Environmental hazard in textile dyeing wastewater from local textile industry

Colorants and chemicals used in the textile coloration process are required to meet the fashion demands; however these introduced serious environmental hazards that are mainly resulted in effluent loading, containing the toxic, carcinogenic, and mutagenic substances, to natural environment. Textile dyeing process and the rinsing of dyed fabric utilize a variety of substances including dyes/ pigment, fixing agent, surfactants, leveling agent, mordant, salts etc. However, all these substances are not fully consumed in the process, and a residual content remains in the dyeing effluent. This review observes the challenges to environment posed by the dyes and chemicals present in spent dye bath, progress in possible remedies in dyeing wastewater treatment including the nanotechnology; and particularly discusses the studies based on the dyeing effluent samples collected from the local textile processing industries. There are obvious case studies made in different regions, using the process wastewater from the local textile dyeing and processing industries, confirming the need for research and innovation to replace or control the hazardous dyes and chemicals in conventional dyeing process and making the resulting effluent more environment- friendly. Moreover, the cleaner production practices and environmental standards are introduced in improving the textile dyeing process. Selection of dyes and chemicals, use of best available techniques, and wastewater treatment technologies can significantly improve the textile dyeing to become an environment- friendly process.

     

Quinoline-Proline,Triazole Hybrids: Design,Synthesis, Antituberculosis,Molecular Docking,and ADMET Studies

A series of novel quinoline-proline hybrids ( 11a-g ) and quinoline-proline-1,2,3-triazole hybrids ( 12-14 ) were synthesized by click chemistry based on molecular hybridization concept and were characterized by NMR, mass spectrometry, and elemental analysis. All the titled target compounds were tested for antitubercular activity by MABA and LORA methods by in vitro. Interestingly, two compounds (2R,4S)-1-((2-cyclopropyl-4-(4-fluorophenyl)-quinolin-3-yl)-methyl)-4-(4-nitrobenzamido)-N-phenylpyrrolidine-2-carboxamide ( 11b ) and (2R,4S)-1-((2-cyclopropyl-4-(4-fluorophenyl)-quinolin-3-yl)-methyl)-4-(4-fluorobenzamido)-N-phenylpyrrolidine-2-carboxamide ( 11c ) exhibited significant activity against the tested Mycobacterium tuberculosis H37Rv strain. Further, the cytotoxicity ( CC ₅₀ ) profile of the titled compounds against the Vero cell was performed and discussed. A molecular docking study of the hit compounds ( 11b and 11c ) was also performed to find their putative binding interaction with the active site of the target proteins. Finally, in silico ADMET properties were also predicted for all the synthesized molecules to evaluate their drug-likeness behavior.     

Ion and pH Sensing with Colloidal Nanoparticles: Influence of Surface Charge on Sensing and Colloidal Properties

Ion sensors based on colloidal nanoparticles (NPs), either as actively ion‐sensing NPs or as nanoscale carrier systems for organic ion‐sensing fluorescent chelators typically require a charged surface in order to be colloidally stable. We demonstrate that this surface charge significantly impacts the ion binding and affects the read‐out. Sensor read‐out should be thus not determined by the bulk ion concentration, but by the local ion concentration in the nano‐environment of the NP surface. We present a conclusive model corroborated by experimental data that reproduces the strong distance‐dependence of the effect. The experimental data are based on the capability of tuning the distance of a pH‐sensitive fluorophore to the surface of NPs in the nanometer (nm) range. This in turn allows for modification of the effective acid dissociation constant value (its logarithmic form, pK_a) of analyte‐sensitive fluorophores by tuning their distance to the underlying colloidal NPs.     

Improving functional properties of ZnO nanostructures by transition-metal doping: role of aspect ratio

Localized surface plasmon resonance (LSPR) of gold nanoparticles (AuNPs) has been used for biosensing and chemical sensing applications because the LSPR peak wavelength depends on the dispersion state and local refractive index of the surrounding medium. In this study, AuNP-loaded silica gels were prepared as sensing chips with high transparency and solution holding capability. The silica gels were prepared at various sintering temperatures from 500 to 900 °C, and the AuNPs precipitated in the gels by using a subsequent thermal reduction process. At sintering temperatures of 700, 800, and 900 °C, transparent and crack-free AuNP-loaded silica gels were obtained. Transmission electron microscopy observation revealed the AuNP size to be approximately 20 nm, and they were highly dispersed in all the silica gel samples. However, the sintering temperature of the silica gels strongly affected the LSPR property of the AuNPs and the porous property of the silica gel. The samples sintered at higher temperature exhibited a lower LSPR sensing ability against the refractive index of immersing solvents. The low sensing ability was considered as a result of a decrease in the contact area between the AuNPs and immersing solvent caused by an increase in the silica gel density with sintering temperature.     

pH-Triggered controlled drug release from mesoporous silica nanoparticles via intracelluar dissolution of ZnO nanolids

Acid-decomposable, luminescent ZnO quantum dots (QDs) have been employed to seal the nanopores of mesoporous silica nanoparticles (MSNs) in order to inhibit premature drug (doxorubicin) release. After internalization into HeLa cells, the ZnO QD lids are rapidly dissolved in the acidic intracellular compartments, and as a result, the loaded drug is released into the cytosol from the MSNs. The ZnO QDs behave as a dual-purpose entity that not only acts as a lid but also has a synergistic antitumor effect on cancer cells. We anticipate that these nanoparticles may prove to be a significant step toward the development of a pH-sensitive drug delivery system that minimizes drug toxicity.     

