Flower-like Shape Research Articles

Degradation performance of three-dimensional flower-like Cu2O/BiOBr composites in tetracycline degradation

A Z-scheme-structured Cu2O/BiOBr photocatalyst was synthesized by depositing Cu2O cubes onto flower-like BiOBr microspheres and used to degrade tetracycline(TC). The rate of TC degradation by the photocatalyst was 85% due to its distinctive physical and chemical features. Its exceptional photocatalytic performance could be attributed to its flower-like shape, which enhanced the scattering and refraction efficiency of light and facilitated the separation and movement of carriers. Furthermore, Cu2O/BiOBr exhibited a broad range of light absorption and possessed exceptional photocatalytic characteristics. This paper discussed the photocatalytic mechanism of the Z-scheme Cu2O/BiOBr photocatalyst.

Protective effects of Marinobacter nauticus strain GH3 exopolysaccharide on the Oreochromis niloticus model for Alzheimer's disease.

Marinobacter nauticus strain GH3 was isolated from the Red Sea, Sharm Elshiekh, and classified according to cultural attributes, biochemical properties, and the analysis of genetic relationships using 16S rRNA sequences. A substantial proportion of exopolysaccharides (EPS) in GH3-EPS contained a sulfate content of 25.4%, uronic acid (12.18%), and N-acetylglucosamine (13.6%). The composition of monosaccharides in this fraction consists of glucose, glucoronic acid, arabinose, and xylose by 2:4:3:3, respectively. SEM showed a flower-like shape with white bundles on the GH3-EPS surface. GH3-EPS enhancement of the RAW264.7 macrophage line RAW 264.7 ATTC number J774 cell proliferation via MTT assay for cell viability. GH3-EPS had a high stimulation effect on releasing TNF-alpha and IL-10. Followed by its effect against cyclooxygenase (COX-2) and lipoxygenase (LOX), with IC50s of 14.74 and 19.4µg/ml, respectively. Antioxidant activity was evaluated for GPx-4, GSS, and MDA with highly significant results, and for DPPH, ABTS, and iron chelating with IC50 (43.51, 31.27, and 84.96µg/ml, respectively). AChE was inhibited by a mean of 52.92 ± 4.54 and 68.22 ± 5.64µg/ml. In a fish animal model, GH3-EPS demonstrated a positive treatment effect for AD, supporting biochemical studies, histopathology for some brain parts, and toxicity.

Enhancement of sodium ion conductivity in phosphate-based glass-ceramics by chemical substitution approach

A NASICON-type sodium-ion conducting material was synthesized via the glass-ceramic route by investigating the zinc doped Na2O–Al2O3–TiO2–P2O5 system. The glasses and glass-ceramics corresponding to the formula Na2+xAl1-xZnxTi(PO4)3 (x = 0, 0.2, 0.4, 0.6, 0.8, 1), labeled as (NAZTP-Gx) and (NAZTP-GCx) respectively, were characterized using different techniques. Differential Scanning Calorimetry (DSC) measurements were carried out to identify the characteristic temperatures, the glass transition (Tg) and the crystallization temperature (Tc). X-ray Diffraction (XRD) analysis of the glass-ceramics confirmed the formation of a solid solution Na2+xAl1-xZnxTi(PO4)3 NASICON phase, Theoretical calculations employing the Perdew–Burke–Ernzerhoff generalized gradients approximation (PBE-GGA) model supported the potential substitution of aluminum by zinc in the octahedral site in the NASICON-phase. Further structural insights were obtained through Infrared (IR) and Raman spectroscopies. Scanning electron microscopy (SEM) analysis revealed a distinct flower-like shape of the formed crystallites in the glass-ceramic NAZTP-GC0.2. Electrical characterization using electrochemical impedance spectroscopy (EIS) demonstrated that the NAZTP-GC0.2 sample exhibited the highest ionic conductivity at 300 °C, reaching 4.1 × 10−5 (Ω−1 cm−1) with an activation energy of 0.25 eV. The DC polarization was performed on the NAZTP-GC0.2 glass-ceramic, revealing that the ions are the main charge carriers in the sample. This comprehensive analysis provides valuable insights into the partial zinc doping of NASICON glass-ceramics, offering potential for improved performance as solid electrolytes in various applications.

