Novel biogenic gold nanoparticles stabilized on poly(styrene-co-maleic anhydride) as an effective material for reduction of nitrophenols and colorimetric detection of Pb(II).

Biogenic gold nanoparticles (AuNPs) have been extensively studied for the catalytic conversion of nitrophenols (NP) into aminophenols and the colorimetric quantification of heavy metal ions in aqueous solutions. However, the high self-agglomeration ability of colloidal nanoparticles is one of the major obstacles hindering their application. In the present study, we offered novel biogenic AuNPs synthesized by a green approach using Cistanche deserticola (CD) extract as a bioreducing agent and stabilized on poly(styrene-co-maleic anhydride) (PSMA). The prepared Au@PSMA nanoparticles were characterized by various techniques (HR-TEM, SEAD, FE-SEM, DLS, TGA, XRD, and FTIR) and studied for two applications: the catalytic reduction of 3-NP by NaBH4 and the sensing detection of Pb2+ ions. The optimal conditions for the synthesis of AuNPs were investigated and established at 60 °C, 20 min, pH of 9, and 0.5 mM Au3+. Morphological studies showed that AuNPs synthesized by CD extract were mostly spherical with a mean diameter of 25 nm, while the size of polymer-integrated AuNPs was more than two-fold larger. Since PSMA acted as a matrix keeping the nanoparticles from coagulation and maintaining the optimal surface area, AuNPs integrated with PSMA showed higher catalytic efficiency with a faster reaction rate and lower activation energy than conventional nanoparticles. Au@PSMA could completely reduce 3-NP within 10 min with a rate constant of 0.127 min-1 and activation energy of 9.96 kJ/mol. The presence of PSMA also improved the stability and recyclability of AuNPs. Used as a sensor, Au@PSMA exhibited excellent sensitivity and selectivity for Pb2+ ions with a limit of detection of 0.03 µM in the linear range of 0-100 µM. The study results suggested that Au@PSMA could be used as a promising catalyst for the reduction of NP and the colorimetric sensor for detection of Pb2+ ions in aqueous environmental samples.

Remediation of pharmaceuticals from contaminated water by molecularly imprinted polymers: a review.

The release of pharmaceuticals into the environment induces adverse effects on the metabolism of humans and other living species, calling for advanced remediation methods. Conventional removal methods are often non-selective and cause secondary contamination. These issues may be partly solved by the use of recently-developped adsorbents such as molecularly imprinted polymers. Here we review the synthesis and application of molecularly imprinted polymers for removing pharmaceuticals in water. Molecularly imprinted polymers are synthesized via several multiple-step polymerization methods. Molecularly imprinted polymers are potent adsorbents at the laboratory scale, yet their efficiency is limited by template leakage and polymer quality. Adsorption performance of multi-templated molecularly imprinted polymers depends on the design of wastewater treatment plants, pharmaceutical consumption patterns and the population serviced by these wastewater treatment plants.

Cu2O/Fe3O4/MIL-101(Fe) nanocomposite as a highly efficient and recyclable visible-light-driven catalyst for degradation of ciprofloxacin.

Nowadays, the widespread production and use of antibiotics have increased their presence in wastewater systems, posing a potential threat to the environment and human health. The development of advanced materials for treating antibiotics in wastewater has always received special attention. This study aimed to synthesize a novel Cu2O/Fe3O4/MIL-101(Fe) nanocomposite and use it to degrade ciprofloxacin (CIP) antibiotics in an aqueous solution under visible light irradiation. The optical, structural, and morphological attributes of the developed nanocomposite were analyzed by XRD, FTIR, FE-SEM, TGA, DRS, BET, VSM, and UV-Vis techniques. Optimum circumstances for CIP photocatalytic degradation were acquired in 0.5 g L-1 of catalyst dosage, pH of 7, and CIP concentration of 20 mg L-1. The degradation efficiency was achieved 99.2% after 105 min of irradiation in optimum circumstances. The chemical trapping experiments confirmed that hydroxyl and superoxide radicals significantly contributed to the CIP degradation process. The results of this study indicated that Cu2O/Fe3O4/MIL-101(Fe) nanocomposite was a highly stable photocatalyst that could effectively remove antibiotics from aqueous solutions. The CIP degradation efficiency only decreased by 6% after five cycles, indicating the excellent recyclability of Cu2O/Fe3O4/MIL-101(Fe) nanocomposites.

