Description:FIELD OF THE INVENTION
This invention relates to Ti3C2 MXene with Colloidal SnO2 Quantum Dots Nanocomposite for the Abatement of Heavy Metals, Organic Pollutants, and Microbial Contaminants from Water.
BACKGROUND OF INVENTION
Water pollution caused by organic pollutants, heavy metals, and microbial contaminants continues to pose severe environmental and health hazards. Conventional water treatment technologies, including filtration, chemical treatment, and biological processes, often fail to completely remove persistent pollutants and require high operational costs. A more efficient, scalable, and environmentally sustainable approach is essential for advanced water purification. The proposed invention introduces a Ti3C2 MXene/SnO2 quantum dots (QDs) nanocomposite that utilizes a combination of photocatalysis, adsorption, and electrochemical degradation to mitigate a broad spectrum of waterborne pollutants.
Several approaches have been explored to address water pollution, including:
Photocatalytic Materials: TiO2 and SnO2-based photocatalysts have been used for water purification, but their limited light absorption and high electron-hole recombination rates reduce their effectiveness.
Activated Carbon and Adsorbents: These systems provide high adsorption efficiency but lack the ability to degrade pollutants, resulting in pollutant saturation over time.
Membrane Technologies: Membrane filtration is effective but prone to fouling, requiring frequent maintenance and operational cost.
September 2022Chemical Engineering Journal 451:138933DOI:10.1016/j.cej.2022.138933 disclosed a novel Ti3C2 MXene quantum dots (MQDs)-modified In2S3/MQDs/SmFeO3 (IMS) Z-scheme heterojunction. We then investigated the crystal phases, chemical states, morphologies, and band structures of the Z-scheme catalysts in detail. The as-prepared IMS heterojunctions greatly facilitated the photocatalytic degradation of sulfamethoxazole (SMX) and 4-chlorophenol (4-CP) compared with the single and binary catalysts. The degradation of SMX under visible-light using the optimized IMS-3 ternary composite was clearly enhanced, and the degradation rates of 4-CP were 98.0% and 95.4% after 120 and 90 min of irradiation, respectively. The significantly enhanced photoactivity of the IMS composite was attributed to the effective spatial separation and charge transfer owing to the introduction of MQDs as charge-transport bridges in the Z-scheme system. Additionally, the unique properties of MQDs further accelerated the surface redox kinetics of the IMS catalyst, thus stimulating the formation of reactive species for pollutant degradation. Furthermore, these results indicate that MQDs not only act as electron mediators but also maintain the strong redox stability of IMS heterojunctions. This study offers a new avenue for developing efficient MQD-based Z-scheme photocatalysts and provides in-depth insights into the SMX degradation mechanism.
https://doi.org/10.1016/j.compositesb.2025.112521 disclosed increasing concerns over environmental pollution and human health hazards caused by pesticides and pharmaceutical residues have driven significant research into the development of highly sensitive and selective electrochemical sensors. MXenes, a class of two-dimensional (2D) transition metal carbides and nitrides along with MXene-based composites, have emerged as promising candidates for electrochemical sensing due to their unique physicochemical properties, including high electrical conductivity, large surface area, hydrophilicity, and tunable surface chemistry. Herein, we have comprehensively discussed the role of MXenes and their composites in the electrochemical detection of drugs and pesticides. Further, they can be classified based on their structural dimensions and explore their fundamental properties, including conductivity, electrochemical stability, mechanical integrity, and chemical reactivity, which govern their sensing performance. However, MXenes can be easily oxidized and undergo gradual structural degradation, which may impact performance over a long time. Therefore, the need for MXene-based composites is highlighted to address the limitations of pristine MXenes and enhance their selectivity, stability, and sensitivity for detecting trace-level analytes. The recent advancements in MXenes modified electrochemical sensors for detecting pesticides and drugs, critically analyzing their sensing mechanisms, detection limits, and response times.
https://doi.org/10.1007/s00604-022-05555-4 disclosed novel SnO2 quantum dots (SnO2QDs)-functionalized Ti3C2 MXene nanocomposite was prepared via in situ synthesis method, resulting in well-regulated the nucleation and growth of SnO2QDs to evenly distribute onto MXene nanosheets. Ultra-small size SnO2QDs decorated on the surface of Ti3C2 MXene nanosheets can effectively prevent the restacking of MXene and remarkably increase the electroactive surface area of the electrode, which can further increase electrocatalytic activity toward dopamine. Then, an ultrasensitive electroanalytical method based on SnO2QDs-functionalized Ti3C2 MXene nanocomposite for dopamine monitoring was developed, and the effects of experimental condition were investigated systematically. Under optimized conditions, the prepared sensor presented a linear dependence for dopamine in the concentration range from 0.004 to 8.0 µM with the detection limit of 2.0 nM (S/N = 3). Moreover, it selectively perceived dopamine in presence of physiological interferents in urine and serum samples with excellent linearities (correlation coefficients higher than 0.9920). The relative recoveries were in the range 97.67-105.3% and 103.0-106.8%, while the limits of quantitation were 10.12 nM and 9.62 nM in urine and serum sample, respectively, demonstrating the method suitability for dopamine sensing and being envisioned as a promising candidate for neurotransmitter monitoring in biological diagnosis.
