The adsorption of dibutyl phthalate (DBP) from aqueous solution using phoenix leaves activated carbon (PLAC) by chemical activation with phosphate was investigated. After scanning electron microscopy, energy dispersive X-ray spectrometry, Brunauer-Emmett-Teller (BET) and infrared spectrum characterization of PLAC, the influences of solution pH, contact time, initial DBP concentration and temperature on the adsorption rate were investigated. The isotherm, kinetic and thermodynamic parameters were explored to describe the experimental data. The PLAC has a heterogeneous distribution of grain and a well-developed porous structure. The main elements of PLAC are 24.26 % carbon, 70.65 % oxygen and 3.75 % phosphor. The BET surface area of the sample is 593.52 m 2 /g with the average pore diameter of 6.31 nm. The single-point total pore volume was found to be 0.52 cm 3 /g. The infrared spectrum showed the complexity of the material. The maximum DBP adsorption rate was 97.36 %, and the maximum adsorption capacity was 48.68 mg/g at pH 13. The monolayer sorption capacity of the biosorbent for DBP was found as 133.33 mg/g with the Langmuir isotherm. The equilibrium data fitted with Freundlich isotherm better than Langmuir, Dubinin-Radushkevich and Temkin isotherm. The kinetic data were best described by the pseudo-second-order model better than pseudo-first-order kinetic, intraparticle diffusion, and Elovich model. The thermodynamic studies indicated that the sorption process spontaneous, thermodynamically favorable and endothermic. The PLAC can be an alternative material for treatment of DBP wastewater.
To consider the influence of the quality of the accelerometer and the installation position on the test frequency, a test scheme was designed to identify the first-order bending frequency with free and cantilever beams as well as the first-order torsion frequency with free plates. According to the energy method and mode shape, the correction relationship between the elastic modulus and the first-order bending frequency of free and cantilever beams is derived alongside the relationship between the shear modulus and first-order torsion frequency of a free plate. These relationships are suitable for informing the influence of the accelerometer mass and installation. The first-order bending frequency and the first-order torsion frequency of Sitka spruce beams, slabs, and oriented strand board have been measured along the length, which verifies the effectiveness of the derived relation in testing the elastic modulus and shear modulus of wood materials. Taking the ratio m/M between the mass of the accelerometer and the mass of the test specimen as a parameter, the scope of application of the modified relation is discussed.
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