ABSTRACT
Using the aldehyde amine condensation procedure and the triphenylamine group as the skeleton structure, the new triphenylamine-aromatic aldehyde-succinylhydrazone probe molecule DHBYMH was created. A newly created acylhydrazone probe was structurally characterized by mass spectrometry (MS), NMR, and infrared spectroscopy (FTIR). Fluorescence and UV spectroscopy were used to examine DHBYMH's sensing capabilities for metal ions. Notably, DHBYMH achieved a detection limit of 1.62 × 10-7 M by demonstrating exceptional selectivity and sensitivity towards Cu2+ ions in an optimum sample solvent system (DMSO/H2O, (v/v = 7/3); pH = 7.0; cysteine (Cys) concentration: 1 × 10-4 M). NMR titration, high-resolution mass spectrometry analysis, and DFT computation were used to clarify the response mechanism. Ultimately, predicated on DHBYMH's reversible identification of Cu2+ ions in the presence of EDTA, a molecular logic gate was successfully designed.
ABSTRACT
Iodine, primarily in the form of iodide (I-), is the bioavailable form for the thyroid in the human body. Both deficiency and excess intake of iodide can lead to serious health issues, such as thyroid disease. Selecting iodide ions among anions has been a significant challenge for decades due to interference from other anions. In this study, we designed and synthesized a new pincer-type acridine-triazole fluorescent probe (probe 1) with an acridine ring as a spacer and a triazole as a linking arm attached to two naphthol groups. This probe can selectively recognize iodide ions in a mixed solvent of THF/H2O (v/v, 9/1), changing its color from colorless to light yellow, making it suitable for highly sensitive and selective colorimetric and fluorescent detection in water systems. We also synthesized another molecular tweezer-type acridine-triazole fluorescent probe (probe 2) that exhibits uniform detection characteristics for iodide ions in the acetonitrile system. Interestingly, compared to probe 2, probe 1 can be detected by the naked eye due to its circulation effect, providing a simple method for iodine detection. The detection limit of probe 1 is determined to be 10-8 mol·L-1 by spectrometric titration and isothermal titration calorimetry measurements. The binding stoichiometry between probe 1 and iodide ions is calculated to be 1:1 by these methods, and the binding constant is 2 × 105 mol·L-1.
ABSTRACT
In this paper, functionalized sodium alginate hydrogel (FSAH) was prepared to efficiently adsorb heavy metals and dyes. Hydrazide-functionalized sodium alginate (SA) prepared hydrazone groups to selectively capture heavy metals (Pb2+, Cd2+, and Cu2+), and another functional group (dopamine grafting), serves as sites for adsorption methylene blue (MB), malachite green (MG), crystal violet (CV). Thermodynamic parameters of adsorption indicated that the adsorption process is endothermic and spontaneous. The heavy metals adsorption by FSAH was physical adsorption mainly due to ΔHθ < 40 kJ/mol, and the adsorption of cationic dyes fitted with the Langmuir models, which indicated that the monolayer adsorption is dominated by hydrogen bonds, electrostatic interactions, and π-π interactions. Moreover, the adsorption efficiency maintained above 70% after five adsorption-desorption cycles. To sum up, FSAH has great application prospect.
ABSTRACT
In the present study, a new potential adsorbent for the separation and removal of heavy metal ions was prepared using hydrazide modification. Characterization of structural and chemical properties of the absorbent indicated the dialdehyde sodium alginate (DSA) grafted adipic acid dihydrazide (AAD) plays a crucial role. The adsorption process correlated well with Freundlich isotherm and pseudo-second-order kinetics models. Additionally, the adsorption capacities for Hg2+, Pb2+, Cd2+, and Cu2+ were 7.833, 2.036, 4.766, and 3.937 mmol g-1, respectively. The thermodynamic parameter for the sorption demonstrated the process is endothermic and spontaneous. FT-IR and XPS analysis revealed the combination of chelation interactions and ion exchange between nitrogen, oxygen atoms and heavy metal ions. Moreover, after 10 times adsorption-desorption recycles, the adsorption efficiency of the adsorbent was slightly decreased. In conclusion, the as-prepared adsorbent has great potential in practical water pollution purification.
ABSTRACT
In this paper, DSA-AAD-DA and DSA-TPDH-DA were prepared to effectively remove metal ions and cationic dyes from aqueous solution. The hydrazone structure was prepared by hydrazide-modified SA which captured metal ions selectively, and the remaining functional groups were used as active adsorption sites for cationic dyes. The thermodynamic parameter for the sorption demonstrated the process is endothermic and spontaneous. In single process, the adsorption of metal ions by DSA-AAD-DA and DSA-TPDH-DA correlated well with the Freundlich model through the hydrazone structure coordination and ion exchange which was mainly chemical adsorption, and cationic dyes adsorption correlated well with the Langmuir model which was shown monolayer adsorption was dominant by hydrogen bonding, electrostatic interaction, and π-π interaction. In binary system, the mixed adsorption shown significant antagonism effect in high concentration, but cationic dyes and metal ions in low concentration were efficiently and simultaneously removed, the adsorption ability of DSA-TPDH-DA was much better than DSA-AAD-DA. Moreover, adsorption efficiency can still maintain more than 80% after five times adsorption-desorption recycle. Therefore, DSA-AAD-DA and DSA-TPDH-DA possessed great potential for wastewater treatment.
