Rhodamine B Research Articles

Ultrasonic-driven degradation of organic pollutants using piezoelectric catalysts WS2/Bi2WO6 heterojunction composites

Water pollution has been made worse by the widespread use of organic dyes and their discharge, which has coincided with the industry's rapid development. Piezoelectric catalysis, as an effective wastewater purification method with promising applications, can enhance the catalyst activity by collecting tiny vibrations in nature and is not limited by sunlight. In this work, we designed and synthesized intriguing WS2/Bi2WO6 heterojunction nanocomposites, investigated their shape, structure, and piezoelectric characteristics using a range of characterization techniques, and used ultrasound to accelerate the organic dye Rhodamine B (RhB) degradation in wastewater. In comparison to the pristine monomaterials, the results demonstrated that the heterojunction composites demonstrated excellent degradation and stability of RhB under ultrasonic circumstances. The existence of heterojunctions and the internal piezoelectric field created by ultrasonic driving work in concert to boost catalytic performance, and the organic dye's rate of degradation is further accelerated by the carriers that are mutually transferred between the composites.

Hybridization of Polymer-Encapsulated MoS2-ZnO Nanostructures as Organic-Inorganic Polymer Films for Sonocatalytic-Induced Dye Degradation.

The development of environmentally friendly technology is vital to effectively address the issues related to environmental deterioration. This work integrates ZnO-decorated MoS2 (MZ) to create a high-performing PVDF-based PVDF/MoS2-ZnO (PMZ) hybrid polymer composite film for sonocatalytic organic pollutant degradation. An efficient synergistic combination of MZ was identified by altering the ratio, and its influence on PVDF was assessed using diverse structural, morphological, and sonocatalytic performances. The PMZ film demonstrated very effective sonocatalytic characteristics by degrading rhodamine B (RhB) dye with a degradation efficiency of 97.23%, whereas PVDF only degraded 17.7%. Combining MoS2 and ZnO reduces electron-hole recombination and increases the sonocatalytic degradation performance. Moreover, an ideal piezoelectric PVDF polymer with MZ enhances polarization to improve redox processes and dye degradation, ultimately increasing the degradation efficiency. The degradation efficiency of RhB was seen to decrease while employing isopropanol (IPA) and p-benzoquinone (BQ) due to the presence of reactive oxygen species. This suggests that the active species •O2- and •OH are primarily responsible for the degradation of RhB utilizing PMZ2 film. The PMZ film exhibited improved reusability without substantially decreasing its catalytic activity. The superior embellishment of ZnO onto MoS2 and effective integration of MZ into the PVDF polymer film results in improved degrading performance.

Rhodamine-B for the mark, release, and recapture experiments in gamma-irradiated male Aedes aegypti (Diptera: Culicidae): Persistence, dispersal, and its effect on survival.

Rhodamine-B (Rh-B) marking shows a great potential for use in mark-release-recapture (MRR) studies for rear-and-release mosquito control strategies, including the radiation-based sterile insect technique. However, its applicability and evaluation in body-stain-irradiated males of Aedes aegypti have received little attention. The present study evaluated the use of Rh-B to mark gamma-irradiated male A. aegypti. Male A. aegypti were irradiated at the pupal stage at a dose of 70 Gy. After emergence, males were fed 0.1, 0.2, 0.3, or 0.4% Rh-B in 10% glucose solution for 4 days. Groups of unirradiated males that received the same feeding treatments were used as control groups. We evaluated the persistence of Rh-B and the longevity of males after Rh-B feeding. Furthermore, the use of Rh-B in irradiated A. aegypti for MRR experiments was evaluated at an urban site. No difference was observed in the Rh-B persistence among all concentrations at the 24-h postmarking period ranging from 91.25 ± 1.61% to 96.25 ± 1.61% and from 90.00 ± 2.28% to 93.13 ± 2.77% for the unirradiated and irradiated groups, respectively. Rh-B persistence significantly decreased over time, and persistence was significantly longer with increased concentrations in both the unirradiated and irradiated groups. Longevity was considerably decreased by Rh-B feeding and irradiation. However, no significant difference in longevity was found among males fed various concentrations of Rh-B. Through MRR experiments, irradiated-Rh-B marked males were mostly detected within a radius of 20 m and 40 m from the center-release point. The mean distance traveled of the released males from the three MRR events was calculated to be 42.6 m. This study confirms that Rh-B body marking through sugar feeding is applicable for irradiated male A. aegypti, with only a slight effect on longevity. Furthermore, considering the significant reduction in persistence over time, further study is needed to assess the impact of this reduction on the calculation of field biological parameters resulting from MRR experiments.

