Norzahir Sapawe

Utilization of bivalve shell-treated Zea mays L. (maize) husk leaf as a low-cost biosorbent for enhanced adsorption of malachite green

In this work, two low-cost wastes, bivalve shell (BS) and Zea mays L. husk leaf (ZHL), were investigated to adsorb malachite green (MG) from aqueous solutions. The ZHL was treated with calcined BS to give the BS-ZHL, and its ability to adsorb MG was compared with untreated ZHL, calcined BS and Ca(OH)(2)-treated ZHL under several different conditions: pH (2-8), adsorbent dosage (0.25-2.5 g L(-1)), contact time (10-30 min), initial MG concentration (10-200 mg L(-1)) and temperature (303-323 K). The equilibrium studies indicated that the experimental data were in agreement with the Langmuir isotherm model. The use of 2.5 g L(-1) BS-ZHL resulted in the nearly complete removal of 200 mg L(-1) of MG with a maximum adsorption capacity of 81.5 mg g(-1) after 30 min of contact time at pH 6 and 323 K. The results indicated that the BS-ZHL can be used to effectively remove MG from aqueous media.

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.

Effective solar-based iron oxide supported HY zeolite catalyst for the decolorization of organic and simulated dyes

A HY zeolite supported by highly dispersed electrogenerated iron oxide nanoparticles (EGFe2O3/HY) was prepared by a facile electrochemical method and has been characterized using XRD, TEM, BET, UV-vis/DRS, and XPS. The formation of EGFe2O3 nanoparticles with a size of <30 nm, well distributed on the surface of HY, led to enhanced catalytic activity for the decolorization of organic dyes such as methylene blue (MB), congo red (CR), and methyl orange (MO) under sunlight irradiation. The MB dye shows the highest decolorization (99.9%) followed by CR (96.4%) and MO (91.3%). Kinetics study signifies that the reaction follows pseudo first-order kinetics, and the rate constants was determined using the Langmuir–Hinshelwood model which gave values of KR = 0.48 mg L−1 h−1, KLH = 3.83 L mg−1 for MB; KR = 0.39 mg L−1 h−1, KLH = 1.78 L mg−1 for CR; and KR = 0.29 mg L−1 h−1, KLH = 0.13 L mg−1 for MO. No dissolution of EGFe2O3 ions was detected during the photoreaction. The catalyst was stable with a slight decrease of decolorization (<13%) after five cycling runs. Good performance of the decolorization of simulated dyes was observed with nearly complete mineralization as measured by COD and TOC removal.

Hybridization of zirconia, zinc and iron supported on HY zeolite as a solar-based catalyst for the rapid decolorization of various dyes

Hybridization of an electrogenerated zirconia/zinc/iron-supported on HY zeolite nanocomposite catalyst (EGZrO2/EGZnO/EGFe2O3/HY) was performed by a facile one-pot electrochemical method. In this study, nanoparticles ( 80%) of other dyes, such as malachite green (MG), congo red (CR), disperse violet (DV), and disperse blue (DB), were also obtained using this promising electrogenerated nanocomposite catalyst.

Wear characterization of aluminum lubricated with palm olein at different normal load

The pin-on-disk tester is a method used for investigating wear. The sliding mechanism between the pin and the disc experimentally creates wear. In this paper, the wear characteristics of an aluminium pin sliding on an SKD11 disc lubricated with double fraction palm olein were investigated. The pin was made from pure aluminum A1100. The results were compared with those of tests in which the disc was lubricated with commercial hydraulic oil. In both sets of experimental conditions, the normal load varied from 4 to 10 kg. Rotational speed was set to 1200 rpm. From this study, it was found that different types of lubricant affect the wear progression and friction coefficient during a sliding movement. The wear progression and friction coefficient depend also on the load applied, surface roughness, pressure applied and contact surface area.

Effect of Addition of Tertiary-Butyl Hydroquinone into Palm Oil to Reduce Wear and Friction Using Four-Ball Tribotester

ABSTRACT 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.

The influence of normal load in wear resistance characteristic of palm fatty acid distillate

The aims of this study were to determine the friction coefficient and the wear behaviour of palm fatty acid distillate (PFAD) using a four-ball tribotester, following the ASTM D-4172. In this paper, the normal load applied on the ball bearings varied from 40 kg to 120 kg. Experimental temperature was held constant at 75oC, while rotational speed was fixed at 1200 rpm. The test duration was one hour. Tests that were carried out using palm fatty acid distillate were conducted in exactly the same way using commercial hydraulic oil (HO) as a reference lubricant. The analyses focused on the friction coefficient and worn scar characteristic. Wear scar diameter was measured and the worn surface condition was observed using a high resolution microscope. Results showed that PFAD has a lower coefficient of friction than commercial hydraulic oil.

Effect of Low Current for Machining Pit Using Electrical Discharge Machine

Electric Discharge Machining Die sinker (EDM DS) is an established technology for surface modification. In this study, experiment were conducted using electrical discharge machine die sinker ZNC to investigate the effect of low pulse current rates to produce pits on SKD 11 (tool steel). Various parameters are considered during machining such as pulse current, gap voltage and dicharge time. Experiments were performed by three pulsed current levels (0.5A, 1.5A and 3.0A). The hollow copper rod as electrode with diameter 0.5mm is used to make spark surface of SKD 11. The experimental result reveals that the pit shape of a surface SKD 11 is significant to low pulse currents. For qualitative analysis, a distinction diameter pits and shapes represented with different low pulsed current. Overall, this study shows that presence of pits of surface embedded on the handle tool and machinery part will improve the existing technology available in surface modification.

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

ABSTRACT 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.

The Effect of Pits on the Curvature Cup: For Reducing Friction in Soft on Hard Sliding Contact

The purpose of this feasibility study is to elucidate the effect of surface modification on the curvature cup made of Acrylonitrile Butadiene Styrene (ABS) against metal ball bearing was investigated. In the tribology soft on hard (SoH), the pits embedded on the curvature cup have shown potential for reducing friction in curvature structure. A modified four ball machine as a hard-on-soft screening machine has been used to evaluate the friction on the curvature cup sample with an inner diameter of 12.8 mm. This study revealed that the treated curvature cup with pit in lubricated of palm oil optimizes the rate of frictional and allows for a stable of soft on hard sliding contact.