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    • 专利摘要:
    Transformation process of polyamide membranes with spiral winding that have exhausted their useful life in membranes of industrial utility. The process comprises the exposure of a polyamide membrane with a discarded spiral winding (11, 21) after being used in an industrial process, such as the desalination of brackish water from wells or the desalination of seawater, to a solution of a compound with a concentration of free chlorine higher than 100 ppm at a level of exposure equal to or greater than {image-01}, said solution being either at rest or in recirculation to keep the concentration of free chlorine constant. Recycled membranes of nanofiltration or ultrafiltration are obtained with a permeability greater than that of the discarded membrane and with a rejection in divalent salts greater than 30% and less than 30%, respectively. (Machine-translation by Google Translate, not legally binding)
    公开号:ES2589151A1
    申请号:ES201630931
    申请日:2016-07-08
    公开日:2016-11-10
    发明作者:Elena CAMPOS POZUELO；Patricia TERRERO RODRÍGUEZ；Domingo ZARZO MARTÍNEZ；Francisco José MOLINA SERRANO；Mercedes Antounet CALZADA GARZÓN；Raquel GARCÍA PACHECO；Serena MOLINA MARTÍNEZ；Laura RODRÍGUEZ SÁEZ；Francisco Javier RABADÁN；Junkal LANDABURU AGUIRRE；Amaia ORTÍZ DE LEJARAZU LARRAÑAGA；Eloy GARCÍA CALVO
    申请人:FUNDACION IMDEA AGUA；Valoriza Agua SL；
    IPC主号:
    专利说明:

    PROCESS OF TRANSFORMATION OF POLYAMIDE MEMBRANES WITH SPIRAL WINDING THAT HAS SOLD OUT THEIR LIFE IN INDUSTRIAL USEFUL MEMBRANES
    FIELD OF THE INVENTION
    The present invention relates to the recycling of spiral wound polyamide membranes that have exhausted their useful life.
    BACKGROUND OF THE INVENTION
    Desalination by means of polyamide membranes with spiral winding has consolidated in the last decade as a mature and well established technology in the international market. In fact, reverse osmosis technology occupies 65% of desalination processes.
    The membranes are made up of a series of very durable materials, mostly polymers such as polyamide, polysulfone, polypropylene, polyester, fiberglass, etc. However, the membranes have a limited shelf life, the duration of which depends on many factors, mainly related to the quality of the water to be treated, the chemicals used in pretreatment and the filtration process conditions. In fact, although many manufacturers advise their replacement after 3-7 years of use, there are plants that extend the life of their membranes much longer. However, sooner or later, the membrane loses its properties with respect to the permeability of water and its ability to reject salts and organic matter. Once these properties decay, the question to be solved is what is done with them.
    It should be taken into account in this regard that according to data from June 2015 offered by the International Desalination Association (IDA) [1], there are more than 18,400 desalination plants installed in 150 countries, which add a desalinated water capacity of more than 86.8 Hm3 / day, of which around 56.4 Hm3 / day are obtained by reverse osmosis membranes and about 1.7 Hm3 / day are obtained by nanofiltration membranes. In both cases they are polyamide membranes with spiral winding. In Spain, the Spanish Association of Desalination and Reuse (AEDYR) has


    711 desalination plants registered with a total installed capacity of 5.4 Hm3 / day. There are also small private plants (with a capacity of less than 500 m3 / day) that increase the total number to approximately 950 installations. In general terms, it is considered that to generate 1,000 m3 of desalinated water, about 100 membrane modules with spiral winding (cylinders 1 m long and 20 cm in diameter) are needed. By making a simple calculation we can see that today the sum of reverse osmosis modules installed in the world could amount to 5.6 million units. If we consider an annual replacement rate of 15% and the average weight of the discarded membranes (22 Kg), more than 80,000 membrane modules (> 1000 Tn) are discarded in Spain per year. Worldwide the figure amounts to more than 840,000 modules. Since currently discarded membranes are stored in landfills, if we consider the above figures, probably more than 14,000 tons per year of plastic material are being deposited in landfills.
    Today there are desalination plants that try to make the most of their membranes, for example, by changing their position within the pressure tubes. However, once the possibilities and cleaning cycles have been exhausted, the membranes inevitably end up being deposited in landfills.
    The general objective of the present invention is to alleviate this situation to some extent and try to recycle or reuse said discarded membranes for different uses, among which we can mention:
    - Sacrificial membranes (recycled membranes but with similar properties to commercial ones). Within the pressure tubes that make up the frames of the osmosis process, the first membrane is the one that suffers the most organic fouling and the last one that suffers the most inorganic fouling. Therefore, instead of using new membranes, recycled membranes are used, the replacement cost will be lower.
    - Brackish water softening (recycled nanofiltration membranes).
    - Water pretreatment before entering the reverse osmosis process. Both recycled nanofiltration and ultrafiltration membranes could be used as pretreatment to improve water quality before subjecting it to the osmosis process. Although in Spain it is not a usual practice, internationally in the


    Desalination plants of new construction are being used (with membranes
    commercial).
    - Wastewater treatment Recycled membranes could be used in the
    wastewater regeneration for later reuse. In function of the
    Desirable water quality could be used osmosis membranes, nanofiltration
    or recycled ultrafiltration.
    At the research level there are some recycling initiatives. Rodríguez et al. [1,2], investigated the transformation of discarded membranes of reverse osmosis by exposing them to various oxidizing agents such as sodium hypochlorite, hydrogen peroxide and potassium permanganate, the latter being the most favorable in the conditions used. Fruit of this work and considering the exposure levels used, the researchers determined that the best transformation agent is potassium permanganate.
    WO 2004/069392 [3] describes a process to convert obsolete reverse osmosis membranes from water desalination plants or similar plants, for later use as filters in the microfiltration range in other types of plants. treatment such as sewage treatment plants. The process involves the removal of the active layer of the membrane, through the use of a suitable stripper product that does not damage the microporous layer of the membrane. The chemical agent used in the transformation was potassium permanganate.
    On the other hand, in subsequent investigations it was determined that the basic, concentrated solutions of free chlorine are the most favorable to eliminate the polyamide layer of the membrane (fundamental layer in the process of reverse osmosis since it is the one that exerts as a selective barrier to ion step). The agent commonly used is sodium hypochlorite.
    Some authors have established the appropriate level of exposure for the transformation of reverse osmosis membranes to ultrafiltration [4,5]. The IMDEA Water membrane technology group has also managed to determine the boundary conditions necessary for the transformation to nanofiltration and ultrafiltration membranes [6,7].