Natural core-shell structure activated carbon beads derived from Litsea glutinosa seeds for removal of methylene blue: Facile preparation, characterization, and adsorption properties.

In this study, natural core-shell structure activated carbon beads (ACBs) from Litsea glutinosa seeds were successfully produced, characterized, and applied for adsorption of methylene blue (MB). The ACBs were prepared using single-step carbonization-activation with NaHCO3 at the optimized activation temperature, time, and activating agent concentration of 450 °C, 60 min, and 5%, respectively. Batch experiments were performed to determine the optimum adsorption conditions, suitable kinetic and isotherm models, and thermodynamic parameters for the adsorption of MB onto ACBs. The results showed that the ACBs were displayed as highly porous natural core-shell spheres with a diameter of about 5 mm. The adsorption of MB dye on ACBs was a spontaneous endothermic process, followed the Langmuir isotherm and the pseudo-second-order kinetic models with the rate-controlling step of both external diffusion and intra-particle diffusion. At the optimum conditions (pH of 9, the contact time of 10 h, the temperature of 40 °C, and an adsorbent dosage of 6 g/L), the maximum adsorption capacity reached 29.03 mg/g. The thermal method turned out to be more suitable for regenerating ACBs compared to the chemical method. The ACBs exhibited high reusability and stability, its adsorption efficiency could maintain more than 90% after five consecutive cycles of use. The electrostatic attraction, π-π interaction, hydrogen bonding, and pore-filling were identified as primary contributions to the adsorption mechanism. The overall results revealed that the ACBs could be used as a potential adsorbent for removing MB from water media.

Effect of pore structure in bismuth metal-organic framework nanorod derivatives on adsorption and organic pollutant degradation.

This study explores the synthesis, characterization, and photocatalytic properties of bismuth metal-organic framework (Bi-MOF) nanorods and their derivatives such as Ag/Bi-MOF and Ag/Bi2O3. Bi-MOF nanorods exhibit significant photocatalytic activity under visible light, with the addition of silver (Ag) enhancing electron-hole pair separation and reducing their recombination. This leads to improved photocatalytic performance, particularly in the degradation of organic pollutants such as Rhodamine B (RhB) and Methylene Blue (MB). The results show that Bi-MOF and its derivatives demonstrate excellent chemical stability and high performance in photocatalytic applications, even when subjected to high temperatures and tested across a wide pH range. The large surface area and microporous structure facilitate selective adsorption of small organic molecules like MB. The pores and large surface area not only provide numerous active sites but also enhance the interaction between reactants and the catalyst surface, improving photocatalytic efficiency. Bi-MOF and its derivatives perform optimally across a broad pH range, from acidic to alkaline environments, where strong oxidizing hydroxyl radicals (·OH) are easily formed, aiding in the effective degradation of organic compounds. The study also shows that Bi-MOF and its derivatives can be reused multiple times without significant loss in performance. This research contributes to the development of advanced materials for environmental remediation, highlighting the potential of Bi-MOF-based nanocomposites in practical applications.

153Sm-labeled Fe3O4@lapatinib nanoparticles as a potential therapeutic agent for breast cancer: synthesis, quality control, and in vivo evaluation.

