at the bottom of the filter head with a pipe system.

1) Water Treatment

Water treatment ion exchange resins in great demand, accounting for ion exchange resins yield of 90%, for the various ions in water removal. Currently, the maximum consumption of ion exchange resin is used in the power plant's water treatment, followed by atomic energy, semiconductors, electronics industries.

2) Food Industry

Ion exchange resins can be used for sugar, MSG, refined wine, biological products and other industrial devices. For example: the manufacture of high fructose syrup extracted from corn starch, and then by hydrolysis to produce glucose and fructose, and then by ion exchange treatment, can produce high fructose syrup. Ion exchange resins in the food industry is second only to water consumption.

3) pharmaceutical industry

Ion exchange resin pharmaceutical industry a new generation of antibiotics and the development of antibiotics on the original play an important role in improving the quality. Successful development of streptomycin is an obvious example. In recent years, so there is still medicine study commission.

4) Synthetic chemical and petrochemical industry

Commonly used in organic synthesis as catalyst for acid and alkaline esterification, hydrolysis, transesterification, hydration reaction. Ion exchange resin instead of inorganic acid, alkali, can be the same reaction, and the advantages more. Such as the resin can be used repeatedly, the product easy to separate the reactor will not be corrosion, no pollution, easy to control response.

Methyl tert-butyl ether (MTBE) in the preparation, is to use ion exchange resins macroporous catalyst made by the reaction of isobutylene and methanol, instead of the original may cause serious pollution to the environment of tetraethyl lead.

5) Environmental Protection

Ion exchange resin has been applied very popular in many environmental issues of concern. Currently, many non-aqueous solution containing the toxic ions or ionic substances, which can be recycled resin. Such as the removal of metal ions in electroplating waste, recycling waste in film production and other useful substances.

6) and other hydrometallurgical

Ion exchange resin can be separated from the depleted uranium mines, enrichment, purification, extraction of uranium and rare earth elements and precious metals.
Ion exchange resin is widely used, mainly for separation and purification. For example, the system used to take away hard water softening and ion water, industrial wastewater recycling metals, rare metals and precious metals separation, separation and purification of antibiotics.

Ion exchange in water treatment have a very wide range of applications. As the sodium ion exchange water softening devices, mainly used in low pressure boiler water treatment. Ion exchange desalination equipment, mainly for the preparation of pure water and high water. Ion exchange equipment for medicine, chemistry, electronics, painting, drinks, and high-pressure boiler feed water, and many other industrial sectors. It is the introduction of RO devices in recent years compared with the complete removal of ionic impurities; low requirement for water pretreatment; equipment, low cost advantages. In the preparation of highly pure water, the ion exchange technology do not replace the current equipment. The total salt content in water 400mg / l below, according to different requirements of customers, water quality between the 1.0-0.2us/cm. If the total salt content in water 500mg / l or more, can be combined with electrodialysis desalination, water quality can improve.

Ion exchange is a special kind of solid adsorption process, it is by the ion exchange agent for the electrolyte solution. Of ion exchange agent is an insoluble solid particulate material, that ion exchange resins. It can absorb some kind of electrolyte solution from the cation or anion, while the self-contained in another sign of the ion with the same charge and other quantities for them, and released into the solution to this is the so-called ion exchange. In accordance with the type of ion exchange, ion exchange agents can be divided into cation exchanger and anion exchanger two categories.

Re-bed is yang, yin two different ion exchange switch in series, such as strong acid cation exchange resin and strong base anion exchange resin in series form. This sun beds and shade beds in series of devices known as re-bed, sun bed after the water first to remove metal ions, the formation of acidic water, then remove the ion through anion bed. Water through the rehabilitation bed most of the inorganic salt in water can be removed.

Mixed ion exchange, short bed, is the yin and yang resin filled by a certain percentage of devices in the same switch, run before they mixed. At this point the water is processed through the mixed bed ion exchange, the resulting H + and OH - ions immediately generate a very low solubility in water, very little formation of cation or anion exchange, the counter ion. Exchange reaction can be very thorough, so water quality is good, so mixed bed or a complex series in reverse osmosis desalination system behind the bed for the preparation of pure water or high water the depth of removal is mainly used for almost all of the ions (dissolved solid).

Ion exchange resin has been applied very popular in many environmental issues of concern. Currently, many non-aqueous solution containing the toxic ions or ionic substances, which can be recycled resin. Such as the removal of metal ions in electroplating waste, recycling waste in film production and other useful substances.

1) the type of ion exchange equipment

Ion exchange equipment in the water station where the species are: Yin bed, sun bed, mixed bed, etc.. Each type of equipment within the resin are also different, so each device works is also different.

