Search Results (10)

The removal and detection of highly toxic mercury(II) ions (Hg²⁺) in water used daily is essential for human health and monitoring environmental pollution. Efficient porous organic polymers (POPs) can provide a strong adsorption capacity toward heavy metal ions, although the complex synthetic process and inconvenient phase separation steps limit their application. Hence, a combination of POPs and magnetic nanomaterials was proposed and a new magnetic porous organic polymer adsorbent was fabricated by a green and mild redox reaction in the aqueous phase with trithiocyanuric acid (TA) and its sodium salts acting as reductive monomers and iodine acting as an oxidant. In the preparation steps, no additional harmful organic solvent is required and the byproducts of sodium iodine are generally considered to be non-toxic. The resulting magnetic poly(trithiocyanuric acid) polymers (MPTAPs) are highly porous, have large surface areas, are rich in sulfhydryl groups and show easy magnetic separation ability. The experimental results show that MPTAPs exhibit good adsorption affinity toward Hg²⁺ with high selectivity, rapid adsorption kinetics (10 min), a large adsorption capacity (211 mg g⁻¹) and wide adsorption applicability under various pH environments (pH 2~8). Additionally, MPTAPs can be reused for up to 10 cycles, and the magnetic separation step of MPTAPs is fast and convenient, reducing energy consumption compared to centrifugation and filtration steps required for non-magnetic adsorbents. These results demonstrate the promising capability of MPTAPs as superior adsorbents for effective adsorption and separation of Hg²⁺. Based on this, the prepared MPTAPs were adopted as magnetic solid-phase extraction (MSPE) materials for isolation of trace Hg²⁺ from aqueous samples. Under optimized conditions, the extraction and quantification of trace Hg²⁺ in water samples were accomplished using inductively coupled plasma mass spectrometry (ICP-MS) detection after MSPE procedures. The proposed MPTAPs-based MSPE-ICP-MS method is efficient, rapid, sensitive and selective for the determination of trace Hg²⁺, and was successfully employed for the accurate analysis of trace Hg²⁺ in tap water, wastewater, lake water and river water samples. Full article

Exfoliated g-C₃N₄ is a well-known semiconductor utilized in heterogenous photocatalysis and water splitting. An improvement in light harvesting and separation of photogenerated charge carriers may be obtained by polymer doping with sulfur. In this work, we incorporate sulfur into the polymer chain by chemical polymerization of trithiocyanuric acid (C₃N₃S₃H₃) to obtain C₃N₃S₃. The XRD measurements and TEM images indicated that C₃N₃S₃, in contrast to g-C₃N₄, does not exist in the form of a graphitic structure and is not exfoliated into thin lamellas. However, both polymers have similar optical properties and positions of the conduction and valence bands. The comparative studies of electrochemical oxygen reduction and hydrogen evolution indicated that the overpotentials for the two processes were smaller for C₃N₃S₃ than for g-C₃N₄. The RDE experiments in the oxygen-saturated solutions of 0.1 M NaOH have shown that O₂ is electrochemically reduced via the serial pathway with two electrons involved in the first step. The spectroscopic experiments using NBT demonstrated that both polymers reveal high activity in the photocatalytic reduction of oxygen to superoxide anion radical by the photogenerated electrons. Full article

A novel phosphorus and oxygen co-doped graphitic carbon nitride (_sheetP-O-CN_SSA) photocatalyst was successfully synthesized and applied for H₂ evolution under visible light. In the synthesis process of _sheetP-O-CN_SSA, the supramolecular complex was developed by the self-assembly and copolymerization reaction among melamine, cyanuric acid (CA) and trithiocyanuric acid (TCA) to act as g-C₃N₄ precursors, while (NH₄)₂HPO₄ was applied as P and O precursors for element doping. The chemical structures, morphologies, and optical properties of the _sheetP-O-CN_SSA were characterized by a series of measurements, i.e., XRD, FT-IR, SEM, TEM, UV-vis DRS, and PL. The results suggested that the introduction of P and O elements could enhance the separation and migration efficiency of photogenerated electrons and holes in the energy band of g-C₃N₄. The photocatalytic tests over Erythrosin B (EB) sensitized _sheetP-O-CN_SSA indicated that the hydrogen evolution was greatly enhanced compared with other catalysts and non-sensitized _sheetP-O-CN_SSA under visible light irradiation. Finally, a possible dye-sensitized photocatalysis mechanism was also proposed on the basis of the as-obtained results. Full article