Synthesis, Characterization and Electrochemical Performance of Bi2S3/Rice Husk-Based Activated Carbon Composites As Lithium Ion Battery Anodes

This study investigates the impact of hydrothermal duration on bismuth sulfide/activated carbon composites (Bi2S3/AC) by varying the duration to 8, 24, and 48 hours. The primary aim is to delineate the composite characteristics and electrochemical performance of Bi2S3/AC composites, aiming to produce anodes for lithium-ion batteries with high capacity, excellent cyclic stability, and minimal volume expansion. Activated carbon derived from rice husks was synthesized via a carbonization process and chemical activation using H3PO4 as an activator. Subsequently, the synthesis of Bi2S3/AC composites used bismuth nitrate pentahydrate and thiourea precursors through the hydrothermal method that involved three variations of hydrothermal duration: 8, 24, and 48 hours, denoted as BC8, BC24, and BC48, respectively. The FTIR test indicates the presence of Bi-S, C=C, and C-O groups in the three composite products, signifying the existence of bismuth sulfide and activated carbon. The XRD result reveals orthorhombic crystal forms in the composites, while the SEM-EDX mapping illustrates particle morphologies resembling flower-like shapes. These compositions comprise Bi 74.16%, S 11.37%, and C 10.43%. The GSA test suggests a mesoporous pore size in these composites. In final result, BC24 exhibits the highest electrical and ionic conductivity, measuring 2.12 × 10−3 S.cm−1 and 2.057 × 10−4 S.cm−1, respectively. The CV data of the BC24 composite indicates two reduction and oxidation peaks in the first cycle. Charge-discharge test on the BC24 composite exhibits a specific charge capacity of 445.51 mAh/g and a discharge capacity of 364.24 mAh/g.

Femtosecond optical vortex-induced flower-shaped surface relief structures in an azo-polymer film

We study the formation of surface relief structures in azo-polymers generated via two-photon induced photoisomerization using a femtosecond near-infrared optical vortex laser beam. These structures exhibit exotic flower-like shapes with petals along the azimuthal direction, and they are formed from spatial mode instability, which is associated with third-order nonlinear effects in the azo-polymer. This process is a unique and exotic interaction between light and matter, which may be applied to the development of advanced optical data storage technologies. Here, an additional degree of freedom is offered by the number of formed petals, which themselves are a function of the topological charge of the optical vortex beam.

Cytotoxic Effect of Biosynthesized Manganese Oxide Nanoparticles on Human Skin Squamous Carcinoma Cell Line (HSSCC) in vitro

The current study intended to biosynthesis of manganese oxide nanoparticles (MnO -NPs) depending on prodigiosin pigment as stabilizing and reducing agent. which produced from environmental isolate of Serratia marcescens . The study of the biosynthesis of MnO NPs was characterized by different techniques, such as ( UV-VIS, XRD, AFM, FE-SEM and FTIR). The results refer, the wavelength of biosynthesis of MnO NPs by using UV-VIS was (284 nm), the average volume was (45) nm). and image FE-SEM shows that the MnO- NPs mainly consists of nanosheets assembled in flower-like shape with different diameters. The cytotoxic effects of (MnO -NPs) on Human Skin Squamous Carcinoma Cell Line (HSSCC) was significant (p≤0.05) comparative with control viability 100%. Maximum effective concentration were 4000 μg/ml for 72hr exposure time which gave the highest inhibition rate 95% comparative with viability control 100%, but the minimum concentration was 3.9 μg/ml which induced proliferation of (HSSCC)cells. So when the exposure time and the concentration was increased, the inhibition rate was increased. Keywords:Serratia marcescens, Human skin squamous carcinoma cell line, cytotoxic effect, prodigiosin, MnO –NP.