https://doi.org/10.1016/j.wri.2023.100202 disclosed a novel family of 2D materials, MXenes provide an extensive variety of applications in water and effluent treatment due to their distinctive properties and attractive applicability, including superior electrical conductivity, higher thermal stability, hydrophilicity, and high sorption-reduction capacity. Their excellent sorption selectivity makes them perfect for removing hazardous contaminants. Currently, MXene-based materials are regarded as one of the most important topics in membrane separation processes. This work presents a comprehensive review of recent developments in MXene-based water treatment materials. The applications of MXene-based membranes, adsorbents, and photo-catalysts in removing antibiotics and heavy metals from water are discussed. A comparison of MXene-based membranes with other 2D membranes is outlined. Finally, prospects and challenges for future research are discussed.
Research gap
Synergistic Nanocomposite Design: The combination of Ti3C2 MXene and SnO2 QDs enables a multifunctional degradation mechanism that addresses organic pollutants, heavy metals, and microbial contaminants.
Enhanced Charge Separation and Photocatalysis: The use of highly conductive Ti3C2 MXene improves charge transport, preventing electron-hole recombination and enhancing photocatalytic efficiency.
Room-Temperature Synthesis and Scalability: The synthesis process is simple, low-cost, and energy-efficient, making the invention suitable for large-scale water treatment applications.
None of the prior art indicate above either alone or in combination with one another disclose what the present invention has disclosed. This invention relates to Ti3C2 MXene with Colloidal SnO2 Quantum Dots Nanocomposite for the Abatement of Heavy Metals, Organic Pollutants, and Microbial Contaminants from Water.

SUMMARY OF INVENTION
This invention relates to a novel Ti3C2 MXene/SnO2 quantum dot (QD) nanocomposite designed for superior water treatment. The synthesis involves selectively etching Ti3AlC2 to obtain Ti3C2 MXene, colloidally synthesizing SnO2 QDs, and then using sonication to deposit the QDs onto the MXene nanosheets. The resulting nanocomposite leverages photocatalytic degradation from SnO2 QDs (generating reactive oxygen species under light), enhanced charge separation due to the MXene acting as an electron reservoir, and the high adsorption capacity of MXene for pollutants. This synergistic effect allows for efficient removal of heavy metals (through adsorption and photocatalytic reduction), organic pollutants (through photocatalytic oxidation), microbial contaminants (via disinfection by reactive oxygen species), and oil/grease residues (through MXene's hydrophilic nature). The invention has potential applications in municipal water treatment, industrial effluent treatment, and agricultural water purification systems.
Detailed Description of invention
The proposed invention involves a Ti3C2 MXene/SnO2 QD nanocomposite synthesized through a combination of selective etching, colloidal synthesis, and sonication-based deposition methods. This nanocomposite demonstrates superior performance in water treatment by leveraging multiple degradation mechanisms to ensure efficient pollutant removal.
Synthesis Procedure:
1. Synthesis of Ti3C2 MXene:
Ti3AlC2 MAX phase (titanium aluminum carbide MAX phase) is selectively etched using a mixture of LiF and HCl or HF to remove the Al layers.
The resulting Ti3C2 MXene nanosheets are washed, centrifuged, and freeze-dried to obtain a stable dispersion.
2. Synthesis of SnO2 Quantum Dots:
1. wet-chemical colloidal synthesis is employed, where SnCl2·2H2O is dissolved in deionized water.
2. Thiourea is added as a sulfur source, and the solution is stirred at room temperature for 72 hours.
3.The resulting SnO2 QDs are collected via centrifugation and redispersed in water.
4. Formation of Ti3C2 MXene/SnO2 QD Nanocomposite:
SnO2 QDs are mixed with Ti3C2 MXene in an aqueous solution under sonication to achieve uniform deposition.
The composite is dried and annealed at a low temperature to enhance bonding and stability.
Flowchart Representation of the Synthesis Process:
1. Etching of Ti3AlC2 MAX phase → 2. Liquid-phase exfoliation of Ti3C2 MXene → 3. Colloidal synthesis of SnO2 QDs → 4. Sonication-assisted deposition of SnO2 QDs onto MXene → 5. Application to water treatment systems
Explanation for Water Pollution Treatment:
Photocatalytic Degradation: SnO2 QDs generate electron-hole pairs under visible and UV light. The electrons react with oxygen to form superoxide radicals (O2⁻), while the holes react with water to form hydroxyl radicals (OH⁻), which oxidize and decompose organic pollutants.
Charge Separation Enhancement: Ti3C2 MXene acts as an efficient electron reservoir, preventing charge recombination and enhancing pollutant degradation.
