CATIONIC DYE

Field of the Invention

The invention is related to an improved method and system for decolorization of textile wastewater.

The present invention is related to a method and system in which air conditioner dust of spinning mill, which is producing cellulosic yarn, is particularly used for decolorization of textile wastewater containing cationic dye.

State of the Art

Textile finishing mills may cause the formation of colored wastewater depending on the type and form of the processed fiber, which has different rates of COD (chemical oxygen demand) and BOD (biological/biochemical oxygen demand). Therefore, it is important to effectively treat this wastewater that emerged during production.

In case these wastewaters containing dye are not disposed of adequately, they create a danger for the environment. If this wastewater is discharged to the receiving water body, it reduces the oxygen recovery capacity of the receiving body and cause the biological life in the water to stop by preventing the passage of sunlight. Moreover, since the colors of the dyes in the wastewater can be easily seen with the naked eye, they cause problems in terms of aesthetics (Bahardir, 2012).

Textile wastewater can be treated with biological and chemical treatment methods in the existing system. Although the methods have various advantages and disadvantages, the methods still used are generally as such. Besides, adsorption techniques can also be applied, especially for decoloring. The adsorption term refers to the accumulation of a substance at the interface between two phases (liquid-solid interface or gas-solid interface) (Yagub et al., 2014). The most commonly used method for decoloring by adsorption is the active carbon method (Kocaer and Alkan, 2002). There are many different studies for textile wastewater treatment with the adsorption method. In these studies it is seen that commercially different forms or the ones obtained from different cellulosic sources can be used. Some examples of said studies are listed below. It is possible to multiply these examples. For example; in a study the adsorption of 23 different textile dyes was examined by using activated carbonobtained from waste apricots by chemical activation, raw clay and zeolite (Tantekin, 2006). In another study on active carbon, the use of active carbon obtained by the carbonization process from Onopordum Acanthium L. in reactive dye adsorption was examined (Erkut, 2008). Removing dyes in textile wastewater with lignins was researched in another study (Erdogan, 2010). Disperse Blue 106 and 124 dyes were tried to be adsorbed using walnut and hazelnut shells in another study and it has been shown that walnut and hazelnut shells can be used for this aim (Kaya et al., 2011). It has been demonstrated in another similar study that hazelnut shells can be a natural dye source for both wool and cotton and can also be used as an adsorbent in basic dye adsorption (Gune§ and Atav, 2017). In our own study, it was seen that the wastes come out in spinning mill from blow room, carding machine, comber, and pneumafil can be used in basic dye adsorption (Bahtiyari et al., 2020). Uysal and Kereci (2016) demonstrated that the waste ashes of the textile mill can be used for dye removal from the wastewater of the same mill (Uysal and Kereci, 2016). In another study, it has been reported that Basic Blue 3 dyestuff can be adsorbed using pine cone and the definition of adsorption was provided mathematically by examining the process parameters of adsorption (Tanyildizi and Uygut, 2016). Koklu and Ozer used cigarette ash as an adsorbent so as to remove Remazol Brillant Blue R dye in their study and mentioned that it can be an alternative adsorbent in the treatment of textile wastewater (Koklu and Ozer, 2018).

In addition to the researches mentioned above, although there are many patents on textile wastewater treatment, no patent was reached for the use of air conditioner dust as an adsorbent.

Consequently, it was seen necessary to make an improvement in the relevant technical field in the direction of the need for alternative applications and adsorbents for decoloring by the adsorption method.

References:

Bahadir, E. B., 2012, Tekstil Endustrisi Aritilmi§ Atiksularinda Renk Ve Oncelikli Kirleticilerin Ozon Teknolojisi lie Gideriminin Ara§tmlmasi (An investigation on color, COD and priority pollutants removal with ozone technology in treated effluents from two textile industries), MSc Thesis, Namik Kemal University, Tekirdag, Turkey. Bahtiyari, M. i., Aydinlioglu, O., Yildiz, Y. §., 2020, Presentation of different cellulosic yarn spinning wastes for decolorization of a basic dye solution. The Journal of The Textile Institute, 111(8), 1214-1222. DOI:10.1080/00405000.2019.1690369

Erkut, E., 2008, Aktif Karbon Adsorbsiyonu ile Boyarmadde Giderimi (Removal Of Dye By Adsorption With Using Activated Carbon), MSc Thesis, Anadolu University, Eskigehir, Turkey.

