Adsorption Of Phosphorus By Zinc Nitrate Modified Silicon Mesoporous Materials And Its Application In DGT Technology

Phosphorus is one of the main elements leading to eutrophication of water bodies,and it is also an important indicator of water quality testing.Therefore,the detection and removal of phosphorus in water bodies has great practical significance.In the first part of the study,zinc nitrate modified mesoporous silica nanosphere mesoporous material?Zn-MSN?was synthesized.The adsorption performance of Zn-MSN on phosphate in water was studied,and the removal conditions of phosphate in water were optimized.The SEM,IR,TGA,XRD and nitrogen adsorption desorption characterization showed that the synthesized Zn-MSN has a mesoporous structure and a spherical appearance,and its specific surface area can reach 912.12m²/g.The adsorption kinetics of phosphorus by Zn-MSN adsorbent accords with the quasi-second-order kinetic equation.The adsorption isotherm description is the most consistent with the Langmuir model.At 298 K,the maximum monolayer adsorption capacity was 78.74 mg/g,and the adsorption process was a spontaneous endothermic process.The optimum removal conditions for phosphorus were determined by orthogonal test:temperature was 35°C,pH=2,the dosage of adsorbent was 0.5g/L,and the adsorption time was 12h.And the removal rate of phosphorus is still 80%after the third reuse of Zn-MSN mesoporous material.In the second part of the study,The amount of phosphorus accumulated in Zn-MSN-DGT device was linear with the accumulation time in the spiked solution?r²=0.9989?,and the recovery was 96.4%.The measurement of phosphorus by Zn-MSN-DGT showed no significant difference in the range of ionic strength?0.00001-0.1 mol/L NaNO₃?and pH?2-10?.The experimental results show that phosphorus in different water and soils can be in situ collected and measured by the combination of Zn-MSN-DGT sampling technology and ammonium molybdate spectrophotometry.