Constructed black phosphorus quantum dots/BiVO4 Z-scheme heterojunction catalysis for efficient Rhodamine b degradation and DFT study

Black phosphorus (BP) is highly regarded in photocatalysis for its bandgap thickness dependency, high hole mobility, and broad visible light absorption. This study introduces a simple hydrothermal method to construct a BP QDs/BiVO4 direct Z-scheme heterojunction. The composite’s crystal structure, morphology, and photochemical properties were comprehensively characterized. The photocatalytic activity was evaluated using Rhodamine B (RhB) degradation under visible light. Notably, BP QDs0.12%/BiVO4 exhibited exceptional performance, achieving a 95.4 % RhB degradation after 100 min, three times higher than BiVO4 alone. The direct Z-scheme heterojunction played a pivotal role in facilitating O2− and h+ involvement in the degradation process. The interfacial interaction between BP QDs and BiVO4 significantly enhanced BiVO4′s visible light absorption, preserving its strong oxidation–reduction capacity. This enhancement was further corroborated by DFT simulation calculations. Overall, this study presents a novel approach for constructing efficient Z-scheme photocatalysts based on BP QDs, laying a solid foundation for their application in the field of photocatalytic degradation.

Regulating band structure, charge transfer and separation, oxygen adsorption and activation by surface ion modification.

As a most promising environmental technology, the substantial enhancement of photocatalytic efficiency is still a big challenge for practical applications. In this work, the surface of Bi2O2CO3 (BOC) nanotubes are modified by Cl and I. The as-obtained samples at different hydrothermal temperatures (T) are designated as T-X-BOC (X = Cl, I). X-ray diffraction (XRD), energy dispersive X-ray (EDX) spectroscopy and X-ray photoelectron spectroscopy (XPS) prove that Cl and I merely chemically adsorb on the BOC surface, rather than dope into the crystal lattice. The surface modification of Cl and I slightly increases light absorption range, while significantly promotes the photoelectron migration from bulk to the surface that greatly enhances the carrier separation efficiency. Density functional theory (DFT) calculations further prove that surface Cl and I have adjusted band structure and surface charge distribution. Besides, the surface Cl and I favor the O2 adsorption and trap the surface photoelectrons, thus promoting the formation of •O2-; while the surface Cl and I impede the surface adsorption of H2O, thus refraining the generation of •OH. In the degradation of rhodamine B (RhB), holes and •O2- radicals play the crucial role. Under ultraviolet light irradiation (λ < 420nm) for 45min, the RhB degradation ratios over 150-Cl-BOC (94%) and 150-I-BOC (85%) are 4.2 and 3.7 times higher than that of original BOC (18%), respectively. This work demonstrates that the simple surface halogenation modification greatly improves the photocatalytic activity.

Boosting piezocatalytic efficiency: Thin carbon layer-modified ZnO for superior rhodamine B degradation

This study aims to enhance the piezocatalytic activity of ZnO by modifying it with a thin carbon layer (TCL). The composite catalysts were synthesized using a simple hydrothermal method. The tightly adhered TCL served as an effective electron transfer medium, enabling the rapid migration of piezoinduced charge carriers from the ZnO to the catalyst surface, thereby facilitating the catalytic degradation of Rhodamine B (RhB). The optimized TCL/ZnO sample exhibits an RhB degradation rate 13.4 times higher than that of pure ZnO. This work demonstrates that TCL/ZnO has significant potential in piezocatalytic water purification and offers new insights into the design of efficient piezocatalytic materials.