3D meso-scale modeling of bond behavior between helical strand and concrete

Excellent interfacial bonding is the foundation for the strand and concrete working together. Helical structure of strand causes its rotation during the pull-out process, which makes it difficult to quantify the bond-slip at the interface. A three-dimensional (3D) meso-scale numerical model is first established to investigate the bond behavior at strand-concrete interface in this study. A refined modeling method is proposed to build a helical strand with the longitudinal helix shape and transverse flower-like shape. The heterogeneous concrete composed of three-phase composite material is built based on the random aggregate model. The interaction between strand and concrete is implemented by the surface-to-surface contact strategy. The rationality of the proposed model is verified by the experimental results. The effects of the helical structure of strand, the lay length of strand, aggregate content and eccentricity of strand on interfacial bond behavior are discussed. The results indicate that considering the helical structure of strand and heterogeneity of concrete can more accurately describe the stress distribution at the strand -concrete interface. The proportion of twisting slip is lower than that of longitudinal slip in the whole pull-out process, and its proportion increases first and then decreases. The interfacial bond strength increases first and then decreases with the increase of lay length of strand and aggregate content, and it reaches the best when the lay length is 14 time of diameter with the aggregate content of 45 %.

Soft-template assisted morphology tuning of NiMoO4 for hybrid supercapacitors

The electrochemical performance of electrode materials depends on various physicochemical properties like particle size, morphology, porosity, etc. of materials. Herewith, a facile surfactant assisted hydrothermal route using cetyltrimethylammonium bromide (CTAB) and hexamethylenetetramine (HMT) is used to successfully synthesize nanostructured nickel molybdate (NiMoO4) with various morphologies. It is found that NiMoO4 possesses different morphologies when synthesized by using these surfactants. With change in morphology, there is a significant increase in diffusion coefficient for sample synthesized with CTAB. It is interesting to note that NiMoO4 synthesized by using CTAB exhibit a high specific capacitance of 947 F g−1 when cycled at 1 A g−1 in 1 M KOH solution as compared to that of 322 F g−1 (synthesized without CTAB), which can be ascribed to its flower-like shape with uniform porosity. Both Ni2+/Ni3+ and Mo6+/Mo4+ redox couples are involved in the capacitive characteristic of NiMoO4, as found from the XPS study. Additionally, a hybrid supercapacitor has been assembled using NiMoO4 as positive electrode and reduced grapgene oxide (rGO) as negative electrode, which can exhibit 107 F g−1 with an operating voltage of 1.6 V with excellent cycling stability of maintaining 94 % capacitance retention after 6000 cycles in 1 M KOH solution. The hybrid supercapacitor can possess an energy density of 37.7 Wh kg−1 and a power density of 8 kW kg−1. Thus, this study enables the importance of tuning the morphology to enhance the capacitance property of transition metal oxide based electrode materials for supercapacitor applications.

High capacity and long service in sodium-ion batteries achieved by the refinement of BiOCl from lamellar to flower-like in ether electrolyte

Sodium-ion batteries (SIBs) have emerged as a promising contender in power systems owing to their cost-effectiveness and safety advantages. However, alloy-type anode materials, crucial for SIB performance, often face challenges such as significant volume expansion and rapid capacity decay at high current densities. In this study, an ion-exchange strategy is used to fabricate ultra-thin and porous BiOCl nanosheets (UTP BiOCl NS) as an anode material for SIB. Remarkably, lamellar UTP BiOCl NSs can transform a flower-like shape in ether electrolytes. This structural change is beneficial in shortening the Na+ transport path, which facilitates rapid electrolyte entry and enhances the dynamic behavior of SIBs. Electrochemically, UTP BiOCl NS demonstrates an exceptional capacity of 212.4 mAh/g and high service stability of up to 3000 cycles at a high current density of 5 A/g, showcasing exceptional durability and promising application potential. Furthermore, the SIB full-cell, coupled with a Na3V2(PO4)3 cathode and UTP BiOCl NS anode, enables an outstanding sodium storage capacity of 140.5 mAh/g and powers a 3 W bulb. This research provides a strategic approach for identifying suitable SIB anodes and aims to inspire researchers to focus on advancing anode materials in SIBs.