Erdogan, S. i., 2010, Tekstil Atik Suyundaki Boyarmaddelerin Lignin Me Adsorpsiyonu (The removal of the textiles dyestuff by the lignin adsorption), MSc Thesis, Pamukkale University, Denizli, Turkey.

Gune§, E., Atav, R., 2017, The use of nutshell firstly as a natural dye for cotton and wool and then as a natural adsorbent for colour removal of basic dye effluent, Coloration Technology, 133(1), 88-93.

Kaya, N., Yucel, A. T., Konkan, A., Mocur, D., Gultekin, M., 2011 , Ceviz Kabugu Ve Findik Kabugu Kullanarak Sulu ozeltilerden Dispers Azo Boya Giderimi (Removal Of Disperse Azo Dyes From Aqueous Solutions By Using Walnut Shell And Hazelnut Shell), Gazi Llniversitesi Muhendislik-Mimarlik Fakultesi Dergisi (J. Fac. Eng. Arch. Gazi Univ), 26(3), 509-514.

Kocaer, F. O., Alkan, U., 2002, Boyar Madde igeren Tekstil Atiksularinin Aritim Alternatifleri (Treatment Alternatives for Textile Effluents Containing Dyes), Uludag Llniversitesi Muhendislik-Mimarlik Fakultesi Dergisi, 7(1), 47-55.

Koklu, R., Ozer, ., 2018, Remazol Brillant Blue R (RBBR) boyarmaddesinin duguk maliyetli bir adsorban olan sigara kulu ile giderimi (Removal of Remazol Brilliant Blue R (RBBR) dyes with a low cost adsorbent, cigarette ash), Sakarya Llniversitesi Fen Bilimleri Enstitusu Dergisi (Sakarya University Journal Of Science), 22(2), 174-180.

Tantekin, T., 2006, Malatya Tekstil Fabrikalarinda Kullamlan egitli Boyalarin Atik Kayisidan Elde Edilen Aktif Karbon Me Adsorpsiyonunun incelenmesi (Invetigation of the adsorption various dyes used at textile plants in Malatya by using activated carbon prepared waste apricot), MSc Thesis, ίhόhϋ University, Malatya, Turkey.

Tanyildizi, M. §., Uygut, M. A., 2016, am Kozalagiyla Bazik Mavi 3 Adsorpsiyonu (Adsorption of Basic Blue 3 by Raw Pinecone), Firat Llniversitesi Muhendislik Bilimleri Dergisi, 28(2), 169-174.

Uysal, Y., Kereci, F. N., 2016, Tekstil Atik Kulu ile Tekstil Atik suyundan Renk Giderimi (Color Removal from Textile Wastewater by Using Textile Fly Ash), KSU Muhendislik Bilimleri Dergisi (KSU Journal of Engineering Science), 19(3), 82-86.

Yagub M. T., Sen T. K., Afroze S., Ang H.M., 2014, Dye and its removal from aqueous solution by adsorption: A review, Advances in Colloid and Interface Science, 209: 172— Brief Description of the Invention

The present invention is related to the use of air conditioner dust of the spinning mill producing cellulosic yarn as an adsorbent for reducing the color of dyehouse wastewater containing basic (cationic) dyes and a method and a combined system for applying air conditioner dust which fulfils the abovementioned requirements, eliminates all disadvantages and brings some additional advantages.

The primary aim of the invention is to introduce a method and system that provides decolorization by recycling waste by using air conditioner dust, which is the spinning mill waste.

The aim of the invention is to provide a decolorization method and a system that provides a cost advantage with the use of air conditioner dust compared to similar adsorbents.

Another aim of the invention is to provide a wastewater decolorization method and system in which a waste is used to dispose of another waste.

