Preparation, characterization and cell labelling of strong pH-controlled bicolor fluorescence carbonized polymer dots

Multicolor fluorescence N-doped CPDs from dextrin water solution in strong acidic and alkaline environments were synthesized and characterized, which revealed that pH value plays a vital role in the process of CPD growth.

Validation of an Image Analysis Method for Evaluating the Chemical Resistance of Glass Fibers to Alkaline Environments

This article is focused on the comparison of the reliability of the results obtained by image analysis (newly proposed evaluation method) with well-known methods of evaluation of long-term corrosion resistance of glass fibers in an alkaline environment (pH > 12). The developed method is based on the analysis of scanning electron microscopy images (diameter and structures on the fiber surface). An experiment (52 weeks) was performed to evaluate two types of glass fibers: anticorrosive glass fibers (ARGFs) and E-glass fibers (EGFs). Three media were used to treat the fibers (23 ± 2 °C): H2O, Ca(OH)2, and K2SiO3. The ARGFs’ tensile strength did not reduce; a decrease by 68% was observed for EGFs in H2O. Tensile strength decreased by 32% and 85–95% in K2SiO3; by 50% and 64% in Ca(OH)2 for the ARGF and EGF, respectively. Statistical analysis was performed to validate the reliability and plausibility of the developed method. ARGFs and EGFs did not show any relationship between the fiber diameter and weight in H2O; however, the linear trends may predict this relationship in Ca(OH)2 and K2SiO3. For the ARGF and EGF, the cubic trend was suitable for predicting the change in fiber weight and diameter over time in Ca(OH)2 and K2SiO3.

Physicochemical Characteristics of Chitosan-Based Hydrogels Modified with Equisetum arvense L. (Horsetail) Extract in View of Their Usefulness as Innovative Dressing Materials

This work focused on obtaining and characterizing hydrogels with their potential application as dressing materials for chronic wounds. The research included synthesizing chitosan-based hydrogels modified with Equisetum arvense L. (horsetail) extract via photopolymerization, and their characteristics determined with regard to the impact of both the modifier and the amount of crosslinker on their properties. The investigations included determining their sorption properties and tensile strength, evaluating their behavior in simulated physiological liquids, and characterizing their wettability and surface morphology. The release profile of horsetail extract from polymer matrices in acidic and alkaline environments was also verified. It was proved that hydrogels showed swelling ability while the modified hydrogels swelled slightly more. Hydrogels showed hydrophilic nature (all contact angles were <77°). Materials containing horsetail extract exhibited bigger elasticity than unmodified polymers (even by 30%). It was proved that the extract release was twice as effective in an acidic medium. Due to the possibility of preparation of hydrogels with specific mechanical properties (depending on both the modifier and the amount of crosslinker used), wound exudate sorption ability, and possibility of the release of active substance, hydrogels show a great application potential as dressing materials.

Hydroxylamine Accelerates the Cycle of Fe(III)/Fe(II)-Cu(II)/Cu(I) to Enhance the Ability of Fe-Cu Bimetallic System to Activate Peroxymonosulfate to Degrade AO7

In this study, a new type of iron/copper bimetallic combined with hydroxylamine (HA) activated peroxymonosulfate (PMS) was constructed to treat organic pollutants. Selecting the azo dye AO7 as the representative of organic pollutants, the new system can achieve nearly 100% degradation of AO7 within 5 minutes. The Fe(Ⅲ)/Cu(Ⅱ)/HA/PMS system mainly generates SO4·- to achieve the degradation of AO7 in acidic environment, while neutral and alkaline environments rely on ·OH. The presence of hydroxylamine accelerates the cycle of Fe(Ⅲ)/Fe(Ⅱ) and Cu(Ⅱ)/Cu(Ⅰ) in the system, and enhances the degradation ability of the system for organic pollutants. The addition of trace Cu(Ⅱ) (1 μM) enhances the ability of a single Fe(Ⅲ)/HA/PMS system to degrade AO7 in neutral and alkaline environments without causing secondary copper pollution. The common inorganic anions Cl- and NO3- in water have almost no effect on the degradation of AO7 in the system. The constructed Fe(Ⅲ)/Cu(Ⅱ)/HA/PMS system is an efficient and clean organic pollutant wastewater treatment process, which has very promising application prospects.

Assessment of the release of metals from cigarette butts into the environment

Cigarette butts are known to contain toxic metals which pose a potential threat to the environment and human health. The seriousness of this threat is largely determined by the leachability of these toxic metals when the butts are exposed to aqueous solutions in the environment. The aims of this study were to determine the presence and mobility of toxic and non-toxic elements found in discarded cigarette butts; to relate this mobility to two different contact situations with leaching liquids: tumbling and trampling (batch test) and percolation in a static position (column test); and finally, to verify possible variations in solubility by simulating different environmental systems. Five leachants with different pH values were used to simulate various environmental conditions The concentrations of the solubilized metals were determined by inductively coupled plasma-atomic emission spectrometry (ICP-AES) and inductively coupled plasma-mass spectrometry (ICP-MS). CH3COOH pH 2.5 showed the greatest capacity to dissolve many elements. On the contrary, weakly acidic or alkaline environments did not favor the leachability of the elements. The best extraction capacity of the column with respect to the batch is statistically significant (p <0.05) for the elements Al, Fe, Ni and Zn, while the batch for P, Si, S. Pb, Cd, As were not detectable in cigarette butts, while Hg had an average concentration of 0.0502 μg/g. However, Hg was < LOD in all different leachants.

