Sufeng Wang,Xiaojuan Lv,Mingwei Fu,Zijing Wang,Dan Zhang,Qina Sun
Artemia egg shell loaded with nano-magnesium (shell-Mg) can be used to recover phosphorus from wastewater. The exhausted Artemia egg shell-Mg (denoted as shell-Mg-P) can be used as a slow-release fertilizer for phosphorus reuse. However, due to the coexistence of heavy metal ions in the environment, the application of slow-release fertilizer for phosphorus removal and reuse may have potential risks. In this paper, the potential risks of Pb 2+ , Cd 2+ , Zn 2+ and Cu 2+ in phosphorus wastewater and soil were studied from the formation and application process of shell-Mg-P. The result showed that shell-Mg adsorbed Pb 2+ , Cd 2+ , Zn 2+ and Cu 2+ in phosphate wastewater during the formation of shell-Mg-P and became shell-Mg-P-metal hybrid biomaterial . Although the experiment proved that the existence of heavy metal ions did not affect the phosphorus slow-release behavior of slow-release fertilizer, but the heavy metal ions in the shell-Mg-P-metal were also slow released. The pot experiment results confirmed that the slow-release phosphorus fertilizers (shell-Mg-P and shell-Mg-P-metal) in the soil polluted in low concentration of heavy metals can reduce the amount of heavy metals in whole wheat seedlings and promote wheat seedling growth. However, the application of slow-release fertilizers increased the translocation efficiency (T FR to SL ) of metal from root (R) to aboveground part (stem and leaves, SL), promoted the transportation of heavy metals from roots to the stems and leaves, and increased the safety risk of the wheat seedling edible. Therefore, besides the positive role of slow-release fertilizers in retaining heavy metals and reducing the amount of heavy metals in whole seedlings, the risk that it may aggravate the translocation of heavy metals to stems and leaves should be paid more attention, so as to ensure the safe and reliable application of slow-release fertilizers.
Zhao Rongxia,Pei Jinxuan,Du Wenbo,Zhao Zhanyong,Zhang Lizheng,Gao Jianfeng,Bai Peikang,Tie Di
The surface of graphene (GNP) has been successfully coated with magnesium nano-metal to form composite structures in situ via the organic chemical reduction method. The results demonstrate that the organic chemistry plated was successfully used to synthesize 30–50 nm Mg nanoparticles (nano-Mg) smoothly occurred on the surface of graphene. The HRTEM results confirmed that heterogeneous nucleation of Mg promoted the tight bonding between the nano-Mg and the graphene interfaces. In addition, the wettability and dispersibility of magnesium-coated graphene within the AZ91 alloy matrix have been greatly improved, resulting in more β-Mg 17 Al 12 strengthening phase with a size of 100–300 nm dispersion and precipitation in the enhanced magnesium-matrix composite. These results reveal that the magnesium-coated graphene significantly affects the microstructure of the composite and exhibits an excellent reinforcement effect. Graphic Abstract
Due to high reaction activity and high combustion heat release, magnesium is widely used in the field of explosives. The research focus of this article is the effect of magnesium powder size and content on the thermal decomposition of PTFE. Two different particle sizes of magnesium powder are regarded as research objects. The thermal behavior of Mg/PTFE energetic system was investigated by TG-DSC analyzer. The experimental results show that magnesium has a catalytic effect on the thermal decomposition of PTFE. With the increase of magnesium content , the decomposition peak temperature of PTFE decreased firstly and when passed the ratio 50% increased, the best mixing ratio is Mg: PTFE =50:50. Within nanopowder, the activation energy of PTFE decreased by 150kJ∙mol-1 compared to 112 kJ∙mol-1 by mixing with micro powder. Obviously nanopowder has a better reactivity than micro powder, so has a more obvious catalytic effect.
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