Another aim of the invention is to provide a decolorization system and method that enables the waste loads of dyehouses to be reduced and the possibilities of re-use of wastewater.

The present invention is a combined decolorization system in which a reactor system and a filtration system function sequentially to provide decolorization in a waste dye bath so as to fulfill the aims mentioned above. Accordingly, the said combined decolorization system contains the followings; air conditioner dust that is used as an adsorbent in the said reactor system so as to provide partially decolored dye bath by performing decolorization in the said waste dye bath and felted and/or pressed air conditioner dust that is used as an adsorbent in said filtration system so as to provide water decolored as much as possible by performing decolorization in said partially decolored dye bath.

The said air conditioner dust, felted air conditioner dust and pressed air conditioner dust are preferably supplied from a spinning mill producing cellulosic yarn so as to fulfill the aims of the invention.

The said waste dye bath is come out as a result of dyeing, preferably with a basic (cationic) dyestuff group so as to achieve the aims of the invention. Moreover, the present invention is a combined decolorization system in which a reactor system and a filtration system function sequentially to provide decolorization in a waste dye bath so as to fulfill the aims mentioned above. Accordingly said method comprises the following process steps; a) Converting air conditioner dusts, which are spinning mill waste belonging to cellulosic yarn production line, into adsorbent, b) Adding air conditioner dust with adsorbent feature into the waste dye bath so as to provide decoloring in said reactor system, c) Obtaining a partially decolored dye bath with the completion of the adsorption process in the waste dye bath and feeding the same to the filtration system, d) Preparing felted air conditioner dust from air conditioner dusts if possible alone or together with different cellulosic wastes for use in the filtration system, e) Preparing pressed air conditioner dust from air conditioner dusts to be used in the filtration system, f) Filtering the partially decolored dye bath with the prepared felted air conditioner dusts and/or pressed air conditioner dusts so as to provide decoloring in said filtration system, g) Obtaining water decolored as much as possible at the outlet of the filtration system.

The converting process into adsorbent in said step (a) is carried out without pre-heat treatment or by performing the burning-drying-carbonizing processes of said air conditioner dust preferably at a temperature of 100-4000, for different durations such as 5, 10 or 15 minutes so as to fulfill the aims of the inventive method.

In order to fulfill the aims of the inventive method, in the reactor system in said step (b), air conditioning dusts are preferably used at a ratio of 0.25-1 g/L.

In order to fulfill the aims of the method subject to the invention, the air-conditioner dusts in the reactor system in said step (b) are used preferably at room temperature, for 2-5 hours.

The structural and characteristic features of the present invention will be understood clearly by the following drawings and the detailed description made with reference to these drawings and therefore the evaluation shall be made by taking these figures and the detailed description into consideration.

Figures Clarifying the Invention

Figure 1, is a schematic view of the sample application that will allow the use of air conditioner dust of the invention as an adsorbent and view of the combined treatment system where the waste water color removal method can be applied.

The figures are not required to be scaled and the details which are not necessary for understanding the present invention may be neglected. Moreover, the elements that are at least substantially identical or have at least substantially identical functions been shown by the same number.

Description of the References

10 Combined Decolorization System

11 Air Conditioner Dust

12 Felted Air Conditioner Dust

13 Pressed Air Conditioner Dust

14 Waste Dye Bath

15 Partially Decolored Dye Bath

16 Water decolored as much as possible 20 Reactor System

21 Adsorption Chamber

211 Mixing Blade

212 Cover

22 Dye Bath Inlet Channel

23 Outlet Channel 30 Filtration System

31 Filtration Chamber

311 Opening-Closing Grid Cover

32 Press

33 Water Discharge Channel

Detailed Description of the Invention

In this detailed description, the use of air conditioner dust as an adsorbent in decolorization, the combined decolorization system (10) and related method are described only for clarifying the subject matter in a manner such that no limiting effect is created. The inventive combined decolorization system (10) is a system in which the color in the waste dye baths (14) is removed and the released water is re-used in textile mills. Said combined decolorization system (10) is a system where air conditioner dusts (11) are used as adsorbents that come out as waste in textile spinning mills, where cellulosic materials are processed. In combined decolorization system (10), air conditioner dust (11) is used as an adsorbent directly in a reactor system (20) and also in a filtration system (30) in the form of pressed air conditioner dust (13) and felted air conditioner dust (12).