Synthesis of carbon nitride nanosheets with N vacancies boosted by S doping for photocatalytic efficient killing of E. coli under visible light

To address the problem of bacterial contamination in drinking water, we synthesized non-metallic photocatalysts for the inactivation of Escherichia coli in drinking water. In this paper, S-g-C3N4 (S-g-CN) composite nanomaterials were synthesized via a one-step calcination method. X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), electron paramagnetic resonance (EPR), and transmission electron microscopy (TEM) analyses confirmed the successful synthesis of S-g-CN with N vacancies. Scanning electron microscopy (SEM) and Fourier transform infrared (FTIR) spectroscopy analyzed the layered morphology and chemical structure of g-C3N4 before and after modification. Optical characterization revealed significantly enhanced light absorption, electron-hole separation efficiency, and carrier mobility in the modified samples. Bactericidal assays demonstrated that under visible light, 0.3 % S-g-CN nanomaterials exhibited superior bactericidal effects against E. coli compared to unmodified g-C3N4. Furthermore, 0.3 % S-g-CN demonstrated excellent degradation of Rhodamine B (RhB) under various conditions (pollutant concentration, pH, and catalyst dosage). Recyclability studies over three cycles confirmed the catalyst's stability and reusability.

Fabrication of luminescent disc-shaped microstructures via wet-chemical etching of hybrid sol–gel layers for potential photonic applications

Sol–gel materials based on SiO2 and TiO2 precursors are attractive as a new platform for planar photonics. Particularly interesting are those based on organically modified silica (ORMOSIL), which may improve the luminescent properties of organic dyes. However, their microstructurization remains a challenge as it requires optimization of various technological stages. Here, we report the structurization of thin layers based on ORMOSIL precursor and titanium(IV) ethoxide (TET) containing luminescent rhodamine B (RhB) dye. Films were fabricated using sol–gel synthesis and dip-coating method. Depending on the time of annealing performed at 200 °C, layers with different thicknesses (300–760 nm) and refractive indices (RI) (1.51–1.68) were obtained. Combining photolithography and wet-chemical etching processes made it possible to fabricate well-separated sol–gel waveguides and discs of different diameters. The etching time in buffered hydrofluoric acid (BHF) affected the depth of the etched luminescent microstructures. Additionally, it was found that a longer layer’s annealing time increased the etching selectivity of the substrate over the sol–gel layer. This enabled the obtaining of under-etched sol–gel goblet microstructures. Selected samples were investigated using scanning electron microscopy (SEM). UV–Vis photoluminescence measurements showed that long heat treatment also influenced the emission spectrum’s shape. The stability of the films under ambient conditions was established using spectroscopic ellipsometry. It was proven that films heat-treated at 200 °C did not change their properties during storage time of around 2 months. Relatively high RI, luminescent properties, and structurization potential make these microstructures interesting for application in integrated photonic devices, e.g., light amplifiers or sensing systems.

Effect of Calcination Temperature on the Structural, Morphological, and Magnetic Properties of Rare-Earth Orthoferrite NdFeO3 Nanoparticles Synthesized by the Sol-Gel Method

The sol-gel technique has been used to synthesize rare Earth orthoferrite NdFeO3 nanopowders. The present investigation examines how calcination temperatures affect the structural, morphological, and magnetic properties of NdFeO3 orthoferrites. X-ray diffraction studies indicate that there is no discernible difference in the observed structures with calcination temperatures other than the bond distances and bond angles. The surface morphology and field-emission scanning electron microscopy (FESEM) indicate that porosity of the samples is regulated by the physical shape of the tiny particles within them. Porosity is minimized as calcination temperature increases, showing a higher density that contributes to reducing leakage current features while improving the break-down strength. These variations are attributed to bond length and bond angle variation of the Fe-O. The photocatalytic activity of the NdFeO3 nonoparticles was assessed by photodegrading a number of organic dyes, including methyl orange (MO), rhodamine B (RhB), and methylene blue (MB). The product displays significant photocatalytic degradation of the dyes whenever exposed to visible light. Overall, this investigation aims to establish a relationship between the physical properties and microstructural parameters to provide valuable insights into the magnetic interactions present in the samples and the comprehensive behavior of NdFeO3 orthoferrites samples calcination at different calcination temperatures.

