Symmetry-breaking malachite green as a near-infrared light-activated fluorogenic photosensitizer for RNA proximity labeling.

Cellular RNA is asymmetrically distributed in cells and the regulation of RNA localization is crucial for proper cellular functions. However, limited chemical tools are available to capture dynamic RNA localization in complex biological systems with high spatiotemporal resolution. Here, we developed a new method for RNA proximity labeling activated by near-infrared (NIR) light, which holds the potential for deep penetration. Our method, termed FAP-seq, utilizes a genetically encoded fluorogen activating protein (FAP) that selectively binds to a set of substrates known as malachite green (MG). FAP binding restricts the rotation of MG and rapidly activates its fluorescence in a wash-free manner. By introducing a monoiodo modification to MG, we created a photosensitizer (MG-HI) with the highest singlet oxygen generation ability among various MG derivatives, enabling both protein and RNA proximity labeling in live cells. New insights are provided in the transcriptome analysis with FAP-seq, while a deeper understanding of the symmetry-breaking structural arrangement of FAP-MG-HI was obtained through molecular dynamics simulations. Overall, our wash-free and NIR light-inducible RNA proximity labeling method (FAP-seq) offers a powerful and versatile approach for investigating complex mechanisms underlying RNA-related biological processes.

Microwave-assisted and methanol/acetic acid-free method for rapid staining of proteins in SDS-PAGE gels.

We describe a microwave-assisted, methanol and acetic acid-free, inexpensive method for rapid staining of SDS-PAGE proteins. Only citric acid, benzoic acid, and Coomassie brilliant blue G-250 (CBG) were used. Microwave irradiation reduced the detection duration, and proteins in a clear background were visualized within 30 min of destaining, after 2 min of fixing and 12 min of staining. By using this protocol, comparable band intensities were obtained to the conventional methanol/acetic acid method.

Removal of malachite green from water: Comparison of adsorption in a residue-derived AC versus photocatalytic oxidation with TiO2 and study of the adsorption-photocatalysis synergy.

The literature rarely compiles studies devoted to the removal of pollutants in aqueous media comparing adsorption and photocatalytic degradation, and does not pay enough attention to the analysis of combined adsorption-photocatalytic oxidation processes. In the present manuscript, the removal of malachite green (MG) from aqueous solutions has been investigated in three different sustainable scenarios: i) adsorption on activated carbon (AC) derived from a residue, luffa cylindrica, ii) photocatalytic oxidation under simulated solar light using titanium dioxide (TP) and iii) combined adsorption-photocatalytic oxidation using TP-AC (70/30 wt./wt.) under simulated solar light. The study has revealed that in the three scenarios and studied conditions, the total removal of this endocrine-disrupting dye from the solution takes place in the assayed time, 2 h, in some cases just in a few minutes. MG adsorption in the AC is a very fast and efficient removal method. MG photocatalytic oxidation with TP also occurs efficiently, although the oxidized MG is not totally mineralized. MG removal using the TP-AC composite under simulated solar light occurs only slightly faster to the MG adsorption in the AC, being adsorption the dominating MG removal mechanism for TP-AC. Thus, more than 90% of the removed MG with TP-AC under simulated solar light is adsorbed in this carbon-containing composite. The obtained results highlight the interest in adsorption, being the selection of the most suitable removal method dependent on several factors (i.e., the cost of the AC regeneration, for adsorption, or the toxicity of the intermediate oxidation species, for photooxidation). Paying attention to MG photooxidation with TiO2, comparison of two working photodegradation schemes shows that the direct photodegradation of MG from solution, avoiding any initial dark equilibrium period, is more efficient from a time perspective. The use of scavengers has proved that MG photodegradation occurs via an oxidation mechanism dominated by superoxide anion radicals.

Controlled solvothermal synthesis of self-assembled SrTiO3 microstructures for expeditious solar-driven photocatalysis dye effluents degradation.