    Specifically, document [7] reveals concentrations of sodium hypochlorite and exposure times for the transformation of discarded reverse osmosis membranes into nanofiltration and ultrafiltration membranes on a laboratory scale. Specifically, we worked with a concentration of 124 ppm of sodium hypochlorite and specific exposure times: 50 h to transform the properties to nanofiltration and 242 h for ultrafiltration. However, the exposure times mentioned in [7] are too long to be scalable at the industrial level, so the inventors continued to explore concentrations and exposure times. The transformation ranges obtained are shown herein.
    The reason why the use of sodium hypochlorite (NaOCl) is more commonly used for the modification and degradation of polyamide membranes lies in their oxidizing power. In aqueous solution, NaOCl dissociates completely forming sodium hydroxide (NaOH) and hypochlorous acid (HOCl). The latter is in equilibrium with two other species: the hypochlorite ion (OCl-) and chlorine gas (Cl2 (g)) [13]. The HOCl and OCl-species are commonly called free chlorine and increase or decrease their concentration depending on whether the pH is acidic or basic, respectively. At basic pH (> 10), the largest species present is OCl (99.7%) [8]. There is abundant literature around the degradation of polyamide by chlorine attack and although in some cases there is controversy, it is commonly accepted that it is a complex process. Variations in filtration yields of membranes exposed to free chlorine are attributed to specific structural changes in the active layer of membranes, polyamide [11]. These structural changes depend to a large extent on the composition of the polyamide, the process of preparing it, the type of polyamide (aromatic or linear), the degree of crosslinking [14] and in addition to the concentration of chlorine, pH and the exposure time to which the membranes are subjected. Generally, acid chlorine solutions (HOCl as the dominant species) cause a decrease in the rejection capacity and permeability of the membranes, while the basic solutions (ClO-as dominant species) decrease the rejection capacity but allow to increase the rejection capacity. membrane permeability.
    Some authors describe various possible mechanisms of polyamide alteration by chlorine attack [9, 10, 12, 14]. Figure 1 shows in general terms what these mechanisms consist of. On the one hand, a reversible activation reaction of the linear chain amide group can occur, to form an N-Chloroamide, which consists of


    a formal replacement of the hydrogen atom with a chlorine atom. In this case, the original amide bond can be restored under basic conditions without loss of polyamide properties. On the other hand, the aromatic chains can react with that of the intermediate product, N-chloroamide (-O = CN-Cl), or with other chlorides of the solution, through an irreversible reaction in the aromatic ring (Orton Transposition) . Finally, a chain reaction occurs, causing defragmentation of the polyamide chain and generating various by-products such as substituted chlorine benzene rings, quinone derivatives or other oxidation groups.
    SUMMARY OF THE INVENTION
    The invention provides a process of transforming a spirally wound polyamide membrane, with at least one selective polyamide layer, discarded for having exhausted its useful life in a recycled nanofiltration membrane whose permeability is greater than that of the discarded membrane and whose rejection in divalent salts is> 30% or in a recycled ultrafiltration membrane whose permeability is greater than that of the discarded membrane and whose rejection in divalent salts is <30%. The process comprises exposing said discarded spiral polyamide membrane to a solution of a compound with a concentration of free chlorine greater than 100 ppm at an exposure level equal to or greater than 1,000 ppm · h and can be carried out while said resting solution when in contact with the discarded membrane (passive transformation process) or by recirculating said solution through the membrane to favor contact between the solution and the membrane surface (active transformation process).
    In the case of membranes used in its useful life to treat brackish water from wells, the exposure level is between 1,000 and 100,000 ppm · h (passive transformation)
    or between 1,000 and 50,000 ppm · h (active transformation). If the discarded membrane has a salt rejection coefficient of less than 90%, the exposure level is between 1,000 and 60,000 ppm · h (passive transformation) or between 1,000 and 35,000 ppm · h (active transformation), obtaining a recycled membrane nanofiltration in the range
    1,000 -15,000 ppm · h in both processes and a recycled ultrafiltration membrane in the range 10,000 -60,000 ppm · h (passive transformation) or in the range 10,000 - 35,000 ppm · h (active transformation). If the discarded membrane has a salt rejection coefficient greater than or equal to 90%, the exposure level is between 2,000 and 100,000 ppm · h