The present study introduces Fe3O4-coated lapatinib-labeled 153Sm nanoparticles (denoted as Fe3O4@lapatinib-153Sm) as a promising avenue for advancing breast cancer treatment. The radiolabeled nanoparticles combine various attributes, offering enhanced therapeutic precision. The integration of lapatinib confers therapeutic effects and targeted delivery. The inherent magnetic characteristics of Fe3O4 nanoparticles contribute to improved imaging contrast and targeted localization. Incorporating the gamma-emitting 153Sm isotope permits single-photon emission computed tomography imaging and radiation dose evaluation, while its beta-emitting nature ensures targeted cancer cell eradication. The synthesis of Fe3O4@lapatinib-153Sm was meticulously optimized by investigating the effects of parameters on radiolabeling efficiency. Physicochemical attributes were scrutinized using several analytical techniques. In-depth in vivo assessment evaluated the biocompatibility, toxicity, and biodistribution in a murine model, illuminating clinical utility. Optimal conditions (153SmCl3 concentration of 10 mCi mL-1, pH 7.4, a reaction time of 30 min, and a temperature of 25 °C) achieved >99% labeling efficiency and radiochemical purity. The TEM analysis indicated that the diameter of Fe3O4@lapatinib-153Sm nanoparticles ranged from 10 to 40 nm. Vibrating-sample magnetometry verified their superparamagnetic behaviour with a saturation magnetization of 41.4 emu g-1. The synthesized radiopharmaceutical exhibited high sterility and in vitro stability. Acute toxicity studies showed the mild effects of Fe3O4@lapatinib-153Sm at a dose of 20 mCi kg-1, with no observed mortality. Notably, lesions from Fe3O4@lapatinib-153Sm use recovered naturally over time. Radiation doses below 20 mCi kg-1 were recommended for clinical trials. The biodistribution study in BT474 xenograft mice revealed rapid clearance of Fe3O4@lapatinib-153Sm within 48 h. Significant accumulation occurred in the liver, spleen, and tumor tissue, while minimal accumulation was found in other tissues. Future steps involve studying biocorona formation and therapeutic efficacy on tumour models, refining its clinical potential.

Utilization of Functionalized Metal-Organic Framework Nanoparticle as Targeted Drug Delivery System for Cancer Therapy.

Cancer is a multifaceted disease that results from the complex interaction between genetic and environmental factors. Cancer is a mortal disease with the biggest clinical, societal, and economic burden. Research on better methods of the detection, diagnosis, and treatment of cancer is crucial. Recent advancements in material science have led to the development of metal-organic frameworks, also known as MOFs. MOFs have recently been established as promising and adaptable delivery platforms and target vehicles for cancer therapy. These MOFs have been constructed in a fashion that offers them the capability of drug release that is stimuli-responsive. This feature has the potential to be exploited for cancer therapy that is externally led. This review presents an in-depth summary of the research that has been conducted to date in the field of MOF-based nanoplatforms for cancer therapeutics.

High-efficient reduction of methylene blue and 4-nitrophenol by silver nanoparticles embedded in magnetic graphene oxide.

In this study, a ternary magnetically separable nanocomposite of silver nanoparticles (AgNPs) embedded in magnetic graphene oxide (Ag/Fe3O4@GO) was designed and synthesized. Beta-cyclodextrin was used as a green reducing and capping agent for decorating of AgNPs on Fe3O4@GO. The fabricated material was characterized using X-ray diffractometry, Fourier transform infrared spectroscopy, scanning electron microscopy, vibrating sample magnetometry, and energy-dispersive X-ray spectroscopy. The catalytic properties of the prepared Ag/Fe3O4@GO for the reduction of 4-nitrophenol (4-NP) and methylene blue (MB) dye with sodium borohydride were investigated in detail. The morphological and structural studies revealed that Fe3O4 and AgNPs with a mean size of 12 nm were uniformly distributed on the GO sheet at high densities. The catalytic tests showed that Ag/Fe3O4@GO exhibited an ultrafast catalytic reduction of 4-NP and MB with a reduction rate constant of 0.304 min-1 and 0.448 min-1, respectively. Moreover, the catalyst demonstrated excellent stability and reusability, as evidenced by the more than 97% removal efficiency maintained after five reuse cycles. The Ag/Fe3O4@GO catalyst could be easily recovered by the magnetic separation due to the superparamagnetic nature of Fe3O4 with high saturated magnetization (45.7 emu/g). Besides, the formation of networking between the formed AgNPs and ß-CD through hydrogen bonding prevented the agglomeration of AgNPs, ensuring their high catalytic ability. The leaching study showed that the dissolution of Fe and Ag from Ag/Fe3O4@GO was negligible, indicating the environmental friendliness of the synthesized catalyst. Finally, the high catalytic performance, excellent stability, and recoverability of Ag/Fe3O4@GO make it a potential candidate for the reduction of organic pollutants in wastewater.

