Antimicrobial Efficiency of Hypochlorous Acid and Its Effect on Some Properties of Alginate Impression Material.

Dental clinicians and professionals need an affordable, nontoxic, and effective disinfectant against infectious microorganisms when dealing with the contaminated dental impressions. This study evaluated the efficiency of hypochlorous acid (HOCl) as an antimicrobial disinfectant by spraying technique for the alginate impression materials, compared with sodium hypochlorite, and its effect on dimensional stability and reproduction of details. HOCl with a concentration of 200 ppm for 5 and 10 min was compared with the control group (no treatment) as a negative control and with sodium hypochlorite (% 0.5) as a positive control. Candida albicans, Staphylococcus aureus, and Pseudomonas aeruginosa were selected to assess the antimicrobial activity with the colony forming unit test in addition to the dimensional stability and reproduction of details tests. The results revealed that HOCl had significant antimicrobial activity against all tested microorganisms and experimental time. Interestingly, HOCl showed no impact on the dimensional stability of alginate impression material. HOCl could be an effective antimicrobial agent for alginate impression material without interfering with their surface details and dimensional stability.

Cellulose-Based Hectocycle Nanopolymers: Synthesis, Molecular Docking and Adsorption of Difenoconazole from Aqueous Medium.

The goal of this work was to develop polymer-based heterocycle for water purification from toxic pesticides such as difenoconazole. The polymer chosen for this purpose was cellulose nanocrystalline (CNC); two cellulose based heterocycles were prepared by crosslinking with 2,6-pyridine dicarbonyl dichloride (Cell-X), and derivatizing with 2-furan carbonyl chloride (Cell-D). The synthesized cellulose-based heterocycles were characterized by SEM, proton NMR, TGA and FT-IR spectroscopy. To optimize adsorption conditions, the effect of various variable such as time, adsorbent dose, pH, temperature, and difenoconazole initial concentration were evaluated. Results showed that, the maximum difenoconazole removal percentage was about 94.7%, and 96.6% for Cell-X and Cell-D, respectively. Kinetic and thermodynamic studies on the adsorption process showed that the adsorption of difenoconazole by the two polymers is a pseudo-second order and follows the Langmuir isotherm model. The obtained values of ∆G ° and ∆H suggest that the adsorption process is spontaneous at room temperature. The results showed that Cell-X could be a promising adsorbent on a commercial scale for difenoconazole. The several adsorption sites present in Cell-X in addition to the semi crown ether structure explains the high efficiency it has for difenoconazole, and could be used for other toxic pesticides. Monte Carlo (MC) and Molecular Dynamic (MD) simulation were performed on a model of Cell-X and difenoconazole, and the results showed strong interaction.

Novel, Environment-Friendly Cellulose-Based Derivatives for Tetraconazole Removal from Aqueous Solution.

In this study, cellulose-based derivatives with heterocyclic moieties were synthesized by reacting cellulose with furan-2-carbonyl chloride (Cell-F) and pyridine-2,6-dicarbonyl dichloride (Cell-P). The derivatives were evaluated as adsorbents for the pesticide tetraconazole from aqueous solution. The prepared adsorbents were characterized by SEM, TGA, IR, and H1 NMR instruments. To maximize the adsorption efficiency of tetraconazole, the optimum conditions of contact time, pH, temperature, adsorbent dose, and initial concentration of adsorbate were determined. The highest removal percentage of tetraconazole from water was 98.51% and 95% using Cell-F and Cell-P, respectively. Underivatized nanocellulose was also evaluated as an adsorbent for tetraconazole for comparison purpose, and it showed a removal efficiency of about 91.73%. The best equilibrium adsorption isotherm model of each process was investigated based on the experimental and calculated R2 values of Freundlich and Langmuir models. The adsorption kinetics were also investigated using pseudo-first-order, pseudo-second-order, and intra-particle-diffusion adsorption kinetic models. The Van't Hoff plot was also studied for each adsorption to determine the changes in adsorption enthalpy (∆H), Gibbs free energy (∆G), and entropy (∆S). The obtained results showed that adsorption by Cell-F and Cell-P follow the Langmuir adsorption isotherm and the mechanism follows the pseudo-second-order kinetic adsorption model. The obtained negative values of the thermodynamic parameter ∆G (-4.693, -4.792, -5.549 kJ) for nanocellulose, Cell-F, and Cell-P, respectively, indicate a spontaneous adsorption process. Cell-F and Cell-P could be promising absorbents on a commercial scale for tetraconazole and other pesticides.

Enhanced Ibuprofen Adsorption and Desorption on Synthesized Functionalized Magnetic Multiwall Carbon Nanotubes from Aqueous Solution.

In recent years, concerns have been raised about the occurrence of active raw materials and pharmaceutical ingredients that may be present in water, including wastewater, in the pharmaceutical industry. Wastewater treatment methods are not enough to completely remove active pharmaceuticals and other waste; thus, this study aims to assess the use of a multiwall carbon nanotube after derivatization and magnetization as a new and renewable absorbent for removing ibuprofen from an aqueous medium. The adsorbents were prepared by first oxidizing a multiwall carbon nanotube and then deriving the oxidized product with hydroxyl amine (m-MWCNT-HA), hydrazine (m-MWCNT-HYD), and amino acid (m-MWCNT-CYS). Adsorbents were characterized by Raman spectroscopy, Fourier Transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM and TEM), Brunauer-Emmett-Teller surface area analysis (BET), thermogravimetric analysis (TGA), and vibrating sample magnetometer (VSM). Batch adsorption studies were conducted to study the effects of pH, temperature, time, and initial concentration of the adsorbate. Adsorption isotherm, kinetics, and thermodynamics studies were also conducted. The results show that the optimal pH for nearly complete removal of Ibu in a short time at room temperature was 4 for three adsorbents. The adsorption followed the Langmuir isotherm model with pseudo-second-order kinetics. The percentage of removal of ibuprofen reached up to 98.4%, 93%, and 61.5% for m-MWCNT-CYS, m-MWCNT-HYD, and m-MWCNT-HA respectively. To the best of our knowledge, the grafted MWCNTs presented in this work comprise the first example in the literature of oxidized MWCNT modified with such functionalities and applied for ibuprofen removal.