Seminar by Assoc. Prof. Arkhincheev Valerii and Dr. Subramanian Ramanathan

At 2:00 p.m., December 31, 2025, IAST organized a seminar at Room 604, 99 Tran Quoc Toan, Cua Nam, Hanoi (Hanoi campus) and the Meeting Room on the 5th floor of the library (Tan Hung campus) with detailed content as follows:

1. Assoc. Prof. Dr. Arkhincheev Valerii reported on the topic: Acceleration of mass transfer processes in complex systems due to the geometric structure: a fractional order equation of mass transfer and its application.
Abstract: The problem of mass transfer in living plants in the framework of the comb model was studied. The fractional order equation for the problem of mass transfer was deduced and its application for transfer in the plants was considered. The different temporal asymptotic, which occurred due to geometry of plants, were obtained. It was established that mass transfer processes in living plants depend on the geometric structure of plants, specifically, it is mass transfer is accelerated from steam to  branches. The discussion of obtained results was given.

2. Dr. Subramanian Ramanathan reported on the topic: Synergistic photocatalytic degradation of crystal violet dye using novel medical waste-derived carbon/ZnO composite: A study on toxicological.
Abstract: The discharge of crystal violet (CV) dye effluents from textile sectors is a significant concern, as these pollutants not only diminish the aesthetic appeal of water bodies but also impede light penetration, thereby disrupting aquatic ecology. Additionally, the COVID-19 pandemic has led to increased usage of disposable face masks, further contributing to medical waste in the environment. In this state-of-the-art study, the aim was to develop a photocatalyst material using medical-waste-derived carbon (MWC) as a support matrix for zinc oxide (ZnO) nanoparticles, facilitating the photocatalytic degradation of CV dye via persulfate (PS) activation. X-ray diffraction and Raman spectroscopy were used to analyze the crystalline and chemical bonding properties of the synthesized photocatalysts, whilst field-emission scanning electron microscopy and transmission electron microscopy with energy-dispersive X-ray spectroscopy mapping were employed to examine the samples’ surface morphology and composition. The UV–vis spectroscopy and photoluminescence spectroscopy were used to confirm the optical properties of the photocatalysts. The degradation analyzes showed that the MWC/ZnO nanocomposite achieved a higher degradation efficiency of 94.4%, with a reusability performance of 91.0% in the fifth cycle. Toxicology assessment was performed using seedling Vigna mungo plants and zebrafish, which significantly revealed developmental deformities in the embryos and adults of zebrafish treated with the CV solution, but not when grown with the degraded CV solution or water, supporting the non-toxic nature of the degraded dye water. Therefore, the proposed MWC/ZnO nanocomposite could be proposed as a potential catalyst for CV dye degradation and an ideal solution for both aquatic and medical waste pollutants.