Electrochemical strategy for grown ZnO nanoparticles deposited onto HY zeolite with enhanced photodecolorization of methylene blue: Effect of the formation of Si O Zn bonds

Nanoparticles of electrogenerated zinc-supported HY zeolite (EGZnO/HY) catalyst were prepared by a simple electrochemical method. The interaction between zinc species and HY support during the electrolysis was found to affect the EGZnO/HY structure. In addition to the formation of EGZnO nanoparticles (<30 nm in size) that distributed on the surface of HY support, an isomorphous substitution of Al with Zn also occurred in the aluminosilicate framework to result in a Si O Zn bonds. The photoactivity of EGZnO/HY was tested on the decolorization of methylene blue (MB). An amount of 0.375 g L−1 of 1 wt% EGZnO/HY was found to be the optimum dosage for 10 mg L−1 MB, which resulted in 80% of maximum decolorization after 6 h of contact time at pH 3 under fluorescent light (420 nm). Increasing the EGZnO loading led to additional formation of Si O Zn bonds and lessened the number of EGZnO nanoparticles, which then reduced the photodecolorization percentage of MB.The photocatalytic reaction was follows the first-order Langmuir–Hinshelwood model, and gives partially mineralization. The photocatalyst was still stable after five cycling runs with no Zn leaching

Surface modification of biomaterial embedded with pits using die sinker machine

Surface modification has been applied in many ways to enhance exclusive implant product. Electrical Discharge Machine Die Sinker (EDM DS) is a new approach to machine a macro surface on the biomaterial. In this study, investigations of current properties of EDM DS to obtain a new surface in titanium alloy (Ti-6Al-4V) and stainless steel (E-316-L), which placed pit on the material-sized (25 mm) diameter sample with a radius of 6.3 mm, were conducted. All the samples of concave textured circular pits with a fixed diameter and depth of 0.5 mm were successfully machined. This study revealed that the pits were produced in the concave cup and the lubricant was confined inside the pits, making easier contact between metal ball and metal concave surface. The results also show that the discharge machine is an attractive machining method for surface modification of biomaterial. This paper suggests that concave implant surface embedded with pits will work as a trap for lubricant and wear debris; in addition, it is possible to increase the lifespan of implant structure

Evaluation on the tribological properties of palm olein in different loads applied using pin-on-disk tribotester

The vegetable oil based lubricant as lubricant in various applications were intensified and eyed by the industry due to its superior tribological properties, and has potential to replace petroleum based lubricants. Palm olein could be suitable and attractive candidate as the lubricant to be studied due to its good advantages and large production in country. Thus, in the study the behavior of RBD palm olein characteristic was investigated by pin on disk experiment in which the hemispherical pin was loaded against the rotating grooved disk. The experiments by sliding were performed in pin on disk tester using titanium as material for both hemispherical pin and grooved disk. The test were implemented by dropping 5 ml of RBD palm olein as lubricating oil on sliding surface at different loads applied which were 5N, 20N, 40N and 80N. The wear rate of the pin and friction coefficient was also investigated. The weight loss and surface roughness before and after experiment were analyzed. All the results obtained were compared to hydraulic oil and paraffinic mineral oil. From the analysis, friction coefficient acquired lubricated with RBD palm olein was the lowest for both conditions. Wear rate obtained for three lubricants increased from 5N to 20N load, then decreased after 40N load and increased again after 80N load exerted. Wear obtained lubricated with hydraulic oil shows the lowest value compared to paraffinic mineral oil and RBD palm olein

Evaluation on the tribological properties of palm olein in different loads applied using pin-on-disk tribotester

The vegetable oil based lubricant as lubricant in various applications were intensified and eyed by the industry due to its superior tribological properties, and has potential to replace petroleum based lubricants. Palm olein could be suitable and attractive candidate as the lubricant to be studied due to its good advantages and large production in country. Thus, in the study the behavior of RBD palm olein characteristic was investigated by pin on disk experiment in which the hemispherical pin was loaded against the rotating grooved disk. The experiments by sliding were performed in pin on disk tester using titanium as material for both hemispherical pin and grooved disk. The test were implemented by dropping 5 ml of RBD palm olein as lubricating oil on sliding surface at different loads applied which were 5N, 20N, 40N and 80N. The wear rate of the pin and friction coefficient was also investigated. The weight loss and surface roughness before and after experiment were analyzed. All the results obtained were compared to hydraulic oil and paraffinic mineral oil. From the analysis, friction coefficient acquired lubricated with RBD palm olein was the lowest for both conditions. Wear rate obtained for three lubricants increased from 5N to 20N load, then decreased after 40N load and increased again after 80N load exerted. Wear obtained lubricated with hydraulic oil shows the lowest value compared to paraffinic mineral oil and RBD palm olein

A new tribological approach on metal cup with optimized pits model using spark discharge machine

