Morphology and Properties of Zn-Al-TiO2 Composite on Mild Steel

The influence of TiO2 composite and dispersed pure Al particle on zinc alloy electrodeposited on mild steel was studied from chloride bath solution.Microstructural and mechanical properties of the alloy were investigated. The structure, surface morphology, and surface topography of the deposited alloys were characterized by scanning electron microscopy (SEM) and atomic force microscope (AFM).In addition, hardness of the coated alloys was measured. It was found that the obtained Zn-Al-TiO2 alloyexhibited more preferred surface morphology and mechanical strength compared tothe substrate. The result shows the existence of interaction between TiO2 compounds and zinc alloy particulate. It also exhibited well bright dominate zinc coating on steel surface

Effect of Tobacco and Kola Tree Extracts on the Corrosion Inhibition of Mild Steel in Acid Chloride

Corrosion and inhibitor protection of mild steel specimens immersed in acid chloride solution was investigated at ambient temperature by gravimetric and potential monitoring methods. The electrode potential monitoring was performed using a digital voltmeter and a saturated calomel electrode (SCE) as the reference electrode. Extracts of kola plant and tobacco in different concentrations were used as ‘green’ inhibitors. This paper reports the results obtained from the weight loss method, calculated corrosion rates and the observed electrochemical response from the electrochemical potential monitoring of the mild steel during the experiments. A reduction in the active corrosion reactions behaviour of the mild steel test specimens in the strong acid chloride was obtained with the addition of different concentrations of the plants extracts. There was a drastic reduction in the weight loss and in the corrosion rate of the test samples. This behaviour was attributed to the protective film provided on the steel’s surface by the complex chemical constituents of the plants extracts. Effective protection of the mild steel was achieved in nearly all the extracts for the greater part of the experimental period. However, the most effective results were obtained from the tobacco extract and also from the extract of kola leaf

Levels of awareness and concentrations of heavy metals in the blood of electronic waste scavengers in Nigeria

Background - Electronic waste (e-waste) contains both valuable and hazardous materials. E-waste scavengers specialize in the collection and crude recycling of waste electronics to retrieve valuable metals, which are then sold. These activities provide an income for scavengers, but also expose them to toxic heavy metals such as lead (Pb) and copper (Cu). Objectives - The aim of the present study was to investigate the level of awareness and concentrations of heavy metals (Pb, Cu, zinc (Zn) and manganese (Mn)) in the blood levels of e-waste scavengers at Jakande dumpsite, Alaba International Market, Lagos, Nigeria. Methods - Material and data were collected by empirical survey with the use of a questionnaire to obtain information from e-waste scavengers. Blood samples of the scavengers in the present study (30 adult males exposed to recycling processes) were collected and concentrations of heavy metals were determined through acid digestion and the use of an atomic absorption spectrophotometer (AGILENT 55B AA, 2010). Results - The geometric means of blood levels of Pb, Cu, Zn and Mn were 11.0, 33.85, 126.15 and 19.38 µg / dL, respectively. High concentrations of Pb and Mn (11.0 and 19.38 µg / dL) were found in the blood samples, while Zn and Cu (126.15 and 33.85 µg / dL) showed low concentrations. The maximum blood level of lead (BPb) (24.0 µg / dL) was extremely high compared to the maximum BPb of occupationally exposed males. Statistical analysis of the questionnaires showed that all of the respondents were male, and more than half (56.7%) were between 21-30 years of age and had been involved in recycling of e-waste for 1-5 years. The results showed that 83% of the respondents were aware that hazardous fractions in e-waste require special treatment, while 76.7% were aware of the possible negative impact on their health. Conclusions - Lack of education, poverty and lack of effective enforcement of e-waste management and regulations are the major contributors to the current situation and thus scavengers carry on with their activities unhindered. The authors recommend the use of protective clothing, sensitization visits and awareness campaigns on the safe disposal of hazardous components

Inhibitive effect of ferrous gluconate on the electrochemical corrosion of aluminium alloy in H2SO4 solution

The use of ferrous gluconate as corrosion inhibitor on aluminium alloy in 0.5M H2SO4 solution was studied using gravimetric and potentiodynamic polarization measurements. The surface morphology of the aluminium alloy was studied after exposure to 0.5 M H2SO4 solution in the presence and absence of inhibitor using high resolution scanning electron microscopy equipped with energy dispersive spectroscopy (HRSEM – EDS). The adsorption behaviour of the inhibitor was investigated. The results of the investigation show that increase in concentration of ferrous gluconate corresponds to an improvement on inhibition efficiency. Equally, the results showed the ferrous gluconate to be an effective corrosion inhibitor for the aluminium in the acidic medium. The results obtained from the two methods used were found to correlate with each other