Photomolecular effect based treatment of industrial and municipal waste water

Abstract

A system and method for photomolecular treatment of wastewater are disclosed for producing potable water through UV-induced evaporation and condensation The system includes one or more vessels having internal surfaces coated with a slurry of a wide band gap UV active material, such as ZnO, TiO₂, MgO, or NiO, prepared in a solvent such as acetone, ethanol, or isopropanol. UV radiation sources are arranged around each vessel to irradiate the wide band gap UV active material, exciting its lattice and generating thermal energy to evaporate water from wastewater. The evaporated water is condensed in a condenser and collected in a downstream storage tank. The method involves repeating the evaporation- condensation process in subsequent vessels receiving condensed water from prior stages, allowing incremental purification. The process continues until the water achieves potable quality. This technology enables chemical-free, modular water purification driven by phononic and thermal interactions at the material interface.

Description

[0001] TITLE

[0002] PHOTOMOLECULAR EFFECT BASED TREATMENT OF INDUSTRIAL AND MUNICIPAL WASTE WATER

[0003] CROSS REFERENCE TO RELATED APPLICATIONS

[0004] The present application is based upon and claims priority to India Complete Application number 202441043034 filed on May 24, 2025, which in turn claims priority to India provisional patent application number 202441043034 filed on June 03, 2024, the entire contents of which is herein incorporated by reference.

[0005] FIELD

[0006] The present disclosure relates to treatment of waste water, more particularly relates to photomolecular effect-based treatment of industrial and municipal waste water and effluents.

[0007] BACKGROUND

[0008] The rapid pace of industrialization has led to a significant increase in the generation of metal-bearing solid wastes, resulting in widespread environmental contamination, particularly of aquatic systems. This has contributed to the depletion of natural resources and exacerbated concerns regarding the scarcity of essential metals. A major environmental concern is the release of highly soluble heavy metals and hazardous substances into water bodies. These contaminants are readily mobilized into the environment, posing serious risks to human health and ecosystems. For instance, the U.S. National Institutes of Health (NIH) has established a Maximum Contaminant Level (MCL) for arsenic in drinking water at <50 pg / L, highlighting the strict regulatory thresholds for heavy metal presence in potable water.

[0009] Various industrial activities — including leather tanning, electroplating, metal and alloy manufacturing, mining, pigment production, and cement manufacturing — release mutagenic, teratogenic, and carcinogenic agents into the environment. Additionally, domestic sources such as sewage and sludge from anaerobic digesters and primary clarifiers in wastewater treatment plants also contribute substantially to water pollution. Given the scale and toxicity of these pollutants, the treatment and remediation of wastewater have become increasingly critical.

[0010] A variety of techniques are currently employed for wastewater treatment, including sedimentation, filtration, chemical precipitation, ion exchange, adsorption, and electrochemical remediation. Among these, electrochemical remediation has emerged as a particularly promising approach due to its advantages such as self-sustainability, minimal sludge production, low operational and maintenance costs, and the absence of complex chemical or membrane requirements. In contrast, conventional methods often necessitate the use of reducing agents, expensive membranes, labour-intensive regeneration processes, and incur high maintenance and operational costs.

[0011] Given that, water evaporation occurs very weakly in visible region of the spectrum, an alternate approach that has gained attention involves the use of a floating, porous, solar-absorbing material on the water surface to enable evaporation, a process known as solar-interfacial evaporation. This method has demonstrated a higher evaporation rate compared to conventional “thermal evaporation”, where heat as thermal energy evaporates water into vapour. Experimental studies on hydrogels have revealed that visible light can directly cleave molecular clusters of water through what is known as “photomolecular effect”. Although visible light has been shown to drive water evaporation via “photomolecular effect”, the process remains difficult to quantify due to the complex and often unknown internal structures of the materials involved. Nevertheless, numerous research efforts worldwide have employed visible-light lasers to investigate and demonstrate photomolecular evaporation, underscoring the growing interest in light-driven water treatment technologies.

[0012] CN111302423B discloses a solar water purifier based on interfacial solar photothermal conversion, which employs a double-layered light-absorbing structure comprising an upper layer of light-to-heat conversion material and a lower layer of heat-insulating material, separated by a dust-free cloth, ensuring that the clean cloth continuously stays in contact with the liquid level in the water storage tray to ensure that enough water is transported to the surface of the light absorbing body to ensure continuous evaporation.