Application Prospects of MXenes Materials Modifications for Sensors.

The first two-dimensional (2D) substance sparked a boom in research since this type of material showed potential promise for applications in field sensors. A class of 2D transition metal nitrides, carbides, and carbonitrides are referred to as MXenes. Following the 2011 synthesis of Ti3C2 from Ti3AlC2, much research has been published. Since these materials have several advantages over conventional 2D materials, they have been extensively researched, synthesized, and studied by many research organizations. To give readers a general understanding of these well-liked materials, this review examines the structures of MXenes, discusses various synthesis procedures, and analyzes physicochemistry properties, particularly optical, electronic, structural, and mechanical properties. The focus of this review is the analysis of modern advancements in the development of MXene-based sensors, including electrochemical sensors, gas sensors, biosensors, optical sensors, and wearable sensors. Finally, the opportunities and challenges for further study on the creation of MXenes-based sensors are discussed.

Silver nanoparticles loaded on lactose/alginate: in situ synthesis, catalytic degradation, and pH-dependent antibacterial activity.

We present the in situ synthesis of silver nanoparticles (AgNPs) through ionotropic gelation utilizing the biodegradable saccharides lactose (Lac) and alginate (Alg). The lactose reduced silver ions to form AgNPs. The crystallite structure of the nanocomposite AgNPs@Lac/Alg, with a mean size of 4-6 nm, was confirmed by analytical techniques. The nanocomposite exhibited high catalytic performance in degrading the pollutants methyl orange and rhodamine B. The antibacterial activity of the nanocomposite is pH-dependent, related to the alterations in surface properties of the nanocomposite at different pH values. At pH 6, the nanocomposite demonstrated the highest antibacterial activity. These findings suggest that this nanocomposite has the potential to be tailored for specific applications in environmental and medicinal treatments, making it a highly promising material.

Highly sensitive and low-cost colourimetric detection of glucose and ascorbic acid based on silver nanozyme biosynthesized by Gleditsia australis fruit.

In this study, a simple, eco-friendly and low-cost approach was used to fabricate silver nanoparticles (AgNPs) from an aqueous extract of Gleditsia australis (GA) fruit. The nanoparticles synthesized in the optimal condition have an average size of 14 nm. The peroxidase-like activity of GA-AgNP in the oxidation of 3,3',5,5'-tetramethylbenzidine (TMB) in combination with hydrogen peroxide (H2O2) was investigated. Further, optimal conditions for the use of peroxidase-like catalytic activity in sensing applications were identified. The colourimetric detection of H2O2 showed a linear range of 1-8 mM with a limit of detection (LOD) of 0.34 mM. The oxidation of TMB (red-TMB) enables the detection of glucose, which is converted into H2O2 and gluconic acid in the presence of the enzyme glucose oxidase. The observations showed linearity from 0.05 to 1.5 mM with a LOD of 0.038 mM. Moreover, the blue colour of oxidized TMB (ox-TMB) was reduced according to ascorbic acid (AA) concentration, with a linear range of 0.03-0.14 mM and a LOD of 3.0 µM. The practical use of the sensing system for the detection of AA was studied using real fruit juice and showed good sensitivity. Hence, the easy-to-use peroxidase-like sensor provides a new platform for the detection of bioactive compounds in biological systems.

Highly sensitive and selective colorimetric detection of Pb(ii) ions using Michelia tonkinensis seed extract capped gold nanoparticles.

