Open Access Original Research Article

Characterization of the Effect of Moisture on Tribology of Titanium Rubbed Against Different Pin Materials

Bodhi R. Manu, Adam M. Schroeder, Ahalapitiya H. Jayatissa

Chemical Science International Journal, Page 1-10
DOI: 10.9734/CSJI/2020/v29i230158

Tribology investigations were conducted to understand the effect of humidity and water adsorption at the interfacial surface on the friction coefficient of titanium. Pin-on-disk tribometer tests were conducted at different levels of humidity ranging from 0% to 71% RH using aluminum and steel pins on a titanium plate. The variation of the mean coefficient of friction was plotted as a function of relative humidity. The friction coefficient slightly decreased when the relative humidity was increased from 0% to 10% RH. However, it increased with a further increase in humidity. The maximum friction coefficients were observed at 55% and 65% RH for steel and aluminum, respectively. The thickness of the wear tracks also showed the same trend as the friction coefficient. Under high humidity conditions, water vapor can condense on the surface of the moving machine parts. To understand the influence of this water film, a pin-on-disk test was carried out on a sample where a thin film of water masks metal surfaces from contact. Although the coefficient of friction was similar for both the aluminum and steel pins’ interaction with titanium (~0.36), the wear tracks were not formed for steel pin/titanium interaction even though this experiment was conducted for more cycles.

Open Access Original Research Article

Adsorptive Efficiency of Activated Carbon from Corncob Compared with Commercial Activated Carbon in the Adsorption of Light Alkanes Contaminant in Hydrogen Gas Product

E. A. Anih, O. A. Babarinde, M. M. Adeyemi

Chemical Science International Journal, Page 11-24
DOI: 10.9734/CSJI/2020/v29i230159

The adsorptive efficiency of activated carbon produced from corncob was compared to commercial activated carbon in the adsorption of light alkanes contaminant in hydrogen gas product. The adsorption was measured over a constant temperature of 27°C and at pressures up to 125 kilo pascal (kPa) using a gravimetric gas adsorption technique. The light alkanes were adsorbed on activated carbon produced from corncob using chemical method with phosphoric acid as the activating agent. The mass of adsorbent used for the adsorption was from 20 – 60 g. Pore size distribution and characteristic functional groups present on the surface of activated carbon were determined using N2 adsorption, Brunauer-Emmett-Teller (BET) method and Fourier Transform Infrared spectroscopy (FTIR spectra) respectively. BET analyses were used to characterise the activated carbons. The BET results of the produced activated carbon compared to the commercial activated carbon has a specific surface area of 1237 m2/g and 2048 m2/g and a pore volume of 0.1162 cm3/g and 0.1959 cm3/g, respectively. FTIR spectra results of the produced activated carbon compared to the commercial activated carbon showed similar band gap at 2337.80 cm-1 with an alkynl C≡C stretch functional group and a vibration type of carbonyl group (carboxylic OH) at 1550.82 cm-1. Experimental data verified using Langmuir isotherm and Freundlich isotherm adsorption models showed best fit for Langmuir adsorption isotherm model indicating the formation of a monolayer adsorbate on the outer surface of the adsorbent with an adsorptive and uptake capacity of 0.016 Pa-1. The adsorptive efficiency of the produced activated carbon compared to the commercial activated carbon was 1.05wt% and 3.55wt%, respectively. Therefore, based on the results obtained, the produced activated carbon may not completely substitute the commercial activated carbon rather it can be used as a potential blend thereby reducing quantity and cost.

Open Access Original Research Article

Effect of Humidity on Friction of Molybdenum Disulfide Films Produced by Thermal Evaporation on Titanium Substrates

Bodhi R. Manu, Ahalapitiya H. Jayatissa

Chemical Science International Journal, Page 25-33
DOI: 10.9734/CSJI/2020/v29i230160

MoS2 is one of the most advanced solid lubricants that have been used in many machineries. In this work, the effect of humidity on the friction of MoS2 solid film lubricant is investigated using a pin-on-disk tribometer. MoS2 film was coated by a thermal evaporation method on a titanium substrate. Steel and aluminum pins were used for the evaluation of friction coefficient of MoS2 films using a tribometer. The tests showed that with an increase in humidity, the coefficient of friction also increased. In practical applications at high humidity levels, the MoS2 films could be covered by condensed water molecules. Therefore, an experiment to understand the effect of water film on the variation of friction coefficient was also conducted. The results showed that the coefficient of friction remained constant for experiments using both aluminum and steel pins, and then the coefficient of friction increased once the water film was evaporated by the heat generated due to friction. An optical and XRD characterization of the MoS2 film was also conducted.

