电动-还原技术修复受铬污染西部黄土的研究

Remediation on chromium-polluted western loess with electric-reduction technology

【目的】研究黄土中Cr6+还原为Cr3+的效果及铬在电极附近的富集作用.【方法】以铁作为阳极,石墨作为阴极,采用电动修复技术对铬污染黄土的修复技术进行了试验室研究.【结果】以铁作为电动修复阳极,增加了阳极的还原反应,增大了电动修复的去除率,反应器中Cr6+还原为Cr3+为主导反应,CrO42-迁移速度远小于还原反应的速率,迁移富集效果不明显.西北湿陷性黄土含水率为10%时电动去除率最大,最大修复去除率为81.35%,且控制黄土含水率为10%,随着试验时间的延长,电动修复去除率增大,试验运行168h后最大修复去除率可达93.54%,CrO42-富集峰值向阳极迁移的趋势明显.铁电极的还原作用在修复中起到了关键作用.【结论】采用电动还原强化技术修复效果优于电动迁移修复效果.

【Objective】To study the effect of Cr^6＋ revert to Cr^3＋ in loess and the enrichment of chromium in the vicinity of the electrode.【Method】The experiments was conducted by adopting electric repair technology to repair of Northwest polluted loess through iron as a node and geaphite electrode as cathode.【Result】The iron as an electric repair anode not only increased the reduction reaction of the anode but also enhanced the removal rate of the electric repair.In the reactor,Cr^6＋ reduced to Cr^3＋ was as the dominant reaction,CrO4^2- migration rate was slower than the rate of reduction reaction,migration enrichment effect showed not significantly.When Northwest collapsible loess with 10% of moisture content had the highest electric removal rate,and had the highest repair removal rate of 81.35%.With the extension of the experiment time,the removal rate of electric repair was increased.The maximum removal rate of 93.54% after168 h,and the migration of CrO4^2- rich peak to anode showed obviously.The reduction of iron electrodes played a key role in the repair process.【Conclusion】The effect of electric reduction and reinforcement technology is better than that of electric migration repair.