2) The characteristics of ion exchange

The introduction of ion exchange water treatment system because the equipment is that the advantages of ion exchange resin performance in stability, high exchange capacity, its biggest feature is able to regenerate after failure, a longer period of the resin can be used repeatedly, using high efficiency low cost, good water quality and so on.

3) The basic principle of ion exchange


Ion exchange is a special kind of solid adsorption process, it is by the ion exchange agent in the electrolyte solution for the. Of ion exchange agent is an insoluble solid particulate material, both ion exchange resins. It can draw from the electrolyte solution, cations or anions, while the self-contained in another sign of the ionic charge with the same equal The exchange came out and released into the solution to this is the basic principle of ion exchange.

4) ion exchange resin exchange process:

Ion exchange process and the general diffusion process is different, because the ion exchange agent in the solution and the solution to establish equilibrium ion exchange process takes a long time, only a small number of ion exchange can be completed in an instant, the general need to exchange long. This is because the ion exchange is not only the surface of ion exchange agent, and in the ion exchange resin within the ion exchange process can be divided into seven consecutive steps:

① regenerant ions from the solution to spread to the surface of ion exchange resin particles,

② regenerant ion through the ion exchange resin particle surface of the boundary film,

③ regenerant ions in the ion exchange resin particles in the internal pore diffusion, and spread to the exchange point,

④ ion exchange reaction,

⑤ After the ion exchange ion exchange resin particles in the internal voids in the spread, and spread to the surface of ion exchange resins,

⑥ After the ion exchange ion exchange resin particle surface through the boundary film

⑦ outward diffusion into the solution to complete the ion exchange process.

In this seven consecutive steps, ① ~ ③ regenerant ion is the ion exchange resin particles inside spread, ⑤ ~ ⑦ is to displace the regenerant regeneration of ion exchange resin, ion, and is the equivalent of ions, ion movement in the opposite direction; ① ⑦ and diffusion of ion in solution, ② and ⑥, ion exchange resins through the boundary film diffusion, ③ and ⑤ is the ion exchange resin in the internal diffusion, then the ion exchange process to determine the speed of ion diffusion rate. F, ion exchange resin regeneration method: fat as possible to restore or close to the original resin, the work of the state.

After the failure of the regeneration of resins in different ways, can be divided into static and dynamic recycling renewable two static regeneration refers to regeneration agent in the container with foam resin, so as to restore to the original method of working state. Dynamic regeneration refers to regeneration agent dressed with continuous flow through the resin container, so as to restore to its original working state, dynamic regeneration has: downstream regeneration; countercurrent regeneration; convection regeneration.

Water in the water system through the sun-bed first (SC) / Yin-bed (WA / SA), through the sun / shade the water from the bottom bed into the sun / shade bed, when the new water system should start debugging on the sun / Anion Bed, Yang / Yin-bed countercurrent regeneration approach is renewable, because the DI water from the yin / yang into the equipment under the bed within the exchange, then exchange resin in the equipment failure within the first highest and lower classes is at most resin, failure is not high in the equipment to the top, then the regeneration agent from the device to join the top, so the higher the utilization of renewable agent and filtered water in the normal regeneration when the last contact with the highest degree of resin layer This water can be sufficient to ensure stability of the water, followed by the address of the counter-current regeneration regenerant flows through the filter layer resin layer disturbance; once again the driving force is such large regeneration. Back wash after regeneration can be washed away part of the regeneration of the resultant.

Water system in the mixed bed (MB) in containing yin / yang two kinds of resin, where the regeneration of two ways, the first step is to deal with, first mixed-bed water have been ineffective against washing, as anion exchange resin light and floating and the cation exchange resin to separate the introduction from the top of the base (NAOH) anion resin regeneration agents, and the regeneration of waste discharged from the central part of mixed-bed, in the regeneration when the lower part from the introduction of anti-mixed-bed washing, by anti-washing and yang resin to keep the lye does not flow into the lower part to prevent pollution of Yang resin, anion resin regeneration after complete bed from the lower part of the introduction of mixed acid (HCL) to regenerate Yang resin regeneration waste from mixed middle of the bed discharge, in the regeneration when introduced from the top of the mixed bed is washed, to maintain a certain pressure to prevent the acid into the upper part of the anion resin pollution, renewable finished, wash again in the positive, and then use oil-free compressed air or high purity nitrogen for adequate mixing of the resin. Yet another approach is to use renewable yin / yang resin regeneration at the same time, the so-called convection regeneration. in the water system yin / yang bed and mixed bed are that is, the former dealing with desalination processes. generally mixed bed water exports could 10MΩ.CM (23 ℃ ~ 25 ℃).

