黄原胶改性微米铁修复地下水中Cr(Ⅵ)污染的试验

Study on Xanthan Gum Modified Micron Iron Slurry for Remediation of Cr(Ⅵ) Polluted Groundwater

为了解决微米铁的重力沉降问题,提高微米铁修复地下水Cr(Ⅵ)污染的原位修复效果,本文利用黄原胶对微米铁进行改性,并通过沉降实验探究改性微米铁浆液的稳定性,同时选择Cr(Ⅵ)作为目标污染物,探究黄原胶改性微米铁去除地下水Cr(Ⅵ)污染的降解能力。实验结果显示:当黄原胶的投加质量浓度分别为0.0、1.0、1.5、2.0、2.5、3.0、6.0 g/L时,改性微米铁浆液的悬浮稳定性逐渐得到加强,在5 h沉降实验结束时,对应的相对分光光度值分别为0.05、0.25、0.46、0.57、0.65、0.73和0.87;黄原胶具有抑制微米铁吸附Cr(Ⅵ)的能力,其可促进Cr(Ⅵ)的还原,提高Cr(Ⅵ)的去除率;随着黄原胶投加质量浓度的增加,对应的Cr(Ⅵ)去除率分别为33.4%、41.2%、47.4%、51.1%、53.0%、63.9%和64.1%;6.0 g/L黄原胶改性的微米铁浆液具有最佳的悬浮稳定性,黄原胶的投加提高了微米铁的反应活性,但当黄原胶投加质量浓度超过3.0 g/L时,其对Cr(Ⅵ)的去除率没有显著提高;黄原胶投加质量浓度越大,黄原胶的缓冲作用就越明显。

In order to solve the gravity sedimentation problem of micron iron, this paper uses xanthan gum to modify the micron iron. The stability of the modified micro iron slurry was explored through sedimentation experiments and the degradation ability was explored by removing Cr(Ⅵ) pollutant. The results show that when the dosages of xanthan gum are 0.0, 1.0, 1.5, 2.0, 2.5, 3.0, 6.0 g/L respectively, the corresponding relative spectrophotometric values are 0.05, 0.25, 0.46, 0.57, 0.65, 0.73, 0.87 at the end of 5 h sedimentation experiment. The suspension stability of the modified micro iron slurry is gradually strengthened with the increase of the mass concentration of xanthan. Xanthan has the ability to inhibit the adsorption of Cr(Ⅵ) by micron iron, which can promote the reduction of Cr(Ⅵ) and improve the removal rate. With the increase of the concentration of xanthan gum, the corresponding Cr(Ⅵ) removal rates are 33.37%, 41.23%, 47.45%, 51.05%, 52.97%, 63.91% and 64.08%, respectively. It can be seen from the results that 6.0 g/L xanthan gum modified micron iron slurry has the best suspension stability and the addition of xanthan gum improves the reactivity of micron iron. However, when the mass concentration of xanthan gum exceeds 3.0 g/L, the removal rate of Cr(Ⅵ) is not significantly improved. The greater the concentration of xanthan gum, the more obvious the buffering effect of xanthan gum.