摘要
水中高压脉冲电晕放电水处理是近年来一种新兴的污水治理技术,其具有处理对象无选择性、高效、无二次污染等优点。研究大体积、低能耗水处理装置是目前研究的重要方向。我们开发了一种同轴棒-筒式电极放电装置,其阳极为直径3mm、长60mm不锈钢棒状电极,阴极为直径44mm、长65mm的不锈钢网圆筒。不锈钢棒状电极用壁厚0.4mm的绝缘管包裹,绝缘管壁上切有一系列间距约4mm、宽20-80μtm的小缝,在高压脉冲作用下,从一系列缝隙中随机形成指向不锈钢网阴极的放电流注。本研究利用这种放电装置对日落黄、亮蓝等染料分别进行脱色处理,定量分析染料的脱色速率与能耗,考察溶液放电脱色处理条件的影响。将这种装置与针-筒式放电装置的放电脱色效果进行对比,揭示大体积放电装置相对于针-筒式电极在脱色处理方面的优越性。实验结果如下：
(1)溶液电导率变化对于染料脱色速率没有显著影响。
(2)溶液pH值变化对于染料脱色速率影响显著,酸性溶液加快溶液脱色,碱性溶液减缓溶液脱色。
(3)放电频率的增加会加快染料溶液脱色,加快程度高于简单的线性增长。
(4)随溶液电导率或pH值的增大,放电脱除单位质量的染料能耗增加。
(5)对于不同染料脱色效果不同,日落黄染料的脱色速率高于亮蓝染料,能耗低于亮蓝染料。
(6)亮蓝溶液pH保持自然值7.8不变,600Hz放电频率下,棒-筒电极系统脱色速率常数是针-筒电极系统3倍左右,脱除单位质量亮蓝染料棒-筒电极系统能耗低于针-筒电极系统。
(7)亮蓝溶液电导率保持为150μS/cm不变,600Hz放电频率下,脱色速率常数随着pH升高而降低,并且棒-筒电极系统脱色速率常数降低更快。在pH<8时,脱除单位质量亮蓝染料,棒-筒电极系统的能耗低于针-筒电极系统,在pH=10时,棒筒电极系统与针筒电极系统能耗相当。
Underwater corona discharge is found to be a good kind of wastewater treatment technology in these years. It has lots of advantages as no selectivity, high efficiency, no secondary pollution and so on. Resently, water treatment device with large volume and low energy consumption has received extensive attention. We have developed a coaxial rod-to-cylinder electrode system. It takes a stainless steel rod with3mm in diameter and60mm in long as the anode, and a stainless steel mesh with44mm in diameter and65mm in long as the cathode. The stainless steel rod electrodes is covered with a insulated pipe of0.4mm in thickness. There are a series of slits on the pipe spaced about4mm with each other and20-80μm in width. Under the high voltage pulse, streamer discharge can be formed from the slits randomly pointing the stainless steel cathode. Decolorize the dyes of sunset yellow and brilliant blue with the rod-to-cylinder electrode system. The decolorization rate and energy consumption are quantitative analyzed. Also, the effect of the solution condition on the decolorization rate and energy consumption are investigated. Compared with the rod-to-cylinder electrode system, it is easy to find the superiority to the pin-to-cylinder one. Main findings are as followed:
(1) The solution conductivity has little effect on decolorization rate.
(2) The decolorization rate decreases and the energy consumption increases with increasing the pH value.
(3) The decolorization rate increases with increasing the frequency, and it's faster than linear growth.
(4) The energy consumption increases with increasing the solution conductivity and pH value.
(5) The decolorization rate constant for the sunset yellow solution is higher and the energy consumption is lower than that for the brilliant blue.
(6) Fixing the pH value at7.8, the frequency at600Hz, the degradation rate constant for the rod-to-cylinder one is about3times larger than that for the pin-to-cylinder one. The energy consumption is lower for the rod-to-cylinder one.
(7) Fixing the solution conductivity at150μS/cm, the frequency at600Hz, the degradation rate constant decreases with increasing the solution pH value, but the rod-to-cylinder one decreases faster. The energy consumption increases with increasing the solution pH value,but it is significantly lower in the rod-to-cylinder one when the solution pH <8, when the solution pH=10, they are nearly the same.
引文
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