125Wibawa Hendra SAPUTERA126Wahyu SRIGUTOMO127Rindia Maharani PUTRIPhotocatalytic Degradation of Pharmaceutical Wastes Using Bismuth Oxybromide (BiOBr) Catalyst(Project 2023)Development of Forward and Inverse Modeling of 2D Transient Electromagnetic Method (TEM) using Finite Element Method (FEM) for Environmental Study(Project 2023)Tuning Surface Properties of Biosilica from Tropical Marine Diatoms for Sustained Delivery of Peptide Drugs(Project 2023)85To address the persistence and toxicological impact of antibiotics such as sulfamethoxazole (SMX) in water, this study focuses on the development of BiOBr photocatalysts to degrade them synthesized through in-situ Bi doping, resulting in various Bi/BiOBr composites via hydrothermal method at different temperatures. Characterization through X-ray diffraction (XRD), UV-vis diffuse reflectance spectroscopy (UV-vis DRS), X-ray fluorescence (XRF) and nitrogen adsorption-desorption isotherms showed that Bi metal was formed at 180 °C (BB180) and completed at 270 °C (BB270). This transformation results in Bi3+ and oxygen vacancies, enhancing electron-hole pair separation and narrowing the band gap for better visible light sensitivity. BB180 showed superior photocatalytic activity, degrading 74.35% of SMX within 4h under Xenon lamp irradiation, with a rate constant of 6.5 x 10-3 min-1, surpassing commercial TiO2 Degussa P25. This discovery paves the way for visible light-responsive catalysts designed to detoxify antibiotics in wastewater, highlighting a new approach in environmental remediation.This research describes the development of a transient electromagnetic (TEM) modeling algorithm. This algorithm includes forward and inversion modeling components that assume 2D subsurface conditions. The selection of a 2D model is used as an intermediate solution to reduce the computational complexity of the 3D model but still provides better detail than the 1D model in describing subsurface conditions. Maxwell's differential problem in the 2D case is solved using the finite element method. This modeling relies on the potential vector form in its calculations because it makes it easier to solve differential equations that run parallel with the source field. Program validation involves comparing synthetic data with data generated from the program to ensure accuracy. The 2D forward modeling has been successfully carried out to describe the electromagnetic (EM) field in the case of a homogeneous earth. The 2D inversion process has also been successfully carried out on synthetic test models but can still be further developed using various constraints. The use of the inversion algorithm for real cases will be carried out in future research.Compared to synthetic silica, biosilica from marine diatoms offers an inherent nanoporous structure from a sustainable and inexpensive marine resource for drug delivery applications. Despite the potential, there is no report on the exploration of diatom biosilica as a delivery system for peptide-based drugs. The aim of this proposed research was to investigate the biosilica of C. striata diatom as a delivery platform for peptide drugs, using insulin as the model peptide. We found that upon contact of biosilica with insulin, the adsorption capacity reached up to 8.3 mg insulin/g biosil using 0.5 mg/ml starting insulin concentration (~83% adsorption capacity). Surface modification with amine groups resulted in a similar adsorption capacity, i.e. 8.2 mg insulin/g biosil. Both modified and non-modified biosilica followed pseudo-first-order kinetics for insulin adsorption. The insulin release from biosilica matrix occurred in the simulated intestinal fluids (phosphate buffer pH 7) and sustained for at least a
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