    (passive transformation) or between 2,000 and 50,000 ppm · h (active transformation), obtaining a recycled nanofiltration membrane in the range 2,000-25,000 ppm · h in both processes and a recycled ultrafiltration membrane in the range 15,000 -100,000 ppm · h (passive transformation) or in the range 15,000 and 50,000 ppm · h (active transformation).
    In the case of membranes used in its useful life to treat seawater, the exposure level is between 2,500 and 400,000 ppm · h (passive transformation) or between
    2,500 and 100,000 ppm · h (active transformation). If the discarded membrane has a salt rejection coefficient of less than 90%, the exposure level is between 2,500 and 200,000 ppm · h (passive transformation) or between 2,500 and 50,000 ppm · h (active transformation), obtaining a recycled membrane nanofiltration in the range
    2,500 - 100,000 ppm · h (passive transformation) or in the range 2,500 and 30,000 ppm · h (active transformation) and a recycled ultrafiltration membrane in the range 20,000
    200,000 ppm · h (passive transformation) or in the range 20,000 and 50,000 ppm · h (active transformation). If the discarded membrane has a salt rejection coefficient greater than or equal to 90%, the exposure level is between 3,500 and 400,000 ppm · h (passive transformation) or between 3,500 and 100,000 ppm · h (active transformation), obtaining a Recycled nanofiltration membrane in the range 3,500 -150,000 ppm · h (passive transformation) or in the range 3,500-35,000 ppm · h (active transformation) and a recycled ultrafiltration membrane in the range 30,000 -400,000 ppm · h (passive transformation) or between 30,000 and 100,000 ppm · h (active transformation).
    Furthermore, using an exposure level of the discarded spiral wound polyamide membrane at said solution between 400,000 ppm · h and 2,000,000 ppm · h, an ultrafiltration membrane with a permeability greater than that of the membrane is obtained as a transformed membrane. discarded membrane and a rejection capacity of organic matter typical of a transformed ultrafiltration membrane.
    The passive transformation process is carried out through the following steps:
    a) arrange the spiral wound polyamide membrane discarded in a tank;
    b) introducing into the tank a solution of a compound (such as sodium hypochlorite) with a certain concentration of free chlorine by a directed flow


    perpendicular to the axis of the discarded spiral polyamide membrane until completely coated;
    c) circulating said solution through the discarded spiral wound polyamide membrane for a predetermined time to release the air contained therein;
    d) exposing the discarded spiral polyamide membrane to a solution of said compound for the time corresponding to the desired exposure level, computed from the end of the previous step, said solution being at rest.
    e) removing said solution from the reservoir and introducing into it a solution of a free chlorine inhibitor agent (such as sodium bisulfite) to stop the transformation reaction.
    The active transformation process is carried out by the following steps:
    a) arrange the polyamide membrane with spiral winding discarded inside a pressure tube;
    b) circulate through the pressure tube a solution of a compound (such as sodium hypochlorite) with a certain concentration of free chlorine during the time corresponding to the desired level of exposure so that contact between the solution and the membrane surface;
    c) removing said solution from the pressure tube and introducing into it a solution of a free chlorine inhibitor (such as sodium bisulfite) to stop the transformation reaction.
    In one embodiment the compound used in the process is sodium hypochlorite.
    Other features and advantages of the present invention will be apparent from the following detailed description of illustrative embodiments of its object in relation to the accompanying figures.
    BRIEF DESCRIPTION OF THE FIGURES
    Figure 1 shows known mechanisms of polyamide degradation by OCl [12].
    Figure 2a shows three schematic perspective views of an installation for carrying out the passive transformation process of the invention and Figure 2b is a


    diagram of an installation for carrying out the active transformation procedure of the invention.
    Figures 3a and 3b are diagrams showing the permeability values of several
    5 samples of recycled membranes using the passive transformation method of the invention. Type 1 membranes correspond to membranes that in their useful life were treating brackish water and type 2 membranes correspond to membranes that in their useful life were treating seawater. Discarded membranes have been obtained using solutions of sodium hypochlorite with four concentrations of chlorine
    10 free (124, 1,240, 6,200 and 12,400 ppm free chlorine) and different exposure times in order to subject the discarded membranes to three fixed levels of exposure (6,200,
    30,000 and 300,000 ppm · h). In addition, for comparison, the permeability value of the two types of discarded membranes (Eol, initials of "End of Life") is shown.
    Figures 4a, 4b are diagrams showing the values of the rejection coefficients in salts of the same recycled membranes referred to in Figures 3a and 3b.
    Figures 5a and 5b are diagrams showing the permeability and rejection coefficients of several samples of recycled membranes using the
    20 passive transformation process of the invention. They have been obtained by transforming discarded reverse osmosis membranes, with different fouling, using sodium hypochlorite solutions with a moderate level of free chlorine exposure (6,556 and 12,601 ppm · h). Some samples are type 1 (brackish water) and others are type 2 (seawater).
    Figures 6a and 6b are diagrams showing the values of permeability and rejection coefficients of several samples of recycled polyamide membranes with spiral winding, using the passive transformation method of the invention. Specifically in this example, they have been obtained by transforming membranes of
    30 discarded reverse osmosis, with different fouling, using sodium hypochlorite solutions with a high free chlorine exposure level (90,917, 369,267 and 660,867 ppm · h). Some samples are type 1 (brackish water) and others are type 2 (seawater).


    Figures 7a and 7b are diagrams showing permeability results and rejection coefficients obtained using the active transformation method of the invention.
    Figures 8a and 8b are diagrams comparatively showing the average results of the rejection coefficients of monovalent and divalent ions of a discarded membrane and of membranes transformed from discarded membranes from the same desalination plant using an active method and a passive process of transformation with two levels of free chlorine exposure.
    DETAILED DESCRIPTION OF THE INVENTION
    The aim of the present invention is to achieve a process of transforming spiral wound polyamide membranes discarded into recycled membranes that are industrially viable and, in particular, recycled nanofiltration (NF) membranes whose permeability is greater than that of the discarded membrane and whose rejection in divalent salts is> 30% or in a recycled ultrafiltration membrane whose permeability is greater than that of the discarded membrane and whose rejection in divalent salts is <30%.
    Preferably, recycled nanofiltration membranes have a permeability greater than 1.5 L · m-2 · h-1 · bar-1 and recycled ultrafiltration membranes have a permeability greater than 4 L · m-2 · h-1 · bar -one .
    The inventors have found that this result can be obtained by exposing the discarded spiral wound polyamide membranes to a solution of a compound (such as sodium hypochlorite) with a certain concentration of free chlorine by properly combining the concentration of free chlorine (ppm) and exposure time
    (h) or, what is the same, subjecting discarded spiral wound polyamide membranes to a pre-established exposure level (ppm · h). The effect of the level of exposure of the membrane to free chlorine, at basic pH, depends fundamentally on the two factors: concentration of free chlorine and exposure time. On the other hand, the transformation of the discarded membranes can be carried out passively or actively.


