Papers by Keyword: Diatomite

Abstract: In this study, the activation of natural diatomite was done with alkaline solution. The diatomite powder was sieved and purified prior to activation at room temperature (Alk-DA RT) and 85 °C (Alk-DA 85 °C). The effect of activation time of Alk-DA 85 °C samples was observed for 1 h, 2 h and 5 h. At temperature interval from room temperature to 530 °C, the weight loss for all of Alk-DA are less than R-DA. The reduction of particle aggregation was found in Alk-DA at both RT and 85 °C as shown in SEM images, indicating the activation by NaOH that effectively breaks down the bulky structure. The formation of silanol group (Si-OH) were obtained on the surface of Alk-DA. However, BET result revealed there is no increment of surface area and porosity in case of RT. In addition, Alk-DA 85 °C samples at 1 h and 2 h provided the spongy surfaces with obvious improvement of surface area, and reduction in porosity and pore size. In contrast, Alk-DA 85 °C 5 h showed more cluster of particle aggregation. Moreover, it can be observed that Alk-DA 85 °C 1 h is the most interesting for further study since it potentially provides high gas adsorption but only requires a shorter activation time.

Abstract: The performance of added 50% reclaimed asphalt (RAP) mixtures was investigated by four-point bending fatigue tests (FPBT). Mixtures with 50% RAP were modified with SBS polymer, diatomite (D) and hydrated lime (HL). Ten specimens were produced and fatigue of specimens was evaluated with FPBT. Some samples give the fatigue breaking cycle compatible with each other. In some samples, the number of cycles is much higher than the average breaking load. Some samples may deteriorate in a short time before the end of test. Although the briquettes are mixed homogeneously for longer mixing times and produced with great care, inconsistent results can be obtained. If water damage is applied to briquettes due to the presence of HL, more compatible results can be obtained. The use of SBS-HL and rejuvenating oil at high RAP ratios will provide more compatible results. As a result of 50% stiffness reduction, the difference in the remaining stiffness values is usually 2-3 times, while there are huge differences between the cycle numbers that cause this. In terms of sustainable and long-term performance, the homogeneity of the pavement composition appears to be essential, having a much more pronounced effect than the number of loadings.

Abstract: The present study deals with the effect of the Diatomite (D) microcomposite with and without chemical modification in a polypropylene (iPP) blend. The objective is to achieve a material with a better performance at a lower cost and more accessible and more suitable processing. The chemical surface modification of Diatomite (MD) was achieved using a crosslinking system based on a mixture of sulfur, accelerator, and peroxide. The iPP/Diatomite composite was prepared by batch melt mixing in a Brabender Plasti-Corde under intense shearing at high temperatures and varying the Diatomite content from 0 to 15 wt%. The rheological behavior was examined by monitoring the Brabender Plasti-Corde torque/time rheographs. Different techniques were used to characterize the sample: Fourier transform infrared spectroscopy (FTIR), WAXS, SEM, and DSC. In addition, tensile strength tests and impact strength mechanical tests were conducted to study the performance. It was found that chemical modification strongly affected rheological behavior and generated a new rheological characteristic compared to the composites without modification. This has induced a new structure form that has improved mechanical properties. Moreover, the chemical modification used and due to its simplicity, can be successfully used on an industrial scale with the appropriate process.

Abstract: The focus of this research paper is the preparation of inorganic foam glass-ceramic with the utilization of waste diatomite as a raw material. The waste diatomite was first comprehensively characterized by the analysis of the chemical and mineralogical composition, particle size, thermal analyses, and microstructure by scanning electron microscopy. Followed by the pretreatment of the mixtures with the addition of a foaming agent which was sodium hydroxide. The mixtures were then formed by pressing them into pellets and fired by a powder sintering method. The pretreatment drying temperatures and firing temperatures of the prepared mixtures were evaluated. After firing, the resulting properties of the foam glass-ceramic were investigated with the utilization of an X-ray diffraction analysis, bulk density, and compressive strength. The possibility of utilization of waste diatomite in raw material mixtures for the preparation of inorganic foam glass-ceramic was investigated.

