MoSe2 DECORATED 3D PYROLYZED PEGDA MICROSTRUCTURE FOR SUSTAINABLE PHOTODEGRADATION OF MIXED TEXTILE DYES UNDER SUNLIGHT IRRADIATION

Abstract

The present invention relates to a novel photocatalytic material and process for wastewater treatment. The invention discloses three-dimensional (3D) pyrolyzed polyethylene glycol diacrylate (PEGDA) microstructures decorated with molybdenum diselenide (MoSe₂) nanosheets, herein referred to as MoSe₂@3D Py-PEGDA. The material is fabricated by digital light processing (DLP) 3D printing of PEGDA followed by pyrolysis to obtain a conductive carbon scaffold, onto which MoSe₂ nanosheets are deposited via a hydrothermal method. The resulting hybrid structure exhibits enhanced photocatalytic degradation of organic dye pollutants, including methyl orange (MO) and methylene blue (MB), under both visible light and direct solar irradiation, achieving degradation efficiencies up to 96%. The immobilization of MoSe₂ on a 3D pyrolytic scaffold overcomes limitations of powdered photocatalysts, such as aggregation, retrieval difficulties, and pipeline blockages, thereby ensuring improved stability, reusability, and scalability. Furthermore, the treated wastewater was demonstrated to support agricultural applications by enabling healthy growth of Hordeum vulgare (barley) seeds, confirming its practical utility.

Description

FIELD OF THE INVENTION

[0001] The present invention pertains to development of MoSe2 nanosheetdecorated3D-printed pyrolytic PEGDA (MoSe2@3D Py-PEGDA) structures.These MoSe2@3D Py-PEGDA structures were employed for efficient wastewatertreatment under both UV and solar irradiation.BACKGROUND OF THE INVENTION

[0002] Background description includes information that may be useful inunderstanding the present invention. It is not an admission that any of theinformation provided herein is prior art or relevant to the presently claimedinvention, or that any publication specifically or implicitly referenced is prior art.

[0003] The growing challenge of wastewater treatment, exacerbated bypollutants from agricultural, domestic, and industrial activities, has drawnsignificant global attention. Despite water covering 71% of the Earth's surface,less than 1% is readily available for drinking. By 2050, water demand is expectedto increase by 55% due to population growth, with a projected global water deficitof 40% by 2030. According to the World Health Organization (WHO), one in fourindividuals lacks access to safe drinking water, contributing to 6% of deaths inlow-income countries in 2017. The textile industry is a major contributor to waterpollution, extensively using non-biodegradable dyes that pose severeenvironmental risks.

[0004] Methyl orange (MO) and methylene blue (MB), widely used in textilessuch as wool, polyester, nylon, and cotton, are particularly challenging to degradein aqueous solutions due to their complex molecular structures. Thus, developingeffective wastewater treatment techniques is crucial for addressing this issue andpromoting sustainable water management. Solar light photocatalysis has emergedas a promising eco-friendly solution, offering an efficient method for degradingorganic pollutants.

[0005] However, its practical application faces challenges, including particleaggregation and the difficulty of separating photocatalysts from treated water. Theuse of powdered photocatalysts in wastewater treatment facilities can lead toretrieval issues and pipe blockages. Recent research has focused on immobilizingphotocatalysts onto substrates, but these approaches often face limitations due tosize and shape mismatches with real-world purification scenarios. Thisunderscores the need for customizable substrates coated with photocatalyticmaterials to enhance efficiency and adaptability.

[0006] CN102992281A discloses a nano-flower MoSe 2 and a preparationmethod thereof. Mainly using sodium molybdate, selenium powder and sodiumborohydride as raw materials, the nano-sized flower-like MoSe 2 is synthesized inone step by hydrothermal method. The raw materials of the method of theinvention are easy to obtain, the preparation process is simple and easy, and thereaction conditions are mild. The prepared MoSe 2 has uniform size, uniformdistribution, and good crystallinity.

[0007] KR101471507B1 discloses an organic-inorganic nanocompositeincluding a titanium dioxide-carbon material composite for decomposing organicpollutants is described, which comprises a titanium dioxide-carbon materialcomposite dispersed within a polymer material, wherein the titanium dioxidecarbonmaterial composite comprises a graphene-carbon nanotube mixture inwhich graphene and carbon nanotubes are mixed as carbon materials, and titaniumdioxide fixed to the surface of the graphene-carbon nanotube mixture.

[0008] Development of Bi2O3 / MoSe2 mixed nanostructures for photocatalyticdegradation of methylene blue dye (DOI: 10.1080 / 16583655.2022.2161333)demonstrate the sample and low coast hydrothermal synthesis of a nanocompositeof Bi2O3 / MoSe2 for hybrid photocatalyst. The structure of as-synthesizedsamples was characterized by using several techniques, including XRDspectroscopy, Raman spectroscopy, XPS, SEM, BET, and UV-visible absorptionspectroscopy. The nitrogen adsorption-desorption measurements show that thesamples have a mesoporous texture with slits like pores. The Bi2O3 / MoSe2nanocomposite had BET surface areas of 36.439 m2 / g, which were more thanthose of Bi2O3 (18.342 m2 / g) and MoSe2 (12.923 m2 / g). Under visibleillumination, the photocatalytic activities of pure samples ( Bi2O3 and MoSe2)and the hybrid Bi2O3 / MoSe2 sample for the disintegration of methylene bluewere assessed. The results show that the Bi2O3 / MoSe2 sample showed thehighest photocatalytic degradation efficiency (i.e. 96.5% after an exposure time of80 min). The increased photocatalytic activity is due to the mixed sample's highcrystallinity and surface area, as well as the small particle size.