Currently, the design of highly efficient materials for photochemical applications remains a challenge. In this study, an efficient semiconductor was prepared, based on a coordination complex (Cu-TTC) of Cu(I) and trithiocyanuric acid on ZnTiO₃/TiO₂ (ZTO/TO). The Cu-TTC/ZTO/TO composite was prepared by the solvothermal method at room temperature. The structural, optical, and electrochemical characteristics, as well as the photocatalytic performance of the composite, were experimentally and computationally studied. The results show that the Cu-TTC/ZTO/TO composite efficiently extended its photoresponse in the visible region of the electromagnetic spectrum. The electrochemistry of the proposed tautomeric architecture (s-Cu-TTC) clearly reveals the presence of metal–ligand charge-transfer (MLCT) and π → π* excitations. The maximum methylene blue (MB) dye photodegradation efficiency of 95% in aqueous solutions was achieved under the illumination of simulated solar light. Finally, computational calculations based on the Density Functional Theory (DFT) method were performed to determine the electronic properties of the s-Cu-TTC tautomeric structure and clarify the adsorption mechanism of this complex on the surface (101) of both ZnTiO₃ and TiO₂ oxides. The results obtained allow us to suggest that the Cu-TTC complex is an effective charge carrier and that the Cu-TTC/ZTO/TO composite can be used efficiently for photochemical applications. Full article

Titanium oxide (TiO₂) is a potential photocatalyst for removing toxic NO_x from the atmosphere. Its practical application is, however, significantly limited by its low absorption into visible light and a high degree of charge recombination. The overall photocatalytic activity of TiO₂ remains too low since it can utilize only about 4–5% of solar energy. Nitrogen doping into the TiO₂ lattice takes advantage of utilizing a wide range of solar radiation by increasing the absorption capability towards the visible light region. In this work, N-doped TiO₂, referred to as TC, was synthesized by a simple co-precipitation of tri-thiocyanuric acid (TCA) with P25 followed by heat treatment at 550 degrees C. The resulting nitrogen doping increased the visible-light absorption and enhanced the separation/transfer of photo-excited charge carriers by capturing holes by reduced titanium ions. As a result, TC samples exhibited excellent photocatalytic activities of 59% and 51% in NO oxidation under UV and visible light irradiation, in which the optimum mass ratio of TCA to P25 was found to be 10. Full article

The electrochemical redox behavior of three trinuclear Ni(II) complexes [Ni₃(abb)₃(H₂O)₃(µ-ttc)](ClO₄)₃ (1), [Ni₃(tebb)₃(H₂O)₃(µ-ttc)](ClO₄)₃·H₂O (2), and [Ni₃(pmdien)₃(µ-ttc)](ClO₄)₃ (3), where abb = 1-(1H-benzimidazol-2-yl)-N-(1H-benzimidazol-2-ylmethyl)methan-amine, ttcH₃ = trithiocyanuric acid, tebb = 2-[2-[2-(1H-benzimidazol-2-yl)ethylsulfanyl]ethyl]-1H-benzimidazole, and pmdien = N,N,N′,N″,N″-pentamethyldiethylenetriamine is reported. Cyclic voltammetry (CV) was applied for the study of the electrochemical behavior of these compounds. The results confirmed the presence of ttc and nickel in oxidation state +2 in the synthesized complexes. Moreover, the antibacterial properties and cytotoxic activity of complex 3 was investigated. All the complexes show antibacterial activity against Staphylococcus aureus and Escherichia coli to different extents. The cytotoxic activity of complex 3 and ttcNa₃ were studied on G-361, HOS, K-562, and MCF7 cancer cell lines. It was found out that complex 3 possesses the cytotoxic activity against the tested cell lines, whereas ttcNa₃ did not show any cytotoxic activity. Full article