Ultralong room temperature phosphorescence and broad color-tunability persistent luminescence via new strategy

Pure organic materials with ultralong room-temperature phosphorescence (RTP) and persistent luminescence in broad color gamut exhibit tremendous potential and broad application prospects due to their unique optical properties. This article proposes a simple strategy, polyatomic synergistic effect, to endow persistent luminescent materials with ultralong lifetime and broad color-tunability through polyatomic synergistic effect and non-traditional phosphorescence resonance energy transfer (PRET). By leveraging the polyatomic synergistic effect to enhance the intersystem crossing (ISC) in bibenzimidazole (BBI) derivatives and suppress the non-radiative transition process, ultralong persistent room-temperature phosphorescence has been successfully achieved after incorporating BBI-Cl-M into poly(methyl methacrylate) (PMMA) to form a rigid matrix(BBI-Cl-M@PMMA). Specifically, the ester functionalized bibenzimidazole with modified chlorine on molecular skeleton (BBI-Cl-M) demonstrates a remarkable phosphorescent lifetime (τp) of up to 256.4 ms. In addition, the behaviors and mechanism of RTP via polyatomic synergistic effect have been further understood by theoretical calculation and single crystal analysis. Subsequently, utilizing BBI-Cl-M as the energy donor and Rhodamine B (RB) as the energy acceptor, persistent and multicolor organic afterglow covering from green to red has been realized successfully by simply regulating the doping composition and concentration of PRET systems. These RTP materials have also been applied in underwater afterglow emission and multilevel anti-counterfeiting technology successfully.

Synthesis of BiOBr/graphene oxide photocatalyst assisted by sodium dodecyl sulfate for efficient degradation of organic pollutants

Surfactant‐assisted synthesis of photocatalysts for water treatment has received extensive attention from researchers. In this paper, a novel and efficient BiOBr/graphene oxide (BiOBr/GO) photocatalyst assisted by sodium dodecyl sulfate (SDS) was synthesized by a simple solvothermal method. Compared with use of other surfactants, like polyvinylpyrrolidone (PVP) and cetyltrimethylammonium bromide (CTAB), BiOBr/GO (SDS) shows outstanding photocatalytic degradation activity under optimal conditions: The degradation rate constants of BiOBr/GO (SDS) for oxytetracycline (OTC), tetracycline hydrochloride (TCH), brilliant blue (BB), and Rhodamine B (RhB) are 0.073, 0.057, 0.166, and 0.626 min−1, which are 2.8, 1.8, 9, and 1.5 times larger than pure BiOBr, respectively. In addition, after five cycles, BiOBr/GO (SDS) exhibits superior cycling stability. The enhanced photocatalytic performance can benefit from the introduction of SDS and GO. With the assistance of SDS in the preparation process, BiOBr/GO (SDS) nanosheets have good adsorption performance and dispersion effect, which is favorable for raising their specific surface area. Meanwhile, the electron capture effect of GO improves the transfer and separation efficiency of photogenerated carriers. Moreover, the possible degradation pathway for TCH is identified through liquid chromatography–mass spectrometry (LC–MS). This research can become a valuable reference for synthesizing photocatalysts with visible light response to degrading organic pollutants such as antibiotics and dyes.

In situ growth of Cs3Bi2Br9/BiOBr S-scheme heterojunction in alcohol aqueous solution for boosting photocatalytic activity

Heterojunction fabrication is a general and practical method for producing high-efficiency photocatalysts. The photocatalyst of S-type heterojunction greatly improves the carrier separation efficiency to a certain extent, thereby promoting the degradation efficiency. In this work, we reported a unique S-scheme heterojunction photocatalyst composed of n-type Cs3Bi2Br9 (CBB) and p-type BiOBr with well-defined junction interfaces for photocatalytic degradation of Rhodamine B (RhB). By soaking CBB in an aqueous alcohol solution, the desirable BiOBr/CBB heterostructure was created in-situ, forming the intimate interfaces and facilitating the separation of photogenerated charge carriers. Compared with the pristine CBB, a substantial enhancement in photocatalytic performance of BiOBr/CBB heterostructure was achieved through an optimized water treatment. The results showed that the degradation efficiency of the optimal BiOBr/CBB heterostructure reached 98.55 % in 20 min.