In this work, the self-assembled SrTiO3 (STO) microstructures were synthesized via a facile one-step solvothermal method. As the solvothermal temperature increased from 140 °C to 200 °C, the STO changed from a flower-like architecture to finally an irregularly aggregated flake-like morphology. The photocatalytic performance of as-synthesized samples was assessed through the degradation of rhodamine B (RhB) and malachite green (MG) under simulated solar irradiation. The results indicated that the photocatalytic performance of STO samples depended on their morphology, in which the hierarchical flower-like STO synthesized at 160 °C demonstrated the highest photoactivities. The photocatalytic enhancement of STO-160 was benefited from its large surface area and mesoporous configuration, hence facilitating the presence of more reactive species and accelerating the charge separation. Moreover, the real-world practicality of STO-160 photocatalysis was examined via the real printed ink wastewater-containing RhB and MG treatment. The phytotoxicity analyses demonstrated that the photocatalytically treated wastewater increased the germination of mung bean seeds, and the good reusability of synthesized STO-160 in photodegradation reaction also promoted its application in practical scenarios. This work highlights the promising potential of tailored STO microstructures for effective environmental remediation applications.

Zinc oxide decorated plantain peel activated carbon for adsorption of cationic malachite green dye: Mechanistic, kinetics and thermodynamics modeling.

Reports have shown that malachite green (MG) dye causes various hormonal disruptions and health hazards, hence, its removal from water has become a top priority. In this work, zinc oxide decorated plantain peels activated carbon (ZnO@PPAC) was developed via a hydrothermal approach. Physicochemical characterization of the ZnO@PPAC nanocomposite with a 205.2 m2/g surface area, porosity of 614.68 and dominance of acidic sites from Boehm study established the potency of ZnO@PPAC. Spectroscopic characterization of ZnO@PPAC vis-a-viz thermal gravimetric analyses (TGA), Fourier Transform Infrared Spectroscopy (FTIR), Powdered X-ray Diffraction (PXRD), Scanning Electron Microscopy and High Resolution - Transmission Electron Microscopy (HR-TEM) depict the thermal stability via phase transition, functional group, crystallinity with interspatial spacing, morphology and spherical and nano-rod-like shape of the ZnO@PPAC heterostructure with electron mapping respectively. Adsorption of malachite green dye onto ZnO@PPAC nanocomposite was influenced by different operational parameters. Equilibrium data across the three temperatures (303, 313, and 323 K) were most favorably described by Freundlich indicating the ZnO@PPAC heterogeneous nature. 77.517 mg/g monolayer capacity of ZnO@PPAC was superior to other adsorbents compared. Pore-diffusion predominated in the mechanism and kinetic data best fit the pseudo-second-order. Thermodynamics studies showed the feasible, endothermic, and spontaneous nature of the sequestration. The ZnO@PPAC was therefore shown to be a sustainable and efficient material for MG dye uptake and hereby endorsed for the treatment of industrial effluent.

Remediation of Safranin-O and acid fuchsin by using Ti3C2 MXene /rGo-Cu2O nanocomposite: Preparation, characterization, isotherm, kinetic and thermodynamic studies.

In recent years, MXene has become one of the most intriguing two-dimensional layered (2Dl) materials extensively explored for various applications. In this study, a Ti3C2 MXene/rGo-Cu2O Nanocomposite (TGCNCs) was developed to eliminate Safranin-O effectively (SO) and Acid Fuchsin (AF) as cationic dyes from the aquatic environment. Multistep was involved in the preparation of the adsorbent system, including the Preparation of Ti3C2, after that, GO synthesis by the Humer method, followed by rGO production, then added CuSO4 to obtain a final Nanocomposite (NCs) called "TGCNCs". The structure of TGCNCs can be varied in several ways, including FTIR, SEM, TGA, Zeta, EDX, XRD, and BET, to affirm the efficacious preparation of TGCNCs. A novel adsorbent system was developed to remove SO and AF, both cationic dyes. Various adsorption conditions have been optimized through batch adsorption tests, including the pH of the solution (4-12), the effect of dosage (0.003-0.03 g), the impact of the contact time (5-30 min), and the effect of beginning dye concentration (25-250 mg/L). Accordingly, the TGCNCs exhibited excellent fitting for Freundlich isotherm mode, resulting in maximum AF and SO adsorption capacities of 909.09 and 769.23 mg g-1. This research on adsorption kinetics suggests that a pseudo-second-order (PSO) model would fit well with the experimental data (RSO2 = 0.998 and RAF2 = 0.990). It is evident from the thermodynamic parameters that adsorption is an endothermic process that is spontaneous and favorable. During the adsorption of SO and AF onto NCs, it is hypothesized that these molecules interact intramolecularly through stacking interactions, H-bond interactions, electrostatic interactions, and entrapment within the polymeric Poros structure nanocomposite. Regeneration studies lasting up to five cycles were the most effective for both organic dyes under study.