As a promising conjugated polymer, binary carbon nitride has attracted extensive attention as a metal-free and visible-light-responsive photocatalyst in the area of photon-involving purification of water and air. Herein, we report sulfur-doped polymeric carbon nitride microrods that are synthesized through thermal polymerization based on trithiocyanuric acid and melamine (TM) supramolecular aggregates. By tuning the polymerization temperature, a series of sulfur-doped carbon nitride microrods are prepared. The degradation of Rhodamine B (RhB) and the reduction of hexavalent chromium Cr(VI) are selected as probe reactions to evaluate the photocatalytic activities. Results show that increasing pyrolysis temperature leads to a large specific surface area, strong visible-light absorption, and accelerated electron-hole separation. Compared to bulk carbon nitride, the highly porous sulfur-doped carbon nitride microrods fabricated at 650 °C exhibit remarkably higher photocatalytic activity for degradation of RhB and reduction of Cr(VI). This work highlights the importance of self-assembly approach and temperature-control strategy in the synthesis of photoactive materials for environmental remediation. Full article

1-(1H-Benzimidazol-2-yl)-N-(1H-benzimidazol-2-ylmethyl)methanamine (abb) and 2-(1H-benzimidazol-2-ylmethylsulfanylmethyl)-1H-benzimidazole (tbb) have been prepared and characterized by elemental analysis. These bis(benzimidazoles) have been further used in combination with trithiocyanuric acid for the preparation of complexes. The crystal and molecular structures of two of them have been solved. Each nickel atom in the structure of trinuclear complex [Ni₃(abb)₃(H₂O)₃(μ-ttc)](ClO₄)₃·3H₂O·EtOH (1), where ttcH₃ = trithiocyanuric acid, is coordinated with three N atoms of abb, the N,S donor set of ttc anion and an oxygen of a water molecule. The crystal of [(tbbH₂)(ttcH₂)₂(ttcH₃)(H₂O)] (2) is composed of a protonated bis(benzimidazole), two ttcH₂ anions, ttcH₃ and water. The structure is stabilized by a network of hydrogen bonds. These compounds were primarily synthesized for their potential antimicrobial activity and hence their possible use in the treatment of infections caused by bacteria or yeasts (fungi). The antimicrobial and antifungal activity of the prepared compounds have been evaluated on a wide spectrum of bacterial and yeast strains and clinical specimens isolated from patients with infectious wounds and the best antimicrobial properties were observed in strains after the use of ligand abb and complex 1, when at least 80% growth inhibition was achieved. Full article

Modification of carbon materials, especially graphene-based materials, has wide applications in electrochemical detection such as electrochemical lab-on-chip devices. A glassy carbon electrode (GCE) modified with chemically alternated graphene oxide was used as a working electrode (glassy carbon modified by graphene oxide with sulphur containing compounds and Nafion) for detection of nucleobases in hydrolysed samples (HCl pH = 2.9, 100 °C, 1 h, neutralization by NaOH). It was found out that modification, especially with trithiocyanuric acid, increased the sensitivity of detection in comparison with pure GCE. All processes were finally implemented in a microfluidic chip formed with a 3D printer by fused deposition modelling technology. As a material for chip fabrication, acrylonitrile butadiene styrene was chosen because of its mechanical and chemical stability. The chip contained the one chamber for the hydrolysis of the nucleic acid and another for the electrochemical detection by the modified GCE. This chamber was fabricated to allow for replacement of the GCE. Full article

The complexes of Fe(II), Mn(II) and Ni(II) with a combination of a Schiff base, nitrogen-donor ligand or macrocyclic ligand and trithiocyanuric acid (ttcH₃) were prepared and characterized by elemental analysis and spectroscopies. Crystal and molecular structures of the iron complex of composition [Fe(L₁)](ttcH₂)(ClO₄)·EtOH·H₂O (1), where L₁ is Schiff base derived from tris(2-aminoethyl)amine and 2-pyridinecarboxaldehyde, were solved. It was found that the Schiff base is coordinated to the central iron atom by six nitrogens forming deformed octahedral arrangement, whereas trithiocyanurate(1-) anion, perchlorate and solvent molecules are not coordinated. The X-ray structure of the Schiff base sodium salt is also presented and compared with the iron complex. The anticholinesterase activity of the complexes was also studied. Full article