聚硅酸铝絮凝剂的制备和性能研究

以高岭土为原料，采用碱熔融水洗酸浸工艺制备聚硅酸铝絮凝剂，初步研究了该絮凝剂制备的工艺条件及pH对产品絮凝沉降性能的影响。实验结果表明：制备聚硅酸铝的最佳工艺条件为焙烧温度900℃，焙烧时间40min，碱与高岭土质量比为0．8，产品最佳pH为2．0；熟化时间的加长可提高产品的聚合度；产品有较好的COD去除率、SS去除率及色度去除率，且处理过后的水透光度高。     

Effects of lanthanum on abscisic acid regulation of root growth in Arabidopsis

Rare earth elements(REEs) were reported to have adverse biology effects on plant growth and production. However, whether REEs are involved in plant hormone abscisic acid signal is not clear. Here we reported that REE lanthanum(La) interacted with abscisic acid(ABA) in the regulation of seed germination and root growth in model plant Arabidopsis. La3+at a concentration of 10 μmol/L alleviated ABA depression of seed germination and reversed ABA inhibition of root elongation growth in Arabidopsis. Previous studies showed that ABA could promote root hair development. In the present study, La3+inhibited root hair development promoted by ABA. Moreover, La3+inhibited H2 O2 generation induced by ABA in root cells. Therefore we inferred that La3+might interact with ABA upstream of H2 O2 generation.