改性膨润土强化低温低浊水混凝试验及其吸附

Effects on Strengthening Coagulation to Low Temperature and Low Turbidity Water and Adsorption Characteristics of Modifi ed Bentonite

针对现行常规给水工艺处理低温低浊有机污染水效果不佳的问题,选用聚合氯化铝铁(PAFC)为混凝剂,聚丙烯酰胺(PAM)为助凝剂,投加盐改性钠基膨润土进行混凝试验,并对钠基膨润土的吸附特性进行研究。结果表明,PAFC、PAM投加量分别为15 mg/L、0.3 mg/L时,投加0.1 g/L的盐改性钠基膨润土混凝效果最好,优于酸改性与未改性膨润土,其对浊度、NH4+-N、COD值降低率分别为56.32%、15.45%、23.58%;盐改性钠基膨润土对NH4+-N的吸附过程可以很好地用准二级动力学方程描述(R2为0.9992),动力学参数k2为0.3919 g/(mg·min),平衡吸附量qe为3.48mg/g,吸附过程符合Freundlich等温方程(R2为0.9865),存在表面吸附与离子交换共同作用。

Aimed at the low efficiency of treating low temperature and low turbidity water containing organic matters, polyaluminum ferric chloride （PAFC） and polyacrylamide （PAM） were used to conduct a coagulation experiment with the addition of sodium bentonite. And the adsorption characteristics of sodium bentonite was investigated. The results showed that the best removal performance could be achieved when the dosages of PAFC, PAM and sodium bentonite were 15 mg/L, 0.3 mg/L and 0.1 g/L respectively. Under this condition the highest reducing efficiencies of turbidity, NH4＋-N, COD value were 56.32%, 15.45%, 23.58% respectively, which was superior to acid modified bentonite and non-modified bentonite. The process of adsorbing NH4＋-N with sodium bentonite could be well described by the pseudo-second-order model （R2=0.9992）. The kinetic parameters k2 and qe were 0.3919 g/（mg.min）, 3.48 mg/g respectively. The equilibrium isotherm date could be fitted to the Freundlich model （R2=0.9865） which indicated that the reaction was not only monolayer adsorption, but also ion-exchanze.