Fluorescence Spectroscopy Analysis Research Articles

Ultra-High Adsorption Capacity of Calcium-Iron Layered Double Hydroxides for HEDP Removal through Phase Transition Processes.

Antiscalant disposal in reverse osmosis concentrate (ROC) treatment is a significant obstacle in desalination. This study investigated the adsorption performance of LDHs for removing 1-hydroxyethylidene-1,1-diphosphonic acid (HEDP). CaFe-LDH presented a specific adsorption behavior and ultrahigh adsorption capacity for HEDP, with a maximum adsorption capacity of 335.7 mg P/g (1116.5 mg HEDP/g) at pH 7.0. X-ray diffraction (XRD) demonstrated that HEDP adsorption induced a structural transformation of CaFe-LDH from a layered configuration to a highly ordered structure, leading to a noticeable phase transition. Time-of-flight secondary ion mass spectrometry (ToF-SIMS) and Raman spectroscopy further confirmed that two distinct binding modes of HEDP, relating to chelation with Ca2+ and adsorption on Fe3+ simultaneously, are connected by phosphonic acid groups (-C-PO(OH)2), forming the CaFe-HEDP complex. X-ray fluorescence (XRF) and X-ray photoelectron spectroscopy (XPS) analyses revealed that the CaFe-HEDP ternary complex exhibits a highly ordered arrangement in an oxygen-bridged framework. The construction of an oxygen-coordinated framework contributes to the incorporation of more HEDP into CaFe-LDH, leading to a well-aligned lattice in the new phase. These findings provide valuable insights into developing novel LDH-based adsorbents for removing phosphorus-containing antiscalants, establishing a sustainable approach to ROC management, and potential environmental risk reduction.

Long Stability of Atomically Precise Red Emissive Copper Nanoclusters within the Gel and Their Use As a Potential Catalyst and Fluorescent Ink.

Herein, an amphiphile-based hydrogel (with 5% DMF) containing natural amino acid residue has been used to prepare and stabilize red-emitting CuNCs for several months. Though different methods have been attempted, amphiphile and 4-mercaptobenzoic acid (4-MBA)-containing hydrogels are pinpointed to be the base medium to stabilize this new Cu-cluster. From a MALDI-TOF MS analysis it was found that it is a Cu8-atom cluster stabilized by three 4-MBA ligands. Copper acetate monohydrate (Cu(CH3COO)2·H2O) has been used as a copper precursor, and l-ascorbic acid has been used as a reducing agent. FEG-TEM analysis shows that the Cu cluster has an average size of 2.83 nm. Interestingly, these clusters can be used as a fluorescent ink with a visibility of the solid state under a UV-lamp with an excitation of 365 nm. This envisaged applying these CuNCs for anticounterfeiting. These Cu-clusters show an excitation of 420 nm with an emission of 620 nm, as is evident from the fluorescence spectroscopic analysis. Based on our knowledge, this is the first example of making and consequently stabilizing Cu-clusters using hydrogel as a template for a few months. Moreover, these CuNCs can also be used as a catalyst for the reduction of nitro derivatives to their amine derivatives in aqueous medium.

Exploration of pyridine-thiazolidin-4-one: Synthesis, DFT study, UV–Vis/ fluorescence spectroscopy analysis, antibacterial evaluation and molecular docking

The synthesis of the objective pyridine-thiazolidin-4-one (DCPI-MBT) was involved via the Knoevenagel reaction between 2-((3,5-dichloropyridinyl)imino)thiazolidinone derivative 1 and 4-methylbenzaldehyde 2 over refluxing in acetic acid and sodium acetate. The confirmed structure of this hybrid was elucidated through detailed spectral analyses. A comparison was made between the density functional theory (DFT) configurations of the frontier molecular orbitals in both the gas and solvated ground state (So) and the solvated excited state (S1). UV–Visible and fluorescence spectra of the thiazolidin-4-one derivative were obtained in DMSO, displaying a significant Stokes’ shift (Δν¯= 3136.81 cm−1). The synthesized DCPI-MBT was established to see how well they killed different kinds of pathogenic microbes, such as bacteria, viruses, and fungi. These results demonstrate that the synthesized DCPI-MBT has a broad-spectrum antibacterial capability that is on par with or even superior to conventional treatments in certain instances. Moreover, molecular docking simulation was used to evaluate the bindings of the synthesized DCPI-MBT with a target protein (PDB: 1kzn). The binding energies, RMSD values, kinds of interactions with amino acid residues, and interaction distances of the hybrids were determined based on their substituent changes. This study analyzed the pharmacokinetic profiles of newly DCPI-MBT, using SwissADME predictions to focus on their potential as therapeutic agents. The DCPI-MBT has the promising pharmacokinetic profile for future development as a therapeutic drug, with optimum solubility, bioavailability, and a favorable interaction profile with biological targets.