Green synthesis of ZnO nanoparticles and its application for methyl green dye adsorption

This research presents a facile and inexpensive method for synthesizing ZnO nanoparticles using Nauclea latifolia fruit extract as a bioreductant and stabilizer. The prepared particles were characterized using some analytical techniques, including X-ray diffraction (XRD) for crystallinity and phase identification, scanning electron microscopy (SEM) to study surface morphology, Fourier transform infrared (FTIR) spectroscopy for functional groups analysis, transmission electron microscopy (TEM) for grain size analysis, UV–Vis spectroscopy for optical properties, and Brunauer-Emmett-Teller (BET) for surface area analysis. XRD analysis revealed a hexagonal wurtzite structure with an average crystallite size of 14.40 nm. FTIR showed absorption peaks at 3659, 1341, and 460 cm−1, corresponding to hydroxyl, carboxylic, and Zn–O, respectively. SEM image showed an agglomerated surface morphology with a flower-like shape. TEM estimated the particle size range to be 12.54–17.35 nm. UV–Vis scanning showed a broad peak at 373 nm. BET revealed 277.420 m2/g as the specific surface area. A batch adsorption experiment conducted on the performance of the nanoparticles for methyl green (MG) removal from aqueous solution showed highest efficiency of 99.96% at 60 min agitation time and pH of 7, with 0.05 g of the ZnO NPs, confirming the efficiency of the particles. The results of adsorption modelling revealed that the adsorption data were best fit to Freundlich isotherm and general-order kinetic models. Thermodynamic investigation confirmed the adsorption process as spontaneous, feasible, endothermic, and physical. Finally, the simplicity of the synthesis method and the performance evaluation of the ZnO nanoparticles indicate that an efficient and cost-effective adsorbent for MG recovery from aqueous solution has been successfully prepared.

Effects of the ZrO2 Crystalline Phase and Morphology on the Thermocatalytic Decomposition of Dimethyl Methylphosphonate.

Thermocatalytic decomposition is an efficient purification technology that is potentially applicable to degrading chemical warfare agents and industrial toxic gases. In particular, ZrO2 has attracted attention as a catalyst for the thermocatalytic decomposition of dimethyl methylphosphonate (DMMP), which is a simulant of the nerve gas sarin. However, the influence of the crystal phase and morphology on the catalytic performance of ZrO2 requires further exploration. In this study, monoclinic- and tetragonal-phase ZrO2 (m- and t-ZrO2, respectively) with nanoparticle, flower-like shape and hollow microsphere morphologies were prepared via hydrothermal and solvothermal methods, and their thermocatalytic decomposition of DMMP was systematically investigated. For a given morphology, m-ZrO2 performed better than t-ZrO2. For a given crystalline phase, the morphology of hollow microspheres resulted in the longest protection time. The exhaust gases generated by the thermocatalytic decomposition of DMMP mainly comprised H2, CO2, H2O and CH3OH, and the by-products were phosphorus oxide species. Thus, the deactivation of ZrO2 was attributed to the deposition of these phosphorous oxide species on the catalyst surface. These results are expected to help guide the development of catalysts for the safe disposal of chemical warfare agents.

Microwave-Assisted Synthesis of Flower-like MnMoO4 Nanostructures and Their Photocatalytic Performance.