    Passive transformation
    Said exposure can be carried out in the manner illustrated in Figure 2a in which the discarded spiral wound polyamide membranes 11 with spiral configuration arranged in a carousel 13 are placed inside a reservoir 15 which is filled with a Sodium hypochlorite solution from a storage tank. Initially the solution is recirculated perpendicular to the axis of discarded spiral polyamide membranes 11. Once the tank 15 is full, the solution is circulated through them a few minutes to release the air. Once the programmed exposure time is over, the tank 15 is emptied (bringing the sodium hypochlorite solution to the storage tank), thus taking advantage of the solution for more membranes. The tank (which still contains the membranes) is then filled with a solution with a free chlorine reducing agent such as sodium bisulfite, to stop the membrane transformation reaction. This procedure can be repeated for another set of membranes.
    Figures 3a, 3b and 4a, 4b refer to tests performed with two types of reverse osmosis membranes (which as already indicated are polyamide membranes with spiral winding), the type 1 membrane being a Toray signature membrane ® model TM 720-400 (BW) used to desalinate well water and Membrane type 2 a membrane of the Hydranautics® signature model HSWC3 (SW) used to desalinate seawater. These Figures illustrate appropriate combinations to transform discarded reverse osmosis membranes into nanofiltration membranes or ultrafiltration membranes. In the case of Type 1 Membrane, it follows that, after exposure to free chlorine at a level of 6,200 ppm · h, the transformed membrane has properties within the nanofiltration range (see Figure 3a), similar to those of membranes such as the NF90 and NF270 models of the Dow Filmtec commercial firm. In all tested type 1 models, from 30,000 ppm · h recycled membranes acquired properties within the ultrafiltration range.
    In the case of Type 2 Membrane (see Figure 3b), they show greater resistance to attack by free chlorine, resulting in recycled nanofiltration membranes with levels below
    300,000 ppm · h and membranes with ultrafiltration properties, after an exposure level of 300,000 ppm · h, although with a low permeability (in any of the


    exposure levels tested, much greater permeability is obtained in type 1 membranes than in type 2 membranes).
    However, and although it is not shown in any figure, the same study was carried out with other models within type 2 membranes, allowing to conclude that there is a difference in resistance of polyamide to the attack of chlorine between different models of type 2 membranes An experimental example is presented below using an exposure level of 30,000 ppm · h and using a solution of 124 ppm of free chlorine. Under these conditions, ultrafiltration recycled membranes were obtained in the case of seawater models such as SW30 and TM820C, while the HSWC3 model, as mentioned above, maintained nanofiltration values.
    Regarding the effects of concentration and time for a fixed level of exposure, it has been shown that low concentrations and very long exposure times, polyamide degradation have a greater effect. Using the dose of 30,000 ppm · h as an example, type 2 membranes such as the SW30 model showed rejection capacity in salts between 20-68% when using transformation solutions with the following concentrations: 1,240, 6,200 and 12,400 ppm, while with the poorly concentrated solution (124 ppm) the salt rejection capacity was <5%.
    Figures 5a and 5b refer to tests performed with type 1 and type 2 membranes. In Figure 5a type 1 membranes coexist (TM1, TM2, TM3, TM4 of TM 720-400 model with different degree of fouling) and of type 2 (HSWC3 1 and 2 with different degree of fouling). The results corroborate the difference in sensitivity to free chlorine between type 1 and type 2 membranes. Type 1 membranes that initially maintain reverse osmosis properties acquire nanofiltration properties using solutions with a low-moderate range of free chlorine (between 6,556 and 12,601 ppm · h of free chlorine). However, when type 1 membranes are initially damaged (salt rejection coefficients below 65%), they are directly transformed to ultrafiltration membranes after 12,601 ppm · h of exposure to free chlorine (due to the loss of the ability to reject salts ).
    On the other hand, from the analysis of Figures 5a and 5b, it is corroborated that type 2 membranes are more resistant to chlorine attack, since with low-moderate levels, it follows


    that this level of exposure does not seem to significantly affect the properties of reverse osmosis membranes used to desalinate seawater, although these recovered membranes could be reinserted in reverse osmosis processes, being used as sacrificial membranes if they were placed in the first and / or the
    5 last position within the pressure pipes of the desalination plants.
    Figures 6a and 6b are diagrams showing the permeability and rejection coefficients of several recycled membranes using the passive transformation procedure. In both Figures, type 1 membranes (TM 5 and TM 6 10 of the TM720-400 model and SU 1 and SU 2 of the SU-720F Model) and type 2 coexist (HSWC3 2 and HSWC3 3). Analyzing these Figures it follows that discarded type 1 membranes are transformed to ultrafiltration membranes using a high range of free chlorine (between
    90,917 and 660,867 ppm · h). On the other hand, it follows that the transformation of type 2 membranes to ultrafiltration membranes is viable using a range of exposure level
    15 between 369,267 and 660,867 ppm · h since the polyamide is completely removed. Experimentation has been carried out up to 2,000,000 ppm · h of free chlorine and it has been observed that although the permeability of the membranes increases considerably (in the case of type 1 membranes they exceed 50 L · h-2 · m-2 · bar-1), the rejection capacity typical of ultrafiltration membranes is still maintained.
    Finally, as a result of other research carried out by the inventors, it has been found that it is possible to transform the properties of the discarded membranes to nanofiltration with a very high rejection capacity, using an exposure level lower than the 6,200 ppm · h shown in Figure 3a and 3b. Samples of membranes initially used
    25 had rejection coefficients in salts greater than 90%. Thus, type 1 membrane models (brackish water) perceive changes in their properties at 2,500 ppm · h (double their permeability and reduce their rejection coefficients in mixed salts measured by conductivity, by more than 3 percentage points). On the other hand, substantial changes are observed in type 2 membranes from 4,000 ppm · h (permeability is doubled and
    30 the percentage of rejection in salts is reduced by more than 2%).


