Study Of Heavy Metal Ion Adsorbent’s Preparation,adsorption And Recovery Performance

As an important pollutant in aquatic system,heavy metal ions have a wide range of sources in electroplating,metallurgy,chemical industries and other industries.They are enriched,poorly degradable,continuing existence,causing great damage to the ecological environment and human health.Among many heavy metal removal technologies,the adsorption method has the advantages of high efficiency,environmental friendliness,and low cost,but it also has the technical bottleneck that waste adsorbents are difficult to handle.Therefore,this article takes the removal of typical heavy metal ions Cd（II）as an example,and prepares a series of high-efficiency adsorbents suitable for heavy metal removal.At the same time,it proposes a conversion path to convert saturated adsorbents into catalysts,which effectively solves the problem of waste adsorbents.To deal with the problem.The main research contents and results of this paper are as follows:（1）Based on natural attapulgite（ATP）materials,a magnetically recyclable Fe₃O₄/ATP composite material was prepared,and its Cd（II）adsorption performance and influencing factors were studied.At the same time,the Cd（II）adsorption mechanism was explored.The study found that when the loading of Fe₃O₄ is 50%（FA-5 adsorbent）,its maximum adsorption capacity for Cd（II）can reach 141.1mg/g,which is 19.8%higher than that of natural ATP materials.;The adsorption process is a single-molecule chemical adsorption,and the FA-5 adsorbent has strong tolerance to p H,hetero ions and natural organic matter in the solution.Through the characterization of the physical and chemical properties of the adsorbent,it is found that Fe₃O₄ can have a strong interaction with ATP,and cause O atoms with higher electronegativity as effective adsorption sites to effectively enhance the adsorption effect of Cd（II）.（2）Aiming at Cd（II）adsorption saturated ATP and Fe₃O₄/ATP composite adsorbent,it is converted into Cd S/ATP and Cd S/Fe₃O₄/ATP photocatalytic material by introducing sulfur source.The study found that FA-5 adsorbent saturated with Cd（II）adsorption can be successfully converted into Cd S/FA-5 photocatalyst,which can complete the rapid degradation of tetracycline within 15 minutes,and degrade antibiotics（25 ppm）effectiveness reached 74.1%within 2 hours.Through a series of physical and chemical characterization,it is found that the existence of heterojunction in the Cd S/Fe₃O₄/ATP catalyst effectively promotes the transfer of electrons and holes,inhibits the recombination of photogenerated carriers,and promotes the photocatalytic degradation of tetracycline.（3）Based on Mg-Al hydrotalcite,a series of Ni-Mg-Al hydrotalcite derivatives（LDOs）composites were prepared by in-situ doping with Ni atoms in its hydrotalcite structure.The Cd（II）adsorption properties and recycling performance were investigated.Studies have found that Ni doping can effectively improve the material’s adsorption performance for Cd（II）.When the Ni/Mg/Al-mole ratio is 0.1/1.9/1,the Cd（II）adsorption capacity can reach 264.6mg/g.At the same time,compared with the Mg/Al-LDOs adsorbent,the modified Ni/Mg/Al-LDOs adsorbent is recovered as a Cd S-based photocatalytic material,and its tetracycline photocatalytic degradation efficiency is from 51.3%of Cd S/Mg/Al-LDOs increased to 75.3%of Cd S/Ni/Mg/Al-LDOs..This is a major breakthrough for the recycling of adsorbents and effectively enhances the economic applicability of the water treatment process.