A simple color absorption analysis of colorimetric loop-mediated isothermal amplification for detection of Raillietina spp. in clinical samples using a 3D-printed tube holder coupled with a smartphone camera and notebook screen.

A simple method has been developed for semi-quantitative analysis of the colorimetric output of loop-mediated isothermal amplification (LAMP) using a 3D-printed tube holder with a smartphone and notebook for the detection of Raillietina, which is the cause of Raillietiniasis affecting free-range chicken farming. In this method, a light is directed from a notebook screen to the LAMP products in the tube holder and the color absorption of the LAMP products is measured by using the appropriate smartphone application. It was found that the malachite green dye-coupled LAMP (MaG-LAMP) assay showed the highest sensitivity and specificity for detecting Raillietina without any cross-reaction with other related parasites and hosts. The limit of detection was 10 fg/µL of DNA. A total of 60 fecal samples were infectively confirmed by microscopic examination and the results of microscopy compared with those of MaG-LAMP and triplex PCR assays. Microscopy and MaG-LAMP based on the color absorption demonstrated high agreement in Raillietina detection with kappa = 1. Rapid, simple, cost-effective, and easy interpretation of colorimetric LAMP assays and their high sensitivity make them superior to PCR and morphological investigation, demonstrating the feasibility of this assay in point-of-care screening to support farm management and solve chicken health problems. Our study presents is an alternative diagnostic method using semi-quantitative analysis of colorimetric LAMP based on the differing solution color absorptions between positive and negative reactions for infectious disease diagnosis.

Artificial neural network-based modeling of Malachite green adsorption onto baru fruit endocarp: insights into equilibrium, kinetic, and thermodynamic behavior.

In this study, artificial neural network (ANN) tools were employed to forecast the adsorption capacity of Malachite green (MG) by baru fruit endocarp waste (B@FE) under diverse conditions, including pH, adsorbent dosage, initial dye concentration, contact time, and temperature. Enhanced adsorption efficiency was notably observed under alkaline pH conditions (pH 10). Kinetic analysis indicated that the adsorption process closely followed a pseudo-second-order model, while equilibrium studies revealed the Langmuir isotherm as the most suitable model, estimating a maximum adsorption capacity of 57.85 mg g-1. Furthermore, the chemical adsorption of MG by B@FE was confirmed using the Dubinin-Radushkevich isotherm. Thermodynamic analysis suggested that the adsorption is spontaneous and endothermic. Various ANN architectures were explored, employing different activation functions such as identity, logistic, tanh, and exponential. Based on evaluation metrics like the coefficient of determination (R2) and root mean square error (RMSE), the optimal network configuration was identified as a 5-11-1 architecture, consisting of five input neurons, eleven hidden neurons, and one output neuron. Notably, the logistic activation function was applied in both the hidden and output layers for this configuration. This study highlights the efficacy of B@FE as an efficient adsorbent for MG removal from aqueous solutions and demonstrates the potential of ANN models in predicting adsorption behavior across varying environmental conditions, emphasizing their utility in this field.

The innovative aspect of this study lies in the utilization of a new and effective adsorbent for the removal of Malachite Green (MG), derived from the fruit endocarp of baru (Dipteryx alata Vog.). The baru fruit endocarp, typically discarded as solid waste during processing, was found to possess favorable characteristics for adsorption processes and provides an adsorption capacity that exceeds that of most other similar adsorbents. Additionally, integrating Artificial Neural Networks (ANNs) enables accurate modeling of the adsorption process, eliminating the need for extensive laboratory experiments. This contributes significantly to wastewater treatment research, enhancing effectiveness and sustainability in unwanted dye removal.

Modeling competitive biosorption for methylene blue removal on rape straw powders using response surface methodology in a ternary dye aqueous solution.

