METHOD FOR SEQUENTIAL RECOVERY OF SINGLE TYPE OF PLASTIC MATERIAL FROM PLASTIC WASTE IN A CLOSED SYSTEM

Abstract

The present disclosure relates to method for sequential recovery of single type of plastic material from plastic waste in a closed system comprising: a) pre-heating a solvent under condition to obtain a pre-heated solvent; b) adding plastic waste in the pre-heated solvent followed by increasing the temperature to cause evaporation of solvent and the plastic waste gets dissolved and concentrated to obtain a mixture and simultaneous recovery of pure, uncolored solvent; and c) cooling and stirring the mixture of step b) to obtain a powder precipitate, wherein simultaneous solvent evaporation and recovery while concentrating the plastic material occurs, followed by a quick precipitation of plastic in its virgin state. The method of the present disclosure showed about 3% higher yield, about 18 % lower energy requirement and about 54 % lower time required than the traditional method.

Specification

Description:FIELD OF INVENTION
[0001] The present disclosure relates to the field of waste plastic recovery. Particularly, the present disclosure relates to a method for sequential recovery of single type of plastic material from the source item or plastic waste one at a time.

BACKGROUND OF THE INVENTION
[0002] Background description includes information that may be useful in understanding the present invention. It is not an admission that any of the information provided herein is prior art or relevant to the presently claimed invention or that any publication specifically or implicitly referenced is prior art.
[0003] Cavalcante et al. [Sustain. Mater. Technol., 2022, 32, e00448] discloses green solvents for the recycling of face masks by taking advantage of their antipathogenic nature for sterilization purposes. The process discloses recovery of polypropylene from face masks, and upcycle of the masks into either a microbead or free-standing membranes as separation materials. Owing to their excellent chemical stability, the membranes are well-suited for organic solvent nanofiltration. The fabricated membranes exhibited molecular weight cut-off values between 665 and 964 g mol−1, which were fine-tuned by adjusting the coagulation bath temperature from 20 °C to 60 °C. The membranes demonstrated long-term stability over 5 days of continuous filtration at 30 bar, with rejection values exceeding 98% for roxithromycin and rose bengal. This scalable methodology for upcycling used face masks into high-value products has the potential to reduce a crucial environmental threat associated with the global rapid growth of the face mask market. Cavalcante et al. replaced xylene by p-cymene for dissolving the polypropylene in facemasks but precipitation was done by the antisolvent method, using ethanol and terpineol. Cavalcante et al. do not disclose the simultaneous recovery of pure solvent in the given method.
[0004] Hanschmann B. [Adv. Polym. Tech., 2023, 2023(2), 1-11] investigated six dissolution-precipitation processes based on high-boiling sustainable green organic solvents and antisolvents for the polypropylene and polyethylene terephthalate with respect to apparent particle morphology for a closed loop production scheme. Of the investigated processes two are considered antisolvent-induced precipitations whereas the other four can be considered temperature induced. The applied solvents included p-cymene, dibutoxymethane, ethylbenzoate, γ-valerolactone, ethanol, and hexanol. All processes yielded powders consisting of agglomerated primary particles at a powder dry substance of less than 25% by weight. The produced powders consist in all cases of agglomerates of smaller primary particles. Thus, Hanschmann B. discloses a method of antisolvent precipitation of polypropylene using ethanol. Hanschmann B. does not disclose the simultaneous recovery of pure solvent in the given method.
[0005] Fang et al. [Adv. Polym. Tech., 2019, 2019, 1-10] investigated the influence of preparation condition on properties of PP powder. The experimental results show that the optimal preparation conditions are as follows: dissolution temperature being about 166 °C, pressure being about 0.7MPa, and the solid-to-solvent ratio being about 0.067g/ml. The prepared PP powder displayed a narrow size distribution with the mean size of about 42.7 𝜇m and the apparent density of powder about 0.40 g/cm3. The specimens produced by laser sintering of the PP powder showed smooth appearance and good dimensional accuracy. The tensile strength and impact strength of the sintered parts were 27.9 MPa and 6.3KJ/m2, respectively, which are basically equal to the properties of the injection molded parts. In this article, the polypropylene resins dissolved by xylene and precipitated by cooling. In view of this article, the simultaneous recovery of pure solvent is not disclosed in the given method.
[0006] US3971749A discloses polypropylene resins dissolved by xylene and precipitated by cooling and various conditions to improve the quality; polypropylene particles are produced. US3971749A does not disclose the simultaneous recovery of pure solvent in the given method.
[0007] US4510305A discloses production of powders of polypropylene by polypropylene dissolution and precipitation by either antisolvent or cooling method. US4510305A does not disclose the simultaneous recovery of pure solvent in the given method.
[0008] Thus, the process of the traditional method having the steps of a) the solvent pre-heating, b) plastic dissolution, c) cooling and precipitation of the plastic. The drawback of these prior arts is that the cooling and precipitation step takes a long time to cool and precipitate. In terms of energy usage, the pre-heating step involves energy investment and during cooling and precipitation, the energy that was used during pre-heating is dissipated/wasted into the environment, thus require high energy in the process, which is dissipated/wasted. It should be noted that the dye material in the mask remains in the solvent even after the procedure is completed, hence it is not returned to its virgin state. Further, some of prior art uses antisolvent also which increases the cost of the process. Thus, the traditional methods do not disclose the simultaneous recovery of pure solvent.
[0009] In view of the above, there is a need to develop a novel method for obtaining single plastic from the plastic waste with higher yield, lesser time and energy requirement along with simultaneous recovery of pure solvent.