Sustainable furfural bis-thymol based benzoxazines: Superhydrophobic, aggregation induced emission and corrosion resistant properties

Sustainable bis-thymol based benzoxazines have been synthesized using furfural bis-thymol (FBT) and paraformaldehyde separately with five different fluorine substituted amines through Mannich condensation process. The molecular structure of the obtained benzoxazines has been verified using spectroscopic analyses. The curing temperature of the synthesized benzoxazines are ranged between 241°C and 277°C. Among the synthesized polybenzoxazines, poly(FBT-pfa) exhibits the highest thermal stability of 52% char yield. All the polybenzoxazines exhibit the value of LOI above the threshold limit of 26 which infers the self-extinguishing property of the polymer. Poly(FBT-pfsa) showed the highest value of water contact angle of 151o, which ascertains that the increased fluorine content contributes to the superhydrophobic nature. Results from hydrophobic durability studies with poly(FBT-pfsa) using coated cotton fabric under acidic and basic conditions indicate its suitability for hydrophobic applications. The corrosion protection ability of polybenzoxazines towards mild steel surfaces was studied and the results obtained suggest that these polybenzoxazines can be used as an excellent coating material. UV-Visible and fluorescence spectroscopic analyses infer that these benzoxazines exhibit aggregation induced emission (AIE) characteristics. Data from different studies suggest that these materials can be conveniently utilized in the form of optical, superhydrophobic and corrosion-resistant coatings.

Thiolated dextrin nanoparticles for curcumin delivery: Stability, in vitro release, and binding mechanism

To achieve the effective loading and delivery of curcumin, novel disulfide-crosslinked nanoparticles based on modified dextrin were developed for the encapsulation of curcumin. Thiolated dextrin (Dt-SH) was obtained via sodium periodate oxidation and cysteamine grafting. The Dt-SH exhibited a rough, flake-like morphology, was classified as an amorphous material and demonstrated enhanced enzyme resistance. Subsequently, spherical nanoparticles with sizes ranging from 92.52 to 157.12 nm and zeta potentials between +23.59 and + 29.90 mV were self-assembled in an aqueous solution. Thiol modification promoted interconnection and aggregation of the nanoparticles. These nanoparticles exhibited pH-dependent size variations. Taking curcumin as a hydrophobic model, nanoparticles showed intestinal targeted release in vitro. Fluorescence spectroscopy and thermodynamic analysis indicated that curcumin bound to Dt-SH nanoparticles primarily through hydrogen bonding and van der Waals forces, with hydrophobic interactions contributing. These findings supported the potential of thiolated dextrin nanoparticles in the effective delivery of hydrophobic compounds.

Multipurpose Fluorescent Nanocarriers: Environmental Behavior, Toxicity and Internalization on Marine Microalgae

AbstractEngineered nanomaterials (ENMs), such as silica mesoporous nanocapsules (SiNC), have emerged as a powerful tool for the controlled delivery and release of active compounds in various fields. However, the environmental impact of SiNC on marine biota, particularly when they enter the marine environment through wastewater effluents or direct release from maritime coatings, remains poorly understood. Studying their effects is thus crucial for environmental and human health protection, the development of safe‐by‐design ENMs, and informed policy‐making. This study aims to assess the ecotoxicological effects and internalization of industrially‐relevant SiNC in marine phytoplankton, namely on the microalgae Tetraselmis chuii, Nannochloropsis gaditana, and Isochrysis galbana, and diatoms Phaeodactylum tricornutum, and Chaetoceros calcitrans. For this purpose, a fluorescent nanocarrier (SiNC‐UMB) is developed by labeling the SiNC with the fluorescent natural dye umbelliferone (UMB). UV–vis and fluorescence spectroscopic analyses confirmed the successful loading of UMB into SiNC. Phytoplankton can internalize these ENMs, even at low concentrations, although adsorption to the cell wall can also occur. This confirms the internal exposure and growth inhibition observed in the microalgae. These findings highlight the potential of using SiNC‐UMB as a valuable tool for tracking their uptake and assessing their effects on marine biota and beyond.