The improvement of biosorption efficiency for selective dye removal in a multi-dye aqueous system has become an increasingly significant research topic. However, the competitive effects of coexisting dyes and the target dye in such systems remain uncertain due to complex interactions between adsorbent and coexisting dyes. Therefore, in this research, response surface methodology (RSM) model was effectively employed to investigate the competitive effects of allura red (AR) and malachite green (MG) on methylene blue (MB) removal in a ternary dye aqueous system using three different parts of rape straw powders. In the current design of RSM, the initial concentrations of AR and MG dyes ranging from 0 mg·L-1 to 500 mg·L-1 were considered as influencing factors, while the removal rates of MB on adsorbents at an initial concentration of 500 mg·L-1 were established as response values. The RSM models exhibited high correlation coefficients with adjusted R2 values of 0.9908 (pith core), 0.9870 (seedpods), and 0.9902 (shells), respectively, indicating a close fitted between predicted and actual values. The proposed models indicated that the perturbation effects of initial AR and MG concentrations were observed on the removal rates of MB by three types of rape straw powders in a ternary dye aqueous system, resulting in a decrease in MB removal rates, particularly at higher initial AR concentration due to stronger competitive effects compared to initial MG concentration. The structures of rape straw powders, including pith core, seedpods and shell, were analyzed using scanning eletron microscoe (SEM), energy dispersive spectroscopy (EDS), N2 physisorption isotherm, frourier transform infared spectroscopy (FTIR), Zeta potential classes and fluorescence spectrum before and after adsorption of MB in various dye aqueous systems. The characteristics of rape straw powders suggested that similar adsorption mechanisms, such as electrostatic attraction, pore diffusion, and group complex formation for MB, AR, and MG, respectively, occurred on the surfaces of adsorbents during their respective adsorption processes. This leads to significant competitive effects on the removal rates of MB in a ternary dye aqueous system, which are particularly influenced by initial AR concentrations as confirmed through fluorescence spectrum analysis.

Impact of AR and MG on MB removal was analyzed using simple methodologies.Competitive behaviors between AR, MG and MB were understood through RSM.Intense restrain effects on MB removal were revealed by AR concentration.

Effective removal of malachite green oxalate from aqueous solution using Newbouldia laevis husk/MWCNTs nanocomposite: equilibrium, kinetics, and thermodynamics.

The discharge of colored effluent into water bodies is a big concern; hence, the current work was designed to fabricate a superior nanocomposite (NBM) using the Newbouldia laevis husk (NB) and functionalized multiwalled carbon nanotubes (f-MWCNTs) for the adsorption of malachite green oxalate (MGO). Brunauer-Emmett-Teller (BET) surface analysis was used to assess the specific surface area of NB (0.7699 m2 g-1) and NBM (94.006 m2 g-1). Fourier transform infrared spectroscopy (FTIR) was employed to determine the chemical moieties on the surface of the adsorbent. Field emission scanning electron microscopy (FESEM) and thermogravimetric analysis (TGA) were used to analyze the surface morphology and the thermal behavior of the adsorbents. Essential factors of the adsorption process were investigated, and it was revealed that pH 6.0, adsorbent dose of 0.05 g, contact time 80 min, concentration of 100 mg dm-3 and maximum adsorption capacity of 35.78 mg g-1 (NB) and 69.97 mg g-1 (NBM) were the optimal parameters. The NB and NBM adsorption processes followed a pseudo-first-order kinetic model. The exothermic and endothermic adsorptive processes were noticed to be the best descriptions of MGO elimination by NB and NBM, respectively. The uptake of MGO by NB and NBM was best described by models of Freundlich and Langmuir isotherms. Besides, NBM demonstrated uptake efficiency that is >80% after the fourth adsorption/desorption cycle. As a result, NBM has a wide range of possible uses in environmental remediation.

The husk of Newbouldia laevis is a frequent waste that must be managed properly. This paper describes the application of Newbouldia laevis husk as a value-added material for the design of a water treatment agent. The use of carbon nanotube in the modification of Newbouldia laevis husk would have a synergistic effect on the overall property of the nanocomposite. Nanocomposite synthesized from multiwalled carbon nanotubes (MWCNTs) and Newbouldia laevis husk were characterized and used for the sequestration of malachite green oxalate from contaminated water. Our primary goal is to optimize the nanocomposite by varying factors of adsorption such as solution pH, equilibrium, kinetic, thermodynamic, and regeneration studies. We believe that this study will contribute to the existing knowledge of Newbouldia laevis husk. Owing to the exceptional potential of the nanocomposite, this adsorbent can be extended to possible field applications.