    Active transformation
    In active transformation, exposure of discarded spiral wound polyamide membranes to a solution of a compound with a certain concentration of free chlorine (such as sodium hypochlorite) is carried out in the manner illustrated in Figure 2b wherein a polyamide membrane with discarded spiral winding 21 with spiral configuration is placed inside a pressure tube 22, through which said solution is circulated from the storage tank 24 thanks to the pump 23. The The solution is recirculated in parallel to the axis of the polyamide membrane with discarded spiral winding 21. In order to maintain the desired concentration of free chlorine in the solution throughout the transformation, the system has a metering pump 27 for continuous dosing of the desired concentration of free chlorine. Once the programmed exposure time is over, the pumping stops and the solution is retained in tank 24 for future transformations. Subsequently, the residual volume is displaced by pumping rinse water from the reservoir 25 that is sent to the reservoir 26 for treatment and neutralization before being poured with appropriate compound supplied by the metering pump 29. This displacement can be carried out by the pump 23 or with another pump installed for that purpose. Subsequently, rinse water is recirculated from the tank 25 with a free chlorine reducing agent (such as sodium bisulfite) supplied by the metering pump 28 as a safety measure to stop the membrane transformation reaction 21. This recirculation can be performed by pump 23 or with another pump installed for this purpose. This procedure can be performed for the simultaneous transformation of one or more membranes.
    In Figure 7a, membranes of type 1 coexist (TM7, TM8 of model TM 720-400 of the same desalination plant and the same degree of fouling) and type 2 (HSWC3 5 and 6 of the same desalination plant and same type of fouling) . The results indicate that there is no significant difference between active and passive transformation to obtain nanofiltration and ultrafiltration membranes in the case of type 1 membranes. However in the case of type 2 membranes the transformation requires lower levels. of exposition. In the case of HSWC3 membranes, nanofiltration values are obtained by recirculating a sodium hypochlorite solution for 23,400 ppm · h and ultrafiltration membranes are obtained after values of 42,500 ppm · h. As in the passive transformation, the difference in sensitivity to free chlorine between


    Type 1 and Type 2 membranes. The industrial utility of actively transformed membranes is the same as passively transformed membranes.
    Figures 8a and 8b show comparatively the average results of the rejection coefficients of monovalent and divalent ions of type 1 membranes, from the same desalination plant and transformed with the active transformation procedure (Fig. 8a) and with the passive transformation procedure (Fig. 8b) using a solution of sodium hypochlorite of similar concentration. In these Figures, the Des code is used to indicate the results of the discarded membrane and the NF1 and NF2 codes to indicate the results obtained with transformations performed with concentrations of, respectively, 6,500 ppm · h and 15,000 ppm · h. As can be deduced from these Figures, similar results are obtained in both types of transformation. The average permeability of the transformed membranes increases with respect to the values of the discarded membranes 1.5 and 2.8 times, for exposure levels 1 and 2 respectively. In all cases the coefficients of divalent ions exceed the value of 30%.
    Although the present invention has been described in connection with various embodiments, it can be seen from the description that various combinations of elements, variations or improvements can be made therein and that are within the scope of the invention defined in the appended claims.
    BIBLIOGRAPHY
    [1] WO 2004/069392 REVERSE OSMOSIS MEMBRANE RECONVERSION PROCESS
    [2] J.J. Rodríguez, V. Jiménez, O. Trujillo, J.M. Veza, Reuse of reverse osmosis membranes in advanced wastewater treatment, 150 (2002) 219-225.
    [3] J.M. Veza, J.J. Rodriguez-Gonzalez, Second use for old reverse osmosis membranes: wastewater treatment, Desalination. 157 (2003) 65–72. doi: 10.1016 / S00119164 (03) 00384-9.
    [4] H.D. Raval, V.R. Chauhan, A.H. Raval, S. Mishra, Rejuvenation of discarded RO membrane for new applications, Desalin. Water Treat 48 (2012) 349–359. doi: 10.1080 / 19443994.2012.704727.