OBJECTS OF THE INVENTION
[0010] The primary objective of the present disclosure is to provide a method for sequential recovery of single type of plastic material from the source item or plastic waste one at a time.
[0011] Another objective of the present disclosure is to develop a novel method for recovery of single plastic one type at a time material from plastic waste with improved energy usage.
[0012] Another objective of the present disclosure is to develop a novel method for recovery of single plastic material one type at a time from plastic waste with improved time required for batch processing.
[0013] Still another objective of the present disclosure is to develop a novel method for recovery of single plastic material one type at a time from plastic waste with improved yield.
[0014] Yet another objective of the present disclosure is to provide a reflux-based method for recovery of the dissolving solution simultaneously while concentrating the plastic material from plastic waste, after which the plastic quickly precipitates.

SUMMARY OF THE INVENTION
[0015] This summary is provided to introduce a selection of concepts in a simplified form that are further described below in Detailed Description section. This summary is not intended to identify key features or essential features of the claimed subject matter, nor is it intended to be used as an aid in determining the scope of the claimed subject matter.
[0016] The present disclosure relates to the field of waste plastic recovery. Particularly, the present disclosure relates to a method for recovery of single plastic material sequentially from plastic waste in a closed system.
[0017] An aspect of the present disclosure relates to a method for sequential recovery of single type of plastic material from plastic waste in a closed system comprising: a) pre-heating a solvent under condition to obtain a pre-heated solvent; b) adding plastic waste in the pre-heated solvent followed by increasing the temperature to cause evaporation of solvent and the plastic waste gets dissolved and concentrated to obtain a mixture and simultaneous recovery of pure and uncolored solvent; and c) cooling and stirring the mixture of step b) to obtain a powder precipitate, wherein simultaneous solvent evaporation and recovery while concentrating the plastic material occurs, followed by a quick precipitation of plastic in its virgin state. Particularly, the present disclosure relates to a method for sequential recovery of single type of plastic material from the source item or plastic waste one at a time along with simultaneous recovery of pure and uncolored solvent.
[0018] Various objects, features, aspects, and advantages of the present disclosure will become more apparent from the following detailed description of preferred embodiments, along with the accompanying drawing figures in which numerals represent features.