[0009] The present invention addresses the challenges faced by the prior arts bydeveloping a photocatalytic system that effectively degrades mixed dye pollutants(MB and MO).

[00010] It integrates MoSe2 nanosheets onto 3D pyrolyzed PEGDAmicrostructures (MoSe2@3D Py-PEGDA), creating an advanced material forwastewater treatment applications. The innovative design enhances dyedegradation under visible and solar light while ensuring stability and reusability,making it a promising solution for sustainable water remediation.

[00011] Prior art on photocatalysis faced issues with particle aggregation,recovery challenges, and dependence on UV light. This work bridges those gapsby immobilizing MoSe2 nanosheets on a durable 3D-printed Pyrolyzed PEGDAscaffold, which ensures easy recovery, high stability, and efficient sunlight-drivenphotocatalysis. This hybrid material was fabricated using digital light processing(DLP) 3D printing with PEGDA as the photoresin, followed by pyrolysis. MoSe2nanosheets were synthesized using a hydrothermal method and subsequentlydeposited onto the pyrolyzed PEGDA structure (MoSe2@3D Py-PEGDA).

[00012] There is synergistic integration of three distinct aspects in the presentinvention:(i) fabrication of customizable pyrolyzed PEGDA scaffolds via DLP-based 3Dprinting(ii) hydrothermal synthesis and deposition of MoSe2 nanosheets on the 3Dscaffold, and(iii) demonstration of enhanced sunlight-driven photodegradation of mixed textiledyes (methylene blue and methyl orange), with validated safe agricultural reuse oftreated water. The aforesaid technical features appear to be new in the context ofimmobilized photocatalytic systems specifically tailored for mixed dyedegradation using solar irradiation.OBJECTIVES OF THE INVENTION

[00013] The primary objective of the present disclosure is to provide MoSe2nanosheet-decorated 3D-printed pyrolytic PEGDA (MoSe2@3D Py-PEGDA)structures.

[00014] Another objective of the present disclosure is to provide a system forefficient wastewater treatment under both UV and solar irradiation.

[00015] Another objective of the present disclosure is to provide a process forsynthesis of provide MoSe2 nanosheet-decorated 3D-printed pyrolytic PEGDA(MoSe2@3D Py-PEGDA) structures.

[00016] Another objective of the present disclosure is to provide a process forefficient wastewater treatment under both UV and solar irradiation.

[00017] Still another objective of the present disclosure is to addresses thelimitations of prior art and furnish MoSe2@3D Py-PEGDA structures that exhibitsenhanced degradation performance.SUMMARY OF THE INVENTION

[00018] This summary is provided to introduce a selection of concepts in asimplified form that are further described below in Detailed Description section.This summary is not intended to identify key features or essential features of theclaimed subject matter, nor is it intended to be used as an aid in determining thescope of the claimed subject matter.

[00019] The invention presents a novel approach to wastewater treatment usingMoSe2 nanosheet-decorated 3D-printed pyrolytic PEGDA (MoSe2@3D Py-PEGDA) structures. This hybrid material was fabricated via digital lightprocessing (DLP) 3D printing using PEGDA as a photoresin, followed bypyrolysis. MoSe2 nanosheets were synthesized using a hydrothermal method andsubsequently deposited onto the pyrolyzed structure.

[00020] In an aspect of the present disclosure a MoSe2 nanosheet-decorated 3Dprintedpyrolytic PEGDA (MoSe2@3D Py-PEGDA) structure is disclosed,wherein the MoSe2 nanosheets are coated uniformly on the 3D Py-PEGDAstructure.

[00021] In another aspect of the present disclosure, a process for synthesis ofMoSe2 nanosheet-decorated 3D-printed pyrolytic PEGDA (MoSe2@3D Py-PEGDA) structures is disclosed. The process comprising the following steps:i. the PEGDA microstructure was subjected to UV and ozone treatmentfor 5 min;ii. treated PEGDA microstructure was coated in a solution of 1 g ofMoSe2 and acetone; andiii. dipping was repeated three times to ensure a uniform coating ofMoSe2 nanosheets on the 3D Py-PEGDA.

[00022] In some embodiments, the MoSe2 nanosheet are prepared by thefollowing process:i. Na2MoO4·2H2O and Se powder were added in a 1:1 ratio, along withNaBH4 to DI water under magnetic stirring.ii. anhydrous ethanol was added to the above solution to form a dark15red mixture;iii. the above mixture was heated at 200°C for 24 h to obtain a blackprecipitate;iv. the black precipitate was dried at 70°C for 6 h;v. the dried powders were dispersed in a 2 mM NaoH solution andplaced in an oven at 70°C for 1 h;vi. the above mixture was centrifuged 2-3 times with DI water andacetone to obtain the MoSe2 nanosheets powder.

[00023] In some embodiments, the3D Py-PEGDA structure are prepared by thefollowing process:i. polyethylene glycol diacrylate (PEGDA) and BAPO (Phenylbis(2,4,6-trimethylbenzoyl)phosphine oxide) were mixed in a 98:2 weight ratio;ii. above mixed PEGDA resin was printed using an exposure duration of0.7 seconds.iii. the printed structures were washed with a 1:1 solution of isopropanoland acetone,iv. the washed structures were dried and cured via UV process;v. PEGDA structures were then carbonized using a horizontal tubefurnace (under a vacuum pressure of 0.9 mbar.