Abstract: A hydrothermal process was proposed to prepare BiVO₄/ diatomite composite photocatalysts, where BiVO₄ was grown from a precursor solution containing diatomite, and EDTA used as a chelating agent to prevent the precipitation of precursor solution compositions on diatomite before hydrothermal treatment. The effect of some processing parameters like diatomite percentage and Ag-loaded amount on their photocatalytic performance were also investigated in detail by X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), BET, and UV‐Vis spectroscopy. The results show that BiVO₄/ diatomite composite photocatalysts can be successfully prepared at 160 °C for the duration of 3h by the hydrothermal process. The diatomite has two significant impacts on their photocatalytic performance: (1) enhancing the dispersion of BiVO₄ crystallites due to its high porosity and specific surface area to favor their photocatalytic performance, and (2) having a light screening effect to incident visible light to decrease their photocatalytic activity. Appropriately incorporating diatomite could improve their photocatalytic performance, but the overuse of diatomite would reduce that. Similarly, depositing Ag could effectively improve their photocatalytic activity because of its good light absorption and photosensitive characteristics, but excessive addition would result in their decrease since the overuse of Ag would also promote the electron-hole recombination.

Abstract: When constructing deep wells for oil and gas production in difficult geological conditions, special lightweight oil-well cements are used. To reduce the density and water separation of the cement slurry as well as to increase the strength, corrosion resistance of cement stone and the quality of well cementing, opal-containing rocks, fly ash, microsphere and other lightening additives are introduced into the cement composition. The influence of sedimentary rocks, such as opoka, tripoli, and diatomite containing from 43 to 81% amorphous silica on the grindability, rheological and physical-mechanical properties of lightweight oil-well Portland cement has been studied. The twelve cement compositions with different content of additives (from 30 to 45%) that meet the requirements of the standard for density, spreadability, water separation, thickening time and flexural strength were selected. The introduction of 45% diatomite or tripoli significantly reduces the duration of cement grinding, provides the cement slurry with water-cement ratio of 0.9 with better density and flexural strength, respectively, 1480 kg/m³ and 1.1–1.5 MPa.

Abstract: The paper presents the results of the determination of the effect of a photocatalytic composite material (PCM) with the composition SiO₂‒TiO₂ on the main properties of white Portland cement: heat release during hydration, phase composition and microstructural features of cement stone, pressure strength and self-cleaning ability. PCM was synthesized by a sol-gel method based on tetrabutoxytitanium and finely dispersed diatomite powder and 15% cement was added instead. The presence of PCM in the cement system provided the reduction of the induction period of cement hydration, consolidation of the microstructure of the cement stone with the products of the pozzolanic reaction, the ability to photocatalytic self-cleaning of the cement stone surface.

Abstract: The purpose of this research is to develop a new type of environmentally friendly container which has thermostatic effect and is biodegradable. This study is based on polylactic acid (PLA) and maleic anhydride grafted polybutylene succinate (MAPBS). Subsequently, the diatomite which adsorbed polyethylene glycol (PEG) was added to prepare a thermostatic biodegradable composite. The addition of MAPBS is to improve the compatibility between PLA and diatomite. In addition, the thermostatic effect, tensile strength, thermal deformation temperature and impact strength of the composite were investigated.

Abstract: This paper presents the studies on physical and chemical properties of the natural diatomite originating from Mae Tha District, Lampang the northern of Thailand as solid catalyst. The diatomite was characterized by X-ray diffraction (XRD), X-ray fluorescence (XRF) and nitrogen adsorption-desorption isotherm. The effect of calcination temperature on chemical composition, cyrytalline phase and textural properties of diatomite was also investigated. The XRF results indicated that the diatomite was composed mostly of SiO₂, K₂O, CaO and MgO. The calcination temperature ranging from 300 to 900 °C had no effect on the crystalline phase of diatiomite. The high surface area and large pore size diameter of diatomite was observed when the calcination temperature was below 900 °C. All the physicochemical results show the existence of SiO₂, K₂O, CaO and MgO, the high surface area and pore size diameter, indicate that the diatomite could potentially be used to a solid catalyst for biodiesel production.

Abstract: In this work, the optimal sintering temperature and time of commercial copper paste were tested experimentally. The electrical properties of conductive paste including square resistance and resistivity were characterized and analyzed. The influence of diatomite with different purification processes on the electrical properties of commercial copper paste was analyzed. The performance of copper slurry modified by copper-based modified diatomite prepared by two-step reduction method was analyzed. The optimum square resistance and resistivity was obtained with copper paste doped by 0.25wt.% and 1 h-ball milled diatomite and was 0.02Ω/_ϒ and 0.011Ω·mm, respectively.