This article describes an affordable method for the synthesis of MnMoO4 nanoflowers through the microwave synthesis approach. By manipulating the reaction parameters like solvent, pH, microwave power, and irradiation duration along this pathway, various nanostructures can be acquired. The synthesized nanoflowers were analyzed by using a powder X-ray diffractometer (XRD), field emission scanning electron microscopy (FE-SEM) with energy dispersive X-ray spectroscopy (EDS), Fourier transform infrared spectroscopy (FT-IR), and UV-vis diffuse reflectance spectroscopy (UV-DRS) to determine their crystalline nature, morphological and functional group, and optical properties, respectively. X-ray photoelectron spectroscopy (XPS) was performed for the examination of elemental composition and chemical states by qualitative and quantitative analysis. The results of the investigations demonstrated that the MnMoO4 nanostructures with good crystallinity and distinct shape were formed successfully. The synthesized MnMoO4 nanoflowers were tested for their efficiency as a photocatalyst in the degradation studies of methylene blue (MB) as model organic contaminants in an aqueous medium under visible light, which showed their photocatalytic activity with a degradation of 85%. Through the band position calculations using the electronegative value of MnMoO4, the photocatalytic mechanism of the nanostructures was proposed. The results indicated that the effective charge separation, and transfer mechanisms, in addition to the flower-like shape, were responsible for the photocatalytic performance. The stability of the recovered photocatalyst was examined through its recyclability in the degradation of MB. Leveraging MnMoO4's photocatalytic properties, future studies may focus on scaling up these processes for practical and large-scale environmental remediation.

Logical formulation and in-situ assembly of MnCo2O4@MnO2 nanoflower arrays on nickel foam as monolithic catalyst for formaldehyde degradation at indoor temperature

The development and design of efficient and cost-effective catalysts for oxidizing low concentrations of formaldehyde at low temperatures, has been a significant challenge in HCHO oxidation. In this study, MnCo2O4@MnO2-NF (Ni foam) was synthesized as a monolithic catalyst for the degradation of HCHO in indoor environments. Using carrier immobilization, morphology modulation, and doping modification. The results revealed that the Co3O4 nanoarrays could be grown in a directional and orderly manner on the surface of the substrate through morphological modulation, showing a pompom-like, flower-like shape of the nanoneedles, thus providing sufficient growth sites for MnO2. Doping the Co3O4 nanoarrays with Mn via in-situ growth resulted in MnCo2O4 nanoarrays, following which the MnO2 expanded the pore sizes of the sample and provide more surface adsorption sites upon using MnCo2O4 as the carrier. In addition, numerous oxygen vacancies formed on the catalyst surface because of the synergistic interaction between Co and Mn, which formed more Mn3+ species and Oads, resulting in superior low-temperature redox ability and catalytic cycle stability. The catalyst achieved a HCHO removal efficiency of over 85 % within 60 min for five test cycles when the KMnO4 concentration was 0.05 M and Mn/Co ratio was 1:2.

Zinc oxide nanoparticles: an experimental study of synthesis, characterization and biological activity

Zinc oxide (ZnO) nanosized structures were synthesized successfully using a benign method. The latter can be achieved by introducing sesame seed extract into the formation process of ZnO nanostructures as a reducing agent, converting zinc (Zn) ions to Zn0. The structural and optical properties of the prepared ZnO particles were studied using many techniques such as Ultraviolet (UV)-Vis spectrophotometry, field emission scanning electron microscopy (FE-SEM), energy-dispersive X-ray spectroscopy (EDS), X-ray diffraction (XRD), and Fourier-transform infrared spectroscopy (FTIR). The estimated band gap energy of ZnO nanoparticles formed in the presence and absence of extract was found to be 3.94 eV and 3.88 eV, respectively, suggesting the effect of quantum confinement. The prepared particles have a flower-like shape with the appearance of small spherical particles. A Tauc plot was utilized to estimate the band gap energy of ZnO nanoparticles. The findings show that ZnO nanoparticles exhibit bactericidal properties against Staphylococcus hominins, which are Gram-positive bacteria, and also on Gram-negative bacteria such as Proteus mirabilis, E. coli, Acinetobacter baumannii, Pseudomonas aeruginosa, and Klebsiella pneumonia.