Adsorption Properties: The high surface area of Ti3C2 MXene captures heavy metals and organic pollutants, enabling prolonged interaction with reactive species.
Industrial Water Pollutants and Their Harm to the Environment: Industrial effluents contain a wide range of hazardous pollutants, including:
Heavy Metals (Lead, Cadmium, Arsenic): These metals are toxic even at low concentrations and accumulate in the food chain, leading to serious health issues such as organ failure and neurological disorders.
Organic Pollutants (Phenols, Dyes, Pesticides): Persistent organic pollutants are resistant to degradation and cause bioaccumulation, leading to carcinogenic and mutagenic effects.
Microbial Contaminants (Pathogenic Bacteria and Viruses): Microbial contamination causes waterborne diseases and poses significant public health risks.
Oil and Grease Residues: These pollutants create surface films that prevent oxygen transfer, disrupting aquatic ecosystems.
Present Invention Addresses These Pollutants:
 Heavy Metals: The high adsorption capacity of Ti3C2 MXene captures metal ions, while SnO2 QDs facilitate photocatalytic reduction to convert toxic metals into less harmful forms.
 Organic Pollutants: Photocatalytic oxidation driven by SnO2 QDs breaks down organic pollutants into harmless byproducts such as CO2 and H2O.
 Microbial Contaminants: Reactive oxygen species generated during photocatalysis destroy microbial cell walls, ensuring disinfection.
 Oil and Grease Residues: The hydrophilic nature of MXene allows effective separation and degradation of hydrophobic residues.
 . COMPARISON:
Aspect Proposed Method Photocatalytic TiO2 Activated Carbon Membrane Filtration
Active Mechanism Photocatalysis + Adsorption + Electrochemical Photocatalysis Adsorption Physical Filtration
Scalability High, applicable in water systems Moderate Low High
Energy Requirement Ambient light-driven UV light required None High operational cost
Pollutant Removal Organics, heavy metals, microbes Organic pollutants Heavy metals Microbes and particulates

Use of invention
Industrial Applicability This invention is applicable in multiple environmental and engineering domains, including:
Municipal Water Treatment Plants: Integration into existing filtration systems to improve pollutant degradation.
Industrial Effluent Treatment: Application in industrial settings to mitigate heavy metal contamination and organic waste.
Agricultural Water Purification: Treatment of water used in irrigation systems to ensure safe and clean water supply.
 
, Claims:1. A Ti3C2 MXene/SnO2 quantum dot nanocomposite for water treatment comprising:
Ti3C2 MXene nanosheets produced by selectively etching a Ti3AlC2 MAX phase (titanium aluminum carbide MAX phase) mixture of LiF and HCl or HF to remove the Al layers;
SnO2 quantum dots synthesized using wet-chemical colloidal method and deposited onto the Ti3C2 MXene nanosheets through sonication.
2. A method for synthesizing a Ti3C2 MXene/SnO2 quantum dot nanocomposite for water treatment, the said method comprising the steps of:
a. Selectively etching a Ti3AlC2 MAX phase with a mixture of LiF and HCl or HF to obtain Ti3C2 MXene nanosheets;
b. Washing, centrifuging, and freeze-drying the Ti3C2 MXene nanosheets to form a stable dispersion;
c. Synthesizing SnO2 quantum dots by dissolving SnCl2·2H2O in deionized water and reacting it with thiourea at room temperature for approximately 72 hours;
d. Collecting the SnO2 quantum dots via centrifugation and redispersing them in water;
e. Mixing the SnO2 quantum dots with the Ti3C2 MXene nanosheets in an aqueous solution under sonication to achieve uniform deposition of the quantum dots onto the nanosheets;
f. Drying and annealing the resulting composite at a low temperature to enhance bonding and stability.
3. The Ti3C2 MXene/SnO2 quantum dot nanocomposite as claimed in claim 1-2, wherein the said nanocomposite is removing pollutants through a combination of photocatalytic degradation and adsorption.
4. The Ti3C2 MXene/SnO2 quantum dot nanocomposite as claimed in claim 1-2, wherein the said nanocomposite removes pollutants include heavy metals, organic pollutants, and microbial contaminants.
5. The Ti3C2 MXene/SnO2 quantum dot nanocomposite as claimed in claim 1-2, wherein organic pollutants are removed through photocatalytic oxidation by the said quantum dots nanocomposite.
6. The Ti3C2 MXene/SnO2 quantum dot nanocomposite as claimed in claim 1-2, wherein said nanocomposite removes heavy metals by photocatalytic reduction to convert toxic metals into less harmful forms.
7. The Ti3C2 MXene/SnO2 quantum dot nanocomposite as claimed in claim 1-2, wherein microbial contaminants are removed through disinfection by reactive oxygen species generated by the said quantum dots nanocomposite.
8. The Ti3C2 MXene/SnO2 quantum dot nanocomposite as claimed in claim 1-2, wherein the hydrophilic nature of said nanocomposite allows effective separation and degradation of hydrophobic residues like Oil and Grease residues.