Rare Earth Adsorbent Nitrogen And Phosphorus Removal Experiment

With the development of economy in recent years, the eutrophication problem of lakes and rivers has become increasingly serious all over the world. The main reason is that many nutrients inputting into the water body, such as nitrogen, phosphorus. So many documents make clear that phosphorus and nitrogen quantity are the key role, and the removal of nitrogen, phosphorus are so urgent to eutrophication of water body, such as lakes and reservoirs.The traditional methods of nitrogen and phosphorus removal are chemical and biological methods. However, biological treatment process is not steady for nitrogen and phosphorus removal because the pollutants are different in style, which result in operating badly, and at the same time temperature and pH value of influence play a great impact on removal ratio which relys on BOD in feed. When BOD: N: P is 100:5:1 can get a better treatment effect. To the chemical methods, which consume a large amount of medical flocculants and coagulating. Contemporarily a large amount of chemical sludge comes into being, and difficult to handle it. Adsorption which takes up the deficiency of biological and chemical measures, which is a high efficiency measure of removing nitrogen and phosphorus, and the technics is simple.The thesis research takes adsorption method to deal with nitrogen and phosphorus which lead to eutrophication of water body, for the purpose of the depth of wastewater for nitrogen and phosphorus removal to provide a practical new ways. The results show that:(1) The appropriate conditions of rare earth adsorbent treated by microwave for nitrogen and phosphorus removal is for the amount of adsorbent 2g/L, and reaction time is 2.5 hours, and the pH value is between 4-6;(2) To La and Ce different proportion of Rare Earth adsorbent, there is not hardly difference in phosphorus removal, the efficiency gets better to nitrogen removal with the increaseing of Ce content;(3) Comparison between roasting-adsorbent and microwave-adsorbent in nitrogen and phosphorus removal, the result shows microwave synthesis method is better than the roasting method. For the phosphorus-containing 1mg/L, nitrogen-containing 15mg/L wastewater, the amount of adsorbent of 2g/L, phosphorus removal rate is more than 99% ,nitrogen removal rate reached more than 80 percent; the largest phosphorus adsorption capacity is 18.3 mg/g; nitrogen adsorption capacity of the largest 6.25 mg/g respectively;(4) On regeneration test, Appropriate regeneration liquid is NaOH concentration of 0.04mol/L, denitrification efficiency below 60% after 10 adsorbent regeneration, phosphorus removal efficiency below 80% after 15 adsorbent regeneration;(5) On adsorbent Molding, appropriate adsorbent molding pressure is 10 MPa, additives of NaHCO₃ is 15% (mass ratio), and temperature of 900℃.when adsorbent dosage is 5g/L in dealing with wastewater , phosphorus removal rate reachex 61.7%,and nitrogen removal rate reachex 51.7%;(6) The guitar experiment shows that, the amount of adsorbent is 5g/L nitrogen and phosphorus removal efficiency can also reach 99% after 8 h.