The heavy discharge of industrial wastewater containing heavy metal ions has caused serious pollution to water bodies and soils. Due to the heavy toxicity and biodegradability of heavy metals, the polluted water bodies have serious consequences for humans, animals and plants. The surface of magnetic materials is easy to be functionally modified and has good magnetic sensitivity. However, some single magnetic materials have problems such as easy aggregation and difficult to disperse and separate, which limits their application. And by combining a single magnetic material with other materials, colleagues who can play their advantages can avoid the defects. The magnetic composite material changes the movement of heavy metal ions in sewage to achieve the effect of adsorption under the action of a magnetic field. It has the advantages of wide source of materials, simple preparation method, efficient adsorption, and repeated use. With a wide range of applications, the research and development of magnetic composite materials has also received widespread attention. This article gives a comprehensive overview of the structural properties of different magnetic composites and their adsorption effects on heavy metal ions, in order to provide research directions and new ideas for magnetic composites on heavy metal ion adsorption.
A novel three-dimensional aluminum sludge/polyvinyl alcohol/sodium alginate(AS/PA/SA) gel spheres were designed and prepared for uranium(VI) adsorption, and it overcomes the shortcomings of poor recycling of powdery aluminum sludge adsorbent and poor stability of sodium alginate. Experiments show that the P-S-AS has a good pH range for removal of uranium (4-5). Fitting experimental data with pseudo-first-order kinetic model and pseudo-second-order kinetic model shows that the adsorption of U(VI) by P-S-AS is a chemical action. The fit of the Langmuir isotherm model and Freundlich isotherm model to the experimental data found that the P-S-AS adsorbed U(VI) to a single layer. Thermodynamic analysis shows that the adsorption occurs spontaneously, and an increase in temperature is favorable for the adsorption of uranium by the P-S-AS. Fourier transform infrared (FTIR) and X-ray photoelectron spectroscopy (XPS) analysis of the P-S-AS before and after adsorption showed that the main adsorption mechanism was the complexation reaction between functional groups and U(VI), the bonding reaction between metal oxides and U(VI).
In recent years, the use of zero-valent metals (ZVMs) to treat environmental pollutants has been a research hotspot in the field of environment.Zero valent aluminium (ZVAl) has attracted much attention due to its lower redox potential and amphoteric properties (reaction pH can be extended to alkaline) than other metals. In this paper, zero-valent aluminium and its composite materials are used to treat pollutants in wastewater, including phenols, organic halides, azo dyes organic pollutants and perchlorate, Cr(VI), As(III) inorganic pollutants. The removal effect and reaction mechanism were also clarified. The existing problems and bottlenecks of this method are further discussed, and the development direction and application prospect of zero-valent metal aluminium redox technology are prospected.
In this study, a new type of plastic carbon fiber filler was applied to biofilm technology. The optimum purification conditions for eutrophic landscape water were discussed by controlling the filling amount, aeration volume and pollutant concentration. The activated sludge from the sewage treatment plant is used for aeration and filming to explore the effect of the filler on the purification effect of the landscape water body. Studies have shown that the composite filler has a good removal effect on CODcr, TN and TP in eutrophic water, and is a highly efficient new water treatment material.
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