Preparation Of Lanthanum-loaded Composite Materials And Their Removal Of Phosphate From Water

Excessive uptake of phosphorus in water enviro nment will lead to eutrophication of water body,which seriously endangers the ecological enviro nment and human health.As the only form of phosphorus that can be absorbed directly by organisms,the removal of phosphate is particularly important.Among all kinds of phosphorus removal processes,adsorption is considered to be an ideal phosphorus removal method because of its low cost,simple operation,high efficiency and fast phosphorus removal speed.Considering that lanthanum?La?species has a strong binding force with phosphate?pKsp=26.15?and is rich in content,cheap and enviro nmentally friendly,we introduced lanthanum into the adsorbent.Specific research contents are as follows:?1?Study on synthesis of lanthanum hydroxide in magnetic dendritic mesoporous nanomaterials and its application in phosphorus removal from waterIn this study,lanthanum hydroxide was synthesized in magnetic dendritic mesoporous silica nanoparticles for the first time.Mag-MSNs-?La product was obtained as phosphorus removal adsorbent,and then the phosphorus removal in water was studied.Mag-MSNs magnetic mesoporous silica nanospheres were synthesized in three steps,and then La?OH?₃was synthesized in dendritic mesoporous silica with different ratios.Mag-MSNs-32%La,Mag-MSNs-41%La and Mag-MSNs-42%La were obtained.Characterization tests show that our materials are spherical particles of core-shell-shell structure with a diameter of 240²90nm and well dispersed.The results of phosphorus adsorption test showed that the maximum phosphorus adsorption capacity of Mag-MSNs-42%La was 54.2 mg/g,which was better than many other P adsorption materials reported at present.The adsorption kinetics was faster and the low concentration phosphorus-containing wastewater?1.9 mg/L?was completely absorbed within 30 minutes.Particularly noteworthy is that the material exhibits better stability than a large number of other La-based adsorbents in a wide range of pH from 4.0 to11.0,and the loss of La is very low.In the presence of other anions and humic acids,the sample has good selective adsorption performance for phosphate.At the same time,the material is easy to be separated and regenerated,which has practical application value.?2?Preparation and characterization of bacterial cellulose/lanthanum hydroxide composite nanomaterialsIn this study,Acetobacter xylinum NUST4.2 was fermented and cultured,and then treated to prepare BC powder.Then BC and La?OH?₃ were silylated separately.La?OH?₃ was loaded into BC by thiol-ene click chemical method for phosphorus adsorption for the first time.Through a series of characterization tests,it is confirmed that La?OH?₃ accumulates in the amorphous state in BC fibers without destroying the three-dimensional interlaced network structure of BC itself,and the loading amount is about 32.14%.It can be used as phosphorus adsorbent.The test of phosphorus removal performance shows that Langmuir maximum adsorption capacity of BC/La?OH?₃ sample is 10.2 mg/g,and the adsorption kinetics is fast,so it can be used as phosphorus adsorption material.In summary,we have successfully prepared La-based adsorbents for phosphorus removal in water,aiming at the eutrophication problem caused by excessive phosphorus in water,which provide a theoretical basis for practical application and have broad prospects in water purification.