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The liquefaction mechanisms of the algal biomass to bio-oil were investigated by using Fourier transform infrared spectroscopy, X-ray diffraction, and scanning electron microscopy, respectively. It was found that NaOH was a satisfactory catalyst and contributed to helping the liquefaction of algal biomass. The bio-oil from algal biomass was composed of many compounds, including carbohydrates, alcohol, hydroxybenzene, carboxylic acid, alkene, ester, and others. The mechanism of hydrothermal catalytic liquefaction was discussed. It was found that, comparing with the husk bio-fuel, the algal bio-oil as a promising alternative fuel was more close to the traditional diesel fuel in physicochemical properties. The novel research outcomes contribute to improving the yield of bio-oil from microalgae, reducing the cost of the bio-oil and accelerating the commercial application of the algal bio-oil in the near future.

One kind of novel biodiesel waste cooking oil ethyl ester (WCOEE) was prepared via transesterfication reaction between waste cooking oil and ethanol. The tribological behavior of diesel/WCOEE blend was evaluated with a four-ball tribometer. The wear resistance, extreme pressure, and friction reduction of the blend were improved with increasing WCOEE. The optimal content of WCOEE in the blend was 20 vol%. It was also found that free fatty acids (FFAs) had a positive effect on the wear resistance of blend. The lubrication improvement of the blend was ascribed to the formation of polyester film and high polarity of fatty acid ethyl ester.

A bio-oil was prepared from planktonic algal biomass via thermochemical liquefaction with a NaOH catalyst. The effects of reaction conditions, including temperature, time, and the ratio of biomass to solvent, on the liquefaction yield were investigated. The liquefaction yield initially increased and then decreased with increasing temperature and reaction time. The maximum yield (61.6%) was observed after liquefaction at 300°C for 30 min with 0.2 mol/L NaOH as a catalyst and a biomass to solvent ratio of 1:10. The chemical components of the obtained bio-oil were analyzed via gas chromatography/mass spectrometry, with results indicating that the algal bio-oil was composed of furan, phenol, acid, and ester derivatives.

An engine cylinder liner–piston ring tribotester was used to investigate the effects of different diesel fuels on the tribological properties of a cylinder liner–piston ring. The wear surface morphology and roughness were analyzed using a scanning electron microscope and a surface profiler. The chemical structures and components of the tested oils were characterized using a Fourier transform infrared spectrophotometer and gas chromatography–mass spectrometry. The chemical components and element distribution on the rubbed surface were studied using energy-dispersive X-ray spectra. The results showed that the cylinder liner–piston ring lubricated with bio-oil (BO) had a lower friction coefficient but higher wear mass and greater surface roughness than one lubricated with diesel oil (DO), and emulsified bio-oil (EBO) can decrease the wear weight loss and surface roughness of the friction pairs. The protective film created by BO between the cylinder liner and piston ring lowered the friction coefficient due t...

Molybdenum disulphide composite particles made of both hollow nanospheres and nanoplatelets were synthesised in a single process using a chemical method that was optimised by adjusting the relative proportions of Na2S and thioacetamide (TAA) precursors. The composite nanoparticles were characterised using powder X-ray diffraction, transmission electron microscopy and thermal analysis; four-ball tribological tests were used to assess their lubricating effect when used as additives in liquid paraffin dispersions. The results showed that composite nanoparticles of appropriate shape distribution could only be synthesised with a high dosage of TAA: too high concentrations of Na2S were shown to destroy the template chain of TAA and disturbed the formation of nanospheres. The MoS2 composite particles exhibited a better lubricating effect as compared to composite particles produced by mechanical mixing of separately produced nanospheres and nanoplatelets, confirming that the chemical method can lead to a better synergistic lubrication between two kinds of MoS2 nanoparticles.

Ni–P coatings were co-deposited with MoS2 nanoparticles on medium carbon steel substrate by electroless plating. The effects of incorporation of MoS2 nanoparticles into the Ni–P coating on the morphology of the coating surface and corrosion properties were investigated. X-ray diffraction pattern and X-ray photoelectron spectroscopy spectra showed that the MoS2 nanoparticles were covered in the nickel phosphor matrix. Corrosion tests were conducted in aqueous 10 wt-%HCl, 10 wt-%NaOH and 3·5 wt-%NaCl using a weight loss method, and in aqueous 3·5 wt-%NaCl by electrochemical measurement for bare substrate, Ni–P coating and Ni–P–(nano-MoS2) composite coating, respectively. The experimental results showed that corrosion resistance of the coating containing MoS2 was slightly lower than that of the coating without MoS2. The corrosion rate of Ni–P–(nano-MoS2) composite coating in HCl aqueous solution was found to be increased owing to the corrosion microcells and high porosity and rougher surface. Ni–P– (...