    [5]  W. Lawler, A. Antony, M. Cran, M. Duke, G. Leslie, P. Le-Clech, Production and characterization of UF membranes by chemical conversion of used RO membranes, J. Memb. Sci. 447 (2013) 203-211. doi: 10.1016 / j.memsci. 2013.07.015.
    [6] S. Molina, R. García-Pacheco, L. Rodríguez-Sáez, E. García-Calvo, E. Campos,
    D. Zarzo, et al., Transformation of end-of-life RO membranes into recycled NF and UF membranes, surface characterization (15WC-51551), in: Proc IDAWC15, San Diego, 30 August-4 Sept. 2015, 2015.
    [7] R. García-Pacheco, J. Landaburu-Aguirre, S. Molina, L. Rodríguez-Sáez, S.B. Teli, E. García-Calvo, Transformation of end-of-life RO membranes into NF and UF membranes: Evaluation of membrane performance, J. Memb. Sci. 495 (2015) JMS151072. doi: 10.1016 / j.memsci. 2015.08.025.
    [8] Donose, B. C., Sukumar, S., Pidou, M., Poussade, Y., Keller, J., & Gernjak, W. (2013). Effect of pH on the ageing of reverse osmosis membranes upon exposure to hypochlorite. Desalination, 309, 97-105. doi: 10.1016 / j.desal.2012.09.027
    [9] Geise, G. M., Lee, H., Miller, D. J., Freeman, B. D., Mcgrath, J. E., & Paul, D. R. (2010). Water Purification by Membranes: The Role of Polymer Science, 48, 1685–1718. doi: 10.1002 / POLB
    [10] Kang, G.-D., Gao, C.-J., Chen, W.-D., Jie, X.-M., Cao, Y.-M., & Yuan, Q. (2007 ). Study on hypochlorite degradation of aromatic polyamide reverse osmosis membrane. Journal of Membrane Science, 300 (1-2), 165-171. doi: 10.1016 / j.memsci.2007.05.025
    [11] Kwon, Y.-N., & Leckie, J. O. (2006). Hypochlorite degradation of crosslinked polyamide membranes I. Changes in chemical / morphological properties. Journal of Membrane Science, 283 (1-2), 21–26. doi: 10.1016 / j.memsci.2006.06.008
    [12] Shin, D. H., Kim, N., & Lee, Y. T. (2011). Modification to the polyamide TFC RO membranes for improvement of chlorine-resistance. Journal of Membrane Science, 376 (1-2), 302–311. doi: 10.1016 / j.memsci. 2011.04.045
    [13] Soice, N. P., Maladono, A. C., Takigawa, D. Y., Norman, A. D., Krantz, W. B., & Greenberg, A. R. (2002). Oxidative Degradation of Polyamide Reverse Osmosis Membranes: Studies of Molecular Model Compounds and Selected Membranes.
    [14] Xu, J., Wang, Z., Wei, X., Yang, S., Wang, J., & Wang, S. (2013). The chlorination process of crosslinked aromatic polyamide reverse osmosis membrane: New insights from the study of self-made membrane. Desalination, 313, 145–155. doi: 10.1016 / j.desal.2012.12.020.

    权利要求:
    Claims (115)
    [1]
    one. Process of transformation of a polyamide membrane with discarded spiral winding (11, 21) for having exhausted its useful life in a recycled nanofiltration membrane whose permeability is greater than that of the discarded membrane and whose rejection in divalent salts is> 30% or in a recycled ultrafiltration membrane whose permeability is greater than that of the discarded membrane and whose rejection in divalent salts is <30%, with the polyamide membrane having a spiral spiral discarded (11, 21) at least one selective layer of polyamide , the transformation process comprising an exposure step of said polyamide membrane with discarded spiral winding (11, 21) to a solution of a compound with a certain concentration of free chlorine for a certain time, characterized in that:
    - said concentration of free chlorine is greater than 100 ppm; -the exposure level of the discarded spiral wound polyamide membrane (11, 21) to said solution is equal to or greater than 1,000 ppm · h.
    [2]
    2.  Process according to claim 1, wherein the recycled nanofiltration membrane has a permeability greater than 1.5 L · m-2 · h-1 · bar-1 and the recycled ultrafiltration membrane has a permeability greater than 4 L · m -2 · h-1 · bar-1.
    [3]
    3.  Process according to any of claims 1-2, wherein the exposure step of said discarded spiral wound polyamide membrane (11) is carried out with said free chlorine solution at rest.
    [4]
    Four.  Process according to claim 3, wherein: - the discarded spiral wound polyamide membrane (11) was used during its useful life to treat brackish water from wells;
    The exposure level of the discarded spiral wound polyamide membrane (11) to said solution is between 1,000 and 100,000 ppm · h.
    [5]
    5.  Process according to claim 4, wherein:
    - the discarded spiral wound polyamide membrane (11) has a rejection coefficient of less than 90%;

    - The exposure level of the discarded spiral wound polyamide membrane (11) to said solution is between 1,000 and 60,000 ppm · h.
    [6]
    6.  Process according to claim 5, wherein: the exposure level of the spiral wound polyamide membrane
    discarded (11) to said solution is between 1,000 and 15,000; -The transformed membrane is a recycled nanofiltration membrane.
    [7]
    7.  Process according to claim 5, wherein: the exposure level of the spiral wound polyamide membrane
    discarded (11) to said solution is between 10,000 and 60,000 ppm · h; -The transformed membrane is a recycled ultrafiltration membrane.
    [8]
    8.  Process according to claim 4, wherein: - the discarded spiral wound polyamide membrane (11) has a rejection coefficient equal to or greater than 90%;
    -the level of exposure of the discarded spiral polyamide membrane (11) to said solution is between 2,000 and 100,000 ppm · h.
    [9]
    9.  Process according to claim 8, wherein:
    - the exposure level of the discarded spiral wound polyamide membrane (11) discarded to said solution is between 2,000 and 25,000 ppm · h;
    - The transformed membrane is a recycled nanofiltration membrane.
    [10]
    10.  Process according to claim 8, wherein: the exposure level of the spiral wound polyamide membrane
    discarded (11) to said solution is between 15,000 and 100,000 ppm · h; -The transformed membrane is a recycled ultrafiltration membrane.
    [11]
    eleven.  Process according to claim 3, wherein:
    - the polyamide membrane with discarded spiral winding (11) was used during its useful life to treat seawater;