[00024] In some embodiments, the heating protocol in tube furnace was:i. heating to 300°C at 5°C / min,ii. maintaining 300°C for 3 hours to remove volatile components;iii. further heating to 410°C at 1°C / min,iv. holding at 410°C for 2 hours,v. ramping to 900°C at 5°C / min,vi. maintaining at 900°C for 5 hours, andvii. natural cooling to room temperature.

[00025] In some embodiments, said structure has superior photocatalytic activity.

[00026] In another aspect of the present disclosure, a process for efficientwastewater treatment under both UV and solar irradiation is disclosed, whereinthe process comprises treating the wastewater with the MoSe2 nanosheet15decorated 3D-printed pyrolytic PEGDA (MoSe2@3D Py-PEGDA) structure asclaimed in claim 1.

[00027] The treated wastewater was evaluated for its potential in supporting thegrowth of Hordeum vulgare (barley) seeds. Results indicated optimal plant growthin both standard deionized (DI) water and treated mixed dye water, whereasuntreated mixed dye water (contaminated with MB and MO) inhibited growth.

[00028] Thus the MoSe2@3D Py-PEGDA structures may be employed forwastewater remediation and the practical utilization of treated water in real-worldsettings.

[00029] Other aspects, advantages, and salient features of the invention willbecome apparent to those skilled in the art from the following detailed description,which, taken in conjunction with the exemplary embodiments of the invention.DESCRIPTION OF THE FIGURES

[00030] The accompanying drawings are included to provide a furtherunderstanding of the present disclosure and are incorporated in and constitute apart of this specification. The drawings illustrate exemplary embodiments of thepresent disclosure and, together with the description, serve to explain the presentdisclosure.

[00031] FIG.1 illustrates A schematic view of preparation of MoSe2 decorated 3DPy-PEGDA architecture (MoSe2@3D Py-PEGDA).

[00032] FIG. 2 illustrates FESEM images of (a-c) 3D Py-PEGDA scaffold, and(d, e) MoSe2@3D Py-PEGDA structure with inset showing the uniformdecoration of MoSe2 nanosheets, (f, g) EDS and elemental composition, (h) XRD,and (i) Wettability results of the MoSe2@3D Py-PEGDA

[00033] FIG.3 illustrates UV-Vis spectra of MB dye using (a) 3D Py PEGDA,(b) MoSe2, and (c) MoSe2 @3D Py PEGDA, (d) C / C0 results under visible lightexposure

[00034] FIG.4 illustrates UV-Vis spectra of (a) MO, (b) Mixed MB+MOdegraded dye, (c-d) experimental and kinetics study results in presence of MoSe2@3D PEGDAunder visible light exposure

[00035] FIG.5 illustrates (a) The degradation mechanisms of mixed dyes usingMoSe2@3D Py-PEGDA scaffold under natural sunlight, and (b) Effect ofMB+MO dye polluted water, DI water, and treated dye water on the growth ofHordeum vulgare (barley) plants

[00036] FIG.6 illustrates UV-Vis spectra of (a) MB, (b) MO, (c) Mixed MB+MOdegraded dye (d-e) experimental and kinetics study results, and (f) stability resultsin presence of MoSe2@3D Py-PEGDAunder sunlight exposure

[00037] Throughout the drawings, the same reference numerals and characters,unless otherwise stated, are used to denote like features, elements, components, orportions of the illustrated embodiments. Moreover, while the subject inventionwill now be described in detail with reference to the drawings, the description isdone in connection with the illustrative embodiments. It is intended that changesand modifications can be made to the described embodiments without departingfrom the true scope and spirit of the subject invention as defined by the appendedclaims.DETAILED DESCRIPTION OF THE INVENTION

[00038] The following is a detailed description of 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 anticipatedvariations of embodiments; on the contrary, the intention is to cover allmodifications, equivalents, and alternatives falling within the spirit and scope ofthe present disclosure as defined by the appended claims.

[00039] Reference throughout this specification to "one embodiment" or "anembodiment" means that a particular feature, structure or characteristic describedin connection with the embodiment is included in at least one embodiment. Thus,the appearances of the phrases "in one embodiment" or "in an embodiment" invarious places throughout this specification are not necessarily all referring to thesame embodiment. Furthermore, the particular features, structures, orcharacteristics may be combined in any suitable manner in one or moreembodiments.

[00040] Unless the context requires otherwise, throughout the specification whichfollows, 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."

[00041] As used in the description herein and throughout the claims that follow,the meaning of "a," "an," and "the" includes plural reference unless the contextclearly dictates otherwise. Also, as used in the description herein, the meaning of"in" includes "in" and "on" unless the context clearly dictates otherwise.

[00042] The recitation of ranges of values herein is merely intended to serve as ashorthand method of referring individually to each value falling within the range.Unless otherwise indicated herein, each individual value is incorporated into thespecification as if it were individually recited herein. Furthermore, the rangesdefined throughout the specification include the end values as well, i.e., a range of1 to 10 implies that both 1 and 10 are included in the range. For the avoidance ofdoubt, the applicant shall be entitled to any equivalents according to applicablelaw.

[00043] All methods described herein can be performed in a suitable order unlessotherwise indicated herein or otherwise clearly contradicted by context. The useof any and all examples or exemplary language (e.g., "such as") provided withrespect to certain embodiments herein is intended merely to better illuminate thedisclosure and does not pose a limitation on the scope of the invention otherwiseclaimed. No language in the specification should be construed as indicating anynon-claimed element essential to the practice of the invention.