BRIEF DESCRIPTION OF THE DRAWINGS
[0019] The following drawings form part of the present specification and are included to further illustrate aspects of the present invention. The disclosure may be better understood by reference to the drawings in combination with the detailed description of the specific embodiments presented herein.
[0020] FIG. 1 illustrates lab-implementation of the closed system of present method.
[0021] FIG. 2 illustrates powder obtained from the (A) traditional method and (B) present method.
[0022] FIG. 3 illustrates FTIR of the plastic obtained by the present method.

DETAILED DESCRIPTION OF THE INVENTION
[0023] The following is a detailed description of the embodiments of the disclosure. The embodiments are in such detail as to clearly communicate the disclosure. However, the amount of detail offered is not intended to limit the anticipated variations of embodiments; on the contrary, the intention is to cover all modifications, equivalents, and alternatives falling within the spirit and scope of the present disclosure as defined by the appended claims.
[0024] All publications herein are incorporated by reference to the same extent as if each individual publication or patent application were specifically and individually indicated to be incorporated by reference. Where a definition or use of a term in an incorporated reference is inconsistent or contrary to the definition of that term provided herein, the definition of that term provided herein applies and the definition of that term in the reference does not apply.
[0025] Reference throughout this specification to "one embodiment" or "an embodiment" means that a particular feature, structure or characteristic described in connection with the embodiment is included in at least one embodiment. Thus, the appearances of the phrases "in one embodiment" or "in an embodiment" in various places throughout this specification are not necessarily all referring to the same embodiment. Furthermore, the particular features, structures, or characteristics may be combined in any suitable manner in one or more embodiments.
[0026] In some embodiments, numbers have been used for quantifying weights, percentages, ratios, and so forth, to describe and claim certain embodiments of the invention and are to be understood as being modified in some instances by the term "about." Accordingly, in some embodiments, the numerical parameters set forth in the written description and attached claims are approximations that can vary depending upon the desired properties sought to be obtained by a particular embodiment. In some embodiments, the numerical parameters should be construed in light of the number of reported significant digits and by applying ordinary rounding techniques. Notwithstanding that the numerical ranges and parameters setting forth the broad scope of some embodiments of the invention are approximations, the numerical values set forth in the specific examples are reported as precisely as practicable.
[0027] The numerical values presented in some embodiments of the invention may contain certain errors necessarily resulting from the standard deviation found in their respective testing measurements.
[0028] Unless the context requires otherwise, throughout the specification which follows, the word "comprise" and variations thereof, such as "comprises" and "comprising" are to be construed in an open, inclusive sense that is as "including, but not limited to."
[0029] As used in the description herein and throughout the claims that follow, the meaning of "a," "an," and "the" includes plural reference unless the context clearly dictates otherwise. Also, as used in the description herein, the meaning of "in" includes "in" and "on" unless the context clearly dictates otherwise.
[0030] The recitation of ranges of values herein is merely intended to serve as a shorthand method of referring individually to each value falling within the range. Unless otherwise indicated herein, each individual value is incorporated into the specification as if it were individually recited herein. Furthermore, the ranges defined throughout the specification include the end values as well, i.e., a range of 1 to 10 implies that both 1 and 10 are included in the range. For the avoidance of doubt, the applicant shall be entitled to any equivalents according to applicable law.
[0031] All methods described herein can be performed in a suitable order unless otherwise indicated herein or otherwise clearly contradicted by context. The use of any and all examples or exemplary language (e.g., "such as") provided with respect to certain embodiments herein is intended merely to better illuminate the invention and does not pose a limitation on the scope of the invention otherwise claimed. No language in the specification should be construed as indicating any non-claimed element essential to the practice of the invention.
[0032] Groupings of alternative elements or embodiments of the invention disclosed herein are not to be construed as limitations. Each group member can be referred to and claimed individually or in any combination with other members of the group or other elements found herein. One or more members of a group can be included in or deleted from a group for reasons of convenience and/or patentability. When any such inclusion or deletion occurs, the specification is herein deemed to contain the group as modified.
[0033] The description that follows and the embodiments described therein are provided by way of illustration of an example, or examples, of particular embodiments of the principles and aspects of the present disclosure. These examples are provided for the purposes of explanation, and not of limitation, of those principles and of the disclosure.
[0034] It should also be appreciated that the present disclosure can be implemented in numerous ways, including as a system, a method or a device. In this specification, these implementations, or any other form that the invention may take, may be referred to as processes. In general, the order of the steps of the disclosed processes may be altered within the scope of the invention.