Acid-activated corn silk as a promising phytosorbent for uptake of Malachite green and Cd (II) ion from simulated wastewater: equilibrium, kinetic and thermodynamic studies.

Malachite green (MG) dye and cadmium metal ion are toxic pollutants that should be removed from aqueous environment. The recent study aimed to examine the adsorption behavior of MG dye and Cd (II) from wastewater onto low-cost adsorbent prepared by activating corn silk with nitric acid (ACS) and characterized by SEM, FTIR, XRD, BET and TGA. The optimum MG and Cd (II) adsorption was observed at pH 7 and pH 9 and maximum uptake of both pollutants was at 0.5 g dosage, 60 mins contact time and 20 mg/L initial concentration. The retention of dye and metal ion by the studied adsorbent was best fit to Langmuir isotherm and Pseudo-second order kinetics. The maximum monolayer coverage capacity of ACS for MG dye and Cd (II) ion was 18.38 mg/g and 25.53 mg/g, respectively. Thermodynamic studies predicted a spontaneous reaction with exothermic process for MG dye whereas an endothermic and spontaneous process was confirmed for Cd ion based on estimated parameters. The adsorption mechanism of MG dye and Cd (II) uptake was by combination of electrostatic interaction, pore diffusion, ion exchange, pie-pie attraction, hydrogen bonding, and complexation. The adsorbed pollutants were effectively desorbed with significant regeneration efficiency after successive five cycles that proved the potential of low-cost biosorbent for selective sequestration of cationic dye and divalent metal ion from effluents.

The use of nitric acid-modified corn silk has been reported to enhance its adsorption performance over the unmodified cob for pollutants such as cadmium ions and malachite green. Although there may be no recorded data on the adsorption efficiency of acid-treated corn silk for selected pollutants, it can be considered as a prospective bio-sorbent owing to its chemical composition and functional groups for exchange of hydrogen ions for other cations.

Removal of malachite green from wastewater using date seeds as natural adsorbent; isotherms, kinetics, Thermodynamic, and batch adsorption process design.

This research explores the feasibility of using date seeds (DS), an agricultural waste, for the adsorption of malachite green (MG) dye from synthesized wastewater. The characterization of the DS before and after adsorption was accomplished by FTIR, SEM, BET, and EDX measurements. Batch adsorption experiments were investigated for MG dye adsorption from aqueous solution onto the DS. The effect of different parameters such as solution pH, adsorbent dose, contact time, temperature, and the initial dye concentration were studied. The optimum pH, adsorbent dose, temperature, and contact time for the dye removal were found to be 5, 0.1 g, 25 °C, and 30 min, respectively. The equilibrium studies for the data with Langmuir, Freundlich, and Temkin isotherms showed that Freundlich isotherm is the best model to describe the adsorption of MG onto the DS particles which has a heterogeneous surface. It was found that the adsorption process follows a pseudo-second-order kinetic model which revealed that the intra-particle diffusion stage is the rate-controlling stage for the process. The thermodynamic parameters ΔG, ΔS, and ΔH suggest the possibility of chemisorption and physisorption simultaneously and indicate the exothermic and spontaneous characters of the adsorption of MG dye on DS with negative values of ΔH and ΔG.

This study used agriculture waste (date seeds) which is proved to be an environmentally friendly and low-cost adsorbent. The date seeds were shown to be a promising adsorbent, demonstrating high surface area and well-developed porosity. The prepared adsorbent will have a great impact on wastewater treatment technology and possible applications at a large scale. Thus, widespread and great progress in this area can be expected in the future.

Exploitation of green synthesized chromium doped zinc oxide nanorods (NRs) mediated by flower extract of Rhododendron arboreum for highly efficient photocatalytic degradation of cationic dyes Malachite green (MG) and Fuchsin basic (FB).

