State Key Laboratory of Clean Energy Utilization, Zhejiang University, Zheda Road 38, Hangzhou 310027, China.
Chemosphere. 2013 Oct;93(7):1413-8. doi: 10.1016/j.chemosphere.2013.07.009. Epub 2013 Aug 3.
The supercritical water oxidation (SCWO) of industrial tannery sludge was investigated to understand the simultaneous destruction of organic pollutants and recovery of high content chromium. Experiments were performed in a batch reactor at temperatures of 350-500 °C, reaction time of 150-300 s and different oxygen ratios, to exhibit the effect of operation conditions. Results showed that removal efficiency of chemical oxygen demand (COD) increased with higher temperature, larger oxidant amount and reaction time; a maximum value of 96% was obtained. Meanwhile, destruction yield was much higher under supercritical conditions than that in subcritical water. In addition, removal efficiency of Cr from sludge reached more than 98% under all conditions; higher temperature played a positive role. Further, leaching toxicity tests of heavy metals in solid products were conducted based on toxicity characteristic leaching procedure. All heavy metals except nickel showed a greatly reduced leaching toxicity through their stabilization. The chromium oxide recovered in ash was amorphous below 550 °C, so that the structure of Cr could not be identified by X-ray diffraction pattern. Special attention should be paid on nickel as its leaching toxicity increased due to the corrosion of reactor surface under severe reaction conditions.
采用间歇式高压反应釜研究了制革污泥的超临界水氧化（SCWO）过程，以实现有机污染物的高效去除和高浓度铬的回收。在 350-500℃、150-300s 反应时间和不同氧碳比条件下考察了操作参数的影响。结果表明，在较高的温度、氧化剂用量和反应时间下，COD 去除率逐渐增大，最大值为 96%；在超临界条件下，Cr 的破坏率明显高于亚临界水。此外，所有条件下污泥中 Cr 的去除率均超过 98%，较高的温度有利于 Cr 的去除。采用毒性特征浸出程序（TCLP）对固体产物中重金属的浸出毒性进行了测试。除镍外，所有重金属的浸出毒性均大幅降低，这是由于其在残渣中以稳定的氧化物形式存在。在 550℃以下，灰分中回收的氧化铬为非晶态，因此无法通过 X 射线衍射图谱确定 Cr 的结构。由于在苛刻的反应条件下，反应器表面发生腐蚀，镍的浸出毒性增加，因此需要特别注意。
