نشریه پژوهش های شیمیایی و نانو مواد
سال دوم شماره 1 (پیاپی 5، بهار 1402)

Nowadays, the water industry has particular importance, for both drinking and industrial water usages. In most parts of the world, water resources are increasingly decreasing due to development and increasing demand. So, wastewater treatment and reuse is a priority. Therefore, currently, treatment technology needs new and innovative processes, according to the quality of raw water and wastewater. The recovered water should have the parameters of purity, sanitary desirability, environmental acceptance and economic feasibility based on industrial water standards for reuse. Therefore, in the current research, a pilot plant equipped with advanced oxidation processes was designed to purify and recover secondary municipal wastewater and remove residual pollutants in the effluent from the secondary urban wastewater treatment plant. During the test period, which was considered with a combination of processes including O3/H2O2, O3/UV, UV/H2O2, O3/UV/H2O2, the efficiency of removing organic pollutants was about 90%. In addition, disinfection, odor and color removal was also provided with very high efficiency. However, since the removal of turbidity and suspended matter was the inhibitory factor for some systems such as UV, by using sand filter, carbon filter and microfiltration, the removal efficiency of contaminants increased up to 98%. The obtained results indicate that the use of technologies based on advanced oxidation for wastewater reuse applications is one of the optimal options, even for wastewater with very high organic matter and it can be a suitable option as an optimal pretreatment method for reverse osmosis method.

In this research, the condensation of 2-hydroxynaphthalene-1,4-dione, malononitrile, aromatic aldehydes, and ortho-phenylenediamine was carried out for green synthesis of benzo[a]pyrano[3,2-c]phenazine under solvent-free conditions. This reaction was catalyzed using ionic liquid, butyl-3-methylimidazolium hexafluorophosphate as a base catalyst with simple reaction condition and easy separation of products. The products were obtained in high to excellent yields and reaction time between 15 to 25 minutes. All products were identified by melting point, FT-IR and 1H NMR techniques.

In this contribution, an analytical method was developed utilizing silver nanozymes as inexpensive and high throughput nanomaterials with high peroxidase-like activity for the selective quantification of hydrogen peroxide in food samples. 3,3’,5,5’-tetramethylbenzidine (TMB) was utilized as peroxidase substrate to produce the blue-colored analytical probe. The method was constructed based on the spectrophotometric probing the oxidation product of TMB by hydrogen peroxide in the presence of silver nanozyme as catalyst and the absorbance of the blue-colored oxidation product at 658 nm was used as analytical signal. The effective parameters on the method sensitivity including nanozyme amount, incubation time, buffer type and concentration, pH, and substrate concentration were optimized. In optimal experimental conditions, a linear dynamic range of 1-80 μM and detection limit as low as 0.12 μM were obtained. Besides, the selectivity studies revealed that the absorbance at 658 nm was increased in the presence of hydrogen peroxide while other co-existing species cannot proceed the oxidation process. Finally, the designed method was applied to quantify hydrogen peroxide of milk samples, revealing highly accurate results. The results of this research can be potentially utilized for food safety verification in food industries.

Host-guest nanochemistry is a branch of supramolecular chemistry in which a so-called host molecule binds to a guest molecule or ion. Host-guest interactions involve two molecules or substances that can form complexes through unique structural relationships and non-covalent bonding. Also called molecular recognition, this type of interaction is widely found in biological recognition processes, such as enzyme-inhibitor and antigen-antibody interactions. Host-guest molecular recognition provides a powerful approach to construct a dynamic interface that allows the resulting assemblies to be structurally manipulated in size and shape. Thus, it opens a path to construct smart supramolecular systems with multilevel reactivity. Host-guest nanochemistry incorporates the idea of molecular recognition and interactions through non-covalent bonding. Noncovalent bonding is critical in maintaining the three-dimensional structure of large molecules such as proteins and is involved in many biological processes in which large molecules are specifically but transiently bound together. Host-guest interactions have attracted considerable attention since their discovery, as many biological processes require host-guest interactions and can be useful in some material designs. In this article, the host-guest molecules and some of their applications are briefly introduced.

In this report, for the first time, the synthesis of nickel oxide nanoparticles (NiO) was carried out by the extract of Ferula plant. No chemical reducing agents, toxic stabilizers, or dangerous solvents were used for the synthesis of nickel oxide nanoparticles, and all fabrication steps were carried out in a green and mild conditions. X-ray diffraction analysis (XRD) and field emission scanning electron microscope (FE-SEM) were employed to determine the phase type and morphology of biosynthesized nickel oxide nanoparticles. After characterization, in order to take a step to protect the environment, biosynthesized nickel oxide nanoparticles were utilized as an effective photocatalyst for the degradation of bromothymol blue as an organic dye. In this manner, a UV lamp was used to activate the nickel oxide photocatalyst. The degradation percentage of bromothymol blue dye reached %77.08 within 3 hours. To evaluate the feasibility of using nickel oxide nanophotocatalyst in industry, the degradation of bromothymol blue was performed on real wastewater and successful results were obtained.

Mercury(II) cation has many risks for the environment and humans. Therefore, detection of mercury(II) cation is of particular importance. In this work, peroxidase-like activity of iron oxide/carbon dots nanocomposite was used for colorimetric determination of mercury(II) cation. To do this, first, iron oxide/carbon dots nanocomposite was prepared, and then the nanocomposite was characterized by Fourier transform infrared spectroscopy and transmission electron microscopy. Next, a sensor for determination of mercury(II) was designed by considering the peroxidase-like activity of the nanocomposite that can accelerate the oxidation of 3,3',5,5'-tetramethylbenzidine (TMB) to the cation radical of TMB* in the presence of H2O2. By using the above method, the dynamic range and detection limit for mercury(II) cation were obtained as 3.4×10-8 to 4.3×10-4 and 3.4×10-8 M, respectively. Also, this method shows good reproducibility for determination of mercury(II).