Helical Ni‐Cluster Organic Framework Constructed from Enantiopure Lactate Derivative: Synthesis, Structure and Properties

AbstractUnder hydrothermal condition, lactate derivative (R)‐4‐(1‐ carboxyethoxy)‐2‐methylbenzoic acid ((R)‐H2cma) as chiral synthon assembled with 4,4′‐di(1H‐imidazol‐1‐yl)‐1,1′‐biphenyl (4,4’‐dib) and Ni(II) ions to obtain complex {[Ni2((R)‐cma)2(4,4’‐dib)2(H2O)] ⋅ 2H2O}n (HU20‐R). In complex HU20‐R, carboxyl group from lactate unit of (R)‐cma2− anion and coordinating H2O molecule adopt a μ2‐coordination mode to obtain dinuclear [Ni2(CO2)2(H2O)]2+ cluster. (R)‐cma2− anions and Ni(II) ions build single left‐handed (R)‐cma‐Ni‐chain, while 4,4’‐dib ligands are bridged by different Ni(II) centers to form double left‐handed 4,4’‐dib‐Ni‐chain. These helical secondary structures are further connected together to result in an 8‐connected 3D framework. PXRD tests indicated that complex HU20‐R has well hydro‐stability. UV‐vis absorption experiment confirmed that HU20‐R is a semi‐conducting material with strong absorption capacity for ultraviolet‐visible (UV‐vis) light. Additionally, electrochemical experiment revealed that HU20‐R has low impedance and high charge transport capacity. Further test results confirm that HU20‐R has noticeable photo‐catalytic effect in photodegradation of Rhodamine B (RhB) and antiferromagnetic property.

Starch-based self-assembled three-dimensional network nanostructure materials for sustainable cascade adsorption

Toward the development of a sustainable utilization strategy for adsorption materials, a starch-based adsorbent starch–chitosan–tannic acid (St–CTS–TA) with a three-dimensional (3D) structure was fabricated in water via electrostatic and hydrogen bonding reactions between St, CTS, and TA without using toxic reducing agents or special instruments. St-CTS-TA demonstrated a high specific surface area of 37 m2/g as well as a mesoporous/macroporous distribution ranging from 30 to 80 nm, which enhanced the mass transfer of adsorbate and the exposure of catechol groups in TA. The Langmuir isotherm adsorption model revealed that the highest adsorption capacities of St–CTS–TA for Fe3+ and Co2+ were 1678.2 and 944.8 mg/g, respectively. Surprisingly, the specific surface area of St–CTS–TA increased from 37 to 87 and 42 m2/g after Fe3+ and Co2+ adsorption, respectively, and the resulting St–CTS–TA–Fe and St–CTS–TA–Co could continuously adsorb basic fuchsin (BF) and rhodamine B (RhB). The adsorption capacities of St-CTS-TA-Fe and St-CTS-TA-Co for BF/RhB were found to be 1854.79/401.19 mg/g and 2229.77/537.49 mg/g, respectively, based on the Langmuir isotherm adsorption model.

Supramolecular Light‐Harvesting Nanoarchitectonics Toward Self‐Locked Logic Gates

AbstractSupramolecules are considered a promising approach for molecular logic gates due to their inherent dynamic responsiveness driven by non‐covalent forces. However, the lack of input sequence dependence in these logic gates may lead to misinterpretation of outputs, compromising their reliability. This study proposes an efficient universal supramolecular Förster resonance energy transfer (FRET) platform for logic gates with self‐locking features. Specifically, well‐designed naphthalene‐based monomers serve as energy donors, while dyes such as eosin Y (EY), rhodamine B (RhB), and sulforhodamine 101 (SR101), spanning from yellow to red, are employed as energy acceptors. Leveraging large exciton migration rates (1.21 × 1014 to 1.36 × 1014 L mol−1 s−1) between donor and acceptors, FRET processes are effectively facilitated. Building upon this framework, supramolecular logic gates with self‐locking features are successfully constructed. Notably, in these logic gates, even with the correct truth table, any deviation in the order of inputs can lead to alterations in the original outputs.