Enhancement mechanism of novel heterojunction Z-scheme-type composite BiOBr/ZnIn2S4 to degrade Congo red

The Z-scheme three-dimensional flower-like shape BiOBr/ZnIn2S4 showed excellent efficiency to degrade Congo red.

Optical and structural behavior of hydrothermally synthesized ZnO nanoparticles at various temperatures with NaOH molar ratios

Small-sized ZnO nanoparticles were synthesized at varying hydrothermal reaction temperatures of 120 °C, 150 °C, 180 °C and NaOH molar ratios (1:2 and 1:8). As-prepared ZnO samples (i.e. Z1-120, Z1-150, Z1-180 and Z2-120, Z2-150, Z2-180) were characterized using XRD, FESEM, EDX, FTIR, and DRS. These tests showed that the fabricated samples were good in crystalline structure and hexagonal wurtzite, suggesting high purity. ZnO crystalline size samples varied from 16 nm to 35 nm as the reaction temperature and NaOH molar ratios increased. The particle morphology changes from a spherical shape to a flower-like rod shape and then to a cluster rod-like shape due to the difference in growth speed between the different crystallographic planes with rising temperature and molar ratios. Tauc's plot range predicted the band gap of all ZnO nanoparticle samples to be approximately 3.2 eV, lower than bulk ZnO's 3.37 eV, resulting in the absorption edge red-shifted in DRS spectra. The optical band gap energy (Eg) of all ZnO nanoparticles is hardly affected by reaction temperature and NaOH molar concentration, and quantum confinement has little effect. This study concluded that based on its small crystalline size (i.e. 16.67 nm) and flower-like shaped nanorod, the Z1-150 sample of ZnO nanoparticles prepared at 150 °C and 1:2 M ratios is suitable for further study. It has an absorption edge at 382 nm near the red region and an interplanar spacing (d) of 0.2471 nm at the plane (101). This study also reveals that zinc oxide nanoparticles' purpose despite their small size, may well recover application in water purification as a photo-catalyst/adsorbate and further used as nanocomposite.

Copper cobalt oxide microstructures resembling marigold flowers were created by solvothermal synthesis for high-performance supercapacitors

The cathode electrode material for the battery-type CuCo2O4 electrode's hybrid supercapacitor applications was investigated. CuCo2O4 (MFCCO) microstructures resembling marigold flowers were created using a straightforward solvothermal procedure. X-ray diffraction (XRD), selected area electron diffraction (SAED) pattern, field emission scanning electron microscopy (FE-SEM), high-resolution transmission electron microscopy (HR-TEM), and X-ray photoelectron spectroscopy (XPS) were used to characterize the structure and morphology of the MFCCO. The flower-like shape, which comprised many nano-petals, was clearly visible in the FE-SEM image. Electrochemical experiments using the MFCCO electrode exhibit typical battery-type electrode materials. The CuCo2O4 electrode, which resembled a marigold flower, displayed good long-term cyclic stability and a maximum specific capacity of 627C g-1 at a current density of 0.5 A/g. The MFCCO electrode's high specific capacity, excellent cyclic stability, and low internal and charge transfer resistance supported the developed material's suitability as a positive electrode for hybrid supercapacitor applications.

Degradation Kinetic Studies of BSA@ZIF-8 Nanoparticles with Various Zinc Precursors, Metal-to-Ligand Ratios, and pH Conditions.