[0013] An article, titled, “Plausible photomolecular effect leading to water evaporation exceeding the thermal limit”, published in October 30, 2023

[0014] (https: / / www.pnas.org / doi / 10.1073 / pnas.2312751120) relates to experimental observations on evaporation from hydrogels under visible light illumination, which includes: 1) Partially wetted hydrogels become absorbing in the visible spectral range, where the absorption by both the water and the hydrogel materials is negligible; 2) Illumination of hydrogel under solar or visible- spectrum lightemitting diode leads to evaporation rates exceeding the thermal evaporation limit, even in hydrogels without additional absorbers; 3) The evaporation rates are wavelength dependent, peaking at 520 nm; 4) Temperature of the vapor phase becomes cooler under light illumination and shows a flat region due to breaking- up of the clusters that saturates air; and 5) vapor phase transmission spectra under light show new features and peak shifts.

[0015] The inventors of the present disclosure have employed a photoactive material responsive to ultraviolet (UV) light as an interface to absorb incident light radiation, and induce water evaporation through photomolecular effect, where upon absorbing UV light, the photoactive material transfers energy to the water molecules, disrupting molecular clusters of water and facilitating water evaporation.

[0016] SUMMARY

[0017] The present disclosure provides a system and a method of photomolecular treatment of waste water to produce potable water.

[0018] The photomolecular treatment system comprises:

[0019] - a vessel having an internal surface coated with a layer of wide band gap UV active material, wherein the wide band gap UV active material is configured to contact waste water to be treated;

[0020] - a plurality of UV radiation sources arranged around the vessel to create phononic vibrations in the lattice of the wide band gap UV active material, wherein the UV radiation sources are configured to emit energy that generates thermal energy and causes evaporation of water;

[0021] - a condenser configured to receive and condense the evaporated water; and

[0022] - a storage tank arranged downstream of the condenser, configured to store the condensed water.

[0023] The UV radiation causes excitation / transition of electrons in the wide band gap UV active material from the Highest Occupied Molecular Orbital (HOMO) to the Lowest Unoccupied Molecular Orbital (LUMO). This excitation initiates phononic vibrations in the lattice of the wide band gap UV active material, leading to thermal energy release. The released thermal energy is taken up by the water molecules causing evaporation.

[0024] A method of photomolecular treatment of waste water to produce potable water is also provided, wherein the method includes the following steps: a. preparing a slurry of a wide band gap UV active material in a solvent as acetone or ethanol or isopropanol, b. coating a layer of the wide band gap UV active material slurry on the internal surface of a vessel, wherein the wide band gap UV active material is configured to contact waste water to be treated; c. supplying waste water into the vessel, wherein the wide band gap UV active material contacts the waste water; d. arranging a plurality of UV radiation sources around the vessel to create phononic vibrations in the lattice of the wide band gap UV active material, wherein the UV radiation sources are configured to emit energy that generates thermal energy and causes evaporation of water; e. receiving and condensing the evaporated water in a condenser; f. receiving and storing the condensed water in a storage tank arranged downstream of the condenser; g. transferring the condensed water to at least one subsequent vessel coated on its internal surface with the wide band gap UV active material slurry, and irradiating the wide band gap UV active material with UV radiation sources to further evaporate and purify the water, followed by condensing the evaporated water in a condenser and storing the resulting water in a downstream storage tank; and h. repeating step g as necessary until the treated water achieves potable quality.

[0025] BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWINGS

[0026] Fig. 1 is an illustrative representation of working principle of photomolecular effect to generate potable water from industrial effluents employing wide band gap UV active material as photoactive material.

[0027] Fig. 2 illustrates the Field Emission Scanning Electron Microscope (FESEM) images of the synthesised ZnO nanorods.

[0028] Fig. 3 illustrates the XRD spectra of the synthesised ZnO nanorods.

[0029] Fig. 4 illustrates the XRD spectra of the synthesised NiO.

[0030] Fig. 5A and 5B illustrate the Scanning Electron Microscope (SEM) images of the synthesised NiO.

[0031] Fig. 5C illustrates the Energy Dispersive X-ray (ED AX) spectra of the synthesised NiO.

[0032] Fig. 6 illustrates a round bottom flask used as a vessel, the internal of which is coated with a wide band gap UV active material.

[0033] DETAILED DESCRIPTION

[0034] The subject matter of the present disclosure is described in detail with reference to the accompanying drawings. Unless otherwise specified, all the technical and scientific terms used herein have the same meaning as is generally understood by a person skilled in the art pertaining to the present disclosure. Headings are used solely for organizational purposes, and are not intended to limit the disclosure in any way.

[0035] The use of the singular includes the plural unless specifically stated otherwise. As used herein, the singular forms “a,” “an” and “the” are intended to include the plural forms as well. The use of “or” means “and / or” unless stated otherwise. Unless otherwise indicated, all numbers used herein to express quantities, dimensions, and so forth used should be understood as being modified in all instances by the term "about." It is to be understood that wherein a numerical range is recited, it includes all values within that range, and all narrower ranges within that range, whether specifically recited or not. As used herein, "including," "containing" and like terms are understood to be synonymous with "comprising" and are therefore open-ended and do not exclude the presence of additional undescribed or unrecited elements, materials, phases or method steps.

