No abstract

The concentration of ammonia nitrogen in a slaughterhouse wastewater sample was determined using Nessler's reagent spectrophotometry with four different pretreatment approaches. Comparison of the results shows that the concentrations increased in the following order: coagulation sedimentation < boric acid absorption < filtration < acidifying filtration. Boric acid absorption method is more favorable, and standard curve method (SCM) should be considered superior to standard addition method (SAM) in the present research.

Adsorption effects of three kinds of activated carbons and a type of machine-made charcoal on the removal of antimony from acidic aqueous solution were investigated and compared. With an initial antimony solution concentration of 1000 μgL-1, the antimony adsorption by selected adsorbents were found to descend in the following order: machine-made charcoal (52.4%) > coconut activated carbon (42.6%) > coal based activated carbon (31.1%) > apricot stone based activated carbon (24.6%). The machine-made charcoal has the best adsorption capacity with a maximum adsorption values of 523.76 μgL-1. Five kinetic models were used for the fitting of the process of antimony adsorption, including Elovich, parabola diffusion, second order, first order and double-constant. Results showed that parabola diffusion and double-constant rate equation were the most suitable models in describing the relationship of antimony adsorption with time in acidic aqueous solution, implying that the adsorption kinetics of the antimony by the selected adsorbents in water might be a surface diffusion. Three adsorptive capacity indicators (iodine number, methylene blue number and phenol number) were determined in this paper. However, machine-made charcoal, which has a relatively high adsorption capacity, is of the lowest levels of the adsorptive capacity indicators. Thus, some complex mechanisms might be involved for the antimony adsorption by the machine-made charcoal, consequently considering the mechanism for the adsorption of antimony by the charcoal has not been verified, a further study still needs to be done.

A series of deep indentation and uniaxial compression tests of closed-cell aluminum foams at room temperature as well as elevated temperatures were conducted. A flat-ended punch (FEP) was used in the indentation tests. Cross-sectional views of the specimens after tests show that the deformation is roughly confined to the material directly underneath the indenter with slightly lateral spread. It is found that plastic collapse strength and energy absorption of the specimens are temperature dependent in both loading conditions. Tear energy of the foam in FEP indentation depends on the indentation depth and temperature.

The affecting factors and kinetic characteristics of antimony (Sb) adsoption onto a type of the coconut shell activated carbon were investigated in this study. The results showed that: the Sb adsorption obeyed the pseudo-second-order kinetics equation, and the coefficients of determination (R2) were higher than 0.97, inferring that this process was mainly the monolayer chemical adsorption. With the reduction of the particle size, the adsorption capacity of activated carbon gradually increased. With the increase of temperature, activated carbon adsorption of antimony content increased gradually, but on the whole the temperature had a limited effect on the adsorption of activated carbon. Effect of the solution pH on antimony adsorption onto the activated carbon was mainly divided into the following two stages: with a pH value of 1 to 3, antimony removal rate was about 60%, and with a pH value of 5 to 11, the removal rate was about 20%.

Aims We aimed to investigate whether left bundle branch block (LBBB) is related to newonset left ventricle (LV) wall motion abnormalities during treatment in hypertensive patients with electrocardiogram (ECG) defined left ventricular hypertrophy (LVH). Methods and results 960 patients with essential hypertension and ECG-LVH participating in the LIFE Echo Sub-study were investigated at baseline and annually with echocardiography, during randomized antihypertensive therapy. After excluding patients with LV wall motion abnormalities at baseline and patients developing new-onset LBBB during study time, we investigated 784 patients. The participants with (n=32) and without (n=752) LBBB were similar regarding most baseline variables. Logistic regression models controlling for LV mass index, Framingham risk score, and randomized treatment assignment were used to assess the odds ratio of developing new-onset abnormal LV wall motion on annual follow-up echocardiograms. The likelihood of developing new global LV wall motion abnormalities in patients with LBBB was not higher compared to those without LBBB except at year 5 (p=0.002). The likelihood of developing new segmental LV wall motion abnormalities in patients with LBBB was however higher compared to patients without LBBB after 1 year (OR=3.

The modified Tessier method was used in the present study to analyze the antimony (Sb) speciation in suspended solids in mining wastewater from Ban-po Antimony Mine in Guizhou province. It was found that the residual fraction and the soluble fraction are the highest and the lowest in the five Sb fractions, accounting for 62.5% and 3% of the total respectively. The order of the five Sb fractions is: the residual fraction > the reduced fraction > the oxidation fraction > the acid-extractable fraction > the soluble fraction. The antimony soluble form in aqueous solution is mainly Sb (V), about 90% of the total. The results from the analysis by X-ray diffraction and scanning electron microscopy showed that the major crystalline forms of suspended solids are K-Mg-Fe-Al-Si-O-H2O, Cu3SbS4, 3CaO·2Sb2O5·8H2O, SiO2 and the content of antimony element is approximately 2.55%.

The single-factorial design of experiments and response surface methodology was applied to optimize ultrasonic-assisted regeneration of coconut shell activated carbon. With the pH values of the solution, solid-liquid ratio, irradiation time chosen as the independent variable and the activated carbon release of antimony as response values, the central composite design method was used to study each of the variables and their interactions on coconut shell activated carbon regeneration. The results of this study showed that: the optimum pH value was 13; solid-liquid ratio was 372 mL·g-1; irradiation time was 6.7 h. The average content of the release of Sb from the activated carbon was 6233.95 μg·g-1 under the optimum condition. Regeneration rate of the activated carbon was 84.45%. This demonstrated that the adsorption efficiency of Sb was close in regenerative carbon and the original carbon. The results proved that the ultrasonic-associated coconut shell activated carbon regeneration process was accurate and reliable, and can provide a reference for the regeneration of coconut shell activated carbon which had adsorbed Sb.