Nanosized zeolitic imidazolate framework particles (ZIF-8 nanoparticles [NPs]) have strong potential as effective carriers for both in vivo and in vitro protein drug delivery. Synthesis of ZIF-8 and stability of protein encapsulation within ZIF-8 are affected by several factors, notably the metal ion source and molar ratio. To systematically investigate these factors, we investigated such effects using BSA as a model test protein to synthesize BSA@ZIF-8 NPs at various metal-to-ligand (M:L) ratios. SEM, FTIR, XRD, and DLS were applied to characterize the morphology and structure of BSA@ZIF-8 NPs and their effects on protein loading capacity. Degradation kinetics and protein release behavior of BSA@ZIF-8 NPs were evaluated at pH 5.0 (to simulate the tumor environment) and pH 7.4 (to mimic the blood environment). Our objective was to define optimal combinations of the high protein loading rate and rapid release under varying pH conditions, and we found that (i) the yield of BSA@ZIF-8 NPs decreased as the M:L ratio increased, but the protein content increased. This highlights the need to strike a balance between cost-effectiveness and practicality when selecting ZIF-8 NPs with different molar ratios for protein-based drug formulation. (ii) BSA@ZIF-8 NPs exhibited cruciate flower-like shapes when synthesized using Zn(NO3)2 as the zinc precursor at M:L ratios of 1:16 or 1:20. In all other cases, the NPs displayed a regular rhombic dodecahedral structure. Notably, the release behavior of the NPs did not differ significantly between these morphologies. (iii) When Zn(OAc)2 was used as the zinc precursor, the synthesized ZIF-8 NPs exhibited a smaller size compared to the Zn(NO3)2-derived ZIF-8 NPs. (iv) The release rate and amount of BSA protein were higher at pH 5.0 compared to pH 7.4. (v) Among the different formulations, BSA@ZIF-8 with an M:L ratio of 1:16 at pH 5.0 was observed to have a shorter time to reach a plateau (0.5 h) and higher protein release, making it suitable for locally rapid administration in a tumor environment. BSA@ZIF-8 prepared from Zn(OAc)2 at an M:L ratio of 1:140 showed the slower release of BSA protein over a 24-h period, indicating its suitability for sustained release delivery. In conclusion, our findings provide a useful basis for the practical application of ZIF-8 NPs in protein-based drug delivery systems.

Colorimetric paper-based device for rapid screening of orlistat in weight loss supplements

The colorimetric paper-based device using lipase inhibition assay was developed for rapid and visual detection of orlistat in weight loss supplements. The paper device with five circular detection zones was simply fabricated from filter paper No 1 using a low-cost paper craft puncher with a design of a flower-like shape. The enzymatic reaction on the detection zone employed a small volume of a substrate, a-naphthyl acetate, a sample, and a lipase enzyme. After incubation, the Fast Blue B solution was used as a chromogenic reagent. The decrease in purple color can be observed by the naked eye, in the presence of orlistat. Under optimized conditions, the paper device showed satisfactory sensitivity and selectivity. The device was applied for rapid screening of orlistat in weight loss supplements and the results agreed with those obtained from TLC analysis.

Synthesis and Characterisation of ZnO/Ag Nanocomposites Prepared via Green Method Using Pineapple Peel Extract for Photocatalytic Enhancement in Degrading Methylene Blue Dye Solutions

Photocatalytic is one of the technological developments of renewable materials in overcoming water pollution due to industrial waste treatment. In this study, photocatalytic observations were carried out with a methylene blue (MB) degradation approach using zinc oxide and silver (ZnO/Ag) nanocomposites (NCs) which were enhanced by a new green synthesis in the form of pineapple peel extract (Ananas comosus) as a bio-stabiliser. The amount of Ag was varied by 5%, 10% and 15%. UV-Vis spectroscopy (UV-Vis), X-ray diffrection (XRD) and scanning electron microscopy-energy dispersive X-ray analysis (SEM-EDX) spectroscopy were analysed to study the optical properties, structure, morphology and composition of the samples. The characterisation results show that the absorption peak occurs in the 359 nm to 368 nm region with a band gap energy of 2.96 eV to 3.00 eV. Based on the XRD pattern, a hexagonal wurtzite structure was obtained with a crystal size of 18.37 nm. The particle morphology shows a flower-like shape with an average diameter of 60 nm. The EDX spectrum confirmed the elemental content of Zn, oxygen (O) and Ag. The photocatalytic activity showed that 10% ZnO/Ag was able to optimally degrade MB (10 ppm) with a reaction rate constant of 0.0091 min−1. Therefore, ZnO/Ag NCs were proven to be able to degrade dyes faster than pure ZnO.