[0036] In addition, it should be appreciated that any figures provided herewith are for explanation purposes to persons ordinarily skilled in the art and that the drawings of them are not necessarily drawn to scale.

[0037] Any method / process steps and / or operations and / or instructions used in this disclosure, are for illustrative purposes in a particular order and / or grouping. Other orders and / or grouping of the process steps or its portions and / or operations or its portions and / or instructions or its portions are possible and, one or more of the process steps and / or operations and / or instructions can be combined and / or deleted.

[0038] The present disclosure provides a system and a method of photomolecular treatment of waste water to produce potable water.

[0039] The photomolecular treatment system comprises:

[0040] - a vessel having an internal surface coated with a layer of wide band gap UV active material, wherein the wide band gap UV active material is configured to contact waste water to be treated;

[0041] - a plurality of UV radiation sources arranged around the vessel to create phononic vibrations in the lattice of the wide band gap UV active material, wherein the UV radiation sources are configured to emit energy that generates thermal energy and causes evaporation of water;

[0042] - a condenser configured to receive and condense the evaporated water; and

[0043] - a storage tank arranged downstream of the condenser, configured to store the condensed water. In an aspect, the layer of the wide band gap UV active material is coated on the entire internal surface of the vessel.

[0044] It is to be noted that, the condensed water is then tested for its potable quality, and if the quality is not satisfying to be potable, the condensed water is transferred to a vessel coated on its internal surface with the wide band gap UV active material, and the wide band gap UV active material was irradiated with UV radiation sources the same way as before to further evaporate and purify the water, followed by condensing the evaporated water in a condenser and storing the resulting water in a downstream storage tank; and this is repeated as necessary until the treated water achieves potable quality.

[0045] In an aspect, the condensed water stored in the storage tank is transferred to another vessel having an internal surface coated with the wide band gap UV active material slurry for further treatment, and the further treatment of the condensed water follows the same treatment chain as the initial wastewater, and this process repeats until potable water is obtained.

[0046] In an aspect, at least one subsequent vessel having an internal surface coated with the wide band gap UV active material slurry is configured to receive the condensed water from the storage tank and at least one subsequent condenser and storage tank arranged downstream of the subsequent vessel and configured to condense and store the further evaporated water.

[0047] In an aspect, a control system configured to repeat the evaporation-condensation cycle in the subsequent vessel(s) until the treated water achieves potable quality.

[0048] Mechanism:

[0049] Fig. 1 is an illustrative representation of working principle of photomolecular effect to generate potable water from industrial effluents employing wide band gap UV active material as photoactive material. As shown in Fig. 1, UV radiation irradiated from the UV sources on the wide band gap UV active material to which the waste water is in contact, wherein the UV radiation causes excitation / transition of electrons in the wide band gap UV active material from the Highest Occupied Molecular Orbital (HOMO) to the Lowest Unoccupied Molecular Orbital (LUMO). This excitation initiates phononic vibrations in the lattice of the wide band gap UV active material, leading to thermal energy release. The released thermal energy is taken up by the water molecules causing evaporation, which is condensed in a condenser which pass through the condenser, and finally the condensed water is stored in a storage tank arranged downstream of the condenser.

[0050] In an aspect, the waste water to be treated is placed inside the vessel, to facilitate the wide band gap UV active material to be in contact with the waste water.

[0051] In an aspect, the vessel is made of a material that allows UV radiation to pass through it, i.e. the vessel material is transparent to UV radiation. The vessel material is selected from glass or quartz, preferably the vessel is made of glass.

[0052] In an aspect, the wide band gap UV active material is selected from ZnO, TiCh, MgO, NiO, preferably ZnO.

[0053] In an aspect, the ZnO is ZnO nanorods.

[0054] The waste water treated according to the present disclosure can be industrial waste water or municipal waste water.

[0055] A method of photomolecular treatment of waste water to produce potable water is also provided, wherein the method includes the following steps: a. preparing a slurry of a wide band gap UV active material in a solvent as acetone or ethanol or isopropanol, b. coating a layer of the wide band gap UV active material slurry on the internal surface of a vessel, wherein the wide band gap UV active material is configured to contact waste water to be treated; c. supplying waste water into the vessel, wherein the wide band gap UV active material contacts the waste water; d. arranging a plurality of UV radiation sources around the vessel to create phononic vibrations in the lattice of the wide band gap UV active material, wherein the UV radiation sources are configured to emit energy that generates thermal energy and causes evaporation of water; e. receiving and condensing the evaporated water in a condenser; f. receiving and storing the condensed water in a storage tank arranged downstream of the condenser; g. transferring the condensed water to at least one subsequent vessel coated on its internal surface with the wide band gap UV active material slurry, and irradiating the wide band gap UV active material with UV radiation sources to further evaporate and purify the water, followed by condensing the evaporated water in a condenser and storing the resulting water in a downstream storage tank; and h. repeating step g as necessary until the treated water achieves potable quality.