    - The exposure level of the discarded spiral wound polyamide membrane (11) to said solution is between 2,500 and 400,000 ppm · h.
    [12]
    12.  Process according to claim 11, wherein: - the discarded spiral wound polyamide membrane (11) has a rejection coefficient of less than 90%;
    -the exposure level of the discarded spiral wound polyamide membrane (11) to said solution is between 2,500 and 200,000 ppm · h.
    [13]
    13.  Process according to claim 12, wherein: the exposure level of the spiral wound polyamide membrane
    discarded (11) to said solution is between 2,500 and 100,000 ppm · h; -The transformed membrane is a recycled nanofiltration membrane.
    [14]
    14.  Process according to claim 12, wherein: the exposure level of the spiral wound polyamide membrane
    discarded (11) to said solution is between 20,000 and 200,000 ppm · h; -The transformed membrane is a recycled ultrafiltration membrane.
    [15]
    fifteen.  Process according to claim 11, wherein: - the discarded spiral wound polyamide membrane (11) has a rejection coefficient equal to or greater than 90%;
    -the exposure level of the discarded spiral polyamide membrane (11) to said solution is between 3,500 and 400,000 ppm · h.
    [16]
    16.  Process according to claim 15, wherein: the exposure level of the spiral wound polyamide membrane
    discarded (11) to said solution is between 3,500 and 150,000 ppm · h; -The transformed membrane is a recycled nanofiltration membrane.
    [17]
    17.  Process according to claim 15, wherein: the exposure level of the spiral wound polyamide membrane
    discarded (11) to said solution is between 30,000 and 400,000 ppm · h; -The transformed membrane is a recycled ultrafiltration membrane.

    [18]
    18. Process according to claim 3, wherein:
    - the exposure level of the discarded spiral wound polyamide membrane (11) to said solution is between 400,000 ppm · h and 2,000,000 ppm · h;
    - The transformed membrane is a recycled ultrafiltration membrane with a permeability greater than that of the discarded membrane.
    [19]
    19.  Process according to any of claims 1-2, wherein the exposure step of said discarded spiral wound polyamide membrane (21) is carried out by recirculating said solution through the membrane to favor contact between the solution and the surface of the membrane.
    [20]
    twenty.  Process according to claim 19, wherein: - the discarded spiral wound polyamide membrane (21) was used during its useful life to treat brackish water from wells;
    -the exposure level of the discarded spiral wound polyamide membrane (21) to said solution is between 1,000 and 50,000 ppm · h.
    [21]
    twenty-one.  Process according to claim 20, wherein: - the discarded spiral wound polyamide membrane (21) has a rejection coefficient of less than 90%;
    The exposure level of the discarded spiral wound polyamide membrane (21) to said solution is between 1,000 and 35,000 ppm · h.
    [22]
    22  Process according to claim 21, wherein: the exposure level of the spiral wound polyamide membrane
    discarded (21) to said solution is between 1,000 and 15,000; -The transformed membrane is a recycled nanofiltration membrane.
    [23]
    2. 3.  Process according to claim 21, wherein: the exposure level of the spiral wound polyamide membrane
    discarded (21) to said solution is between 10,000 and 35,000 ppm · h; -The transformed membrane is a recycled ultrafiltration membrane.

    [24]
    24.  Process according to claim 20, wherein: - the discarded spiral wound polyamide membrane (21) has a rejection coefficient equal to or greater than 90%;
    -the level of exposure of the discarded spiral wound polyamide membrane (21) to said solution is between 2,000 and 50,000 ppm · h.
    [25]
    25.  Process according to claim 24, wherein: the exposure level of the spiral wound polyamide membrane
    (21) discarded from said solution is between 2,000 and 25,000 ppm · h; -The transformed membrane is a recycled nanofiltration membrane.
    [26]
    26.  Process according to claim 24, wherein: the exposure level of the spiral wound polyamide membrane
    discarded (21) to said solution is between 15,000 and 50,000 ppm · h; -The transformed membrane is a recycled ultrafiltration membrane.
    [27]
    27.  Process according to claim 19, wherein: - the discarded spiral wound polyamide membrane (21) was used during its useful life to treat seawater;
    -the exposure level of the discarded spiral wound polyamide membrane (21) to said solution is between 2,500 and 100,000 ppm · h.
    [28]
    28.  Process according to claim 27, wherein: - the discarded spiral wound polyamide membrane (21) has a rejection coefficient of less than 90%;
    -the exposure level of the discarded spiral wound polyamide membrane (21) to said solution is between 2,500 and 50,000 ppm · h.
    [29]
    29.  Process according to claim 28, wherein: the exposure level of the spiral wound polyamide membrane
    discarded (21) to said solution is comprised between 2,500 and 30,000 ppm · h; -The transformed membrane is a recycled nanofiltration membrane.

    [30]
    30. The process according to claim 28, wherein: the exposure level of the discarded spiral wound polyamide membrane (21) to said solution is between 20,000 and 50,000 ppm · h;
    -The transformed membrane is a recycled ultrafiltration membrane.5
    [31]
    31. The process according to claim 27, wherein: the discarded spiral wound polyamide membrane (21) has a rejection coefficient equal to or greater than 90%;
    - The exposure level of the discarded spiral wound polyamide membrane 10 (21) to said solution is between 3,500 and 100,000 ppm · h.
    [32]
    32. Process according to claim 31, wherein: -the exposure level of the spiral wound polyamide membrane
    discarded (21) to said solution is between 3,500 and 35,000 ppm · h; 15-The transformed membrane is a recycled nanofiltration membrane.
    [33]
    33. Process according to claim 30, wherein: the exposure level of the spiral wound polyamide membrane
    discarded (21) to said solution is between 30,000 and 100,000 ppm · h; 20-The transformed membrane is a recycled ultrafiltration membrane.
    [34]
    34. Process according to any of claims 3-18 comprising the following steps: a) arranging the discarded spiral wound polyamide membrane (11) 25 in a tank (15);
    b) introducing into the tank (15) a solution of a compound with a certain concentration of free chlorine by a flow directed perpendicularly to the axis of the polyamide membrane with discarded spiral winding (11) until completely covered;
    C) circulating said solution through the discarded spiral wound polyamide membrane (11) a predetermined time to release the air contained therein;