The combined decolorization system (10) shown in detail in Figure 1 mainly consists of the following; said reactor system (20) and said filtration system (30) connected with the reactor system (20). The waste dye bath (14) is fed to the reactor system (20) and partially decolored dye bath (15) is obtained. The partially decolored dye bath (15) coming out of the reactor system (20) is fed to the filtration system (30), and the water decolored as much as possible (16) is obtained. Therefore, it will be possible to remove the color of the cationic (basic) dye-based waste dye bath (14) as much as possible by using the air conditioner dust (11) of the spinning mill, producing cellulosic yarn, as an adsorbent.

Reactor system (20) consists of an adsorption chamber (21), a dye bath inlet channel (22) connected to said adsorption chamber (21) and an outlet channel (23). There is a cover (212) on the adsorption chamber (21) and mixing blades (211) at the bottom of the chamber. In the reactor system (20), waste dye bath (14) is fed to the adsorption chamber (21) from the dye bath inlet channel (22) and air conditioner dust (11) is added so as to provide decoloring. Air conditioner dust (11) and waste dye bath (14) are mixed by said mixing blades (211) in a closed environment. By this mixing process; the efficiency of the air conditioner dusts (11), added to the chamber as adsorbent, to bind the dyestuff particles in the waste dye bath (14) increase and the adsorption process accelerate. The partially decolored dye bath (15) is obtained and fed to the filtration system (30) from the outlet channel (23) with the completion of the adsorption process. Air conditioner dust (11) that remains in the adsorption chamber (21) is also removed from the chamber.

Filtration system (30) comprises the following; the filtration chamber (31), opening-closing grid covers (311) in said filtration chamber (31), a press (32) that can be moved inside the filtration chamber (31) and a water discharge channel (33) connected with the filtration chamber (31). Between said opening-closing grid covers (311) within the filtration chamber (31), the felted air conditioner dust (12) is placed at the bottom and pressed air conditioner dust (13) prepared with said press (32) at the top. The partially decolored dye bath (15) is fed to the filtration chamber (31) from the outlet channel (23) of the adsorption chamber (21) and is exposed to the decoloring process with the adsorbent effect of the pressed air conditioner dust (13) and felted air conditioner dust (12) with the activity of the opening-closing grids (311). At the end of the filtration process, the water decolored as much as possible (16) which is free of dye particles held by adsorbents exits from the water discharge channel (33). The felted air conditioner dust (12) and pressed air conditioner dust (13), with adsorbent feature remaining in the filtration chamber (31) are also removed from the chamber.

In the combined decolorization system (10), air conditioner dust (11) that is used as an adsorbent and is a waste of spinning mill is used without pre-heat treatment or preferably by performing the burning-drying-carbonizing processes at a temperature of IOO^OOΌ for different durations such as 5, 10 or 15 minutes. These air conditioner dusts (11), which are prepared as adsorbents, are added preferably at a ratio of 0.25-1 g/L into different colored textile wastewater depending on the initial dye concentration of wastewater. And by this way they cause a decrease in the color of the wastewater after incubation for 2-5 hours, preferably at room temperature, depending on the concentration of the adsorbent and the color darkness of the wastewater.

Sample studies carried out under laboratory conditions in accordance with the invention, and their results on decolorization of cationic (basic) dye baths using spinning mill air conditioner dust (11) of the cotton yarn production line are given herein below.

Example 1

If 0.02g of air conditioner dust (11) is added as an adsorbent into a 40ml bath at pH 7 containing 0.1 g/L Basic Blue 41 dye concentration without pre-heat treatment or with pre-heat treatment at 100-200-300-400°C for different durations (5-10-15) and then if the baths containing air conditioner dust are agitated at 200 rpm for 180 minutes at room temperature, the decolorization, expressed as the adsorption yield (%) with the help of Equation 1 , is obtained as given in Table 1. The experiments were carried out in an incubator shaker in erlenmeyer flasks.