[0056] In an aspect, the recovery speed and amount of portable water generated from industrial waste water depends on the TDS and turbidity in the effluent. With less TDS and turbidity, the yield can be 80% and conversion rate is > 95%.

[0057] In an aspect, for large scale industrial applications where gallons of industrial effluent or waste water need to be treated, cooling tower can replace the condensation set up in the design.

[0058] In an aspect, a filter at the inlet of the industrial effluent to the photomolecular effect (PME) set up (as shown in Fig. 1) would reduce or eliminate turbidity and TDS and increase the efficiency or conversion rate to less than 24 hours.

[0059] Some of the wide band gap UV active materials mentioned in this disclosure have been synthesised by the inventors. Synthesis of ZnQ nanorods

[0060] ZnO nanorods were freshly synthesised by the inventors to be used as wide band gap UV active material in the present disclosure.

[0061] Method of synthesis of ZnQ nanorods

[0062] A solution of 1.5M ZnSO4 and 2.5M NH4HCO3 were prepared in distilled water. To 126 ml of 2.5M NH4HCO3, 100ml of 1.5M ZnSO4 was added dropwise under constant stirring at 45°C. The white coloured slurry of zinc carbonate was obtained in the form of precipitate. The precipitate was then filtered, washed, and dried. ZnO nanorods were obtained by calcining the precipitate at 500°C for about Ihr.

[0063] Characterisation of the synthesised ZnO nanorods

[0064] Fig. 2 illustrates the Field Emission Scanning Electron Microscope (FESEM) images of the synthesised ZnO nanorods.

[0065] The morphological and compositional analysis of the synthesised ZnO nanorods sample was done using FESEM (FEI, Quanta) with EDS from Oxford Instruments.

[0066] As shown in Fig. 2, the ZnO nanorods are agglomerated and appear like cluster of fibres with 18.808 m long and 13.160 pm wide. The nanorods of ZnO can be segregated via ultrasonication method in solvent such as acetone or isopropanol.

[0067] Fig. 3 illustrates the XRD spectra of the synthesised ZnO nanorods.

[0068] XRD of ZnO was recorded using Bruker D8 Advance Diffractometer with CuKa radiation at X=l.5406 A0.

[0069] As shown in Fig. 3, the peaks of ZnO nanorods are in good agreement with the literature and all the diffraction peaks indexed with ZnO hexagonal structure with cell parameter a=0.2520 A0& c=2.7770 A0(JCPDS No:79-0208). Synthesis of NiQ

[0070] The present inventors also freshly synthesised NiO to be used as wide band gap UV active material in the present disclosure.

[0071] Method of synthesis of NiQ

[0072] NiO bulk material is synthesized by alkaline hydrolysis of Nickel Sulphate with potassium hydroxide in the ratio of 2:6. The obtained precipitate of NiO is washed several times with deionised water and dried in an oven at 120°C for 3 hrs to obtain powder of dry NiO.

[0073] Characterisation of the synthesised NiO.

[0074] Fig. 4 illustrates the XRD spectra of the synthesised NiO.

[0075] The experimentally obtained XRD peaks and their corresponding planes from the JCPDS database (89-3060) are summarized in Table 1.

[0076] Table 1

[0077] The presence of peaks corresponding to (111), (200), (220), (311), and (222) planes confirm the phase purity and structural integrity of the sample. These peaks suggest a cubic structure, which is common in many metallic and ceramic materials.

[0078] The XRD analysis and comparison shows a strong agreement between the observed peak positions and the JCPDS reference values, confirming that the synthesized NiO exhibits a well-ordered crystalline structure with phase purity. The slight deviations in peak positions may be attributed to instrumental errors, strain effects, or slight variations in composition. Fig. 5A and 5B represent the Scanning Electron Microscopy (SEM) images of the synthesized NiO material at different magnifications. The morphological examination reveals that the particles exhibit a random orientation, making it difficult to draw definitive conclusions about their uniformity or specific structural attributes. However, one clear observation is that the particles appear relatively large, indicating that further grinding or milling may be necessary to reduce the particle size for enhanced material properties.

[0079] Fig. 5C shows the Energy Dispersive X-ray Spectroscopy (EDX) analysis, which was conducted to determine the elemental composition of the synthesized Nickel Oxide (NiO). The obtained elemental weight percentages and atomic percentages are summarized in Table 2.