[0035] The headings and abstract of the invention provided herein are for convenience only and do not interpret the scope or meaning of the embodiments.
[0036] The following discussion provides many example embodiments of the inventive subject matter. Although each embodiment represents a single combination of inventive elements, the inventive subject matter is considered to include all possible combinations of the disclosed elements. Thus, if one embodiment comprises elements A, B, and C, and a second embodiment comprises elements B and D, then the inventive subject matter is also considered to include other remaining combinations of A, B, C, or D, even if not explicitly disclosed.
[0037] The term "or," as used herein, is generally employed in its sense, including "and/or" unless the content clearly dictates otherwise.
[0038] Various terms are used herein to the extent a term used is not defined below; it should be given the broadest definition persons in the pertinent art have given that term as reflected in printed publications and issued patents at the time of filing.
[0039] The present disclosure relates to the field of waste plastic recovery. Particularly, the present disclosure relates to a method for sequential recovery of single type of plastic material from the source item or from plastic waste one at a time.
[0040] The present disclosure is on the premise of using a modified setup that essentially allows simultaneous plastic concentration and solvent recovery, followed by a quick precipitation. The novel method thus developed promises significant reduction in time for each batch to be processed, reduction in energy requirement, and a statistically significant increase in yield. Furthermore, finer quality powder polypropylene was obtained from the novel method compared to the traditional method, thereby producing plastic that can be recycled in almost virgin form for relevant industries. The present disclosure focuses on removing the plastic one layer at a time using a solvent that can specifically target a particular plastic.
[0041] An embodiment of the present disclosure is to provide a method for sequential recovery of single type of plastic material from plastic waste in a closed system comprising: a) pre-heating a solvent under condition to obtain a pre-heated solvent; b) adding plastic waste in the pre-heated solvent followed by increasing the temperature to cause evaporation of solvent and the plastic waste gets dissolved and concentrated to obtain a mixture and simultaneous recovery of pure, uncolored solvent; and c) cooling and stirring the mixture of step b) to obtain a powder precipitate, wherein simultaneous solvent evaporation and recovery while concentrating the plastic material occurs, followed by a quick precipitation of plastic in its virgin state. Particularly, the present disclosure relates to a method for sequential recovery of single type of plastic material from the source item or plastic waste one at a time along with simultaneous recovery of pure and uncolored solvent. Thus, the key feature of the present disclosure is simultaneous recovery of pure solvent while concentrating the plastic, followed by a quick precipitation.
[0042] In an embodiment, the closed system comprises a reactor vessel connected to a condenser with a collector for the pure solvent.
[0043] In an embodiment, the plastic material is any thermoplastic polymer. In an embodiment, the thermoplastic polymer is selected from a group consisting of polypropylene (PP), polyethylene terephthalate (PET), High-density polyethylene (HDPE) and the like.
[0044] In an embodiment, the solvent is selected on the basis of chemical nature similar to plastic monomer such that it dissolves the plastic. In an embodiment, the solvent is any aromatic hydrocarbons. Some examples of aromatic hydrocarbons include benzene, toluene, xylenes, cumene, tetralin, decalin, styrene, biphenyl and the like. The foregoing are illustrative examples and should not be construed as limiting the scope of the invention.
[0045] In an embodiment, the condition in step a) includes pre-heating temperature and time period is based on the type of solvent and volume of solvent respectively. In some embodiment, the pre-heating temperature is the boiling point of the selected solvent at 1 atm pressure. Some examples for the pre-heating temperature of the solvents are benzene (80 °C), toluene (110 °C), o-xylene (144 °C), m-xylene (139 °C), p-xylene (138 °C), cumene (152 °C), tetralin (207 °C), decalin (187 °C), styrene (145 °C), biphenyl (256 °C) at 1 atm pressure. If the pressure in the reactor is increased the pre-heating temperature will also increase accordingly.
[0046] In an embodiment, the plastic waste is selected from surgical mask, kidney dishes, gallipots and combination thereof. Certain waste streams, such as waste from hospitals comprising mask material, kidney dishes, gallipots, etc., are made of a single plastic type; in the aforementioned example, polypropylene (PP) is used.
[0047] In an embodiment, the plastic waste is added in the pre-heated solvent in an amount in the range of 1 to 80 % w/v. Preferably, the amount of the plastic waste is added in the pre-heated solvent is atleast 1 % w/v or 2 % w/v or 3 % w/v or 4 % w/v or 5 % w/v or 6 % w/v or 7 % w/v or 8 % w/v or 9 % w/v or 10 % w/v or 11 % w/v or 12 % w/v or 13 % w/v or 14 % w/v or 15 % w/v or 16 % w/v or 17 % w/v or 18 % w/v or 19 % w/v or 20 % w/v or 21 % w/v 22 % w/v or 23 % w/v or 24 % w/v or 25 % w/v or 26 % w/v or 27 % w/v or 28 % w/v or 29 % w/v or 30 % w/v or 31 % w/v or 32 % w/v or 33 % w/v or 34 % w/v or 35 % w/v or 36 % w/v or 37 % w/v or 38 % w/v or 39 % w/v or 40 % w/v or 41 % w/v or 42 % w/v or 43 % w/v or 44 % w/v or 45 % w/v or 46 % w/v or 47 % w/v or 48 % w/v or 49 % w/v or 50 % w/v or 51 % w/v or 52 % w/v or 53 % w/v or 54 % w/v or 55 % w/v or 56 % w/v or 57 % w/v or 58 % w/v or 59 % w/v or 60 % w/v or 61 % w/v or 62 % w/v or 63 % w/v or 64 % w/v or 65 % w/v or 66 % w/v or 67 % w/v or 68 % w/v or 69 % w/v or 70 % w/v or 71 % w/v or 72 % w/v or 73 % w/v or 74 % w/v or 75 % w/v or 76 % w/v or 77 % w/v or 78 % w/v or 79 % w/v or 80 % w/v.