In this study, gold nanoparticles (AuNPs) were synthesized via a green and environmentally-friendly approach and applied as a colorimetric probe for detecting Pb2+ ions in aqueous solution. Instead of toxic chemicals, Michelia tonkinensis (MT) seed extract was used for reducing Au3+ and stabilizing the formed AuNPs. The synthesis conditions, including temperature, reaction time, and Au3+ ion concentration, were optimized at 90 °C, 40 min, and 1.25 mM, respectively. The physicochemical properties of the produced MT-AuNPs were assessed by means of transmission electron microscopy, X-ray diffraction, field emission scanning electron microscopy, dynamic light scattering, and Fourier-transform infrared spectroscopy. The characterization results revealed that the MT-AuNPs exhibited a spherical shape with a size of about 15 nm capped by an organic layer. The colorimetric assay based on MT-AuNPs showed excellent sensitivity and selectivity toward Pb2+ ions with the limit of detection value of 0.03 µM and the limit of quantification of 0.09 µM in the linear range of 50-500 µM. The recoveries of inter-day and intra-day tests were 97.84-102.08% and 98.78-102.34%, respectively. The MT-AuNPs probe also demonstrated good and reproducible recoveries (98.71-101.01%) in analyzing Pb2+ in drinking water samples, indicating satisfactory practicability and operability of the proposed method.

Design synthesis of Y-90 glass microspheres and study of their therapeutic effects on mouse liver cancer cell line Hep3B.

In this article, a system for synthesizing Y-90 glass microspheres (Y-90-GM) was successfully designed in the Da Lat nuclear reactor (Vietnam), and the therapeutic effects of Y-90-GM on mice liver cancer cell line Hep3B were studied. The effects of synthesis factors, including heating time, heating temperature, gas flow rate, sample conduit length and diameter, were investigated to establish the optimal parameters. The size and shape of Y-90-GM were checked by field emission scanning electron microscope, and the radioactivity measurement was performed on a dosimeter. The results indicated that the optimal conditions for the synthesis of Y-90-GM were determined as the heating temperature of 1600 °C, heating time of 2 h, conduit length and diameter of 50 cm and 3.6 cm, and gas/oxygen flow rate of 15 mph. The Y-90-GM samples obtained at the optimal parameters have a size of 18-30 µm with a density of 3.53 g cm-3 and a specific radioactivity of 630 mCi g-1. The results of the therapeutic study on mice liver cancer cell line Hep3B showed that after two weeks of treatment with Y-90-GM (1mCi/mouse), the tumor volume was reduced by about 30.7% and after 3 consecutive treatment cycles, the liver cancer tumor was completely reduced. It was demonstrated that Y-90-GM is promising radiopharmaceuticals in the treatment of liver cancer by the radioembolization method.

Effect of targeting ligand designation of self-assembly chitosan-poloxamer nanogels loaded Paclitacel on inhibiting MCF-7 cancer cell growth.

In this study, we investigated two formulations of chitosan-Pluronic P123 with different folate ligand designation for targeted delivery of Paclitaxel (PTX), in which folic acid (FA) was directly conjugated to chitosan (FA-Cs-P123) or substituted onto P123 (Cs-P123-FA). The results showed that the FA content of Cs-P123-FA was determined at 0.71 wt/wt% which was significantly higher than that of FA-Cs-P123 (0.31 wt/wt%). Two copolymers were low critical gel concentrations (CGC). FA-Cs-P123 and Cs-P123-FA nanogels performed high PTX encapsulation efficiency reaching 95.57 ± 5.51 and 92.51 ± 6.68 wt/wt%, respectively. Transmission electron microscopy (TEM) and zeta potential analysis indicated that the PTX-loaded nanogels were spherically formed around 60 nm in diameter along with positive charge. Furthermore, the PTX release profile was slow and it was controlled by the pH of the medium. In particular, in vitro biocompatibility assays indicated that both FA-Cs-P123 and Cs-P123-FA exhibited good biological compatibility with a human foreskin fibroblast cell line and well uptake efficiency into MCF-7 cancer cells. Cs-P123-FA nanogel significantly enhanced the cytotoxicity of PTX in comparison with FA-Cs-P123. The result indicates that Cs-P123-FA nanogels with a higher decorated FA content perform a better targeting efficiency; therefore, they could have great potential application towards breast cancer treatment.