[00044] Groupings of alternative elements or embodiments of the inventiondisclosed herein are not to be construed as limitations. Each group member can bereferred to and claimed individually or in any combination with other members ofthe group or other elements found herein. One or more members of a group can beincluded in, or deleted from, a group for reasons of convenience and / orpatentability. When any such inclusion or deletion occurs, the specification isherein deemed to contain the group as modified.

[00045] The description that follows, and the embodiments described therein, isprovided by way of illustration of an example, or examples, of particularembodiments of the principles and aspects of the present disclosure. Theseexamples are provided for the purposes of explanation, and not of limitation, ofthose principles and of the disclosure.

[00046] The headings and abstract of the invention provided herein are forconvenience only and do not interpret the scope or meaning of the embodiments.

[00047] The following discussion provides many example embodiments of theinventive subject matter. Although each embodiment represents a singlecombination of inventive elements, the inventive subject matter is considered toinclude all possible combinations of the disclosed elements. Thus, if oneembodiment comprises elements A, B, and C, and a second embodimentcomprises elements B and D, then the inventive subject matter is also consideredto include other remaining combinations of A, B, C, or D, even if not explicitlydisclosed.

[00048] The term "or", as used herein, is generally employed in its senseincluding "and / or" unless the content clearly dictates otherwise.

[00049] Various terms are used herein to the extent a term used is not definedbelow, it should be given the broadest definition persons in the pertinent art havegiven that term as reflected in printed publications and issued patents at the timeof filing.

[00050] In an aspect of the present disclosure a MoSe2 nanosheet-decorated 3Dprintedpyrolytic PEGDA (MoSe2@3D Py-PEGDA) structure is disclosed,wherein the MoSe2 nanosheets are coated uniformly on the 3D Py-PEGDAstructure.

[00051] In another aspect of the present disclosure, a process for synthesis ofMoSe2 nanosheet-decorated 3D-printed pyrolytic PEGDA (MoSe2@3D Py-PEGDA) structures is disclosed. The process comprising the following steps:i. the PEGDA microstructure was subjected to UV and ozone treatmentfor 5 min;ii. treated PEGDA microstructure was coated in a solution of 1 g ofMoSe2 and acetone; andiii. dipping was repeated three times to ensure a uniform coating ofMoSe2 nanosheets on the 3D Py-PEGDA.

[00052] In some embodiments, the MoSe2 nanosheet are prepared by thefollowing process:i. Na2MoO4·2H2O and Se powder were added in a 1:1 ratio, along withNaBH4 to DI water under magnetic stirring.ii. anhydrous ethanol was added to the above solution to form a dark-redmixture;iii. the above mixture was heated at 200°C for 24 h to obtain a blackprecipitate;iv. the black precipitate was dried at 70°C for 6 h;v. the dried powders were dispersed in a 2 mM NaoH solution andplaced in an oven at 70°C for 1 h;vi. the above mixture was centrifuged 2-3 times with DI water andacetone to obtain the MoSe2 nanosheets powder.

[00053] In some embodiments, the3D Py-PEGDA structure are prepared by thefollowing process:i. polyethylene glycol diacrylate (PEGDA) and BAPO (Phenylbis(2,4,6-trimethylbenzoyl)phosphine oxide) were mixed in a 98:2 weight ratio;ii. above mixed PEGDA resin was printed using an exposure duration of0.7 seconds.iii. the printed structures were washed with a 1:1 solution of isopropanoland acetone,iv. the washed structures were dried and cured via UV process;v. PEGDA structures were then carbonized using a horizontal tubefurnace (under a vacuum pressure of 0.9 mbar.

[00054] In some embodiments, the heating protocol in tube furnace was:i. heating to 300°C at 5°C / min,ii. maintaining 300°C for 3 hours to remove volatile components;iii. further heating to 410°C at 1°C / min,iv. holding at 410°C for 2 hours,v. ramping to 900°C at 5°C / min,vi. maintaining at 900°C for 5 hours, andvii. natural cooling to room temperature.

[00055] In some embodiments, said structure has superior photocatalytic activity.

[00056] In another aspect of the present disclosure, a process for efficientwastewater treatment under both UV and solar irradiation is disclosed, whereinthe process comprises treating the wastewater with the MoSe2 nanosheetdecorated3D-printed pyrolytic PEGDA (MoSe2@3D Py-PEGDA) structure asclaimed in claim 1.

[00057] The invention presents a novel approach to wastewater treatment usingMoSe2 nanosheet-decorated 3D-printed pyrolytic PEGDA (MoSe2@3D Py-PEGDA) structures.

[00058] This hybrid material was fabricated via digital light processing (DLP) 3Dprinting using PEGDA as a photoresin, followed by pyrolysis. MoSe2 nanosheetswere synthesized using a hydrothermal method and subsequently deposited ontothe pyrolyzed structure. The MoSe2@3D Py-PEGDA structures exhibitedenhanced degradation performance, achieving 89% and 96% degradation of MOand MB, respectively, in mixed dye solutions under visible light. Under directsunlight, the degradation efficiency reached 74% for MO and 68% for MB inmixed dye solutions. This demonstrates the capability of the fabricatedMoSe2@3D Py-PEGDA structures to efficiently degrade dyes without requiringadditional instrumentation. Furthermore, the treated wastewater was evaluated forits potential in supporting the growth of Hordeum vulgare (barley) seeds. Resultsindicated optimal plant growth in both standard deionized (DI) water and treatedmixed dye water, whereas untreated mixed dye water (contaminated with MB andMO) inhibited growth. These findings highlight the promising application ofMoSe2@3D Py-PEGDA structures for wastewater remediation and the practicalutilization of treated water in real-world settings.EXAMPLES

[00059] The present invention is further explained in the form of the followingexamples. However, it is to be understood that the following examples are merelyillustrative and are not to be taken as limitations upon the scope of the invention.