Novel thiazole-based cyanoacrylamide derivatives: DNA cleavage, DNA/BSA binding properties and their anticancer behaviour against colon and breast cancer cells

A novel series of 2-cyano-3-(pyrazol-4-yl)-N-(thiazol-2-yl)acrylamide derivatives (3a–f) were synthesized using Knoevenagel condensation and characterized using various spectral tools. The weak nuclease activity of compounds (3a–f) against pBR322 plasmid DNA was greatly enhanced by irradiation at 365 nm. Compounds 3b and 3c, incorporating thienyl and pyridyl moieties, respectively, exhibited the utmost nuclease activity in degrading pBR322 plasmid DNA through singlet oxygen and superoxide free radicals’ species. Furthermore, compounds 3b and 3c affinities towards calf thymus DNA (CT-DNA) and bovine serum albumin (BSA) were investigated using UV–Vis and fluorescence spectroscopic analysis. They revealed good binding characteristics towards CT-DNA with Kb values of 6.68 × 104 M−1 and 1.19 × 104 M−1 for 3b and 3c, respectively. In addition, compounds 3b and 3c ability to release free radicals on radiation were targeted to be used as cytotoxic compounds in vitro for colon (HCT116) and breast cancer (MDA-MB-231) cells. A significant reduction in the cell viability on illumination at 365 nm was observed, with IC50 values of 23 and 25 µM against HCT116 cells, and 30 and 9 µM against MDA-MB-231 cells for compounds 3b and 3c, respectively. In conclusion, compounds 3b and 3c exhibited remarkable DNA cleavage and cytotoxic activity on illumination at 365 nm which might be associated with free radicals’ production in addition to having a good affinity for interacting with CT-DNA and BSA.Graphical

Promoting effects of ferric ions on Microcystis aeruginosa growth and arsenate accumulation and reduction at different phosphorus environments

The effects of different dissolved organic phosphorus (DOP) associated with distinct iron conditions (iron deficient (dFe), ferric ions (Fe3+), and colloidal iron (CFe)) on algal growth and arsenate (As(V)) metabolism were systematically evaluated and compared in Microcystis aeruginosa. Two chemical forms of DOP (D-glucose-6-phosphate (GP) and phytic acid (PA)), as well as dissolved inorganic phosphorus (DIP), were employed as distinct phosphorus environments. The results revealed that As(V) metabolism of M. aeruginosa was more influenced by different phosphorus forms than by different iron conditions. Conversely, the release of microcystins in the media was found to be significantly more affected by the different phosphorus forms than by the iron conditions. Moreover, DOP was observed to promote arsenic (As) biotransformation, particularly the efflux of methylated As from a single algal cell, whereas DIP was found to primarily facilitate As(V) accumulation in algae. The total As metabolism amount per algal cell under PA was observed to be five times that observed under DIP and GP. The influence of iron conditions on the synthesis of algal metabolites was notable, as evidenced by the metabolites identified in algae of aliphatic (δ 1.28–1.68), humic acid-like and aromatic protein-like substances through 1H-NMR spectra and three-dimensional excitation-emission matrix fluorescence spectroscopy analysis. This impact was particularly notable at Fe3+ conditions, due to the role of Fe3+ as a micronutrient with highly bioavailable forms, which enhanced the synthesis of organic compounds in algae and promoted algal growth. Consequently, Fe3+ could inhibit As accumulation under DIP but promote it under DOP. The obtained results facilitate a more comprehensive understanding of the combined role of different phosphorus forms and iron conditions in algal bloom outbreaks and As(V) metabolism.

