http://lib.buet.ac.bd;localhosthttp://:8080/xmlui/handle/123456789/1494 Post graduate dissertations (Theses) of Nanomaterials and Ceramic Engineering (NCE) Sun, 05 Apr 2026 09:01:51 GMT 2026-04-05T09:01:51Z http://lib.buet.ac.bd;localhosthttp://:8080/xmlui/handle/123456789/6896 In-house design and construction of a photocatalytic reactor rig and its performance evaluation Zubair, Dr. Md. Abdullah; Rana, Md Shahjalal; 0416172013; 660/SHA/2023 The treatment of wastewater and the development of catalystsusing photocatalytic reactors are rapidly growing areas of interest for both researchers and wastewater treatment technology.This thesis analyzes the role of photocatalytic technology in wastewater treatment; followed by a comprehensive discussion of photocatalytic reactor design from multiple perspectives, including photocatalyst selection, light source design, and controlof reaction conditions. Additionally, the cost of reactor design is considered. Additionally the cost of reactor design is considered. Finally,the optimizationstrategy of the designed photocatalytic reactor rig and the criteria for evaluating photocatalytic performance aresummarized. The main innovationof this thesis lies in a comprehensive analysis of thein-house design and construction of aphotocatalytic reactor, a cost-effective and high-performance solution with a focus on optimization of a laboratory-based photocatalytic reactor at NCE, BUET. The reactor is housed in a metal cabinet, inside of which is a lamp and power supply. The vessels are integrated within a reactor scheme, which is sequentially connected to the chiller and air blower.To determine the schematic design of the reactor rig and electric circuit, solid Worksand Protious software are used and the construction process is followed by the creation of a flow chart.Regarding the performance evaluation, the photocatalytic reactor rig undergoes a sequence of dye degradation experiments,including experimental setup, dye and catalyst selection, reaction monitoring, and data analysis. The degradation studies were conducted without catalysts under UV-A and LED light individually, using double jacket and triple jacket immersion well beakers. The maximum dye degradation observed in 60 minutes was up to 17.52%, which is relatively low. Additionally, degradation analysis was conducted using a catalyst (TiO2) under UV-A and LED light individually, as well as in combination (i.e., UV-A plus LED lamp together), in double jacket and triple jacket immersion well beakers. The maximum dye degradation of up to 80% was observed after 60 minutes of irradiation. Significant degradation occurred with the combination of catalyst and light, with approximately 80 to 99.9% degradation of pollutants or dye noted in the triple jacket beaker. Sat, 09 Sep 2023 00:00:00 GMT http://lib.buet.ac.bd;localhosthttp://:8080/xmlui/handle/123456789/6896 2023-09-09T00:00:00Z http://lib.buet.ac.bd;localhosthttp://:8080/xmlui/handle/123456789/6879 Synthesis and characterization of Barium and Strontium doped Sodium Bismuth Titanate Md. Abdullah Zubair, Dr.; Aliful Islam, Md.; 1014172023; 620.195/ALI/2023 This study investigates (Na0.5Bi0.5)1-(x+y)BaxSryTiO3 (NB-BST) ceramics synthesized via the solid-state reaction method. Varied compositions were sintered at 950°C, 1000°C, and 1050°C, influencing average grain sizes (227.20 nm to 481.15 nm). X-ray diffraction affirmed crystal structures. Barium and Strontium doping induced structural transitions from orthorhombic to tetragonal and cubic phases, evidenced by Rietveld analysis. Polarization-Electric Field (P-E) loops exhibited exhibit lossy and dielectric behaviors, revealing temperature-dependent trends. In current-voltage (I-V) characteristics, significant current at lower electric fields, saturating at higher fields, suggests balanced electron and hole conduction. Dielectric measurements illustrate a frequency-dependent increase in dielectric constant at lower frequencies and a decrease at higher frequencies, with loss tangents showing an increasing trend. (Na0.5Bi0.5)1-(x+y)BaxSryTiO3 (NB-BST) ceramics reveals diverse bandgap energies, such as for x=0.6, and y=0, 0.05, 0.10, 0.15, 0.20, the indirect and direct bandgap energies range from 2.84 eV to 3.23 eV. Similarly, at y=0.15, and x=0.30, 0.40, 0.50, 0.60, the bandgap energies vary from 2.84 eV to 3.22 eV, providing a comprehensive understanding of the optical behavior under different compositional and thermal conditions. This comprehensive analysis contributes to the development of lead-free materials, highlighting the impact of dopants on NBT-based ceramics for diverse applications. Sat, 11 Nov 2023 00:00:00 GMT http://lib.buet.ac.bd;localhosthttp://:8080/xmlui/handle/123456789/6879 2023-11-11T00:00:00Z http://lib.buet.ac.bd;localhosthttp://:8080/xmlui/handle/123456789/6762 Effect of pH and aging time on pore characteristics of dried silica xerogel Muhammad Hasanuzzaman, Dr.; TanjilaTanha; 1015172008; 666.1/TAN/2023 Porous glasses with interconnected pores and voids offer unique properties, including high surface area, permeability, and