[00060] Example 1: Fabrication of 3D Py-PEDGA microstructureThe fabrication process commenced with designing a 3D microlattice geometry.An octet unit cell configuration was chosen due to its well-studied mechanicalrobustness. The scaffold was modeled using Creo Parametric, a CAD software,featuring a unit cell size of 1.2 mm and a lattice diameter of 200 μm. To preparethe design for 3D printing, the CAD model was sliced into 10 μm thick layersusing Chitubox software. For DLP 3D printing, a photosensitive resin wasformulated by blending polyethylene glycol diacrylate (PEGDA, molecularweight 700; Sigma Aldrich, product number 455008) with the photoinitiatorBAPO (Phenylbis(2,4,6-trimethylbenzoyl)phosphine oxide; Sigma Aldrich,product number 511447) in a 98:2 weight ratio. The prepared PEGDA resin wassubsequently used in a Phrozen Mini 8K S printer using an exposure duration of0.7 seconds. Upon completion, the printed structures were washed with a 1:1solution of isopropanol and acetone, followed by a drying and a final UV curingprocess. The fabricated PEGDA structures were then carbonized using ahorizontal tube furnace (GSL-1100X-LD, MTI Corporation, USA) in a vacuumcondition (vacuum pressure -0.9 mbar). The heating protocol was:(i) heating from ambient temperature to 300°C at 5°C / min,(ii) maintaining 300°C for 3 hours to remove volatile components andstabilize the precursor,(iii) further heating to 410°C at 1°C / min,(iv) holding at 410°C for 2 hours,(v) ramping to 900°C at 5°C / min,(vi) maintaining at 900°C for 5 hours, and(vii) allowing natural cooling to room temperature.

[00061] FIG. 1 illustrates a schematic view of preparation of MoSe2 decorated 3DPy-PEGDA architecture (MoSe2@3D Py-PEGDA).

[00062] Example 2: Synthesis of MoSe2 nanosheets and MoSe2@3D Py-PEGDA microstructureThe MoSe2 nanosheets were synthesised via a hydrothermal method usingthe sodium molybdate dihydrate (Na2MoO4·2H2O) and selenium powder (Se) asthe molybdenum and selenium sources, respectively. Specifically,Na2MoO4·2H2O and Se powder were added in a 1:1 ratio, along with a 0.2595 gof NaBH4 to 20 mL DI water under magnetic stirring. Once a uniform solutionwas achieved, 20 mL of anhydrous ethanol was gradually introduced into theprecursor solution. The resulting dark-red mixture was stirred for 5 min to ensurehomogeneity. Subsequently, the uniformly mixed precursor solution wastransferred into a 50 mL autoclave reactor and heated at 200°C for 24 h. After thereaction, the obtained black precipitate was collected, washed with acetone and DIwater, and then dried at 70°C for 6 h. In the final step, the dried powders weredispersed in a 2 mM NaoH solution and placed in an oven at 70°C for 1 h toremove the excess Se powder. The product was then centrifuged multiple timeswith DI water and acetone to obtain the MoSe2 nanosheets powder.

[00063] To obtain MoSe2@3D Py-PEGDA, the pyrolyzed microstructure wassubjected to UV and ozone treatment for 5 min, followed by dip coating in asolution of 1 g of MoSe2 and acetone. This process was repeated three times to ensure a uniform coating of MoSe2 nanosheets on the 3D Py-PEGDA.

[00064] Example 3: Photocatalysis performance measurementThe photocatalytic performance of 3D Py-PEGDA and MoSe2@3D Py-PEGDA was evaluated for the degradation of both MB and MO dyes under both visible and natural sunlight irradiation. The dye solutions were prepared by dissolving the respective dyes in DI water at a standard concentration of 10 mg L-1. To achieve adsorption-desorption equilibrium, the solutions were stirred in darkness for 30 mins before initiating the photocatalytic process. Subsequently, the prepared dye solutions were transferred into individual 15 mL glass containers, each containing MoSe2@3D Py-PEGDA as photocatalyst. To assess the degradation rate, 1 mL of treated dye solutions were extracted from each container every 20 mins, and their absorption spectra (ranging from 300 to 700 nm) was recorded. The experiments were conducted over a duration of 100 to 160 mins under both visible and sunlight exposure. The integration of 3D printing and nanotechnology facilitates the development of a high surface-area, self-supported and durable photocatalyst, minimizing risk associated with environmental contamination and water pollution. This eliminates the need for expensive catalyst recovery process while utilizing abundant solar light for cost-effective wastewater treatment. Furthermore, the degradation efficiency (E%) was determined using Equation 1, while kinetics of the process were analyzed using first order rate equations (Equations 2 and 3), where C0, C is the dye concentration at the initial, final time and k denotes the first-order rate constant.E (%)=(1-C0)x100 (1)-dCdt=-kc (2) lnC0=kt+constant (3)

[00065] Example 4: Characterization of 3D Py-PEGDA and MoSe2@3D Py-PEGDA:A 3D PEGDA octet lattice scaffold was fabricated using DLP printing with a unit cell length of 1.2 mm and lattice beam diameters of 200 μm. The 3D PEGDAscaffold was then pyrolyzed in a horizontal tube furnace under vacuum, following an optimized heating protocol described in the experimental section. During pyrolysis, the polymer undergoes thermal decomposition, leading to the release of volatile compounds (e.g., CO, CO2, hydrocarbons, and H2O) and leaving behind a carbonaceous structure composed of interconnected sp²-hybridized carbon rings, typically containing amorphous defects and sp³-hybridized sites. The pyrolysis process generally proceeds through three stages:(i) monomer evaporation and cyclization,(ii) chemical degradation, and(iii) carbonization.