In this work, green method to synthesize chromium-doped zinc oxide (ZnO) nanorods (NRs) using an aqueous flower extract from Rhododendron arboretum is explored. Herein, chromium-doped ZnO NRs were prepared with different amount of chromium doping, varied as 2-10%. The green synthesized products underwent substantial analysis through X-ray diffraction (XRD), spectroscopic such as ultraviolet spectroscopy(UV-Vis) and scanning electron microscopy (SEM) methods. All samples were found to have hexagonal wurtzite ZnO, with average particle sizes of 52.41, 56.6, 54.44, 53.05, and 56.99 nm, respectively, for 2, 4, 6, 8, and 10% chromium doping in ZnO NRs. The Cr-doped ZnO NRs exhibited remarkable photocatalytic degradation activity of cationic dyes under UV-light, i.e., Malachite Green and Fuchsin Basic with degradation of 99.604 and 99.881%, respectively in 90 min. The reusability tests for these green synthesized Cr-doped ZnO NRs have also been carried out, showed 9-11 cycles with 85% of degradation efficiency. In addition, the Cr-doped ZnO NRs exhibited high selectivity for cationic dyes when experiments against mixture of dyes were performed. Photodegradation kinetics followed the pseudo-first-order model. The flower-extract-stabilized chromium-doped ZnO NRs demonstrated high photocatalytic activity toward malachite green and fuchsin basic dyes, potential material for pollution remediation.

Cr-doped ZnO NRs by green method using flower extract of Rhododendon arboretum were prepared for the first time under ambient reaction conditions.Effect of Dopant i.e. Cr on Photocatalytic activity have been exploited.Selective photocatalytic degradation of cationic dyes i.e. MG, and FB has been achieved in 60­90 minutes.Optimization of reaction condition and various parameters has also been carried out.Recyclability of Cr-doped ZnO NRs was also evaluated and were found to be reusable for 11 cycles for degradation.

"Core/Shell" Nanocomposites as Photocatalysts for the Degradation of the Water Pollutants Malachite Green and Rhodamine B.

"Core/shell" composites are based on a ferrite core coated by two layers with different properties, one of them is an isolator, SiO2, and the other is a semiconductor, TiO2. These composites are attracting interest because of their structure, photocatalytic activity, and magnetic properties. Nanocomposites of the "core/shell" МFe2O4/SiO2/TiO2 (М = Zn(II), Co(II)) type are synthesized with a core of MFe2O4 produced by two different methods, namely the sol-gel method (SG) using propylene oxide as a gelling agent and the hydrothermal method (HT). SiO2 and TiO2 layer coating is performed by means of tetraethylorthosilicate, TEOS, Ti(IV) tetrabutoxide, and Ti(OBu)4, respectively. A combination of different experimental techniques is required to prove the structure and phase composition, such as XRD, UV-Vis, TEM with EDS, photoluminescence, and XPS. By Rietveld analysis of the XRD data unit cell parameters, the crystallite size and weight fraction of the polymorphs anatase and rutile of the shell TiO2 and of the ferrite core are determined. The magnetic properties of the samples, and their activity for the photodegradation of the synthetic industrial dyes Malachite Green and Rhodamine B are measured in model water solutions under UV light irradiation and simulated solar irradiation. The influence of the water matrix on the photocatalytic activity is determined using artificial seawater in addition to ultrapure water. The rate constants of the photocatalytic process are obtained along with the reaction mechanism, established using radical scavengers where the role of the radicals is elucidated.

Co-immobilizing laccase-mediator system by in-situ synthesis of MOF in PVA hydrogels for enhanced laccase stability and dye decolorization efficiency.

The laccase mediator system (LMS) with a broad substrate range has attracted much attention as an efficient approach for water remediation. However, the practical application of LMS is limited due to their high solubility, poor stability and low reusability. Herein, the bimetallic Cu/ZIFs encapsulated laccase was in-situ grown in poly(vinyl alcohol) (PVA) polymer matrix. The PVA-Lac@Cu/ZIFs hydrogel was formed via one freeze-thawing cycle, and its catalytic stability was significantly improved. The mediator was further co-immobilized on the hydrogel, and this hierarchically co-immobilized ABTS/PVA-Lac@Cu/ZIFs hydrogel could avoid the continuous oxidation reaction between laccase and redox mediators. The co-immobilized LMS biocatalyst was used to degrade malachite green (MG), and the degradation rate was up to 100 % within 4 h. More importantly, the LMS could be recycled synchronously from the dye solutions and reused to degrade MG multiple times. The degradation rate remained above 69.4 % after five cycles. Furthermore, the intermediate products were detected via liquid chromatography-mass spectrometry, and the potential degradation pathways were proposed. This study demonstrated the significant potential of utilizing the MOF nanocrystals and hydrogel as a carrier for co-immobilized LMS, and the effective reuse of both laccase and mediator was promising for laccase application in wastewater treatment.

