Removal Of Ammonium And Phosphate From Water By Nano Magnesium Oxide Modified Artemia Egg Shell Biochar

Excess amounts of Ammonia nitrogen and phosphate can cause eutrophication and deterioration of ecosystems and water quality,which will cause serious harm to the environment and physical health.In this paper,the Artemia egg shell biochar composites loaded with nano-MgO?MgCS-char?were obtained by impregnation and slow pyrolysis of Artemia egg shells for adsorption of phosphate in water.The adsorbed product?MgCS-char-P?is used to remove ammonia nitrogen from water.In this paper,a series of MgCS-chars were prepared by changing the pyrolysis temperature,pyrolysis time and Mg²⁺immersion concentration.Phosphorus adsorption experiments showed that the best preparation conditions are immersion concentration 2mol/L,heating rate 5?/min,pyrolysis temperature 600?,pyrolysis time 6 h.The XRD,FTIR,SEM and TEM were used to analyze the morphology and structure of the material.The results showed that the pore structure of the Artemia egg shell was not damaged by high temperature.Nano MgO particles were successfully loaded on the surface and internal channels of MgCS-char.The results of phosphate adsorption experiments confirmed the high efficiency of MgCS-char materials in removing phosphate.Under the conditions of coexistence of HCO₃^-,NO₃^-and Cl^-ions,MgCS-char still maintains high capacity and selective adsorption for phosphate.The results of isothermal adsorption experiments show that the adsorption of phosphate by the material is an endothermic reaction,and the maximum adsorption capacity for phosphorus reaches 399.6 mg/g.Column adsorption experiments have proven that MgCS-char material has excellent treatment capacity for phosphate?700 L water/kg adsorbent?,and the effluent concentration is lower than the Grade A standard?0.5 mg/L?in the discharge standard of pollutants for municipal wastewater?GB18918-2002?.And can be regenerated by alkaline solution.MgCS-char-P has good sedimentation performance and can be separated and collected by gravity sedimentation.In addition,through the co-precipitation mechanism,MgCS-char-P can remove ammonia nitrogen in water.The combination of MgCS-char and MgCS-char-P can not only remove nitrogen and phosphorus in domestic wastewater,but also realize the recycling of materials.The phosphorus concentration in the effluent is excellent and the removal rate of ammonia nitrogen reaches 80%.The final product can be used as soil improver or slow-release fertilizer to realize waste-free treatment.