[00066] The FESEM images (FIG. 2 (a, b)) show that the 3D Py-PEGDA scaffold undergoes isotropic shrinkage of approximately 60% after pyrolysis, resulting in a disk-shaped structure with a diameter of 1.1 cm and a thickness of 1 mm, featuring a square lattice with 100 μm unit cells and beam diameters of 20 μm. High-resolution SEM imaging (FIG. 2(c)) revealed that the 3D Py-PEGDA architecture possessed a distinctly rough surface morphology. Elemental analysis via EDS confirmed the presence of carbon (C) and oxygen (O) within the 3D Py-PEGDA architecture. The fabricated 3D Py-PEGDA structure demonstrated excellent mechanical integrity, uniformity, and a well-defined surface texture. Furthermore, FESEM image in (FIG. 2 (d, e) illustrated the homogeneous distribution of MoSe2 nanosheets across the 3D Py-PEGDA scaffold. The inset in FIG. 2 (e) indicates that the average lateral dimension of the MoSe2 nanosheets is ~200 nm. Additionally, EDS mapping and elemental analysis ((FIG. 2 (f, g)) verified the incorporation of C, O, Mo, and Se within the MoSe2@3D Py-PEGDA composite. The resulting high-surface-area framework is particularly well-suited for wastewater treatment applications, offering enhanced adsorption capacity for large-sized pollutant molecules.

[00067] As shown in the XRD patterns of Py-PEGDA and MoSe2@3D Py-PEGDA structures (see (FIG. 2 (f)), two broad diffraction peaks can be successfully indexed to the (002) and (101) planes of carbon, consistent with previous reports. Moreover, the two additional peaks at 2θ = 31.6° and 56°, whichcorrespond to the (100) and (110) planes of the hexagonal-phase MoSe2 nanosheets, are consistent with previously reported literature and JCPDS No. 29-0914. The Raman spectrum of 3D Py-PEGDA scaffold shows two distinctive peaks at 1360 cm⁻¹ and 1599 cm⁻¹ for the disorder-induced D-band and the graphitic G-band, respectively, yielding an ID / IG intensity value of 0.94 The wettability of the microstructure scaffolds was significantly influenced by the addition of MoSe2 nanosheets; for instance the contact angle of the 3D Py-PEGDA structure was 110.1°, while that for the MoSe2@3D Py-PEGDA was 122°. The higher contact angle of MoSe2@3D Py-PEGDA structure is due to the combined hydrophobic nature of MoSe2 and carbon and the roughened surface morphology contributing to increased surface hydrophobicity.

[00068] Example 5: Photocatalytic degradation of mixed textile dyeThe photocatalytic degradation performance of the microstructure was systematically investigated against 10 mg L-1 solutions of MB, MO, and their mixture using UV-Vis absorption spectroscopy (see (FIG. 3). Prior to visible irradiations, all the samples were kept for 20 mins in dark to allow for adsorption-desorption equilibrium between the dyes and the photocatalyst. The progressive degradation process of the dyes was followed through the gradual decrease of the adsorption characteristic peaks of MB and MO at 663 nm and 445 nm, respectively. All three samples, 3D Py PEGDA, MoSe2 and MoSe2@ 3D Py PEGDA were initially evaluated for the degradation of MB dye. The degradation profiles indicated that the MoSe2@ 3D Py PEGDA exhibited a significantly faster degradation rate compared to 3D Py PEGDA and MoSe2 alone (see (FIG. 3(a-d)). After 100 mins, the MB degradation efficiencies were approximately 17%, 65% and 83% for 3D Py-PEGDA, MoSe2, and MoSe2@3D Py-PEGDA, respectively. Given the superior performance of MoSe2@ 3D Py PEGDA in degrading MB dye, this composite was further selected for additional studies involving the degradation of MO dye and mixed dye systems.

[00069] In the presence of MoSe2@3D Py-PEGDA, MB was degraded by ~83% after 100 mins, while a degradation efficiency of ~76% was obtained for MO with the same degradation time (see (FIG. 4 (a-b)). The results of degradation profilesindicated that the degradation rate of MB was more rapid in comparison with MO, which it can be ascribed to their different chemical structures affecting their photocatalytic activity. The logarithmic plots of plot C₀ / C versus time were used to determine the apparent rate constants (k), whose values supported pseudo-first-order kinetics of 8.08 x 10⁻3 min-1 and 1.38 x 10⁻4 min-1 for MB and MO, respectively. For mixed dyes, the UV-Vis spectra exhibited distinct peaks for MB and MO at 663 nm and 445 nm, respectively. Both dyes underwent gradual photodegradation after visible irradiation in the presence of MoSe2@3D Py-PEGDA. In contrast, degradation rates for individual dyes were lower because of competitive adsorption on the active sites of the photocatalyst. The corresponding rate constants for MB and MO in the mixed solution were determined to be 6.3 x 10⁻5 min-1 and 5.04 x 10⁻3 min-1, respectively, after 160 mins of degradation, with degrading efficiencies of ~97% and ~88% for MB and MO, respectively (see FIG. 3 (c-d)). This reduction in rate constants highlights the influence of competitive interactions between the dyes during simultaneous photodegradation.