Co3O4-ZnO hierarchical nanostructures by electrospinning and hydrothermal methods

A new hierarchical nanostructure that consists of cobalt oxide (Co₃O₄) and zinc oxide (ZnO) was produced by the electrospinning process followed by a hydrothermal technique. First, electrospinning of a colloidal solution that consisted of zinc nanoparticles, cobalt acetate tetrahydrate and poly(vinyl alcohol) was performed to produce polymeric nanofibers embedding solid nanoparticles. Calcination of the obtained electrospun nanofiber mats in air at 600 °C for 1 h, produced Co₃O₄ nanofibers with rough surfaces containing ZnO nanoparticles (i.e., ZnO-doped Co₃O₄ nanofibers). The rough surfaced nanofibers, containing ZnO nanoparticles (ZnNPs), were then exploited as seeds to produce ZnO nanobranches using a specific hydrothermal technique. Scanning electron microscopy (SEM), and transmission electron microscopy (TEM) were employed to characterize the as-spun nanofibers and the calcined product. X-ray powder diffractometery (XRD) analysis was used to study the chemical composition and the crystallographic structure.     

Structural, magnetic and electronic structure studies of Mn doped TiO2 thin films

We report structural, magnetic and electronic structure study of Mn doped TiO₂ thin films grown using pulsed laser deposition method. The films were characterized using X-ray diffraction (XRD), dc magnetization, X-ray magnetic circular dichroism (XMCD) and near edge X-ray absorption fine structure (NEXAFS) spectroscopy measurements. XRD results indicate that films exhibit single phase nature with rutile structure and exclude the secondary phase related to Mn metal cluster or any oxide phase of Mn. Magnetization studies reveal that both the films (3% and 5% Mn doped TiO₂) exhibit room temperature ferromagnetism and saturation magnetization increases with increase in concentration of Mn doping. The spectral features of XMCD at Mn L_3,2 edge show that Mn²⁺ ions contribute to the ferromagnetism. NEXAFS spectra measured at O K edge show a strong hybridization between Mn, Ti 3d and O 2p orbitals. NEXAFS spectra measured at Mn and Ti L_3,2 edge show that Mn exist in +2 valence state, whereas, Ti is in +4 state in Mn doped TiO₂ films.     

Synthesis and characterization of bovine femur bone hydroxyapatite containing silver nanoparticles for the biomedical applications

Bovine femur bone hydroxyapatite (HA) containing silver (Ag) nanoparticles was synthesized by thermal decomposition method and subsequent reduction of silver nitrate with N,N-dimethylformamide (DMF) in the presence of poly(vinylacetate) (PVAc). The structural, morphological, and chemical properties of the HA–Ag nanoparticles were characterized using X-ray diffraction (XRD), scanning electron microscopy (SEM), field-emission scanning electron microscopy (FE-SEM), transmission electron microscopy (TEM), and X-ray photoelectron spectroscopy (XPS). TEM images showed that the Ag nanoparticles with size ranging from 8 to 20 nm and were arranged at the periphery of HA crystals. Bactericidal activity of HA–Ag with different concentration of Ag nanoparticles immobilized on the surface of HA was investigated against gram-positive Staphylococcus aureus (S. aureus, non-MRSA), Methicillin resistant S. aureus (MRSA) and gram-negative Escherichia coli (E. coli) by the disc diffusion susceptibility test. The HA–Ag nanoparticles showed that broad spectrum activity against non-MRSA, MRSA, and E. coli bacterial strains.     

Beyond Counterarguing: Simple Elaboration,Complex Integration,and Counterelaboration in Response to Variations in Narrative Focus and Sidedness

This study attempts to advance theorizing about narrative persuasion by explicating types of thoughts, beyond counterarguing, generated in response to a short narrative with persuasive intent. We examine responses to four types of narratives (focus: individual vs. community; by sidedness: one‐ vs. two‐sided) about causes and solutions for obesity in an attempt to increase support for policies to address the issue. Using a randomized experiment (n = 245), we show that narrative focus and sidedness interact to produce different patterns of thoughts, attributions, and policy support. Simple elaboration, counterelaboration, and counterarguing predicted causal attributions and policy support, but only simple elaboration mediated message effects on intended persuasive outcomes. We conclude by discussing the study's contributions to communication theory and practice.     

Effect of annealing on electrical resistivity of rf-magnetron sputtered nanostructured SnO2 thin films

Tin oxide (SnO₂) thin films were deposited by radio frequency (RF) magnetron sputtering on clean corning glass substrates. These films were then annealed for 15 min at various temperatures in the range of 100-500°C. The films were investigated by studying their structural and electrical properties. X-ray diffraction (XRD) results suggested that the deposited SnO₂ films were formed by nanoparticles with average particle size in the range of 23-28 nm. XRD patterns of annealed films showed the formation of small amount of SnO phase in the matrix of SnO₂. The initial surface RMS roughness measured with atomic force microscopy (AFM) was 25.76 nm which reduces to 17.72 nm with annealing. Electrical resistivity was measured as a function of annealing temperature and found to lie between 1.25 and 1.38 mΩ cm. RMS roughness and resistivity show almost opposite trend with annealing.