Efficient and fast degradation of 4-nitrophenol and detection of Fe(III) ions by Poria cocos extract stabilized silver nanoparticles.

In this study, a simple and environment-friendly method has been successfully applied for the production of silver nanoparticles (AgNPs) using Poria cocos extract. The reaction time of 60 min, the temperature of 90 °C, and silver ion concentration of 2.0 mM were identified as the best condition for the PC-AgNPs fabrication. The XRD analysis confirmed a highly crystalline face-centered cubic structure of the biosynthesized material. The PC-AgNPs were presented separately in a spherical shape with an average crystal size of 20 nm, as endorsed by the TEM and FE-SEM measurements. The presence and crucial role of biomolecules in stabilizing the nanoparticles were elucidated by FTIR, EDX, and DLS techniques. The prepared biogenic nanoparticles were further applied for the reduction of 4-nitrophenol (4-NP) and colorimetric detection of Fe3+ ions. The study results proved that PC-AgNPs exhibited superior catalytic activity and reusability in the conversion of 4-NP by NaBH4. The complete reduction of 4-NP could be achieved in 10 min with the pseudo-first-order rate constant of 0.466 min-1, and no significant performance loss was found when the material was reused five times. The colorimetric probe based on PC-AgNPs displayed outstanding sensitivity and selectivity towards Fe3+ ions with a detection limit of 1.5 µM in a linear range of 0-250 µM. Additionally, the applicability of the developed assay was explored for testing Fe3+ ions in tap water. PC-AgNPs have a great potential for further applications as a promising catalyst for reducing nitrophenols and biosensors for the routine monitoring of Fe3+ in water.

Flexible and high-sensitivity sensor based on Ti3C2-MoS2 MXene composite for the detection of toxic gases.

It is vital to have high sensitivity in gas sensors to allow the exact detection of dangerous gases in the air and at room temperature. In this study, we used 2D MXenes and MoS2 materials to create a Ti3C2-MoS2 composite with high metallic conductivity and a wholly functionalized surface for a significant signal. At room temperature, the Ti3C2-MoS2 composite demonstrated clear signals, cyclic response curves to NO2 gas, and gas concentration-dependent. The sensitivities of the standard Ti3C2-MoS2 (TM_2) composite (20 wt% MoS2) rose dramatically to 35.8%, 63.4%, and 72.5% when increasing NO2 concentrations to 10 ppm, 50 ppm, and 100 ppm, respectively. In addition, the composite showed reaction signals to additional hazardous gases, such as ammonia and methane. Our findings suggest that highly functionalized metallic sensing channels could be used to construct multigas-detecting sensors that are very sensitive in air and at room temperature.

Novel biogenic silver and gold nanoparticles for multifunctional applications: Green synthesis, catalytic and antibacterial activity, and colorimetric detection of Fe(III) ions.

In this study, novel biogenic silver (AgNPs) and gold nanoparticles (AuNPs) were developed using a green approach with Ganoderma lucidum (GL) extract. The optimization of synthesis conditions for the best outcomes was conducted. The prepared materials were characterized and their applicability in catalysis, antibacterial and chemical sensing was comprehensively evaluated. The GL-AgNPs crystals were formed in a spherical shape with an average diameter of 50 nm, while GL-AuNPs exhibited multi-shaped structures with sizes ranging from 15 to 40 nm. As a catalyst, the synthesized nanoparticles showed excellent catalytic activity (>98% in 9 min) and reusability (>95% after five recycles) in converting 4-nitrophenol to 4-aminophenol. As an antimicrobial agent, GL-AuNPs were low effective in inhibiting the growth of bacteria, while GL-AgNPs expressed strong antibacterial activity against all the tested strains. The highest growth inhibition activity of GL-AgNPs was observed against B. subtilis (14.58 ± 0.35 mm), followed by B. cereus (13.8 ± 0.52 mm), P. aeruginosa (12.38 ± 0.64 mm), E. coli (11.3 ± 0.72 mm), and S. aureus (10.41 ± 0.31 mm). Besides, GL-AgNPs also demonstrated high selectivity and sensitivity in the colorimetric detection of Fe3+ in aqueous solution with a detection limit of 1.85 nM. Due to the suitable thickness of the protective organic layer and the appropriate particle size, GL-AgNPs validated the triple role as a high-performance catalyst, antimicrobial agent, and nanosensor for environmental monitoring and remediation.