Novel tempo oxidized polyvinyl alcohol/ cellulose nanocrystal-based nanocomposite membrane for malachite green dye removal.

In this study, in-situ modification by TEMPO oxidation was performed after nanocomposite synthesis to improve its properties toward dye molecule removal. The unoxidized and oxidized polymeric-based nanocomposite was denoted as PNC6 and PNC6O respectively. The nanocomposites were characterized using FESEM, FTIR, contact angle, XRD and BET analysis. Measurements of swelling ratio and chemical stability were also performed to provide insight into the durability of the nanocomposites. The effects of changing variables included contact duration, pH of aqueous solution, initial pollutant concentration, and temperature were observed. The kinetic study showed that the experimental data is best fitted with pseudo-second-order kinetics (R2 = 0.988 and 0.997 respectively), whereas on observing isotherm data, in both unoxidized and oxidized nanocomposite it fits well with Langmuir isotherm (R2 = 0.951 and 0.993 respectively). In addition, the effects on Gibb's free energy, Enthalpy, and Entropy were measured in terms of thermodynamic characteristics, it was established that dye molecules adsorption mechanism is endothermic and spontaneous in behaviour. To check regeneration tendency of the nanocomposite seven consecutive adsorption desorption cycles were run and about 90% and 80%, regeneration ability could be seen in an unoxidized state (PNC6) and an oxidized state (PNC6O) respectively upto 5th cycle after that the tendency get reduced. This study suggests that this novel polymeric nanocomposite can be employed as an efficient and relatively inexpensive adsorbent for dye removal from aqueous solutions.

[A fluorescence method based on malachite green/aptamer for detection of ochratoxin A in traditional Chinese medicines].

A label-free fluorescence method based on malachite green/aptamer was developed for the detection of ochratoxin A(OTA) in traditional Chinese medicines. Malachite green itself exhibits weak fluorescence. Upon interaction with the aptamer specific to OTA, the G-quadruplex structure of the aptamer provides a protective microenvironment for malachite green, which significantly enhances its fluorescence signal. After OTA is added, preferential binding occurs between the aptamer and OTA, and malachite green will be released from the aptamer, which weakens the fluorescence signal. According to this principle, this paper established a fluorescence method with the aptamer of OTA as the recognition element and malachite green as the fluorescent probe for the detection of OTA in traditional Chinese medicines. The key experimental factors such as the concentrations of metal ions, aptamer, and malachite green were optimized to improve the performance of the method. OTA was detected under the optimal experimental conditions, and the results showed that with the increase in OTA concentration, the fluorescence signal gradually weakened. Within the range of 20-1 000 nmol·L~(-1), the OTA concentration was linearly correlated with the fluorescence signal ratio ΔF/F(ΔF=F_0-F, where F_0 is the fluorescence signal of aptamer/malachite green, and F is the fluorescence signal of OTA/aptamer/malachite green), with R~2 of 0.995. The limit of detection of the established method was 7.1 nmol·L~(-1). Furthermore, three substances structurally similar to OTA and two mycotoxins that may coexist with OTA were selected for experiments, which aimed to examine the cross-reactivity and specificity of the established method. The cross-reactivity experiments demonstrated that the interferers did not significantly affect the fluorescence signal of the detection system. The specificity experiments revealed that when mycotoxins were mixed with OTA, the fluorescence signal generated by the mixture closely resembled that of OTA itself. The results indicated that even in the presence of interferents, the established method remained unaffected and demonstrated excellent specificity. Additionally, this method exhibited remarkable reproducibility and stability. In the case of simple centrifugation and dilution of traditional Chinese medicine samples(Puerariae Lobatae Radix, Sophorae Flavescentis Radix, and Periplocae Cortex), the OTA detection method was applicable, with recovery rates ranging from 91.5% to 121.3%. Notably, this approach does not need complex pretreatment of traditional Chinese medicines while offering simple operation, low detection costs, and short detection time. Furthermore, by incorporating aptamers into the quality evaluation of traditional Chinese medicines, this method expands the application scope of aptamers.

