改性凹凸棒土对废水脱氮除磷研究

Phosphate and Ammonium Adsorption Removal from Wastewater by Modified Attapulgite

采用碱干法/湿法改性凹凸棒土除磷、热改性凹凸棒土脱氮,考察不同改性方法、不同pH、投加量对凹凸棒土脱氮除磷的影响,并解析凹凸棒土脱氮除磷的机理。结果表明,热改性温度为500℃,2 h时,凹凸棒土脱氮效率为57%;而氢氧化钠与凹凸棒土为之比1:1时,碱干法改性凹凸棒土除磷效率达到约92%;pH为4时,碱改凹凸棒土除磷除效率达到最佳,约92%;改性凹凸棒土脱氮除磷投加量分别为1.0 g/100 ml和0.5 g/100 ml时,氨氮和磷酸盐去除率分别超过58%和83%。FTIR和XRD结果表明,碱改性会破坏凹凸棒土的晶体结构,而热改性则会脱除凹凸棒土的矿物吸附水、沸石水和层间水。

Phosphate adsorption removal by alkaline dry/wet modification and ammonium removal by thermal modification wereinvestigated. The effects of modification methods, pH and dosage on the removal rate of phosphate/ammonium by modified attapulgite werestudied, and the mechanism of attapulgite adsorption of phosphate and ammonium was discussed. The results showed that, the removal rateof ammonium by thermal modification of attapulgite was 57% at 500℃ for 2 h; the removal rate of phosphate by dry modification was about92% at the mole ratio of NaOH：attapulgite of 1：1; the best pH was 4 for phosphate adsorption, and the removal rate of phosphate was about92%; when the dosage was 1.0 g/100 ml and 0.5 g/100 ml, the ammonium removal and phosphate adsorption ratio were above 58% and 83%,respectively. The results of FTIR and XRD showed that, the crystal structure of attapulgite was damaged by alkaline modification, while theadsorbed water by mineral, zeolite-water and interlayer water of attapulgite were stripped by thermal modification.