An interference friction causes tear and wear in metal-on-metal (MoM) hip joint. The purpose of this research is to examine the optimization of pit embedded in the acetabular cup using a spark discharge machine. Tribology tests on cup with 8, 21, and 40 pits embedded produced promising results. A modified pin-on-disk tribometer was used to measure the effects of the coefficient of friction and wear on a 28-mm-diameter acetabular cup. Microscopy image analysis was used to examine particle debris and surface disfigurement. This study revealed that the more pits were produced in the hemispherical or curvature cup, the more lubricant was confined inside the pits, and the easier the contact was for MoM. The results also show that the curvature surface modification with pits can positively influence friction and wear and stability optimization of MoM implants

Cost–effective microwave rapid synthesis of zeolite NaA for removal of methylene blue

In this study, microwave rapid synthesized NaA (NaAmw) was used to adsorb a methylene blue (MB) from an aqueous solution. The adsorption was optimized under four independent variables including: pH, adsorbent dosage, initial concentration, and ageing time based on central composite design (CCD) with response surface methodology (RSM). A period of 15 min was determined to be the optimum microwave ageing time for the synthesis of NaAmw, which is about sixteen times shorter than using conventional heating technique. An amount of 1.0 g L1 NaAmw demonstrated the optimum dosage for adsorption of 120 mg L1 MB, with predicted adsorption uptake of 53.5 mg g�1, at pH 7 within 1 h of contact time at room temperature. This result approximated the laboratory result, which was 50.7 mg g�1. The experimental data obtained with NaAmw best fits the Langmuir isotherm model and exhibited a maximum adsorption capacity (qmax) of 64.8 mg g�1, and the data followed the first-order kinetic equation. The intraparticle diffusion studies revealed that the adsorption rates were not controlled solely by the diffusion step. Thermodynamic studies showed that the adsorption is endothermic, non-spontaneous in nature, and favor at high temperature. These results confirm that the adsorption process of MB onto NaAmw was controlled by both physisorption and chemisorption. The reusability study shows that the NaAmw was still stable after five cycling runs. These results indicate that NaAmw efficiently adsorbed MB, and could be utilized as a cost-effective alternative adsorbent for removing cationic dyes in the treatment of wastewater

A new approach using palm olein, palm kernel oil, and palm fatty acid distillate as alternative biolubricants: improving tribology in metal-on-metal contact

Metal-on-metal (MoM) hip replacements are commonly used hip implants. However, one of the issues under debate is the interference of friction and wear. The purpose of this feasibility study is to elucidate the performance of palm lubrication between the femoral head and the acetabular cup. In the tribology of hip implants, the use of palm olein, palm kernel oil, and palm fatty acid distillate as synthetic lubricants for human joints has shown tremendous potential. A modified pin-on-disc as hip screening has been used to evaluate the friction and wear on an acetabular cup with an inner diameter of 28 mm. The wear debris was then observed with microscopy image analysis. This study revealed that the physical and unique chemical properties in palm oil can optimize the rate of friction and wear on the metal acetabular cup and thus allow for a stable implant of MoM

Effect of addition of tertiary-butyl hydroquinone into palm oil to reduce wear and friction using four-ball tribotester

Replacing mineral oil with vegetable oils as lubricants continues to attract interest due to their environmentally friendly characteristics and ease of disposal. However, one disadvantage can be low thermal oxidative stability. The purpose of our research is to investigate the ways in which oxidation can be contained by combining palm oil with a phenolic antioxidant. A homogeneous mix of palm oil and tertiary-butyl hydroquinone was found to exhibit satisfactory antioxidant properties and reduce wear and friction. Superior mineral engine oil was used to benchmark the performance

Synthesis of reverse micelle alpha-FeOOH nanoparticles in ionic liquid as an only electrolyte: inhibition of electron-hole pair recombination for efficient photoactivity

Discrete alpha-FeOOH nanoparticles (5-10 nm) were synthesized by a simple electrochemical method using an ionic liquid (IL), dodecyltrimethylammonium bromide (IL - FeOOH). IL that acts as an only electrolyte is capable of producing IL - FeOOH nanoparticles without any agglomeration. Its crystallinity, morphology, functional characteristics, and surface area were analyzed using an X-ray diffractometer, a transmission electron microscope, a Fourier-transform infrared spectrometer, and the Brunnauer-Emmett-Teller (BET) method, respectively. The characterization results verified that reverse micelle formation of IL plays an important role in the stabilization and miniaturization of the alpha-FeOOH nanoparticles. The activity of IL-FeOOH was tested on a photo-Fenton-like degradation of 2-chlorophenol (2-CP). Results showed that a nearly neutral condition of pH 5 was able to completely degrade 2-CP within 180 min of reaction at 50 degrees C, using 0.03 g L-1 of catalyst dosage and 50 mg L-1 of 2-CP initial concentration, with only a small amount of H2O2 (0.156 mM). It was found that the reverse micelle formed around the catalyst surface could trap the photogenerated electron to inhibit the recombination of photo-induced electron-hole pairs thus enhancing its catalytic activity. Kinetic studies using the Langmuir-Hinshelwood model illustrated that a surface reaction was the controlling step of the process. A reusability study showed that the catalyst was still stable after four subsequent reactions as shown by infrared spectroscopy. The results provide strong evidence to support the potential use of using IL as an alternative electrolyte to synthesize photo-Fenton-like nanocatalyst that can be used to treat organic pollutants such as 2-CP