Dye degradation by early colonizing marine bacteria from the Arabian Sea, India.

Malachite green dye belongs to the triphenylmethane group and is a common environmental pollutant that threatens non-target organisms. We report the potential of the early colonizing marine bacterium Pseudomonas sp. ESPS40 isolated from the Arabian Sea, India, to decolorize malachite green (MG). The bacterium ESPS40 exhibited a higher ability for MG degradation (86-88%) at varying NaCl concentrations (1-3%). The highest MG degradation (~ 88%) was observed at 1% NaCl. The bacterial strain ESPS40 showed degradation up to 800 mg L-1 MG. Further, enzyme activities such as tyrosinase (63.48-526.52 U L-1) and laccase (3.62-28.20 U L-1) were also analyzed with varying concentrations (100 mg L-1-1000 mg L-1) of MG during the degradation process. The dye degradation was confirmed by Fourier transform infrared spectroscopy (FTIR) and high-performance liquid chromatography (HPLC). The outcome of the present study demonstrated Pseudomonas sp. ESPS40 as a potential strain for the efficient degradation of MG at higher concentrations. Thus, Pseudomonas sp. ESPS40 can be utilized as a potential candidate for the biodegradation of MG in wastewater treatment.

Removal of the Basic and Diazo Dyes from Aqueous Solution by the Frustules of Halamphora cf. salinicola (Bacillariophyta).

Industrial wastes with hazardous dyes serve as a major source of water pollution, which is considered to have an enormous impact on public health. In this study, an eco-friendly adsorbent, the porous siliceous frustules extracted from the diatom species Halamphora cf. salinicola, grown under laboratory conditions, has been identified. The porous architecture and negative surface charge under a pH of 7, provided by the various functional groups via Si-O, N-H, and O-H on these surfaces, revealed by SEM, the N2 adsorption/desorption isotherm, Zeta-potential measurement, and ATR-FTIR, respectively, made the frustules an efficient mean of removal of the diazo and basic dyes from the aqueous solutions, 74.9%, 94.02%, and 99.81% against Congo Red (CR), Crystal Violet (CV), and Malachite Green (MG), respectively. The maximum adsorption capacities were calculated from isotherms, as follows: 13.04 mg g-1, 41.97 mg g-1, and 33.19 mg g-1 against CR, CV, and MG, respectively. Kinetic and isotherm models showed a higher correlation to Pore diffusion and Sips models for CR, and Pseudo-Second Order and Freundlich models for CV and MG. Therefore, the cleaned frustules of the thermal spring-originated diatom strain Halamphora cf. salinicola could be used as a novel adsorbent of a biological origin against anionic and basic dyes.

Efficient and Selective Adsorption of Cationic Dye Malachite Green by Kiwi-Peel-Based Biosorbents.

In this study, pristine kiwi peel (KP) and nitric acid modified kiwi peel (NA-KP) based adsorbents were prepared and evaluated for selective removal of cationic dye. The morphology and chemical structure of KP and NA-KP were fully characterized and compared, and results showed nitric acid modification introduced more functional groups. Moreover, the adsorption kinetics and isotherms of malachite green (MG) by KP and NA-KP were investigated and discussed. The results showed that the adsorption process of MG onto KP followed a pseudo-second-order kinetic model and the Langmuir isotherm model, while the adsorption process of MG onto NA-KP followed a pseudo-first-order kinetic model and the Freundlich isotherm model. Notably, the Langmuir maximum adsorption capacity of NA-KP was 580.61 mg g-1, which was superior to that of KP (297.15 mg g-1). Furthermore, thermodynamic studies demonstrated the feasible, spontaneous, and endothermic nature of the adsorption process of MG by NA-KP. Importantly, NA-KP showed superior selectivity to KP towards cationic dye MG against anionic dye methyl orange (MO). When the molar ratio of MG/MO was 1:1, the separation factor (αMG/MO) of NA-KP was 698.10, which was 5.93 times of KP. In addition, hydrogen bonding, π-π interactions, and electrostatic interaction played important roles during the MG adsorption process by NA-KP. This work provided a low-cost, eco-friendly, and efficient option for the selective removal of cationic dye from dyeing wastewater.