Production process in thermal power plants, water is the working medium heat system or some of the thermal equipment cooling medium. Thermal power plants have strict water quality standards, high pressure thermal equipment unit above water close to the water supply. As the general power plant raw water from untreated surface water and groundwater, it must pass rigorous pretreatment and desalting before they can use as boiler feed water. Jiangsu color to match the current order thinking Resin Co., Ltd. the world's desalination power plant supplies water treatment commonly used ion exchange process. However, restrictions on working exchange capacity of resin bed must be periodically regenerated. Common method is to use a certain concentration of acid, alkali, as agent on the resin bed regeneration processing, there is regeneration of the method of high dose, low utilization, environmental pollution caused by large emissions of acid waste, and labor intensive, the working conditions of workers poor ills. Therefore, the search for a regeneration of acid-base method is not significant.

In recent years, according to electrodialysis and ion exchange each other's strengths, electrodialysis and ion exchange technology will combine to create a new water treatment technologies - EDI (electro-deionization) technology. EDI within the mixed anion and cation exchange resin, not chemical but rather rely on renewable electricity renewable. This technique has achieved good economic and environmental benefits, but also prompt us to rely on electricity as EDI regeneration within the resin, it can use power directly to the ion exchange resin regeneration failure issue. In recent years it has been suggested that water from the failure to regenerate ion exchange resins, this method only consumes power. If the technology can be applied to practice, you avoid the drawbacks of acid regeneration, will have great significance. It is inspired by both, the author was the power mixed-bed ion exchange resin regeneration failure in rats.
In addition to the failure of the primary brine with ion exchange resin fed into the common good has been modified electrodialysis regeneration chamber. Since the initial addition of salt contained little salt, they can not take the limit under current conducting tasks, resulting in a small amount of water produced from the H + and OH-to take the remaining conductive tasks, these salt ions and H +, OH-, in DC field induced, respectively, to both sides of migration, H + Once failure resins foreign layer, it may be related to Ca2 +, Mg2 +, Na +, plasma replacement reaction, so that Yang resins are regenerated into H-type. Caused by the replacement down the Ca2 +, Mg2 +, Na + just moving a short distance to the sun on the boundary membrane, which membrane active groups by the sun's attractive, accelerating through the membrane into the concentrated water, sun room was removed. Therefore, to enable the regeneration reaction can proceed smoothly. The smooth progress of the reaction has been to promote ionization of weak electrolyte water, so that the failure of mixed bed ion exchange resins are fully recycled. Similarly, by HCO3-, Cl-, SO42-saturated anion exchange resin was invalid from the produced water is replaced by OH-, so that anion exchange resin has been regenerated.

1> experimental device

Electrical regeneration unit. Three-compartment single-stage ion exchange resin regeneration unit, as shown, its composition is similar to ordinary electrodialysis, respectively cathode and anode chamber and the regeneration chamber. Which the regeneration chamber size 160mm × 160mm × 10mm, filled completely ineffective within the anion and cation exchange resin (2:1) 60mm × 160mm × 70mm, using two 300mm × 300mm × 500mm tank, with a peristaltic pump cycle in order to adjust the room temperature regeneration. Anode 150mm × 150mm × 1.2mm ruthenium titanium mesh cathode with 150mm × 150mm × 2mm porous iron. With 100V, 30A silicon rectifier, with voltmeter, ammeter, to measure the condition of voltage and current, water inlet and outlet water with DDS-11A conductivity measured. Ion-exchange membrane produced by Shanghai Chemical 3361BW, 3362BW heterogeneous membrane, ion exchange resins by Rohm and Haas Shanghai Chemical Industry Co., Ltd. produced 001 × 7 Styrene of strong acid cation exchange resin and 201 × 7 Strong Base Styrene anion exchange resins.

2> Experimental Methods

Advance in the regeneration chamber into chemically completely ineffective anion and cation exchange resin, very room access certain concentration sodium sulfate solution, power on, adjust the voltage, at any time to monitor voltage and current changes, and close attention to the regeneration chamber temperature control In less than 50 ℃. Regeneration after removal resin with high water, for small water treatment experiment as the evaluation indicators of regeneration (experimental use of American Society for Testing Materials ASTM standard test methods).

Regeneration of mixed bed resin in the basic trend is that as the electric power through the increase of exchange capacity is also increasing, and the ability to reach the scene standard, 300mmol / L or more. However, as the number of experiments increases, there has been some serious problems.

(1) long regeneration time

50V voltage in the regeneration, found that the current slow growth, the intended communication power 10A &8226; h, the maximum current is 1.1A, a total regeneration time up to 10.33h. Water experiments showed that the resin exchange capacity for the 320.8mmol / L, to reach the scene standards. But its too long, is not conducive to production practice.

