Study Of The Preparation And Performance On The Phosphorus Removal Of La₂O₂CO₃ Urchin-like Adsorbent

Phosphorus is not only an important component constituting organism ATP and other energy substances, but also an essential element in the synthesis of nucleic acids and certain proteins, so phosphorus is indispensable for the organism. In the water,phosphorus can promote the growth of aquatic plants, maintain the ecological balance of the water, but too much phosphorus in the water can lead to eutrophication.Eutrophication of Surface water is one of the water pollution need to be solved, and phosphorus elimination from water bodies is the key to control eutrophication.By comparing the various removal methods used at home and abroad currently, it’s found that phosphorus removal by adsorption with its simple operation, high efficiency,is in the area of concern.Firstly, this paper achieved the preparation and characterization of the adsorbent.Using a simple precipitation reaction synthesizes adsorbent precursor, and then calcining the precursor forms the efficient phosphorus adsorbent.Using scanning electron microscopy（SEM）, transmission electron microscopy（TEM）, XRD, thermal gravimetric analysis（TG） and other methods characterizes the adsorbent. Watch the surface morphology of the adsorbent and analysis the phase composition of the adsorbent. The results show that the adsorbent is a urchin-like microsphere formed by the nanorods with a regular reunion having both the adsorption property of nano-materials and a settling of large particles on the macroscopic properties. The main component of the adsorbent material is La₂O₂CO₃. The adsorbent preference experiments show that the material calcined 500℃ works best.Secondly, the paper explores the adsorption properties. Static adsorption experiments to remove phosphorus were carried out to investigate the phosphorus remove efficiency caused by the factors such as the adsorption time, the substrate concentration of phosphorus, the adsorbent dosage, p H value and coexisting ions, so as to arrive the variation of adsorption with single factor variables, determine the optimum p H ranged 3-8, clear that phosphorus removal will weaken by the anionic in the solution to some extent. Quasi-second-order kinetic model can be more accurately described the process of phosphorus removal. Freundlich adsorption model is more accurate to describe the adsorption behavior of La₂O₂CO₃ adsorbent than the Langmuir adsorption model.The maximum adsorption capacity（Qe=144.51mg/g） was determined based on the Langmuir adsorption model（25℃）. The adsorption thermodynamic parameters indicate that ΔG0<0, ΔH0>0, ΔS0>0,illustrating that the reaction is spontaneous, the adsorption process is endothermic reaction and the adsorption of phosphorus in solutionoccurs preferentially at the surface of the adsorbent. It’s show that La₂O₂CO₃ adsorbent has a good removal effect in low concentrations of phosphorus by the low concentration of phosphorus removal with adsorbent. The concentration of phosphorus could be removed to 10μg/L or less, which is much lower than the occurrence of concentration eutrophication.Finally, the phosphorus adsorption experiments carried out using the Songhua River. The results show that La₂O₂CO₃ adsorbent for phosphorus removal of eutrophic water is feasible. It was also explored a method of regenerating the adsorbent. The adsorption capacity after regeneration can reach 80% of the original adsorbent.