Characterization of pyroplastics from the North Atlantic

This work describes for the first time the presence of pyroplastics in the Canary Islands (Spain). A total of 300 pyroplastics, identified between 2021 and 2024 in three beaches of the island of Tenerife, present mainly grey and dark colors, a mean weight of 6.8 ± 13.4 g and mean dimensions of 34.2 ± 17.0 mm (X), 24.5 ± 12.2 mm (Y) and 14.4 ± 6.4 (Z). A wide variety of encapsulated and semi-encapsulated materials were also found in the pyroplastics matrix, such as rocks, wood, charcoal and unmelted plastic inclusions. Fourier-transform infrared spectroscopy analysis revealed that polyethylene and polypropylene were the main types of plastic found, 61.3 % and 33.6 %, respectively. However, an important number of pyroplastics composed of more than one polymer were also found, coexisting even mixtures of polyester and polyethylene or polyethylene and styrene-ethylene-butylene-styrene in the same matrix. X-ray fluorescence spectroscopy analysis revealed the presence of a wide range of elements, being remarkable the high concentration of some heavy metals such as Pb and Cr, registering mean concentration values of 205.3 ± 6.3 mg·kg−1 and 51.1 ± 8.9 mg·kg−1, respectively. A good correlation was also found for these two metals in a total of 22 pyroplastics, which could be indicative of the presence of PbCrO4 as additive, widely used in the plastic industry for its bright yellow color, but currently regulated and restricted due to its harmful effects on human and environment health. Also noteworthy is the large variety of remains of marine organisms identified attached to the surface of the pyroplastics, such as algae, bryozoans, arthropods and molluscs, among others, which could indicate that these formations may act as a transport vector for such marine organisms.

Experimental evaluation of expansive soil stabilised with sustainable binder incorporating blast furnace slag and bagasse ash

ABSTRACT Civil engineering structures made upon expansive soils known in India as Black Cotton (BC) soils are susceptible to structural damages due to their seasonal swell-and-shrink behaviour. This study focuses on assessing the mechanical performance of BC soil stabilised using unconventional binders, specifically Sugarcane Bagasse Ash (SCBA) and Ground Granulated Blast Furnace Slag (GGBS) with different proportions. The experimental evaluation included Compaction tests, Unconfined Compressive Strength (UCS) tests, Triaxial tests, and Atterberg’s limits tests. Additionally, mineralogical and morphological studies were carried out using x-ray diffraction (XRD), scanning electron microscopy (SEM), energy-dispersive x-ray spectroscopy (EDS), and chemical analysis using x-ray fluorescence spectroscopy analysis (XRF). The results showed that the mixture containing 21% SCBA and 9% GGBS produced cementitious-siliceous-hydrate (C-S-H) molecule, which improved the strength. Based on the soil-binder percentage ratio obtained from UCS tests, a regression equation was developed to estimate consolidated soil strength. The regression model, exhibiting an impressive R2 value of 93.69%, was analysed within the framework of existing empirical correlations by other researchers. This statistical model, with its good fit, is a useful tool for evaluating the compressive strength of stabilised expansive soil. The findings provide insights into successful stabilisation solutions for expansive soils found locally and globally.

Computed Tomography and Fluorescence Spectroscopy Blood Plasma Analysis Study for Kynurenic Acid as a Diagnostic Approach to Chronic Coenurosis in Sheep.

Coenurosis is a parasitic disease caused by the larval stage of Taenia multiceps, Coenurus cerebralis, typically found in the central nervous system of different livestock such as sheep and goats. The blood plasma from fifteen clinically healthy sheep and six sheep with neurological symptoms was studied by fluorescence spectroscopy in order to establish the contribution of kynurenic acid (KYNA), the neuroprotective metabolite of the kynurenine pathway, to the total fluorescence of the plasma. CT scans were used to confirm the presence of cysts in the central nervous system of sheep with neurological symptoms. The fluorescence spectroscopy analysis and further spectra deconvolution process revealed some significantly lower KYNA contributions to the total plasma fluorescence in sheep with coenurosis compared to healthy controls. Our results indicate that KYNA emission parameters could serve as valuable diagnostic markers, particularly for detecting preclinical cases of coenurosis, thus allowing for improved farm management practices.