(2) poor reproducibility

Experimental results show that the same experimental conditions, the regeneration of reproducibility is poor. In order to avoid ion-exchange membrane leakage on the electrical regeneration of each experiment are the introduction of new ion exchange membrane, the voltage of 50V, 10A &8226; h electricity through renewable resin under the conditions, repeated 6 times experiments, the measured exchange resin work capacity, respectively: 287.5,320.8,162.5,179.2,204.2,195.8 mmol / L. Shows changes in resin exchange capacity and no clear trend fluctuated. At 163.5 and 320.8mmol / L between the volatility difference between the maximum and minimum values nearly 2-fold. Poor reproducibility is the electrical regeneration of a serious problem exists.

(3) resin serious decline in physical and chemical properties

In the experiment found that with the increase in the number of experiments, the resin became clear degree of fragmentation, which will affect the regeneration of the resin. Resin exchange capacity and the wear rate of all dropped significantly. The resin used during wear rate experiments, the basic no complete round particles, most of the powder has become. The physical and chemical properties of resin significantly reduced, will inevitably lead to the regeneration of instability, poor reproducibility.

(4) Yin and Yang imbalance resin regeneration

Yin and Yang mixed resin (yin and yang of 2:1) in the electrical regeneration, regeneration degree of imbalance. Resin regeneration was completed, the separation of water, the results show that the more thorough regeneration of anion resin reached the power plant site standards 300mmol / L, while yang resin regeneration is very low level, far below the site requirements.
EDI is the power to regenerate the resin, it can run continuously for a long time. This experiment has identified a number of serious problems, following regeneration by comparing the mixed-bed resin with EDI in the renewable power to analyze the reasons.

(1) EDI in filling the H-and OH-type ion exchange resin, in EDI in the Preparation of pure and ultra pure water, the electrodialysis can be ignored. Only consider the role of ion exchange. Put into operation soon, ion exchange water chamber stratification can occur.

When To deal with the water level to flow from the failure of the work of the bottom layer, due to failure of resin is saturated, can no longer participate in ion exchange, Gu Yu processing water ions, through the failure of resin layer is not absorbed, but by the DC field the role of horizontal transfer and be working to reach the bottom layer, all ions have moved out of fresh water chamber. As the protective layer, the electrolyte ions rarely, prone to concentration polarization, so that water dissociation into H + and OH-, in order to maintain the protective layer of resin and OH for the H-type. Failure level and work in layers, because of the relatively high concentration, not prone to concentration polarization, hydrolysis does not occur from the basic phenomenon.

Electrical regeneration in the mixed bed, filled with resin resin complete failure of the salt, the resin layer in a chaotic state, unable to form a protective layer, so the regeneration is regeneration in the room. Hydrolysis produced only from the h + and OH-in the amount sufficient for a long time to achieve adequate regeneration of resin, while the water dissociation is more difficult in itself. For all resins are renewable so good, and takes time and higher rate of water decomposition.

(2) mixed bed regeneration process, resulting from the hydrolysis of h + and OH-and the failure of the yin and yang replacement reaction to resin regeneration. Since h + and OH-as opposed to other cations and anions, its migration speed, which will inevitably lead to part of the H + and OH-is not the ion exchange resin regeneration failure, we have moved out of the regeneration chamber; also be replaced down the yin and yang ion if they can not move away in time, you may re-enter the ion exchange resin matrix frame the scope of activity of the Group's potential, H + and OH-again displace. Therefore, the resin particles failure occurred in renewable ---- ---- regeneration cycle, resulting in numerous resin particles of expansion - contraction, so that resin easy to break down physical and chemical properties, regeneration instability. And H + ion migration is the fastest of all, the direct migration of the regeneration chamber of the H + much more than OH-, resulting in lower anion cation regeneration. In EDI, because of the resin to be recycled only a small part of the studio, so physical and chemical properties of resin, the impact is very small, to ensure the continued stable operation of EDI

Ion exchange technology has a long history, some natural substances, such as foam zeolite and coal obtained through sulfonation sulfonation of coal are used as ion exchanger. However, with modern organic synthesis industry, rapid technological development, research and made a number of types of ion exchange resins with excellent performance, and the development of a variety of new application methods, ion exchange technology developed rapidly, in many industries, especially high-tech industry and widely used in scientific research in the field. In recent years, domestic production of resin, up to hundreds of species, hundreds of tons of annual production.

In industrial applications, the advantages of ion exchange resins are mainly large capacity, marking a wide range of high capacity bleaching can remove a variety of ions, can be repeated use of renewable, long working life, lower operating costs (although the cost of an input larger). Ion exchange resin Wei basis of a variety of new technologies, such as chromatographic separation, ion exclusion method, electrodialysis law, Ge with Dute of Gongneng, Keyijinxing various special work is difficult to achieve in other ways. Jiangsu color can SHINES order ion-exchange resin Co., Ltd. The development and application of technology is still rapidly evolving.


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