[0080] Table 2

[0081] The elemental composition confirms the successful formation of NiO. The high percentage of Ni (74.49% by weight, 46.24% by atomic percentage) indicates that nickel is the dominant element in the sample. The presence of oxygen (22.17% by weight, 50.50% by atomic percentage) further supports the formation of nickel oxide. A trace amount of sulphur (0.70%) is detected, likely due to residual nickel sulphate used as a precursor in the synthesis process. Additionally, a small quantity of potassium (2.64%) is present, which can be attributed to the use of KOH during synthesis. These minor impurities may have originated from incomplete washing or adsorption of reactants onto the material’s surface. While these minor impurities do not significantly affect the overall structural integrity, further optimization in the washing and purification steps may help eliminate residual contaminants. Overall, the combined structural and compositional analyses confirm the successful synthesis of high-purity NiO with well-defined crystallinity.

[0082] Fig. 6 illustrates a round bottom flask used as the vessel for the lab scale experiment purpose of the present disclosure wherein the internal of the round bottom flask is coated with a wide band gap UV active material. The wide band gap material can be selected from ZnO, TiCh, NiO, and MgO.

[0083] In an aspect, a slurry of the wide band gap UV active material was prepared in acetone or ethanol or isopropanol as solvent, wherein the slurry is coated on the internal surface of the vessel. As evident to a person skilled in the art, the thickness of the slurry needs to be such that when coated to the internal surface of the vessel, it sticks to the surface without falling or flowing down, when it comes in contact with the waste water.

[0084] The slurry can be coated with paint and brush on the inner wall of the round bottom flask and allowed to dry at room temperature.

[0085] Examples:

[0086] The present disclosure will now be explained in further detail by the following examples. These examples are illustrative of certain embodiments of the disclosure without limiting the scope of the present disclosure.

[0087] Example 1: TiCh as wide band gap UV active material: 48 hours of treatment The internal surface of a 5-litre capacity round bottom (RB) flask (RB-Flask-1) (made of glass) was coated (leaving the neck region) with a TiCh slurry in acetone. Ten UV lamps were arranged in a cardboard box of dimension 45cm*45cm*75cm (length*breadth*height). Each of the 10 UV lamps is of 20 W power creating a total of 200W power, wherein 4 UV lamps were placed at the bottom of the cardboard box, and 3 lamps on each side of the cardboard box. The RB -Flask- 1 was placed on a o-ring stand to avoid any direct contact with the UV lamps. The narrow long neck of the round bottom flask is connected to Liebig condenser continuously circulated with cold water from an external pump. The rear end of the condenser is connected to a receiver RB flask (RB-Flask-2) of 5- litre capacity to collect the purified water from the industrial waste water. 5 litres of industrial waste water was filled in the internal TiCh slurry coated RB -Flask- 1, and the UV lamps were switched on, where the photoactive material TiCF was exposed to UV radiation causing evaporation of water, which was condensed in the condenser and stored in the RB -Flask-2.

[0088] It is to be noted that the required energy for excitation / transition of electrons in the TiCF molecule from the Highest Occupied Molecular Orbital (HOMO) to the Lowest Unoccupied Molecular Orbital (LUMO) is 3.2 eV, the frequency / wavelength at which the excitation occurs would be between 40 to 200 nm (UV-region).

[0089] Hence, the UV lamps in the cardboard box were configured to emit radiation in the above UV-region.

[0090] The waste water used here is the left out aqueous waste from a GHG to VAP unit set-up by the inventors of the present disclosure, where Green-house gas (GHG) is converted to value added products (VAP) through electrocatalytic reaction, and the waste water is the aqueous waste remained after evaporation and condensation of the VAPs from the GHG to VAP unit. This waste water was tested for different parameters and the results of the tests are tabulated in Table 3.

[0091] Table 3

[0092]

[0093] Important observed parameters of the waste water before treatment:

[0094] • pH = 4.16. • The presence of Cu is 1.64 g / L. (Not provided in Table)

[0095] • Hardness: 53 mg / L.

[0096] • Total dissolved solids (TDS): 100 mg / L.

[0097] Now, as discussed here under Example 1, this waste water was subjected to photomolecular treatment of a combined 200W power of UV radiation for 24 hours.

[0098] Day 1 (24 hours of treatment)

[0099] The condensed water collected is then tested for its quality under different parameters and the results of the tests are tabulated in Table 4.

[0100] Table 4

[0101] Important observed parameters of the obtained condensed water after initial 24 hours of treatment: • pH = 4.14.

[0102] • The presence of Cu is reduced to 0.594 g / L.

[0103] • Hardness has decreased from 53 mg / L to 32 mg / L.