Designing Zn-MOF/AgCl composites for the photocatalytic degradation of rhodamine B dye and tetracycline antibiotic

The agglomeration tendency of AgCl, as a photocatalyst, hampers its advancement and practical application. In this paper, a simple composite method is designed based on the precipitation characteristics of AgCl. Ag+ ions introduced from outside combines with Cl− anions in complex [Zn(L)Cl]n (M1) [L = 2-(1-(carboxymethyl)-1H-benzo [d] imidazol-3-ium-3-yl)acetate)] to directly form Zn-MOF/AgCl composites (ZA-x, x = 0.5, 1 and 2), which may effectively prevent agglomeration of AgCl. The morphology and structure analysis displays a remarkable dispersity of AgCl. Further characterization and analysis of PL, UV–Vis, EIS, and TPC reveal that the composites have potential as excellent photocatalysts. The subsequent visible light catalytic degradation of Rhodamine B (RhB) and tetracycline hydrochloride (TC) has shown that the optimal composite ZA-0.5 with M1 to AgCl ratio of 1:0.5 exhibits the highest degradation efficiency in the 20 mg/L solution of RhB or TC, achieving 99.1 % for RhB within 20 min and 81.9 % for TC within 50 min. The free radical trapping test shows that ⋅O2− is the main catalytic species in the degradation process. In addition, the possible degradation mechanism was analyzed by VB-XPS and LC-MS. In a word, the in-situ combination of Cl− in M1 with Ag+ improves the dispersity of AgCl, enhances the interaction between M1 and AgCl, and leads to the effetive separation of electrons and holes, therefore improving the photocatalytic performance.

Magnetic-supported catalyst derived from red mud-based Fe-Co PBA for efficient degradation of organic pollutants by activating peroxymonosulfate under visible light

To alleviate the environmental pressure caused by the continuous accumulation of solid waste red mud (RM) and organic pollutants, we developed a magnetic-supported catalyst derived from RM-based Fe-Co Prussian blue analogues (RM-Co PBA-D) using RM as the iron source and carrier. Then, the catalyst was used to activate peroxymonosulfate (PMS) under visible light for the degradation of tetracycline (TC) and rhodamine B (RhB). Due to the superior dispersion, strong visible light response, and high photo-generated carrier separation efficiency of the RM-Co PBA-D, the RM-Co PBA-D/PMS/Vis system could completely degrade both TC (10 mg/L) and RhB (20 mg/L) in 30 min, with mineralization efficiencies as high as 70.12 % and 60.59 %, respectively. Several reactive oxygen species (ROS) such as SO4⋅−, ⋅OH−, ⋅O2−, 1O2, and h+ were involved in the degradation process, with SO4⋅− and 1O2 playing a dominant role. More importantly, except for the production of ROS, the regeneration of active sites (Co2+/Fe2+) mediated by photo-generated carriers was also a critical factor in enhancing the removal of organic pollutants. In addition, the constructed system demonstrated significant potential for practical applications, which was attributed to the stable structure and catalytic performance of the catalyst as well as the strong ability of the system to resist interference by impurity anions and detoxify organic pollutants.

SARS-CoV-2 N protein IgG antibody detection employing nanoporous anodized alumina: A rapid and selective alternative for identifying naturally infected individuals in populations vaccinated with spike protein (S)-based vaccines

