| Phosphorus pollution is one of the main pollution in rivers, lakes and even in the marine environment. It is an important problem to control the phosphorus emission and remove phosphorus in water. The application of rare earth lanthanum on phosphorus adsorption has high efficiency and specificity, and has good prospects in the research and development of phosphorus removal materials. Based on the preliminary experimental study, the main purpose of this paper is to solve the problem of low efficiency of La-Fe-O phosphate removal agent.The La-Fe-O phosphorus removal agent was prepared by Sol-co precipitation method, and the adsorption characteristics of phosphorus removal agent were studied, the results showed that:For the initial phosphorus concentration is 30mg/L and 50mg/L phosphorus solution, the amount of La-Fe-O dephosphorizing agent investment is lg/L and 1.5g/L, the phosphorus removal efficiency tends to be 100%. The adsorption efficiency of La-Fe-O phosphorus removal agent pH was better than that of 5-7, which showed that the phosphorus removal agent was suitable for weak acid water. La-Fe-O phosphorus removal agent reaction after 28h, basically reached the adsorption saturation, at this time the equilibrium adsorption amount is 110.81 mg/g. By the La-Fe-O phosphorus removal agent XRD spectrum shows that La-Fe-O phosphorus removal agent contains La2O3, Fe2O3 and LaFeO3. The crystallinity of La-Fe-0 phosphorus removal agent was prepared by the sol-gel method was increased from 24% to 33%. The La-Fe-0 phosphorus removal agent casting proportion is also increased by the amount of 99.92mg/g to 110.81 mg/g.The optimum conditions for the regeneration of La-Fe-0 phosphorus removal agent by NaOH method were:NaOH concentration 3mol/L, regeneration temperature of 120 ℃, liquid to solid ratio 80:1 by NaOH method. The reaction of 5 hours, the dephosphorization efficiency can reach 93.62%. Regeneration La-Fe-O dephosphorization agent, the optimum conditions for:NaOH concentration is 3mol/L, regeneration temperature of 120℃, liquid to solid ratio 80:1, the reaction of 5 hours, the dephosphorization efficiency can reach 93.62%. The first regeneration efficiency of 94.95%. After many times of regeneration, the regeneration rate of phosphorus removal agent decreased, the first 3 cycles of regeneration rate can reach 84.8%.By TG analysis, it is concluded that the addition of mass ratio of Na2CO3 to 100:1 is the best. After the regeneration of the vacuum distillation, the regeneration rate was 57.8%, and the regeneration rate with the additive was 66.32%. It could be seen that the additive was beneficial to increase the regeneration rate, but it did not reach the requirement of phosphorus removal.By XRD, FT-IR, BET analysis and obtained the following results:The main products of NaOH solution were La(OH)3 and La2O3, and the product of the vacuum distillation regeneration method had a small amount of LaPO4 and La2O3, vacuum distillation residue regeneration of a certain amount of phosphorus, and the regeneration efficiency and the dephosphorization efficiency is lower than that of NaOH solution regeneration method. It also shows that the samples are not completely regenerated by the method of vacuum distillation. The specific surface area was 64.316 m2/g before regeneration and the specific surface area of NaOH solution was 161.621 m2/g, however, the specific surface area of vacuum distillation after regeneration was significantly reduced, and only 5.810 m2/g. This shows that NaOH solution regeneration method on the one hand to achieve phosphate desorption, on the other hand to achieve phosphorus removal agent, increase its specific surface area. The internal structure of phosphorus removal agent has been changed, and some pore channels have been blocked, so that the specific surface area is reduced... |
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