Exploring the impact of TiO2 microstructures fabricated via alcoholysis on the optical and electrical properties of α-quaterthiophene for photovoltaic applications

In this study, we investigate the optical, photovoltaic, and structural properties of TiO2 nanostructures produced by alcoholysis using various alcohols. An X-ray diffraction study highlights how the choice of alcohols affects the process by revealing variations and separation. The anatase phase is confirmed by Raman spectroscopy, which also sheds light on the effects of various alcohols. The granular nature of TiO2 microstructures is demonstrated using scanning electron microscopy. We demonstrate how the size and shape of microstructures influence the band gap using absorption spectroscopy. Using fluorescence spectroscopy and Franck-Condon analysis, we investigated the performance of the α-Quaterthiophene + 40 % TiO2 nanocomposite. Important parameters are then taken out of the analysis using the Franck-Condon technique. Studies on the photovoltaic performance of the α-Quaterthiophene + 40 % TiO2 nanocomposite active layer show significant improvements in both open-circuit voltage and short-circuit current when TiO2 nanostructures are incorporated. This demonstrates the enormous potential of TiO2 nanostructures to improve solar cell applications’ efficiency. Self-assembly fabrication of TiO2 microspheres via the alcolysis process and their effect on exciton dissociation in hybrid systems is a topic of interest in materials science and nanotechnology.

Soil fertility prediction using combined USB-microscope based soil image, auxiliary variables, and portable X-ray fluorescence spectrometry

This study explored the application of portable X-ray fluorescence (PXRF) spectrometry and soil image analysis to rapidly assess soil fertility, focusing on critical parameters such as available B, organic carbon (OC), available Mn, available S, and the sulfur availability index (SAI). Analyzing 1133 soil samples from various agro-climatic zones in Eastern India, the research combined color and texture features from microscopic soil images, PXRF data, and auxiliary soil variables (AVs) using a Random Forest model. Results indicated that integrating image features (IFs) with auxiliary variables (AVs) significantly enhanced prediction accuracy for available B (R² = 0.80) and OC (R² = 0.88). A data fusion approach, incorporating IFs, AVs, and PXRF data, further improved predictions for available Mn and SAI with R² values of 0.72 and 0.70, respectively. The study demonstrated how these integrated technologies have the potential to provide quick and affordable options for soil testing, opening up access to more sophisticated prediction models and a better comprehension of the fertility and health of the soil. Future research should focus on the application of deep learning models on a larger dataset of soil images, developed using soils from a broader range of agro-climatic zones under field condition.

The impacts of different modification techniques on the gel properties and structural characteristics of fish gelatin

Fish gelatin hydrogels are typically characterized by weak texture and poor thermal stability. To address this issue, fish gelatin (FG) was modified using κ-carrageenan (κC) and transglutaminase (TG). FG-κC, FG-TG, and FG-κC-TG gels were prepared. The results demonstrated that the particle size and textural properties of FG gels were significantly enhanced by κC and κC-TG composite modifications, and their zeta potential was reduced (P < 0.05). As opposed to that, the improvement effects of TG modification were weaker. The highest particle size and hardness, along with the lowest zeta potential, were exhibited by the FG-κC-TG0.06% gel. Additionally, the FG-κC-TG gel system possessed higher apparent viscosity and elastic storage modulus. Fluorescence spectroscopy and UV absorption analysis indicated that fluorescence intensity was reduced by all three modification methods, and the conformational structure of FG was altered to varying degrees. Microstructure, FTIR, and XRD results revealed that the number of hydrogen bonds and isopeptide bonds in the composite gel systems was increased by κC and κC-TG modifications, enhancing the stability and orderliness of the gel's helical structure, and forming larger aggregates and denser network structures. Furthermore, due to the presence of covalent cross-linking, improved thermal stability was exhibited by the modified gelatin hydrogels. This study not only provides theoretical support for enhancing the performance of fish gelatin but also facilitates the application of modified fish gelatin in improving the sensory quality and flavor characteristics of food, as well as in serving as a matrix material in the biomedical field.

Indole Schiff Base Complex: Synthesis and Optical Binding Investigation with Biogenic Amines.

