Application Of LDHs Super-Stable Mineralization Materials In Soil And Phosphorus-Containing Wastewater Treatment

Clear waters and lush mountains are invaluable assets.However,due to man-made reasons and geological changes,the problem of environmental pollution has become increasingly prominent,which has posed a serious threat to people’s health.Among them,heavy metal pollution in soil and eutrophication of water bodies are particularly prominent and have become green development.key issues that need to be addressed in the process.Due to the characteristics of non-biodegradability,easy accumulation and high toxicity of heavy metal ions in the natural circulation process,it is very harmful to animals,plants and humans,especially soil heavy metal pollution.It poses a serious threat to human health;in addition,eutrophication of water bodies not only deteriorates water quality,but also causes the death of aquatic animals due to lack of oxygen.Therefore,the treatment of soil heavy metal pollution and water eutrophication is imminent.In situ mineralization technology has become a very promising repair technology among many repair technologies because of its quick effect and large-scale use,and has been widely used in practice.However,given the huge amount of polluted water and soil,designing low-cost,green and environmentally friendly remediation agents with strong mineralization remains a huge challenge.Hydrotalcite-like（LDHs）have attracted extensive attention in basic research and practical applications due to their high removal efficiency,simple operation method,good long-term effect,and low cost,LDHs have great potential in the field of wastewater/soil remediation.In this work,LDHs was used as a remediation agent,and a new process of low-cost,easy-to-operate,and continuous production of high-performance Ca Al-LDHs super-stable mineralizer was successfully realized through synthetic strategy innovation.Then,the Cu Al-LHD obtained by the mineralization was fully utilized to realize the effective fixation of phosphorus;through elemental etching,a Ca Fe-based repair agent with good adsorption properties for heavy metals arsenic and cadmium was obtained.Magnetism achieves effective separation of heavy metals from soil.The specific research work is as follows:（1）Through the innovation of synthesis strategy,the Ca Al-LDH super-stable mineralizer with different proportions of components was prepared by a clean process,and the efficient removal of copper ions in wastewater was realized by using the isomorphous substitution characteristics of Ca Al-LDH,and Cu Al-LDH was obtained.;Further,the obtained Cu Al-LDH was used as a mineralizer,and the strong chemical binding ability between copper and phosphate was used to explore its ability to remove phosphate in wastewater.The experimental results showed that when the p H of the reaction system was adjusted to 6.6,The mineralization ability of Cu Al-LDH to P is significantly improved,and the adsorption capacity of Cu Al-LDH to P reaches 49.55 mg·g^-1,which is better than most of the existing phosphorus adsorption materials,and the removal rate reaches 93.58%,and can effectively avoid Cu²⁺in water Dissolution effectively avoids the secondary pollution of Cu²⁺to the water body,and explores the possible mechanism of action in the mineralization process,providing new ideas and materials for the reuse of waste resources.（2）In view of the excellent mineralization properties of the hydrotalcite-like materials containing calcium,iron and other elements to heavy metals such as cadmium and arsenic in the previous work,in this work,the Ca Mg Fe-LDH precursor was prepared by co-precipitation,and the composite metal was obtained by high temperature roasting The composite spinel material with rich pore structure was obtained by dissolving Mg in the composite oxide by NH₄⁺,and showed good magnetic properties.Using this material as a mineralizing material,it was used for the mineralization of As（III）and Cd（II）in water/soil,and the adsorption amount of As（III）in the water system could reach 11.91mg·g^-1,and the removal of As（III）could reach 11.91 mg·g^-1.The adsorption rate of Cd（Ⅱ）can reach 98.58 mg·g^-1,and the removal rate is82.15%,which is higher than most of the reported magnetic adsorption materials.Using its magnetic properties,the separation of contaminants from the substrate can be effectively achieved to achieve complete removal of contaminants.The research in this paper provides a new strategy for the green preparation of LDHs super-stable mineralizer,and provides technical support for further practical applications;at the same time,it provides new materials and new ideas for the remediation of heavy metal contaminated soil and phosphorus-containing wastewater The recycling of resources provides a new way.