[00070] The photocatalytic process commences when the energy of the incident light is equal to or greater than the bandgap of the photocatalyst. Upon exposure to visible or sunlight, MoSe2 absorbs incoming photons, where high-energy photons promote electrons from the valence band (VB) to the conduction band (CB). These photoexcited electrons are subsequently transferred to the surface of carbon particles derived from 3D Py-PEGDA. This efficient electron migration plays a significant role in minimizing the recombination of electron-hole pairs within the MoSe2@3D Py-PEGDA photocatalyst. The generated holes in VB follow two primary approaches; some directly oxidize dye molecules adsorbed on the photocatalyst surface, while others react with water molecules or surface hydroxyl groups to generate hydroxyl radicals, which are highly reactive species capable of breaking organic dyes into harmless byproducts. The superior photocatalytic activity of the MoSe2@3D Py-PEGDA system is primarily attributed to the efficient charge carrier and the fast electron transfer facilitated by the conductive carbon matrix. In addition to serving as electron acceptors due to their low work function, carbon particle enhance system stability and offerabundant active sites for dye adsorption. This adsorption enriches the local concentration of dye molecules near the active sites, thereby accelerating their degradation. Moreover, the strong synergistic interaction between MoSe2 and the 3D carbon network significantly enhances the photocatalytic performance. The following reactions illustrate the detailed degradation mechanism of mixed dyes under the experimental conditions, which are also presented schematically in (FIG. 5 (a).MoSe2@PyPEGDAUV-> eCB-+hVB+ (7)O2+eCB-->O2.- (8)O2.-+eCB-+2H+->H2O2 (9) H2O2->2 (∙OH) (10)h++OH--> ∙OH (11)h++H2O-> ∙OH+H+ (12)∙OH+Mixed Dyeads->Degraded Product (13)

[00071] To demonstrate the practical applicability of the MoSe2@Py-PEGDA structure, we evaluated its efficiency in degrading a mixed dye solution under direct sunlight. The experiment was conducted at a geographical location of 26.4710° N, 73.1134° E (Jodhpur, India) during March, between 10:30 AM and 2:30 PM, with a total exposure duration of 100 to 160 mins. The inset of (FIG. 6 (a-c) visually confirms the attenuation of dyes due to direct sunlight irradiation in presence of MoSe2@3D Py-PEGDA structure. The result shows that the degradation efficiency of MB dye was ~72%, while a degradation efficiency for MO was ~67% in 100 mins with pseudo-first-order kinetics of 2.00 x 10⁻4 min-1 and 2.18 x 10⁻4 min-1 for MB and MO, respectively. For mixed dyes, the corresponding rate constants for MB and MO were determined to be 4.80 x 10⁻5 min⁻¹ and 6.06 x 10⁻5 min-1, respectively, after 160 mins of degradation, with degrading efficiencies of ~75% and ~66% for MB and MO, respectively (see FIG. 6 (d, e)). The reduced efficiency observed under sunlight compared to visible light exposure can be attributed to the broad spectrum of sunlight, which includes ultraviolet (UV), visible, and infrared (IR) components. The visible portion constitutes only a fraction of the total solar spectrum. Additionally, fluctuations insunlight intensity due to factors such as time of day, weather conditions, and geographical location contribute to a less concentrated and variable irradiation. Despite these challenges, the MoSe2@3D Py-PEGDA structure effectively facilitated the one-step photodegradation of mixed dyes under direct sunlight, eliminating the need for additional instrumentations. This capability highlights its potential for purifying river and ocean water directly in their natural environments. Furthermore, the practical viability of the developed structure was assessed through repeatability tests, as illustrated in FIG. 6 (f). A four-cycle degradation test demonstrated the excellent repeatability and sustained efficiency of MoSe2@3D Py-PEGDA, with only a negligible decline in performance over time.

[00072] Additionally, an ecotoxicological experiment with monitoring the growth of plants from germinated Hordeum vulgare seeds was conducted to assess the suitability of the entire adsorption process, concerning the potential recycling of the treated wastewater. In this experiment, one day germinated Hordeum vulgare seeds were placed on cotton inside plastic petri dishes. The seeds were then irrigated with 10 mL of three different water sources: MB+MO dye water, standard DI water, and treated dye water. Every two days, the respective water solutions was added to each petri dish. Small holes were made in the dishes to allow excess water to drain. After six days of growth, the germination was observed. The results show that the growth of Hordeum vulgare plants was inhibited by MB+MO dye water, however a comparable growth of plant is resulted with treated dye water and DI water growth as shown in (FIG. 5(b). This growth strongly advocated the non-toxic behavior of treated dye water towards the plant growth. The results obtained are generally supportive of the safe utilization of treated wastewater in regular maintenance of garden, or parks. However, when it comes to using it for growing edible plants, there is a need for more precise and comprehensive studies in future.Table 1. A comparison table based on the reported MoSe2 based nanocomposite for textile dye degradation.

[00073]

[14] R. Zazpe, R. Krumpolec, H. Sopha, J. Rodriguez-Pereira, J. Charvot, L. Hromadko, E. Kolibalova, J. Michalička, D. Pavliňak, M. Motola, J. Přikryl, M. Krbal, F. Bureš, J.M. MacAk, Atomic Layer Deposition of MoSe2Nanosheets on TiO2Nanotube Arrays for Photocatalytic Dye Degradation and Electrocatalytic Hydrogen Evolution, ACS Appl. Nano Mater. 3 (2020) 12034-12045. https: / / doi.org / 10.1021 / ACSANM.0C02553.