Biogenic amines, produced by bacterial enzymatic reactions in food storage or processing, serve as indicators in food processing industries to assess food quality and freshness. Biogenic amines also often associated with various health problems, including abnormal immune responses and gastrointestinal disease. Previously, salphen base complexes have been reported but still exhibited low fluorescence enhancement upon biogenic amines. This research focused on synthesizing and characterizing new Zn(II) Schiff base complex with indole sidechain to enhance the fluorescence property and exploring their binding behaviour with the biogenic amines, which were phenylethylamine and cadaverine. The Zn(II) indole Schiff base complex's structure was verified by diverse spectroscopic techniques. Then, the binding behaviours between the Zn(II) indole Schiff base complex with the biogenic amines were analyzed using UV-Vis, fluorescence spectroscopy, and Job's plot analysis. UV-Vis binding study results indicated that the synthesized complexes could bind stronger with phenylethylamine than cadaverine, with binding constant, Kb= (8.21 ± 0.58) × 104 M- 1 and (2.506 ± 0.004) × 104 M- 1 respectively. Moreover, Zn(II) indole Schiff base complex-phenylethylamine binding also generated higher fluorescence enhancement than cadaverine, which were 54% and 51% respectively. Based on Job's plot analysis, the complex and biogenic amines were bound in the ratio of 1:1. To conclude, the synthesized complex has promising potential as a sensing material for biogenic amines detection in food. The complex is recommended to be deployed in the development of solid-state fluorescence sensor for biogenic amines detection for monitoring the food spoilage in the food industry in the future.

Simple turn-on fluorescent probe for ultrafast and highly selective detection of hydrogen sulfide in aqueous solutions

5H-Benzimidazo[1,2-c]quinazoline-6-thione (BI–QT), was synthesized as a benzimidazole-based probe to detect H2S. BI–QT exhibits a fluorescent “turn-on” response in DMSO/H2O (9:1, HEPES 10 mM, pH 7.4) upon the addition of H2S. The BI–QT probe can determine micromolar (0–600 µM) H2S concentrations in aqueous systems, with a detection limit of 1.12 µM. Interestingly, BI–QT exhibited an ultrafast response to H2S, with maximum intensity achieved almost instantly when exposed to H2S. BI–QT is largely unaffected by pH and responds reliably over the wide 4–11 pH range, which highlights its applicability to various physiological scenarios. UV–vis, fluorescence, and 1H NMR spectroscopic analyses investigated the sensing mechanism. The practicality of the probe was demonstrated using water samples and living cells.

Vaccinium corymbosum–Derived Carbon Dots and Anthocyanin‐Infused Gelatin Multifunctional Films for Smart Packaging Applications

ABSTRACTConsumers and food industry stakeholders have expressed great interest in using simple, non‐destructive and inexpensive methods to control/maintain or monitor the freshness of perishable foods. The idea of smart packaging has been introduced to address these requirements satisfactorily, revolutionizing conventional food packaging. Vaccinium corymbosum (VC)–based carbon dots (CDs) and anthocyanin were matrixed on gelatin (GEL) to fabricate smart packaging film. The VC biowaste–derived carbon dots (VC‐CDs) were characterized using photoluminescence, fluorescence spectrometry, FTIR, antibacterial/antioxidant potential, TEM and XPS analysis. Fabricated films were subjected to physico‐chemical, antioxidant and optical properties, SEM, TGA simulation and in vivo food model system. The VC‐CDs exhibited excellent functional properties like ultraviolet (UV) blocking and antibacterial properties. The reinforcement with 1.5% VC‐CDs and 6% VC anthocyanins (VCA) in the GEL polymer matrix improved UV blocking (&gt; 189%) properties and showed potent antioxidant potential (&gt; 164%) compared to the neat GEL film. In vivo food packaging (minced pork, fish and shrimp) with films has shown that indicator films work efficiently and non‐destructively and monitor real‐time freshness. The GEL/VC‐CDs/VCA‐based active and intelligent films are expected to be applied as multifunctional nanocomposite packaging materials that can indicate quality changes in real time, maintain quality and prolong the shelf life of packaged foods.