An overview of the chemical composition and biological activities of essential oils from Alpinia genus (Zingiberaceae).

Alpinia Roxb. is the largest genus of the Zingiberaceae family. A large number of Alpinia species has been used as food and traditional medicines. Alpinia essential oils have been studied for their chemical profiles, in which 1,8-cineole, ß-pinene, α-pinene, ß-myrcene, camphor, γ-terpinene, p-cymene, geraniol, α-fenchyl acetate, ocimene, methyl cinnamate, and ß-caryophyllene have been found to be the major compounds. Essential oils isolated from Alpinia plants have been reported to have antimicrobial, cytotoxic, antioxidant, anti-inflammatory, anti-asthmatic, tyrosinase inhibitory, insecticidal, and larvicidal activities and slimming aromatherapy. In this review, the comprehensive information regarding the volatile components of various Alpinia plants, the bioactivities of Alpinia essential oils and their major compounds are provided.

Photocatalytic degradation of methyl orange dye by Ti3C2-TiO2 heterojunction under solar light.

Photocatalytic activity is a feasible solution to tackle environmental pollution caused by industrial pollutants. In this research, Ti3C2-TiO2 composite with a unique structure was fabricated successfully via a hydrothermal method. Especially, the in-situ transformation of TiO2 from Ti3C2 MXene creates an intimate heterostructure, which leads to prolonging separation and migration of charged carriers. Thus, this Ti3C2-TiO2 composite enhances effectively methyl orange (MO) degradation efficiency (around 99%) after 40 light-exposed minutes. Besides, the optimal concentration of MO solution was estimated at 40 mg/L and Ti3C2-TiO2 photocatalyst also exhibited good stability after five runs. Moreover, the radical trapping test and the MO photodegradation mechanism over Ti3C2-TiO2 system were also demonstrated. This research illustrates the potential of MXenes as effective co-catalysts for photocatalysis and extends the applications of two-dimensional materials.

Effective reduction of nitrophenols and colorimetric detection of Pb(ii) ions by Siraitia grosvenorii fruit extract capped gold nanoparticles.

This study presents a simple and green approach for the synthesis of Siraitia grosvenorii fruit extract capped gold nanoparticles (SG-AuNPs). The SG-AuNPs samples prepared under the optimized conditions were characterized by various techniques (UV-Vis, XRD, FTIR, HR-TEM, EDX, DLS). The biosynthesized nanoparticles were then studied for the reduction of 2-nitrophenol (2-NP) and 3-nitrophenols (3-NP) and for colorimetric detection of Pb2+ ions. The characterization results revealed that the crystals of SG-AuNPs were spherical with an average size of 7.5 nm. The FTIR and DLS analyses proved the presence of the biomolecule layer around AuNPs, which played an important role in stabilizing the nanoparticles. The SG-AuNPs showed excellent catalytic activity in the reduction of 3-NP and 2-NP, achieving complete conversion within 14 min. The catalytic process was endothermic and followed pseudo-first-order kinetics. The activation energy was determined to be 10.64 and 26.53 kJ mol-1 for 2-NP and 3-NP, respectively. SG-AuNPs maintained high catalytic performance after five recycles. The fabricated material was also found to be highly sensitive and selective to Pb2+ ions with the detection limit of 0.018 µM in a linear range of 0-1000 µM. The practicality of the material was validated through the analyses of Pb2+ in mimic pond water samples. The developed nanoparticles could find tremendous applications in environmental monitoring.