[00074]

[15] H. Mittal, A. Ivaturi, M. Khanuja, MoSe2-modified ZIF-8 novel nanocomposite for photocatalytic remediation of textile dye and antibiotic-contaminated wastewater, Environ. Sci. Pollut. Res. 30 (2023) 4151-4165. https: / / doi.org / 10.1007 / S11356-022-22487-X.

[00075]

[16] Y. Huang, F. Chen, Z. Guan, Y. Luo, L. Zhou, Y. Lu, B. Tian, J. Zhang, S-Scheme BiOCl / MoSe2 Heterostructure with Enhanced Photocatalytic Activity for Dyes and Antibiotics Degradation under Sunlight Irradiation, Sensors 22 (2022) 3344. https: / / doi.org / 10.3390 / S22093344.

[00076]

[17] M. Alahmadi, W.H. Alsaedi, W.S. Mohamed, H.M.A. Hassan, M. Ezzeldien, A.M. Abu-Dief, Development of Bi2O3 / MoSe2 mixed nanostructures for photocatalytic degradation of methylene blue dye, J. Taibah Univ. Sci. 17 (2023) 2161333. https: / / doi.org / 10.1080 / 16583655.2022.2161333.

[00077] The foregoing examples are merely illustrative and are not to be taken as limitations upon the scope of the invention. Various changes and modifications to the disclosed embodiments will be apparent to those skilled in the art. Such changes and modifications may be made without departing from the scope of the invention.ADVANTAGES OF THE PRESENT INVENTION

[00078] The present invention offers a novel 3D Py-PEGDA structure decorated with MoSe2 nanosheets for wastewater treatment.

[00079] The MoSe2@3D Py-PEGDA structures effectively purify wastewater using direct sunlight without requiring additional equipment.

[00080] The MoSe2@3D Py-PEGDA structures exhibited enhanced degradation performance, achieving 89% and 96% degradation of MO and MB, respectively, in mixed dye solutions under visible light. Under direct sunlight, the degradation efficiency reached 74% for MO and 68% for MB in mixed dye solutions, respectively. This demonstrates the capability of the fabricated MoSe2@3D Py-PEGDA structures to efficiently degrade dyes without requiring additional instrumentation.

[00081] This invention provides an innovative, scalable, and efficient solution for wastewater treatment while ensuring sustainability, reusability, and environmental safety.

[00082] The present invention may be employed for wastewater treatment in textile, pharmaceutical, and chemical industries.

[00083] The present invention provides a sustainable, cost-effective water purification for rural and urban settings.

[00084] The present invention provides a future applications in biomedical devices and self-cleaning surfaces.

Claims

1. A MoSe2 nanosheet-decorated 3D-printed pyrolytic PEGDA (MoSe2@3D Py-PEGDA) structure, Wherein the MoSe2 nanosheets are coated uniformly on the 3D Py-PEGDA structure.

2. A process for synthesis of MoSe2 nanosheet-decorated 3D-printed pyrolytic PEGDA (MoSe2@3D Py-PEGDA) structures, the process comprising the following steps: i. the PEGDA microstructure was subjected to UV and ozone treatment for 5 min; ii. treated PEGDA microstructure was coated in a solution of 1 g of MoSe2 and acetone; and iii. dipping was repeated three times to ensure a uniform coating of MoSe2 nanosheets on the 3D Py-PEGDA.

3. The process as claimed in claim 2, wherein the MoSe2 nanosheet are prepared by the following process: i. Na2MoO4·2H2O and Se powder were added in a 1:1 ratio, along with NaBH4 to DI water under magnetic stirring. ii. anhydrous ethanol was added to the above solution to form a dark-red mixture; iii. the above mixture was heated at 200°C for 24 h to obtain a black precipitate; iv. the black precipitate was dried at 70°C for 6 h; v. the dried powders were dispersed in a 2 mM NaoH solution and placed in an oven at 70°C for 1 h; vi. the above mixture was centrifuged 2-3 times with DI water and acetone to obtain the MoSe2 nanosheets powder.

4. The process as claimed in claim 2, wherein the3D Py-PEGDA structure are prepared by the following process: i. polyethylene glycol diacrylate (PEGDA) and BAPO (Phenylbis(2,4,6-trimethylbenzoyl)phosphine oxide) were mixed in a 98:2 weight ratio; ii. above mixed PEGDA resin was printed using an exposure duration of 0.7 seconds. iii. the printed structures were washed with a 1:1 solution of isopropanol and acetone, iv. the washed structures were dried and cured via UV process; v. PEGDA structures were then carbonized using a horizontal tube furnace (under a vacuum pressure of 0.9 mbar.

5. The process as claimed in claim 4, wherein the heating protocol was: i. heating to 300°C at 5°C / min, ii. maintaining 300°C for 3 hours to remove volatile components; iii. further heating to 410°C at 1°C / min, ) holding at 410°C for 2 hours, iv. ramping to 900°C at 5°C / min, v. maintaining at 900°C for 5 hours, and vi. natural cooling to room temperature.

6. The MoSe2 nanosheet-decorated 3D-printed pyrolytic PEGDA (MoSe2@3D Py-PEGDA) structure as claimed in claim 1, wherein said structure has superior photocatalytic activity.

7. A process for efficient wastewater treatment under both UV and solar irradiation, wherein the process comprises treating the wastewater with the MoSe2 nanosheet-decorated 3D-printed pyrolytic PEGDA (MoSe2@3D Py-PEGDA) structure as claimed in claim 1.