Geochemical Evaluation of Itakpe Iron Ore Mine Tailings, Itakpe, Nigeria

The study focus on the characterisation of the tailings attributes with a view to understanding the geotechnical properties, leaching potential and possible major oxides. The samples were composited into five. The composited samples were subjected to both physical and chemical tests. The physical tests include particle size distribution, specific gravity, density, residual humidity and Atterberg limits. The chemical tests include pH, organic matter, and Energy Dispersive X-Ray Fluorescence Spectrometry (ED-XRFS). Mineralogical analyses were also carried out on the composited samples using the Scanning Electron Microscopy (SEM) coupled with Energy Dispersive X-ray Spectroscopy (SEM-EDX). The results from the physical tests show that the tailings are mostly fine-medium sands, having high specific gravity and bulk density, with low residual humidity. The chemical analyses show that the tailings are weakly acidic and neutral with low organic matter. The energy dispersive x-ray fluorescence spectroscopy analysis of the samples shows that they contain high concentrations of Fe2O3, SiO2, and other trace compounds. The Fe2O3 of the samples ranged from 15.03 to 20.12% and SiO2 ranged from 57.26 to 60.10%. SEM micrographs obtained revealed the interlocking nature of the minerals constituting the ore matrix. EDX analysis of the regions within the ore matrix revealed the presence of Si, Fe, Al, K, Ca, Nb, Y, Ag, Zn, Mg, Cl, P, S, Na, Ti, Zr; such that silicon and iron are the major elemental constituents of the ore matrix while other elements exists in trace form.

Multiple approaches for heavy metal contamination characterization and source identification of farmland soils in a metal mine impacted area

Heavy metal and metalloid contamination of farmland soils are closely related to human health. Soil contamination caused by small-scale mining activities has been largely neglected, especially in developing countries. This research studies the characteristics and the source of heavy metals and metalloids in farmland soils in the Bailing Cu–Zn deposit area in Northeastern China through multiple approaches. Geochemical mapping conducted by portable X-ray fluorescence (pXRF) spectrometry and elemental fractionation analysis (sequential extraction) revealed the spatial variations in elemental concentration and fractionation of the farmland soils. The elemental variations in the sediment and water samples in a stream passing by the farmland were determined by inductively coupled plasma mass spectroscopy (ICP-MS) and inductively coupled plasma atomic emission spectroscopy (ICP-AES) analysis. Results indicate elevated As, Zn, Fe, and Mn concentrations in the west bank of the farmland and the associated environmental risks caused by extremely high As concentrations (>500 mg kg−1). The upstream mining activities are identified as a dominated source of contamination in the studied farmland based on the variations of elemental concentrations and fractionations, as well as multivariate analysis results. This study revealed potential ecological risks caused by heavy metal and metalloid contamination in farmland soils in the metal mine impacted area and the stream as a primary pathway for the migration of pollutants associated with mining activities.

PH-induced fluorescent active sodium alginate-based ionically conjugated and REDOX responsive multi-functional microgels for the anticancer drug delivery

A sodium alginate (Alg) based REDOX (reduction and oxidation)-responsive and fluorescent active microgel was prepared via water in oil (w/o) mini-emulsion polymerization technique. Here, we initially synthesized sodium alginate-based disulfide cross linked microgels and after that those microgels were tagged with rhodamine amine derivative (RhB-NH2) by ionic interaction to get the pH-responsive fluorescent property. Functionalized microgels were characterized using 1H NMR, FTIR, DLS, HRTEM, FESEM, UV–vis, and fluorescence spectroscopy analyses. Presence of the REDOX-responsive disulfide-containing crosslinkers in the microgels enhances the release of doxorubicin (DOX), an anti-cancer drug in the reducing environment of the cancer-cells (simulated). Existence of the rhodamine-amine derivative in the microgels triggers the pH-dependent fluorescence property by showing fluorescence emission at 560–580 nm at pH 5.5 (cancer cell pH). The cytotoxicity of the biopolymer based microgel was assessed over both cancerous HeLa (IC50 100 µg/mL) and non-cancerous MDCK (IC50 200 µg/mL) cells by MTT assay which showed the synthesized microgel is non-toxic whereas DOX-loaded microgels showed significant toxicity. FACS and cell uptake (in vitro) analyses were conducted to understand the cell apoptosis cycle and behavior of the cancer cells in presence of the DOX-loaded microgels. This pH-responsive fluorescent active alginate-based biomaterial could be a promising material for the anti-cancer drug delivery and other medical fields.