[0048] In an embodiment, the temperature in step b) depends on the boiling point of the solvent. Some examples for the heating temperature of the solvents are benzene (80 °C), toluene (110 °C), o-xylene (144 °C), m-xylene (139 °C), p-xylene (138 °C), cumene (152 °C), tetralin (207 °C), decalin (187 °C), styrene (145 °C), biphenyl (256 °C) at 1 atm pressure. If the pressure in the reactor is increased the heating temperature will also increase accordingly.
[0049] In an embodiment, the mixture of step c) is cooled at a temperature in the range of 15 to 30°C. Preferably, the mixture of step c) is cooled at a temperature in the range of 16 to 30°C or 17 to 30°C or 18 to 30°C or 19 to 30°C or 20 to 30°C or 21 to 29°C or 22 to 28°C or 23 to 27°C or 24 to 26°C or 25°C. Basically, the cooling precipitation can be done at room temperature or in the fridge.
[0050] In an embodiment, the method removes the plastic one layer at a time using a solvent that specifically targets a particular plastic.
[0051] The present disclosure provides a method for sequential recovery of single type of plastic material from plastic waste in a closed system. Particularly, the present disclosure relates to a method for sequential recovery of single type of plastic material from the source item or plastic waste one at a time along with simultaneous recovery of pure and uncolored solvent. Thus, the key feature of the present disclosure is simultaneous recovery of pure solvent while concentrating the residual plastic, followed by a quick precipitation.
[0052] While the foregoing describes various embodiments of the disclosure, other and further embodiments of the disclosure may be devised without departing from the basic scope thereof. The invention is not limited to the described embodiments, versions or examples, which are included to enable a person having ordinary skill in the art to make and use the invention when combined with information and knowledge available to the person skilled in the art.
EXAMPLES
[0053] The present invention is further explained in the form of the following examples. However, it is to be understood that the following examples are merely illustrative and are not to be taken as limitations upon the scope of the invention.
Example 1
[0054] In the present novel method, the round-bottom flask was connected to a condenser as shown in FIG. 1. In terms of the procedure, 100 mL of xylene was first placed in the round-bottom flask. This volume was pre-heated to the desired temperature (138 °C), after which 1.9 g of a polypropylene (PP) surgical mask was placed in the heated solvent. Subsequently, the heating from the mantle was increased just enough to cause evaporation of the solvent at the same temperature; in the process of this evaporation, the solvent was purified of both the PP and the dye in the mask. After this evaporation has resulted in a very small quantity of solvent to remain behind with the concentrated PP and dye, the heating mantle was switched off. Thus, in the procedure, only a small amount of solvent was left to cool with the powder of PP. Only 5 minutes was required for this small quantity of left-behind mixture to cool as are shown in Table 1. The total time required was 26 minutes which is much lesser than the Comparative Example 1. Results on yield and energy requirement by Example 1 (present invention) and Comparative Example 1 (Traditional method) are as shown in Table 2. FIG. 2 showed that the powder of plastic obtained from the present method is much finer than the traditional method. FTIR of the plastic obtained by the present method showed that the quality basically same as the virgin plastic as illustrated in FIG. 3. FTIR analysis was carried out to assess the chemical composition of all the samples, including the mask sample and those heated at 110°C, 120°C, and 130°C. The FTIR peaks confirm that all samples are composed purely of polypropylene (PP). The characteristic peaks were identified as follows: the peak at 2952 cm⁻¹ corresponds to the asymmetric stretching of the methyl group (-CH₃), while the peak at 2918 cm⁻¹ is attributed to the asymmetric stretching of the methylene group (-CH₂-). The symmetric stretching vibrations of -CH₃ and -CH₂- are observed at 2868 cm⁻¹ and 2840 cm⁻¹, respectively. Additionally, the bending vibrations of -CH₂- and -CH₃ are found at 1455 cm⁻¹ and 1375 cm⁻¹, respectively. The peaks at 1169 cm⁻¹ and 972 cm⁻¹ are due to the stretching vibrations of C-C bonds in the polymer backbone. Notably, no peaks were observed around 3300-3400 cm⁻¹, indicating the absence of hydroxyl (O-H) stretching vibrations, which rules out any contamination by cellulose or glucose. Therefore, the results confirm that no paper contamination occurred in the samples.
Comparative Example 1 (Traditional method)
[0055] 100 mL of xylene was first placed in the round-bottom flask. This volume was pre-heated to the desired temperature (138oC), after which 1.9 g of a polypropylene (PP) surgical mask was placed in the heated solvent. The mask material was seen to dissolve almost instantaneously in the heated solvent. Subsequently, the heated round-bottom flask was allowed to cool, and due to this cooling, precipitation of the PP material occurred; stirring was done to obtain powder of PP. The major time required in this process is for the cooling and precipitation, which takes approximately 50 minutes when the process starts off with 100 mL of solvent as shown in Table 1. Results on yield and energy requirement by Example 1 (present invention) and Comparative Example 1 (Traditional method) are as shown in Table 2.
Table 1: Results on time required by Example 1 and Comparative Example 1 (Traditional method).
Sub-process Time required in Example 1 Time required in Comparative Example 1
Pre-heat of solvent 6 minutes 6 minutes
Dissolution of mask material Instantaneous Instantaneous
Evaporation and condensation of solvent 15 minutes
Not applicable
Cooling and precipitation 5 minutes 50 minutes
Total time 26 minutes 56 minutes