[0104] • TDS increased from 100 mg / L to 110 mg / L. This increase in TDS is attributed to the reduction of Cu2+ions existing as salts in the effluent as insoluble copper oxide in the system.

[0105] Day 2 (further 24 hours of treatment)

[0106] As the quality is not satisfying to be potable, the condensed water is transferred to a vessel coated on its internal surface with TiCL slurry, and was subjected to the same photomolecular treatment of a combined 200W power of UV radiation for a further 24 hours.

[0107] The condensed water collected is then tested for its quality under different parameters and the results of the tests are tabulated in Table 5. Table 5

[0108] Important observed parameters of the obtained condensed water after further 24 hours (total 48 hours) of treatment:

[0109] • pH - 6.37

[0110] • The presence of Cu is reduced to 5mg / L.

[0111] • Hardness decreased to 5mg / L.

[0112] • TDS reduced to 2.5 mg / L.

[0113] This obtained water is potable.

[0114] Example 2: NiO as wide band gap UV active material: 72 hours of treatment

[0115] The process was carried out in the same manner as elaborated in Example 1, with the difference that the internal surface of a 5-litre capacity RB flask was coated with a NiO slurry in isopropanol.

[0116] It is to be noted that the required energy for excitation / transition of electrons in the NiO molecule from HOMO to LUMO is 3.6 to 4.0 eV, the frequency / wavelength at which the excitation occurs would be between 10 to 200 nm (UV-region).

[0117] Hence, the UV lamps in the cardboard box were configured to emit radiation in the above UV-region. Source of waste water: Aqueous waste from the GHG to VAP unit as discussed under Example 1. This waste water was tested for different parameters and the results of the tests are tabulated in Table 3.

[0118] Important observed parameters of the waste water before treatment:

[0119] • pH = 4.16.

[0120] • The presence of Cu is 1.64 g / L. (Not provided in Table)

[0121] • Hardness: 53 mg / L.

[0122] • Total dissolved solids (TDS): 100 mg / L.

[0123] This waste water was subjected to photomolecular treatment of a combined 200W power of UV radiation for 24 hours.

[0124] Day 1 (24 hours of treatment)

[0125] The condensed water collected is then tested for its quality under different parameters and the results of the tests are tabulated in Table 6.

[0126] Table 6 Important observed parameters of the obtained condensed water after initial 24 hours of treatment:

[0127] • pH = 4.14.

[0128] • The presence of Cu: 0.82 g / L. • Hardness: 32 mg / L.

[0129] • TDS: 110 mg / L.

[0130] Day 2 (further 24 hours of treatment)

[0131] As the quality is not satisfying to be potable, the condensed water is transferred to a vessel coated on its internal surface with NiO slurry, and was subjected to the same photomolecular treatment of a combined 200W power of UV radiation for a further 24 hours.

[0132] The condensed water collected is then tested for its quality under different parameters and the results of the tests are tabulated in Table 7.

[0133] Table 7 Important observed parameters of the obtained condensed water after further 24 hours of treatment:

[0134] • pH = 4.2.

[0135] • The presence of Cu: 0.354 g / L.

[0136] • Hardness: 25 mg / L.

[0137] • TDS: 96 mg / L.

[0138] Day 3 (further 24 hours of treatment)

[0139] As the quality is not satisfying to be potable, the condensed water is transferred to a vessel coated on its internal surface with NiO slurry, and was subjected to the same photomolecular treatment of a combined 200W power of UV radiation for a further 24 hours.

[0140] The condensed water collected is then tested for its quality under different parameters and the results of the tests are tabulated in Table 8.

[0141] Table 8

[0142] Important observed parameters of the obtained condensed water after further 24 hours (total 72 hours) of treatment:

[0143] • pH - 6.37.

[0144] • The presence of Cu: 0.008 g / L.

[0145] • Hardness: 5 mg / L.

[0146] • TDS: 5 mg / L. This obtained water is potable.

[0147] Example 3: MgO as wide band gap UY active material: 96 hours of treatment

[0148] The process was carried out in the same manner as elaborated in Example 1 , with the difference that the internal surface of a 5 -litre capacity RB flask was coated with a MgO slurry in ethanol.

[0149] It is to be noted that the required energy for excitation / transition of electrons in the MgO molecule from HOMO to LUMO is 7.6 eV, the frequency / wavelength at which the excitation occurs would be between 10 to 100 nm (UV-region).

[0150] Hence, the UV lamps in the cardboard box were configured to emit radiation in the above UV-region.

[0151] Source of waste water: Aqueous waste from the GHG to VAP unit as discussed under Example 1. This waste water was tested for different parameters and the results of the tests are tabulated in Table 3.

[0152] Important observed parameters of the waste water before treatment:

[0153] • pH = 4.16.

