The current study proposes a novel and improved cigarette filtration design comprising cellulose nanofibers (CNFs) and powdered activated carbons (PACs) with different dry matter contents. The proposed filter samples were primarily analyzed to verify their applicability as cigarette filters via measurements and standard tests, such as SEM, BET, DSC, and airflow permeability analysis. The results were compared with the cellulose acetate (CA) sample used as a conventional cigarette filter. The preliminary results indicated noticeable improvement compared to the reference CA. Also, the cigarettes were tested using a smoking machine, and the filtered smoke was analyzed using GC–MS to evaluate the filters' performance in reducing the harmful substances present in the smoke. The results showed that the filters made of CNF and PAC significantly decreased the toxic substances compared with the reference but did not affect the nicotine substantially and therefore will not negatively impact the trance level of smokers.
With the common application of nanoscale zinc oxide (nZnO) and significant potential for its release directly into aquatic environments, it is urgent to carry out research on ecotoxicological impact of nZnO. The characterization of nZnO, the amount of ˙OH in suspensions in the presence of light and the acute toxicity of nZnO and its bulk counterpart suspensions, as well as the acute toxicity of Zn(2+) solution to zebrafish (Danio rerio) at 96 h were studied. It was found that nZnO aggregated into irregular shapes in suspensions, and showed a relationship between its size distribution and concentration. In the presence of light, nZnO suspensions could generate ˙OH, the concentration of which increased with time. Although it was generally thought that ˙OH played a role in the biotoxicity to zebrafish, similar toxicity was observed for the nZnO and bulk ZnO suspensions (96 h LC(50) 3.969 mg L(-1), 2.525 mg L(-1), respectively). Furthermore, the sedimentation of nZnO and bulk ZnO in suspensions, and the accumulation of Zn in zebrafish were studied. The results showed that dissolved Zn(2+), from nZnO and bulk ZnO in suspensions, were toxic to zebrafish, while the aggregation and sedimentation of nZnO suspensions reduced the toxicity of nZnO. However, Zn(2+) may not be the main source of acute toxicity of nZnO and bulk ZnO to zebrafish. The experimental results highlight the importance of a systematic assessment of toxicity mechanisms of metal oxide nanoparticles (NPs) to determine definitively whether their toxicity is caused by nano-effects. 相似文献
Environmental Chemistry Letters - Highly active TiO2 photocatalysts prepared at a low temperature are promising reagents to degrade organic pollutants. Moreover, the addition of... 相似文献
A new type of designed hyperbranched ethylenediamine trazine polymer (HBETP) is successfully synthesized and characterized based upon NMR and GPC. The prepared HBETP is used to modify the poly(hydroxybutyrate-co-hydroxyvalerate) (PHBV)/poly(butylene adipate-co-terephthalate) (PBAT) blends. The effect of HBETP on the microstructure, mechanical properties and thermal properties of the blends is studied. The results indicate that upon addition of 1.0 wt% of HBETP, the impact strength of the PHBV/PBAT blends is increased by 47.1%; ?Tg of the blends decreases from 53.2 to 49.9 °C. These results, together with the morphology analysis of the fractured surface of the blends, conclude the formation of the transition layer between PHBV and PBAT. Also, the XRD result shows that the addition of HBETP can limit the growth of the PHBV crystals and causes the decrease of both the crystallinity and the grain crystalline size. The DSC result demonstrates that the addition of HBETP mainly affects the crystallization of the HB-HV binary eutectic region within PHBV. The mechanism of PHBV/PBAT toughening is due to the formation of the strong physical hydrogen bonding and the chemical micro-crosslinking between HBETP and PHBV/PBAT, which is proposed based on XPS characterization. 相似文献
In this study, three stillborn and five premature and blind calves from cows suffering from chronic nitrate poisoning were examined pathologically. The live calves were euthanized, due to a poor prognosis. Complete necropsy was performed on all the eight affected calves. Hydroperitoneum and ascites were the most predominant lesions in the stillborn calves. Edema and hemorrhage were observed in the lungs of all the calves. Hemorrhages were seen in the digestive systems of four calves. Blood samples were taken from five live calves and their mothers, and from two cows that had delivered stillborn or blind calves, for biochemical observations and measurement of methemoglobin levels. Blood values of five healthy cattle from a herd with no history of stillborn or blind calves were used as controls. Water and feed samples were taken from five different farms with a history of stillborn or blind calves and examined for nitrates. Nitrate and nitrite levels of feeds ranged from 154 to 480 and 1.5 to 20?ppm respectively; these levels can cause chronic poisoning. Levels of nitrates and nitrites in blood samples from cows and calves were found to be high. While hemoglobin values were found to be low, methemoglobin values were very high. No differences were observed between liver enzyme levels of the affected and control cattle. There were no bacteria or virus isolated from these animals, and histopathological examination revealed no indication of any other diseases. 相似文献