Molecular Interactions and Binding Free Energy of Polydopamine and Methylene Blue: A DFT Study (original) (raw)
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Removal of Methylene Blue from Aqueous Solution By Polydopamine@Zeolitic Imidazolate-67
Research Square (Research Square), 2021
Herein, a facile and low-cost route was used to prepare Polydopamine@Zeolitic Imidazolate Framework-67 (PDA@ZIF-67). The structure, morphology, surface functional groups and particle size distribution of PDA@ZIF-67 were studied using FTIR, FESEM, EDS, and BET analyses. The specific surface area and diameter of PDA@ZIF-67 were equal to be 78.203 m 2 /g and 4.179 mm, respectively. The PDA@ZIF-67 was used as an adsorbent for the adsorption of methylene blue dye. The results show that the maximum adsorption efficiency of methylene blue on the surface of PDA@ZIF-67 is achieved at pH 2, the temperature of 65°C, 10 mg of adsorbent, and methylene blue concentration of 7.5 ppm. Moreover, the adsorption process's isothermal, thermodynamic, and kinetics were studied entirely to consider the adsorption mechanism. The methylene blue molecules located in the fine pores of the PDA@ZIF-67 adsorbent determine the adsorption rate. Moreover, the adsorption process of methylene blue at high temperatures is a spontaneous and endothermic reaction. The adsorption efficiency of PDA@ZIF-67, after the recovery, reached 62.21%, which is an excellent advantage for using this adsorbent.
International Journal of Molecular Sciences
Mussel-inspired chemistry was usefully exploited here with the aim of developing a high-efficiency, environmentally friendly material for water remediation. A micro-structured material based on polydopamine (PDA) was obtained by using liposomes as templating agents and was used for the first time as an adsorbent material for the removal of methylene blue (MB) dye from aqueous solutions. Phospholipid liposomes were made by extrusion and coated with PDA by self-polymerization of dopamine under simple and mild conditions. The obtained Liposome@PDA microspheres were characterized by DLS and Zeta potential analysis, TEM microscopy, and FTIR spectroscopy. The effects of pH, temperature, MB concentration, amount of Liposome@PDA, and contact time on the adsorption process were investigated. Results showed that the highest adsorption capacity was obtained in weakly alkaline conditions (pH = 8.0) and that it could reach up to 395.4 mg g−1 at 298 K. In addition, adsorption kinetics showed that...
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Polydopamine is a biomimetic self-adherent polymer, which can be easily deposited on a wide variety of materials. Despite the rapidly increasing interest in polydopamine-based coatings, the polymerization mechanism and the key intermediate species formed during the deposition process are still controversial. Herein, we report a systematic investigation of polydopamine formation on halloysite nanotubes; the negative charge and high surface area of halloysite nanotubes favour the capture of intermediates that are involved in polydopamine formation and decelerate the kinetics of the process, to unravel the various polymerization steps. Data from X-ray photoelectron and solid-state nuclear magnetic resonance spectroscopies demonstrate that in the initial stage of polydopamine deposition, oxidative coupling reaction of the dopaminechrome molecules is the main reaction pathway that leads to formation of polycatecholamine oligomers as an intermediate and the post cyclization of the linear ...
Polydopamine – its Prolific Use as Catalyst and Support Material
ChemCatChem, 2020
Polydopamine is a mussel-inspired functional material with a unique ability to form surface coatings. It is a green, environmentally benign product available very easily for a multitude of varied applications. This review attempts to collect useful information with respect to polydopamine-based catalytic studies with the use of polydopamine and modified polydopamine preparations. The latter catalysts, in most cases, are loaded with metal ions and metal particles. Major sections are about the use of polydopamine as catalyst material, utilization of immobilized enzymes, removal of toxic materials, results in organic synthesis, and fuel cell applications. A few examples of chiral catalysis and results of recycling studies are also treated. Data collected and analyzed indicate the importance and high potential of polydopamine-based catalysts in sustainable chemistry.
ACS Omega, 2019
Cyclic voltammetry (CV) studies of 4-dicyanomethylene-2,6-4H-pyran (DDP) dye with alkyl-substituted amides were carried out in an aqueous solution. Formamide and substituted amide interaction with DDP dye were characterized by fluorescence spectral techniques in an aqueous solution, but the electrochemical nature and the interaction at the interface region between dye−amide remains largely unexplored. The introduction of formamide to DDP dye exhibits an increase in the peak current accompanied with potential values gradually shifting more toward a less positive region. A large variation in the current−potential characteristics is observed in alkyl-substituted amides. The cyclic voltammograms of alkyl amides are found to be entirely different from each other. The role of alkyl substitution in the amide molecular framework influences the reduction potential of the dye in an aqueous medium. The mode of interaction of the dye with alkyl-substituted amides is predominantly due to the electrostatic behavior, even though hydrogen-bonding interactions coexist throughout the aqueous phase. The binding constant parameter (K), free-energy changes (ΔG), and the variation in the potential behavior of the dye in the presence of formamide and alkyl amides authenticate that the nature of interaction operates by both hydrogen-bonding mode and electrostatic interactions. Electrochemical techniques when coupled with fluorescence methods provide an efficient method of determining the interaction at the bulk and the interface regions of a water-soluble dye with nonfluorophoric solutes.