[0154] • The presence of Cu is 1.64 g / L. (Not provided in Table)

[0155] • Hardness: 53 mg / L.

[0156] • Total dissolved solids (TDS): 100 mg / L.

[0157] This waste water was subjected to photomolecular treatment of a combined 200W power of UV radiation for 24 hours.

[0158] Dav 1 (24 hours of treatment)

[0159] The condensed water collected is then tested for its quality under different parameters and the results of the tests are tabulated in Table 9. Table 9

[0160] Important observed parameters of the obtained condensed water after initial 24 hours of treatment: • pH = 4.43.

[0161] • The presence of Cu: 0.925 g / L.

[0162] • Hardness: 30 mg / L.

[0163] • TDS: 90 mg / L. Day 2 (further 24 hours of treatment)

[0164] As the quality is not satisfying to be potable, the condensed water is transferred to a vessel coated on its internal surface with MgO slurry, and was subjected to the same photomolecular treatment of a combined 200W power of UV radiation for a further 24 hours.

[0165] The condensed water collected is then tested for its quality under different parameters and the results of the tests are tabulated in Table 10. Table 10

[0166] Important observed parameters of the obtained condensed water after further 24 hours of treatment: • pH = 4.48.

[0167] • The presence of Cu: 0.432 g / L.

[0168] • Hardness: 22 mg / L.

[0169] • TDS: 80 mg / L. Dav 3 (further 24 hours of treatment)

[0170] As the quality is not satisfying to be potable, the condensed water is transferred to a vessel coated on its internal surface with MgO slurry, and was subjected to the same photomolecular treatment of a combined 200W power of UV radiation for a further 24 hours.

[0171] The condensed water collected is then tested for its quality under different parameters and the results of the tests are tabulated in Table 11. Table 11

[0172] Important observed parameters of the obtained condensed water after further 24 hours of treatment:

[0173] • pH = 4.6.

[0174] • The presence of Cu: 0.15 g / L.

[0175] • Hardness: 24 mg / L.

[0176] • TDS: 82 mg / L.

[0177] Day 4 (further 24 hours of treatment)

[0178] As the quality is not satisfying to be potable, the condensed water is transferred to a vessel coated on its internal surface with MgO slurry, and was subjected to the same photomolecular treatment of a combined 200W power of UV radiation for a further 24 hours.

[0179] The condensed water collected is then tested for its quality under different parameters and the results of the tests are tabulated in Table 12. Table 12

[0180] Important observed parameters of the obtained condensed water after further 24 hours (total 96 hours) of treatment:

[0181] • pH - 6.37.

[0182] • The presence of Cu: 0.1 g / L.

[0183] • Hardness: 5 mg / L.

[0184] • TDS: 2.5 mg / L.

[0185] This obtained water is potable.

[0186] Best Mode:

[0187] Example 4: ZnO nanorods as wide band gap UV active material: 24 hours of treatment

[0188] The process was carried out in the same manner as elaborated in Example 1 , with the difference that the internal surface of a 5 -litre capacity RB flask was coated with a ZnO nanorods slurry in acetone.

[0189] It is to be noted that the required energy for excitation / transition of electrons in the ZnO molecule from HOMO to LUMO is 0.27 eV, the frequency / wavelength at which the excitation occurs would be between 288 to 305 nm (UV-region).

[0190] Hence, the UV lamps in the cardboard box were configured to emit radiation in the above UV-region. Source of waste water: Aqueous waste from the GHG to VAP unit as discussed under Example 1. This waste water was tested for different parameters and the results of the tests are tabulated in Table 3.

[0191] Important observed parameters of the waste water before treatment:

[0192] • pH = 4.16.

[0193] • The presence of Cu is 1.64 g / L. (Not provided in Table)

[0194] • Hardness: 53 mg / L.

[0195] • Total dissolved solids (TDS): 100 mg / L.

[0196] This waste water was subjected to photomolecular treatment of a combined 200W power of UV radiation for 24 hours.

[0197] Day 1 (24 hours of treatment)

[0198] The condensed water collected is then tested for its quality under different parameters and the results of the tests are tabulated in Table 13.

[0199] Table 13

[0200] Important observed parameters of the obtained condensed water after 24 hours of treatment:

[0201] • pH = 6.37.

[0202] • The presence of Cu: 0.0052 g / L.

[0203] • Hardness: 5 mg / L. TDS: 2.5 mg / L.

[0204] This obtained water is potable.

[0205] Advantages:

[0206] The system and a method of photomolecular treatment of waste water to produce potable water of the present disclosure has the following non-limiting advantages.

[0207] - No requirement of very high power and complex design.

[0208] - Photoactive material is easy to synthesize and requires to just coat the inner wall of the RB.

[0209] - Able to remove all metal ions including hazardous materials and heavy metals.

