排序方式: 共有4条查询结果,搜索用时 0 毫秒
1
1.
Raisibe Florence Lehutso James Wesley-Smith Melusi Thwala 《International journal of molecular sciences》2021,22(22)
The study investigated the toxicity effects of ‘form specific’ engineered nanomaterials (ENMs) and ions released from nano-enabled products (NEPs), namely sunscreens, sanitisers, body creams and socks on Pseudokirchneriella subcapitata, Spirodela polyrhiza, and Daphnia magna. Additionally, risk estimation emanating from the exposures was undertaken. The ENMs and the ions released from the products both contributed to the effects to varying extents, with neither being a uniform principal toxicity agent across the exposures; however, the effects were either synergistic or antagonistic. D. magna and S. polyrhiza were the most sensitive and least sensitive test organisms, respectively. The most toxic effects were from ENMs and ions released from sanitisers and sunscreens, whereas body creams and sock counterparts caused negligible effects. The internalisation of the ENMs from the sunscreens could not be established; only adsorption on the biota was evident. It was established that ENMs and ions released from products pose no imminent risk to ecosystems; instead, small to significant adverse effects are expected in the worst-case exposure scenario. The study demonstrates that while ENMs from products may not be considered to pose an imminent risk, increasing nanotechnology commercialization may increase their environmental exposure and risk potential; therefore, priority exposure cases need to be examined. 相似文献
2.
Gcina D. Vilakati Ajay K. Mishra Shivani B. Mishra Bhekie B. Mamba Justice M. Thwala 《Polymer Engineering and Science》2012,52(4):760-767
This study describes the applicability of lignocellulosic fiber dispersed in ethylene vinyl acetate (EVA) to adsorb Pb(II), Cr(III), and Cr(VI) ions in aqueous solutions. Water absorption studies revealed that metal‐ion uptake does not only take place on the surface of the adsorbent but ions can also diffuse into the composite. The adsorption of the metal ions under different experimental conditions was studied. Solute concentration, pH, and contact time were used to assess the adsorption capacity and efficiency. The amount of metal adsorbed increased to 7 mg/g with an increase in solute concentration but compromising the efficiency. Adsorption equilibrium was reached after 3 h, when the maximum lead adsorption was above 80%. The optimum pH for the adsorption of Pb(II) and Cr(III) was 6.5, and pH 2.5 was used for the adsorption of Cr(VI). Competitive adsorption revealed the order of adsorption to be: Pb(II) > Cr(VI) > Cr(III). POLYM. ENG. SCI., 2011. © 2011 Society of Plastics Engineers 相似文献
3.
Description of philophonetics counselling as expressive therapeutic modality for treating depression
AI & SOCIETY - Depression is ranked as most common type of mental illness by the World Health Organization (WHO in Depression and other common mental disorders: Global health estimates. World... 相似文献
4.
G. D. Vilakati A. K. Mishra S. B. Mishra B. B. Mamba J. M. Thwala 《Journal of Inorganic and Organometallic Polymers and Materials》2010,20(4):802-808
The effect of nano-particles of TiO2 on the mechanical and thermal properties of sugarcane bagasse (SCB)–ethylene co-vinyl acetate (EVA) composite was investigated.
Composite materials were prepared using a melt-mix intercalation method on a rheomex mixer coupled with a single screw extruder.
differential scanning calorimeter (DSC), thermogravimetric (TG) analyser and an Instron, were used to probe the thermal and
mechanical properties of the samples. Composites with TiO2 were compared with those without TiO2 but with the same content of sugarcane bagasse (SCB). After the addition of TiO2, the tensile strength increased by 10%, from 11.26 MPa for neat EVA, which correlated with the enthalpy of fusion, however,
the tensile strength decreased by 18% at higher SCB loading. Elongation at break decreased from 463 to 0% as the filler (SCB)
was increased which was inversely proportional to the modulus. The composite showed an improved thermal stability with the
addition of TiO2. 相似文献
1