Table 1. The adsorption yields (%) caused by addition and then 180 min agitation of the air conditioner dusts, that are pre-heat treated at different temperatures and durations and not pre heat treated, into 0.1 g/L Basic Blue 41 dye solution. Example 2

The air conditioner dusts at different concentrations that are pre-heat treated for 200°C-5 minutes or not pre-heated were added to a 40ml bath at pH 7 containing 0.1 g/L Basic Blue 41 dye concentration. And then with the help of equation 1 , the decolorizations were calculated for different agitation/incubation durations. Accordingly, 0.01 -0.02-0.03-0.04g of air conditioner dust (11) was added to 40 ml of dye bath and the processes were carried out at room temperature under 200 rpm agitation conditions, and decolorization, i.e. adsorption yields (%) were calculated according to the amount of adsorbent and agitation/incubation durations. The obtained results are given in Table 2. The experiments were carried out in an incubator shaker in erlenmeyer flasks.

Table 2. The Adsorption yields (%) caused by different air conditioner dust concentrations for 0.1 g/L Basic Blue 41 dye solution

Equation 1 mentioned in the examples: Adsorption Yield (%) = (Co-C)/Cox100. In this calculation; (Co) refers to the initial dye concentration (g/L) and (C) refers to the final dye concentration (g/L) after incubation of the dye bath with spinning mill waste. Although the initial dye concentrations were adjusted as 0.1 g/L in the calculations, absorbance values of dye baths that do not contain air conditioner dust (11) were also measured for each application during the trials. The concentrations were calculated again by means of the calibration graphs from the obtained absorbance values and these values were determined as the initial dye concentration for each working condition. Therefore, it is aimed to eliminate the deviations that may occur during the agitation and measurement process.

According to the experiments and the data obtained, it is understood that the air conditioner dust (11) can provide different adsorption yields and can remove the color of the basic (cationic) dye solutions depending on the pre-treatment, the amount of adsorbent (the amount of air conditioning dust) and the agitation/incubation duration. It is thought that this effect is caused by the negative zeta potential of the waste, that is, especially by bonding/adherence of cationic based dye to negatively charged air conditioner dust with the help of secondary bonds and ionic bonds during the process. Thus, it has been observed that the air conditioner dust of the spinning mill producing cellulosic yarn has a negative Zeta potential.

Wastewater emerges in different steps in and after the dyeing processes in dyehouses. In general, the waste dye bath (14) and the first rinsing waters have a darker color and the subsequent rinsing waters have a lighter color and they are cleaner. In the inventive system, these two categories of different wastewater are passed separately through the air conditioner dust (11) based reactor system (20) and filtration system (30) before being fed to conventional treatment plants. Reuse possibilities may occur by processing these two different categories of wastewater separately. Thus, the rinsing water among the wastewater is passed through the combined decolorization system (10) based on air conditioner dust (11) after passing through the heat exchangers for decolorization and afterwards this water can be given back to the mill as process water for dyeing. Meanwhile, the dye bath and the first rinsing water are passed through a different air conditioner dust (11) based combined system (10) to be installed in the facility and decolorization will be completed substantially and afterwards this water can be discharged to the conventional treatment system. Therefore, the wastewater load in the factories will be reduced with the use of the inventive combined decolorization system (10). Moreover, waste recycling will be provided and the adsorbent cost will be reduced by using air conditioner dust (11) which is the waste of spinning mills.

The inventive decolorization system (10) is carried out by using air conditioner dust (11) of the spinning mill producing cellulosic yarn in decolorization of basic (cationic) dye baths. Different dyestuffs can be used according to the fiber type used in textile dyeing processes. Accordingly, the content of the waste dye bath (14) may vary depending on the dyestuff groups (basic, reactive, direct, disperse, vat, acid, metal complex, etc.) used. In this sense, it is also estimated that the air conditioner dust (11) can be used for decolorization at different ratios under different application conditions in the waste dye baths (14) arising from the use of different dyestuff groups.