Abstract: A newly water-sparged aerocyclone (WSA) reactor was employed for treatment of Cr(Ⅵ)-containing wastewater by direct reduction using sulfur dioxide（SO₂）, and a satisfactory result obtained. The results show that a removal efficiency above 99.9% of Cr(Ⅵ) is achieved after 6 min of cycling treatment by gas of SO₂ concentration 3582 mg·m^-3 for the wastewater containing Cr(Ⅵ) 1134 mg·L^-1. Alkaline of wastewater is beneficial to absorb SO₂, go up SO₂ utility, and enhance the efficiency of Cr(Ⅵ) reduction. Initial concentrations of SO₂ and Cr(Ⅵ) have significant influence on the efficiency of Cr(Ⅵ) removal, whereas the effect of wastewater jet velocity is less. The efficiency of Cr(Ⅵ) removal increase with increasing SO₂ concentration and decrease with increasing initial Cr(Ⅵ) concentration. Comparing with the SO₂ reduction process conducted in traditional gas-liquid reactors like packed towers, this reduction process in WSA has some obvious advantages, such as no need for adjusting pH of wastewater to 2—3 before SO₂ reduction, easy operation and no Cr(OH)₃ deposition in reactor. So, this investigation could be a basis for developing new reduction process using SO₂ for treating Cr(Ⅵ)-containing wastewater.

Key words: hexavalent chromium, sulfur dioxide, waste water, absorption, reduction, gas-liquid flow

摘要： 以SO₂为还原剂，采用一种新型的气液传质设备——水力喷射空气旋流器（WSA）对含Cr（Ⅵ）废水进行直接还原处理，得到了比较满意的效果。研究结果表明：当SO₂浓度为3582 mg·m^-3时，对Cr（Ⅵ）含量为1134 mg·L^-1的模拟含铬废水，循环处理6 min，Cr（Ⅵ）去除率可达99.9%以上。废水初始pH为碱性比其为酸性条件下，更有利于SO₂的吸收，提高了SO₂利用率，增强了处理效率。废水射流流速对处理效果的影响较小，但SO₂和Cr（Ⅵ）的浓度对处理效果有明显影响。随着SO₂浓度增大，处理效率增大；Cr（Ⅵ）的初始浓度增大，处理效率降低。研究结果为建立含硫气体还原处理含Cr（Ⅵ）废水新工艺提供了依据。

关键词: 六价铬, 二氧化硫, 废水, 吸收, 还原, 气液两相流