Table 2: Results on yield, energy requirement and time required by Example 1 and Comparative Example 1 (Traditional method).
Method Yield Energy requirement Time required for one batch
Comparative Example 1 96.73% 1.30
5.24 kJ 56 mins
Example 1 99.73 0.50
4.30 kJ 26 mins
Change in Example 1 compared to Comparative Example 1

[0056] It is clear from Table 1 and Table 2 that the present method has a significant increased yield about 3 % with about 18% reduction in energy requirement and about 54% reduction in time requirement. Further, the particle size of the obtained plastic is much finer than the powder obtained by the traditional method and can be recycled in almost virgin form for relevant industries. Simultaneous solvent recovery is done in present invention which is not possible in traditional method. Thus, the present method is better than the traditional method and this is achieved by simultaneous solvent evaporation and recovery while precipitating plastic material.
Mechanical Strength of extracted PP powder
[0057] The tensile strength of the extracted PP powder as mentioned in example 1 was determined. The tensile strength of virgin PP power is in the range of 30-40 MPa and the results of the present extracted PP power is in the same range as shown in Table 3.
Table 3: Mechanical Strength of extracted PP powder.
Sample no. Tensile Strength (MPa) Elongation at yield (%)
1 46 13
2 41 15
3 44 11
4 41 13
Average 43 13