[0210] - Chemical-free, water purification driven by phononic and thermal interactions.

[0211] - UV radiation kills any pathogens and microbial growth presence in the industrial effluent.

[0212] - No solid waste or gaseous products, completely zero waste and adheres to 5R compliance.

[0213] - Easy to scale up.

[0214] Applications:

[0215] The system and a method of photomolecular treatment of waste water to produce potable water of the present disclosure has the following non-limiting industrial applications.

[0216] - Recovery of potable water from industrial or municipal waste water.

[0217] Although the present disclosure is described in terms of one or more embodiments, it is to be understood that they have been presented by way of example, and are not limiting. Thus, the present disclosure should not be limited by any of the above-described exemplary embodiments, but should be defined only in accordance with the following claims and their equivalents.

Claims

CLAIMS1. A water purification system for treating wastewater to produce potable water, comprising:- a vessel having an internal surface;- a coating of a wide band gap UV active material applied to at least a portion of the internal surface of the vessel, the wide band gap UV active material being configured to contact wastewater supplied into the vessel;- a plurality of ultraviolet (UV) radiation sources arranged around the vessel, the UV radiation sources configured to irradiate the wide band gap UV active material to excite its lattice and generate thermal energy sufficient to evaporate water from the wastewater;- a condenser fluidly connected to the vessel and configured to receive and condense evaporated water; and- a storage tank fluidly connected downstream of the condenser and configured to store the condensed water.

2. The water purification system as claimed in claim 1, wherein the condensed water stored in the storage tank is transferred to another vessel having an internal surface coated with the wide band gap UV active material slurry for further refinement, and the further processing of the condensed water follows the same treatment chain as the initial wastewater, and this transfer process is repeated until potable water is obtained.

3. The water purification system as claimed in claim 1, wherein the wide band gap UV active material is selected from ZnO, TiCh, MgO, NiO.

4. The water purification system as claimed in claim 1, wherein the coating of the wide band gap UV active material is prepared using a solvent selected from the group consisting of acetone, ethanol, and isopropanol.

5. The water purification system as claimed in claim 1, wherein the vessel is selected from a glass vessel or a quartz vessel.

6. A system for photomolecular treatment of wastewater to produce potable water, the system comprising:- a first vessel having an internal surface coated with a slurry of a wide band gap UV active material prepared in a solvent selected from acetone, ethanol, or isopropanol;- a plurality of ultraviolet (UV) radiation sources arranged around the first vessel, the UV radiation sources being configured to irradiate the wide band gap UV active material to induce phononic lattice vibrations, thereby generating thermal energy and causing evaporation of water from wastewater introduced into the first vessel;- a first condenser arranged downstream of the first vessel and configured to condense the evaporated water;- a first storage tank configured to receive and store the condensed water;- at least one subsequent vessel having an internal surface coated with the wide band gap UV active material slurry and configured to receive the condensed water from the first storage tank;- a plurality of UV radiation sources arranged around the subsequent vessel to irradiate the wide band gap UV active material, causing further evaporation of water;- at least one subsequent condenser and storage tank arranged downstream of the subsequent vessel and configured to condense and store the further evaporated water; and- a control system configured to repeat the evaporation-condensation cycle in the subsequent vessel(s) until the treated water achieves potable quality.

7. A method for treating wastewater to produce potable water, the method comprising the steps of: a. preparing a slurry of a wide band gap UV active material in a solvent; b. coating a layer of the wide band gap UV active material slurry on an internal surface of a vessel such that the wide band gap UV active material is exposed to wastewater introduced into the vessel; c. supplying wastewater into the vessel such that the wastewater contacts the wide band gap UV active material; d. irradiating the wide band gap UV active material by arranging a plurality of UV radiation sources around the vessel, the UV radiation configured to excite the lattice of the wide band gap UV active material and generate thermal energy sufficient to evaporate water from the wastewater;e. condensing the evaporated water in a condenser; f. storing the condensed water in a storage tank fluidly connected downstream of the condenser; g. transferring the condensed water to a subsequent vessel coated on its internal surface with the wide band gap UV active material slurry, and irradiating the wide band gap UV active material with UV radiation sources to further evaporate and purify the water, followed by condensing the evaporated water in a condenser and storing the resulting water in a downstream storage tank; and h. repeating step g as necessary until the treated water achieves potable quality.

8. The method for treating waste water to produce potable water as claimed in claim 7, wherein the solvent is selected from the group consisting of acetone, ethanol, and isopropanol.

9. The water purification system as claimed in claim 7, wherein the wide band gap UV active material is selected from ZnO, TiCh, MgO, NiO.

10. The water purification system as claimed in claim 7, wherein the vessel is selected from a glass vessel or a quartz vessel.

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