controlled pore size distribution. This research focuses on the preparation of porous glasses through the sol-gel route, specifically investigating the influence of pH and aging time on the pore characteristics of Silica Xerogel. Xerogel is a porous structural material that can be obtained via the evaporative drying of any precursor’s wet gel. Sol-gel processing using tetraethyl orthosilicate (TEOS) as the precursor and HCl as the acid catalyst was employed to obtain porous silica glasses. By manipulating the pH and aging time, custom pore size distributions in the mesoporous or macroporous range were achieved. Scanning Electron Microscopy (SEM) analysis revealed interconnected porous morphologies, with the average pore size increasing linearly with aging time. Xerogel aged for 2 days exhibited a mesoporous structure, while those aged for 4 and 6 days showed a conversion to a macroporous structure. Varying the pH as well as the acid concentration of the catalyst during synthesis resulted in average pore sizes of ~ 31 nm and ~ 59 nm, with pH 3 favoring mesoporous structures and pH 6 enabling the synthesis of macroporous silica xerogel. A higher concentration of the acid catalyst (from 0.05 M to 0.1 M HCl) was found to promote faster gelation, resulting in a denser network with smaller pores.Elemental analysis confirmed the presence of silicon and oxygen as the main constituents in the porous silica xerogel. EDS mapping analysis provided a visual representation of the surface distribution of the elements of silica xerogel. X-ray Diffraction (XRD) confirmed their amorphous nature. The sol-gel method provides a versatile synthesis route for tailoring the microstructure and properties of the resulting materials. By modifying the synthesis parameters, materials with customized porosity can be obtained. Moreover, the sol-gel technique offers the advantage of direct synthesis of high-purity multi-component materials without the need for powder intermediates or costly vacuum-based processes. These findings highlight the potential of sol-gel synthesis for the development of functional materials with varied structures and porosity, catering to specificapplications such as liquid filters, batteries,sensors, support, capturer, matter transport and bio-scaffolds. Tue, 22 Aug 2023 00:00:00 GMT http://lib.buet.ac.bd;localhosthttp://:8080/xmlui/handle/123456789/6762 2023-08-22T00:00:00Z http://lib.buet.ac.bd;localhosthttp://:8080/xmlui/handle/123456789/6760 Synthesis of porous nano-hydroxyapatite ceramic membrane and antimicrobial study Md. Saiful Islam, Dr.; Rashedul Alam Chowdhury; 0421172009; 666/RAS/2023 The present research aims to synthesize ceramics with porous structures and antibacterial properties. Currently, medical applications and wastewater filtration are associated with various kinds of ceramic material originating from nature and synthesizing processes. Doped Hydroxyapatite (HAp) as an antibacterial agent has the potential importance to overcome bacterial infection in biomedical and environmental-related applications. However, the porous structure of HAp has elevated importance in the filtration process. Seven compositions of pristine, doped, and co-doped Hap Ca10-x-yAgx Niy (PO4) (OH)2 (x=0, 0.2, 0.4, 0.6, 0.55, 0.3, 0.5 and y= 0,0,0,0, 0.05, 0.1, 0.15) samples were synthesized by Sol-gel precipitation method and made porous structure by a pore former. These are sintered at 800-1100°C to obtain Hexagonal HAp (JCPDS#09-432) was identified in the entire sample. Also, the former pore percentage changed the morphology of the particle. Then their chemical and biological characterizations were carried out along with the standard Hydroxyapatite. Phase content was studied by XRD analysis; crystallite size has found to be around 7-67 nm. XPS analysis confirms the presence of the doping element. The particle size and shape changed regarding the concentration of doping agent and sintering temperature in the range of 49.56-71.23 nm for Nanocrystalline HAp and 271.1 nm to 709.92 nm for porous HAp sintered in higher temperatures. The peaks of O-H and P-O bonds have been found in the FTIR analysis of the pristine HAp and doped samples.Particle size analysis and the distribution were calculated and shown from SEM images. BET analysis helped to determine the surface area, which is calculated as 43.21 and 57.94 m2/g, respectively, for pristine porous HAp and 0.6 Ag doped HAp. The pore volume of the pristine HAp through BJH calculation has been found to be 0.0445 g/cc. The macro pores in the sample analyzed by liquid intrusion which gives the range of 330 nm to 550 nm diameter of the macropore. AAS analysis shows the absorption capacity of lead (Pb) solution by different samples of HAp in the range 0f 99.9%. The result of in vivo bioactivity revealed that the antibacterial activity of the HAp samples was sensitive to Staphylococcus aureus (ATCC 25923). Increased Ag+Ni concentration altered the antibacterial activity against the bacteria.   Sat, 29 Apr 2023 00:00:00 GMT http://lib.buet.ac.bd;localhosthttp://:8080/xmlui/handle/123456789/6760 2023-04-29T00:00:00Z