γ-射线辐照法去除水中的六价铬

以人工配制的含Cr水溶液[Cr(VI)=42mg/L]为研究对象,从动力学的角度考察了不同实验条件对γ-射线辐照还原Cr(VI)的影响.结果表明,初始pH值对Cr(VI)还原影响较大,酸性条件有利于Cr(VI)的还原,在15kGy的辐照强度下,pH2时,Cr(VI)的去除率达86.2%,而pH5和pH7时,Cr(VI)的去除率仅分别为36.3%和22.2%.乙醇的存在提高了Cr(VI)的辐照还原动力学常数.在乙醇添加量为0.1%(体积比),pH2的条件下,在较低的辐照强度(5kGy)下就可获得较高的Cr(VI)去除率(99.9%).中性条件下(pH7),添加1mmol/L的碳酸钠对Cr(VI)的还原有一定促进作用,而酸性条件下(pH2)则效果不明显.试验还考察了充N₂或充O₂对Cr(VI)辐照还原效果的影响,充N₂气可增强Cr(VI)的还原效果,而充O₂则抑制Cr(VI)的还原.

The removal of chromium (VI) in water by gamma-irradiation

The influence of different test conditions on the reduction of chromium (VI) by gamma-irradiation was discussed from dynamics aspect, using artificial compound in aqueous solution containing Cr(VI) with Cr(VI) concentration was 42mg/L as studied object. The initial pH value had relatively greater influence on the reduction of Cr(VI). Acidic condition was favorable to the reduction of Cr(VI). Under the irradiation strength of 15kGy and pH 2, the removal rate of Cr(VI) reached 86.2%; while pH 5 and pH 7, the removal rate of Cr(VI) were only 36.3% and 22.2%, respectively. The kinetics constant of the irradiation reduction of Cr(VI) increased remarkably in the presence of ethanol. Under the conditions of ethanol adding amount of 0.1% (volume rate) and pH 2, relatively high reduction rate of Cr(VI) (99.9%) could be obtained under relatively low irradiation strength (5kGy). Under neutral condition (pH 7), the addition of 1mmol/L Na2CO3 had definite promoting action on the reduction of Cr(VI); while under acidic condition (pH 2), the effects was not obvious. The influence of saturated N2 or O2 on the effect of irradiation reduction was also examined in test. The saturated N2 could enhance the reduction effect of Cr(VI); while the saturated O2 could restrain the reduction of chromium (VI).