    d) exposing the discarded spiral wound polyamide membrane (11) to a solution of said compound for the time corresponding to the desired exposure level, computed from the end of the previous step, said solution being at rest;
    e) removing said solution from the reservoir (15) and introducing into it a solution of a free chlorine inhibiting agent to stop the transformation reaction.
    [35]
    35. Process according to any one of claims 19-33 comprising the following steps: a) arranging the polyamide membrane with discarded spiral winding (21) 10 inside a pressure tube (22);
    b) circulating through the pressure tube (22) a solution of a compound with a certain concentration of free chlorine for the time corresponding to the desired exposure level;
    c) removing said solution from the pressure tube (22) and introducing into it a solution of a free chlorine inhibitor to stop the transformation reaction.
    [36]
    36. Process according to any of claims 34 and 35 wherein said compound is sodium hypochlorite.
    37. A process according to any of claims 34 and 35 wherein said free chlorine inhibiting agent is a sodium bisulfite solution.

     Or hn
    Or hn
    Or hn
    OR
    N
    OR
    N
    ORN
    H
    H
    H
    Hydrolysis
    NaOCl
    H
    Cl
    OR
    ON
     Or oh
    ON
    N-halogenation
    Oxidation
    H
    H
    H
    N
    N
    N
    OR
    Amino-quinone
    N-Chloroamide
     Or hn
    Or hn
    Or hn
    NO nO nOR
    H H
    HH
    Hydrolysis
    Cl
    OON NaOCl O
    N
    OR
    OH Oxidation
    N-halogenation
    H
    H
    HNN
    N
    ClCl Cl
    O N-Chloroamide Derivative-quinone
    FIG. one
    FIG. 2nd
    FIG. 2b

    Permeability (L / m2 · h.bar) Permeability (L / m2 · h.bar)
    [100]
    100.00
    [90]
    90.00
    [80]
    80.00
    [70]
    70.00
    [60]
    60.00
    [50]
    50.00
    [40]
    40.00
    [30]
    30.00
    [20]
    20.00
    [10]
    10.00
    [0]
    0.00
    Exposure level (ppm · h)
     FIG. 3rd
    124 ppm Free ClO
    1240 ppm Free ClO
    6200 ppm Free ClO 12400 ppm Free ClO
    [100]
    100.00
    [90]
    90.00
    [80]
    80.00
    [70]
    70.00
    [60]
    60.00
    [50]
    50.00
    [40]
    40.00
    [30]
    30.00
    [20]
    20.00
    [10]
    10.00
    [0]
     0.00 Eol 6,200 30,000 300,000
    Exposure level (ppm · h) FIG. 3b
    0 ppm free ClO
    124 ppm Free ClO
    12400 ppm Free ClO
    6200 ppm Free ClO 124000 ppm Free ClO

    % Rejection
    % Rejection
    [100]
    100.00
    [90]
    90.00
    [80]
    80.00
    [70]
    70.00
    [60]
    60.00
    [50]
    50.00
    [40]
    40.00
    [30]
    30.00
    [20]
    20.00
    [10]
    10.00
    [0]
     0.00 -10.00
    [100]
    100.00
    [90]
    90.00
    [80]
    80.00
    [70]
    70.00
    [60]
    60.00
    [50]
    50.00
    [40]
    40.00
    [30]
    30.00
    [20]
    20.00
    [10]
    10.00
    [0]
     0.00 -10.00
     Type 1 membrane
    124 ppm Free ClO
    1240 ppm Free ClO 6200 ppm Free ClO
    12400 ppm Free ClO
    Exposure level (ppm · h) FIG. 4th
     Type 2 membrane
    124 ppm Free ClO
    1240 ppm Free ClO 6200 ppm Free ClO
    12400 ppm Free ClO
    Eol 6,200 30,000 300,000
    Exposure level (ppm · h)
     FIG. 4b

    High exposure level (ppm · h)
    Exposure level (ppm · h) FIG. 6a High exposure level (ppm · h)
    [100]
    100.00
    [90]
    90.00
    [80]
    80.00
    [70]
    70.00
    [60]
    60.00
    [50]
    50.00
    [40]
    40.00
    [30]
    30.00
    [20]
    20.00
    [10]
    10.00
    [0]
     0.00 -10.00
    % Rejection
    TM 5 TM 6 SU 1
    SU 2 HSWC3 2 HSWC3 3
    [-20]
    - 20.00
    FIG. 6b

    % Rejection
    [100]
    100.00
    [90]
    90.00
    [80]
    80.00
    [70]
    70.00
    [60]
    60.00
    [50]
    50.00
    [40]
    40.00
    [30]
    30.00
    [20]
    20.00
    [10]
    10.00
    [0]
    0.00
    [-15]
    - 15.00
    Exposure level (ppm · h) FIG. 7a
    TM 7
    TM 8 HSWC3 5
    HSWC3 6
    Eol 6,670 17,400 23,400 42,500
    Exposure level (ppm · h)FIG. 7b

    Des.
    NF1
    NF2
    % Rejection
    Cl-NO3-SO4 + 2 Na + K + Ca + 2 Mg + 2
    Compound FIG. 8a
    Des.
    NF1 NF2
    [100]
    100.00
    [90]
    90.00
    [80]
    80.00
    [70]
    70.00
    [60]
    60.00
    [50]
    50.00
    [40]
    40.00
    [30]
    30.00
    [20]
    20.00
    [10]
    10.00
    [0]
    0.00
    Compound FIG. 8b
    NO3-SO4 + 2 K + Mg + 2
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