氢氧化钽及其焙烧产物对磷酸盐的吸附

Adsorption of Phosphate by Tantalum Hydroxide and its Calcined Product

研究了氢氧化钽原样及其焙烧产物对磷酸盐的吸附行为,考察了吸附剂用量,吸附时间,焙烧温度,共存阴离子对吸附量的影响以及焙烧温度对吸附剂物理化学性质的影响。结果表明,在磷酸盐初始浓度为50 mg/L,温度为25℃,吸附剂投加量为0.4 g/L,pH值为2的条件下,30 min达到吸附平衡,原样及100℃,200℃3,00℃焙烧后产物的吸附量依次为55.88 PO43-mg/g,27.17 PO34-mg/g,8.78 PO34-mg/g,8.45 PO34-mg/g,而400℃,500℃焙烧产物对磷酸盐不具有吸附性,可见焙烧后吸附剂的吸附能力明显降低。常见共存阴离子(SO24-,Cl-,NO3-)几乎不影响磷酸盐的吸附。热重、红外谱图分析表明随着焙烧温度的升高氢氧化钽的表面活性基团(NH4+,-OH)逐渐消失,并且吸附性能也渐消失。

The adsorption performance of tantalum hydroxide and its calcined product for phosphate were studied.The effects of dosage,adsorptive time,calcined temperature,co-existing anions on the adsorption capacity and the effect of calcined temperature on the physical and chemical properties of adsorbent have been investigated.The adsorption capacity of PO3-4 is 55.88、27.17、8.78、8.45 PO3-4 mg/g,when calcined temperature is 0 ℃,100 ℃, 200 ℃,300 ℃ respectively,and initial concentration of phosphate is 50 mg/L,adsorption temperature is 25 ℃,adsorbent dosage is 0.4 g/L,pH value is 2 and equilibrium time is 30 min.However,the calcined products of 400,500 ℃ do not have the capacity to adsorb phosphate.The adsorption capacities of calcined samples have been reduced significantly.Phosphate adsorption is almost unaffected with the presence of common anions such as SO2-4,Cl-and NO-3.TG and FTIR analysis suggest that the active functional groups on the surface of tantalum hydroxide（NH＋4,-OH） and adsorption capacity are disappeared gradually with the increasing calcined temperature.