Preparation And Adsorption Properties Of Porous Phosphate Ceramics

With the rapid development of the economy and the increase of industrial scale,more and more heavy metal wastewater is produced in the industrial production process.Heavy metal ions can easily accumulate in animals and plants due to their high toxicity,super permeability,and difficult removal.At the same time,because of the enlargement characteristics of the food chain itself,these heavy metals may eventually accumulate in large quantities in the human body,threatening human health.Therefore,the treatment of heavy metal pollution has become the focus of attention,and how to achieve the stabilization of heavy metal ions is one of the main means to eliminate heavy metal pollution.Chemically bonded phosphate ceramics,also known as phosphate cement,are currently commonly used for rapid curing of heavy metal ions.They have an excellent binding ability with heavy metal ions and can effectively reduce the leaching rate of heavy metal ions.Therefore,this paper intends to prepare porous phosphate ceramic particles by various physical and chemical means,improve the specific surface area of the material,make it more conducive to heavy metal ions into the material,effectively improve the adsorption performance of the material,so as to provide the corresponding theoretical and technical support for the treatment of heavy metal pollution.In this paper,porous phosphate ceramics were prepared with magnesium phosphate cement as matrix and foaming agent,and the adsorption properties of heavy copper,lead,chromium and cadmium wastewater were studied.The effects of M/P and foaming agent content on nitrogen adsorption,desorption curve,pore size distribution curve and specific surface area of porous phosphate ceramics were studied.The adsorption performance and adsorption principle of heavy copper,lead,chromium,and cadmium waste liquor were also studied.In order to further study,the modification of porous phosphate ceramics,the effects of modifier concentration,modification temperature and modification time on nitrogen adsorption,desorption curve,pore size distribution curve and specific surface area of modified porous phosphate ceramics,as well as the adsorption performance and adsorption principle of heavy copper,lead,chromium and cadmium waste liquor were studied.In this paper,porous phosphate ceramics were prepared by using a foaming agent by chemically bonded phosphate ceramics,and the adsorption properties of heavy copper,lead,chromium and cadmium wastewater were studied.The effects of M/P ratio and foaming agent content on pore structure,pore size distribution curve,specific surface area,phase and microstructure of porous phosphate ceramics were studied using nitrogen adsorption,X-ray diffraction,and electron microscopy.The adsorption properties and adsorption principles of heavy metal ions such as copper,lead,chromium,and cadmium waste liquor were also studied.In order to optimize the adsorption performance of porous phosphate ceramics,the effects of modifier concentration,temperature and time on the porous phosphate ceramics,pore structure,pore size distribution,and specific surface area were studied.At the same time,the adsorption performance and adsorption principle of heavy copper,lead,chromium,and cadmium wastewater were also studied.The results show that the specific surface area of porous magnesium phosphate ceramics with 3% Na HCO3 as foaming agent reaches 67.085 m2/g and the pore concentration is between 3 and 10 nm.With the increase of M/P,the specific surface area of samples without foaming agent decreases.The specific surface area of samples without foaming agent is only 8.255 m2/g,while that of samples with 5% Na HCO3 as a foaming agent can reach 114.204 m2/g.It can be seen that the specific surface area of samples with a foaming agent can reach 114.204 m2/g.It can increase the specific surface area of the material.The highest adsorption amounts of heavy copper,lead,chromium,and cadmium waste liquor were 69.031 mg/g,93.654 mg/g,56.026 mg/g,and 59.124 mg/g,respectively.All these adsorption principles accorded with a quasi-second-order kinetic equation,namely chemical adsorption.Porous phosphate ceramics were modified by microwave hydrothermal treatment with an M/P of 1 and a porous phosphate ceramic with a foaming agent content of 3% as a modified matrix.When the hydrothermal temperature was 150? and the holding time was 30 min.The specific surface area of the sample with the largest specific surface area after modification reached 129.224 m2/g,which was 62.139 m2/g higher than the original sample.The modified porous phosphate ceramics have the highest adsorption capacity for heavy metal copper,lead,chromium,and cadmium waste liquids of 20.007 mg/g,97.728 mg/g,60.609 mg/g,and 49.126 mg/g,and all the reactions comply with the standard.The first-order kinetic equation,namely physical adsorption.The main reason for these changes may be the decomposition of some crystalline struvite due to excessive temperature during the modification process,resulting in the reduction of struvite,indicating that struvite plays a significant role in the adsorption of heavy metal ions.In conclusion,the porous ceramics prepared by chemical bonding phosphate ceramics can effectively adsorb heavy metal ions,and the specific surface area can be effectively improved by hydrothermal modification,but the improvement of adsorption performance still needs further study.This study can provide new materials for the treatment of heavy metal pollution,to achieve better environmental safety.