Microstructural characterization and corrosion behaviour of ultrasound-assisted synthesis of Ni–xCo–yTiO2 nanocomposites in alkaline environments

Electroplated protective thin film is highly promising materials for advanced applications such as high corrosion resistance and energy conversion and storage. This work is to investigate the effect of Co content and TiO2 on the corrosion resistance of Ni–xCo–yTiO2 nanocomposites in alkaline media. The nanocrystalline Ni–xCo–yTiO2 composites were electroplated using the sulfate-gluconate bath containing the suspended TiO2 nanograins under ultrasound waves and mechanical stirring. The microstructure and corrosion behavior of the electroplated Ni–xCo–yTiO2 nanocomposites have been investigated via X-ray diffraction (XRD), scanning electron microscopy (SEM), energy dispersive X-ray (EDX), potentiodynamic polarization and electrochemical impedance spectroscopy (EIS) techniques. The XRD pattern of the electroplated Ni–Co matrices with 1–75% of cobalt arranged in face-centered cubic (FCC) system, while the electroplated Ni–Co matrices of further Co% more than 76% converted to hexagonal closed-package (HCP) crystal system. The surface of the Ni–xCo–yTiO2 nanocomposites after immersion in 1.0 M KOH electrolytes was investigated via SEM, atomic force microscopy and EDX. The results displayed that the rate of corrosion of the different composites decreased by combining Ni, Co and the inclusion of TiO2. The improved corrosion resistance of Ni–47Co–3.77TiO2 composites is due to the formation of Ni/Co oxy/hydroxide layer and rebelling effect of OH− by TiO2 sites, which reduces the attacking effect of OH−, O2, and H2O, and notably retards the overall corrosion processes.

Comparative Modeling And Enzymatic Affinity of Novel Haloacid Dehalogenase From Bacillus Megaterium Strain BHS1 Isolated From Alkaline Blue Lake In Turkey

This is the first structural model of L-haloacid dehalogenase (DehLBHS1) isolated from alkalotolerant Bacillus megaterium BHS1, which has been known to degrading halogenated environmental contaminants. The study suggested five important key amino acid residues of DehLBHS1, namely Arg40, Phe59, Asn118, Asn176 and Trp178 important for catalysis and molecular recognition of haloalkanoic acid. Alkatolerant DehLBHS1was modeled by I-TASSER with the best C-score 1.23. Model validation was carried out utilising PROCHECK to produce the Ramachandran map with 89.2 percent of its residues were found in the most preferred region, indicating that the model was appropriate. The Molecular docking (MD) simulation found that the DehLBHS1 preferred 2,2DCP more than other substrates and formed one hydrogen bond with Arg40 and minimum energy -2.5 kJ/ mol. Molecular dynamics has verified the substrate preference towards 2,2DCP based on RMSD, RMSF, Gyration, Hydrogen bond and Molecular distance. This structural knowledge from DehLBHS1 structural perspective gives insights into substrate specificity and catalytic function to exploit DehLBHS1 of BHS1 strain in degrading 2,2-DCP in the polluted alkaline environments.

Electrochemical Surface Restructuring of Phosphorus-Doped Carbon@MoP Electrocatalysts for Hydrogen Evolution

The hydrogen evolution reaction (HER) through electrocatalysis is promising for the production of clean hydrogen fuel. However, designing the structure of catalysts, controlling their electronic properties, and manipulating their catalytic sites are a significant challenge in this field. Here, we propose an electrochemical surface restructuring strategy to design synergistically interactive phosphorus-doped carbon@MoP electrocatalysts for the HER. A simple electrochemical cycling method is developed to tune the thickness of the carbon layers that cover on MoP core, which significantly influences HER performance. Experimental investigations and theoretical calculations indicate that the inactive surface carbon layers can be removed through electrochemical cycling, leading to a close bond between the MoP and a few layers of coated graphene. The electrons donated by the MoP core enhance the adhesion and electronegativity of the carbon layers; the negatively charged carbon layers act as an active surface. The electrochemically induced optimization of the surface/interface electronic structures in the electrocatalysts significantly promotes the HER. Using this strategy endows the catalyst with excellent activity in terms of the HER in both acidic and alkaline environments (current density of 10 mA cm−2 at low overpotentials, of 68 mV in 0.5 M H2SO4 and 67 mV in 1.0 M KOH).