Open Access Original Research Article

Effect of Drilling Wastes on Urease Activities and Substrate Induced Respiration (SIR) in Wetland Soil of Delta and Bayelsa States, South-South, Nigeria

E. Mirinn, E. P. Berezi, K. T. Nwauche

Chemical Science International Journal, Page 34-47
DOI: 10.9734/CSJI/2020/v29i230162

The effect of drilling waste on urease activities and substrate-induced respiration in wetland soil of Niger Delta of Nigeria was investigated, using Fadama, mangrove and meander soils respectively. Urease activity and substrate-induced respiration (SIR) were measured after 1, 7, 14, 28, 42, 56, 70, 105 and 140 days of incubation to evaluate the effects of drilling waste on soil biochemical perimeters. Results obtained indicated that Fadama soil urease activities varied from 13.5 to 2.10 mg NH4 – Hg-1 dry soil in drilling waste. Mangrove soil varied from 13.5 to 2.22 mg NH4 – Ng-1 dry soil in drilling waste. Meander soil activities varied from 14.7 to 3.10 mg NH4 – Ng-1 dry soil in drilling waste. Also, the substrate-induced respiration in Fadama and mangrove soil range from 2.05 to 0.05 ml CO2 kg-1 24 h-1 in drilling waste respectively. Analysis of enzyme activities indicated positive relationship between urease activities and SIR (r = 0.78, p < 0.05 Fadama (r = 1, P < 0.05 Mangrove) and (r = 0.83, P < 0.05 Meander). There was also a positive relationship between 5%, 10% and 15% treatment levels in Fadama, meander and mangrove soils.

Open Access Original Research Article

Extraction and Characterization of Selected Carrier Oils

Akuma Oji, Ikediasor Chinenye Vivian

Chemical Science International Journal, Page 48-54
DOI: 10.9734/CSJI/2020/v29i230163

Extraction and characterization of carrier oil has been conducted experimentally on coconut, avocado and carrot oil. FTIR scan analysis was carried out on the extracted oil. Also physical and chemical properties of the carrier oils were assessed to evaluate oil quality including Specific gravity, peroxide value, saponification value, acid value and free fatty acid. The result showed all the extracted oils were liquid at room temperature an indication of the presence of oleic acid and linoleic acid and other unsaturated fatty acids. The specific gravities of 0.92, 0.91 and 0.93 for coconut, avocado and carrot oils indicate that each of the oils could be used on commercial scale. The Peroxide value recorded 0.11-0.12 meq/kg which is far below the maximum limits of 1-5 meq/kg and can last for a long time without going rancid. The low saponification values of coconut, avocado and carrot oils  of 127.62 meq/kg oil, 120.12 meq/kg oil and 130.47 meq/kg oil respectively indicates that the oils could be used industrially (soap making). An iodine value of 54.63g I2/100g coconut oil, 49.21g I2/100g avocado oil and 55.01g I2/100g carrot oil obtained indicates high level of unsaturated fatty acids and can explain its liquid state on storage at room temperature. Acid values of 6.10 mg KOH/g coconut oil, 9.40 mg KOH/g avocado oil and 6.50 mg KOH/g carrot oil indicated that the oils are acceptable for industrial purposes. The % FFA values obtained as 3.10%, 4.70% and 3.30% for coconut, avocado and carrot oils respectively indicates the suitability of the oils for consumption. The FTIR scan analysis showed the various compounds present in the oils and by indication presented that coconut oil have dominant properties over that of carrot oil and should not be used as base oil for its extraction. Carboxylic acid (effective in providing antioxidant and anti-aging protection as well as improving moisture retention) and aromatic groups were found present as well as esters (excellent hydrating and softening agents). These compounds are found in all vegetable oils thereby validating their quality and explain the excellent properties of carrier oils and why they are used in conjunction with essential oils for aromatherapy purposes as well as for human consumption.