Methods to detect naturally infected individuals, especially during or after a pandemic, are valuable in populations with a high rate of vaccination. Having in mind that after the COVID-19 pandemic people has been vaccinated against the virus by Spike protein (S)-based vaccines, we present in this paper a novel nanosensor based on gated nanoporous anodic alumina (NAA) material to detect naturally infected individuals in populations with high rates of vaccination. The nanosensor developed is based on a protein-capped nanomaterial for the identification of IgG antibodies that can detect nucleocapsid protein (N) of SARS-CoV-2. The NAA material has been loaded with an indicator (Rhodamine B (RhB)) and the pores of the material have been blocked with SARS-CoV-2 nucleocapsid protein (N) attached to a specific aptamer. In presence of antibodies against this antigen, the pores are uncapped, triggering the dye release and a fluorescent signal as a result. The biosensor has been tested in vitro and simulated serum for IgG detection, proving a detection limit of 1 µg/mL. Moreover, specificity assays with N proteins from other coronaviruses have proved the robustness and efficacy of this nanosensor. Finally, the system has been tested on samples from patients that contained SARS-CoV-2 antibodies, demonstrating its potential for the discrimination of individuals that have been vaccinated or infected by SARS-CoV-2 virus.

Green synthesized silver and zinc doped hydroxyapatite photocatalysts to remove methylene blue and Rhodamine B dyes from industrial wastewater

The present study focussed on the Scallop Sea shell waste utilized Hydroxyapatite and green synthesis of Canna indica leaf extracted Zinc (Zn) and Silver (Ag) doped Hydroxyapatite (HAp) formed by microwave irradiation method which is respectively represented as H, CIZH, and CIAH. The functional and structural characterizations (FTIR and XRD) of products confirm that the formed material was Hydroxyapatite due to the existence of characteristic absorption peaks and diffracted planes. The structural parameters such as average crystallite size, micro-strain (ε), dislocation density (δ), and particle size of the H, CIZH, and CIAH were calculated and the average Crystallite size are 42, 40, and 31nm. The morphology of the H, CIZH, and CIAH were assessed through FE-SEM and HR-TEM which could be majorly hexagonal-like (well distinct, and cluster of few rods). The EDAX spectrum and mapping confirmed the presence of chemical compositions of studied products. The anti-bacterial activities of studied products were assessed against Escherichia coli and Staphylococcus aureus, which exhibit good antibacterial activity. The photocatalytic activity of H, CIZH, and CIAH was examined against Methylene blue (MB) and Rhodamine B (RhB) dyes under UV light illumination. The degradation efficiency (%) of H, CIZH, and CIAH against MB and RhB dye were 58, 63, and 71%, and 58, 82 and 90%, respectively. A possible mechanism of the photocatalytic activity against the above-mentioned dyes is proposed. Thus, the present CIAH photocatalyst could be effective in degrading the wastewater.

Aptamer-controlled gold nanozyme sensor for fluorescent and colorimetric dual-channel detection of methamphetamine

Methamphetamine (METH) is the second abused drug which affects abusers’ health and induces social crimes, developing novel methods with high sensitivity and selectivity for METH detecting is still challenging. In this paper, a colorimetric and fluorescent dual-channel sensor for METH has been constructed. We combine the enzyme-mimic catalytic activity of gold nanoparticles (GNPs) with high target specificity of METH aptamer to create a nanosensor (Apt-GNP), in the presence of METH, the absorption of 3,3′,5,5′-tetramethylbenzidine (OxTMB) at 650 nm enhanced with METH concentration increasing, while the absorption characteristic peak of GNPs at 530 nm remained almost unchanged. The ratio of A650nm/A530nm and METH concentration had a good linear relationship when METH concentration was in the range of 5–50 μM, and the corresponding linear equation is A650nm/A530nm = 0.00727CMETH (μM) + 0.783 with R2 = 0.997 and LOD = 0.40 μM (LOD = 3σ/s, n = 11). Interestingly, the fluorescence emission of Rhodamine B (RB) overlaps with the absorption spectrum of OxTMB which represents the content of METH and the fluorescence signal of RB can be quenched through internal filtering effect (IEF). Hence, when RB was doped to the detection system, the decay of RB fluorescence can reflect the concentrations change of METH. Accordingly, the linear equation is F/FR = –0.00751CMETH (μM) + 0.895 with R2 = 0.993 and LOD = 0.40 μM, where F was the fluorescence of the analytical solution at 580 nm with METH and FR was fluorescence of RB control solution. The dual-channel sensor can measure METH in serum and artificial urine successfully which is potential to be applied in drug-using crime sites and provide direct evidence to law enforcement officials.