ADVANTAGES OF THE INVENTION
[0058] The major advantages of the present disclosure over the traditional method are the recovery of pure solvent due to the evaporation step, the reduced cooling time and wasted/dissipated heat due to the lowered amount of left-behind solvent, and better quality (finer) powder of PP left behind (presumably due to the agitation due to the evaporating solvent). Additionally, a small but statistically significant increase in the PP yield was observed in the present method as compared to the traditional method. The PP powder from the present method appeared finer than that from the traditional method.
, Claims:1. A method for sequential recovery of single type of plastic material from plastic waste in a closed system comprising:
a) pre-heating a solvent under condition to obtain a pre-heated solvent;
b) adding plastic waste in the pre-heated solvent followed by increasing the temperature to cause evaporation of solvent and the plastic waste gets dissolved and concentrated to obtain a mixture and simultaneous recovery of pure, uncolored solvent; and
c) cooling and stirring the mixture of step b) to obtain a powder precipitate,
wherein simultaneous solvent evaporation and recovery while concentrating the plastic material occurs, followed by a quick precipitation of plastic in its virgin state.

2. The method as claimed in claim 1, wherein the closed system comprises a reactor vessel connected to a condenser with a collector for the pure solvent.

3. The method as claimed in claim 1, wherein the plastic material is any thermoplastic polymer.

4. The method as claimed in claim 1, wherein the solvent is selected on the basis of chemical nature similar to plastic monomer such that it dissolves the plastic.

5. The method as claimed in claim 1, wherein the condition in step a) includes pre-heating temperature and time period is based on the type of solvent and volume of solvent respectively.

6. The method as claimed in claim 1, wherein the plastic waste is selected from surgical mask, kidney dishes, gallipots and combination thereof.
7. The method as claimed in claim 1, wherein the plastic waste is added in the pre-heated solvent in an amount in the range of 1 to 80 % w/v.

8. The method as claimed in claim 1, wherein the temperature in step b) depends on the boiling point of the solvent.

9. The method as claimed in claim 1, wherein the mixture of step c) is cooled at a temperature in the range of 15 to 30°C.

10. The method as claimed in claim 1, wherein the method removes the plastic one layer at a time using a solvent that specifically targets a particular plastic.

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