高含硫废水中硫的受限氧化过程及影响因素研究

Study on sulfide limited oxidation and influencing factors in high concentration sulfide wastewater

针对含硫气田采出水硫化物浓度高及氧化产物种类多的特点,通过控制氧化反应使得单质硫为主要产物,实验考察了偏重亚硫酸钠投加量、初始p H和反应时间对硫化物氧化过程及氧化产物组成的影响。结果表明,偏重亚硫酸钠氧化法是处理含硫废水的一种有效手段,最佳反应条件为偏重亚硫酸钠的投加量为6 g/L,初始p H=6,反应时间35 min,此时硫化物的质量浓度从800 mg/L降至21.34 mg/L,硫化物去除率可达97.33%;主要产物为单质硫和硫代硫酸盐,在最佳反应条件下,这2种主产物的转化率为36.63%和57.57%,固体产物元素分析结果表明,其主要成分为S(质量分数为92.056%),偏重亚硫酸钠氧化硫化物过程符合表观二级反应动力学规律,R2=0.9819,反应速率常数为k=0.0063 L/(mg·min)。

High concentration sulfide was in sulfur gasfield water and the sulfide oxidation products were various.According to the features,oxidation reaction was controlled to make elemental sulfur be major product.Treatment of sulfide wastewater by oxidation with Na2S2O5 was investigated in laboratory-scale experimental apparatus under the conditions of atmospheric pressureand room temperature.The effects of Na2S2O5 dosage,initial p H and reaction time on the sulfide removal efficiency were studied.The oxidation products were determined and analysed.The kinetics of the sulfide oxidation was studied.The results indicated that sodium pyrosulfite oxidation method could be an effective approach.The sulfide concentration could be decreased from 800 mg/L to21.34 mg/L,and the sulfide removal rate could reach 97.33% under the optimal conditions of Na2S2O5 dosage of 6 g/L,initial p H 6 and 35 min.The major oxidation products were sulfur and S2O2-3,the conversion rate of which could be 36.63% and 57.57%,respectively under the optimal conditions.The elemental analysis indicated that the major content in the solid oxidation product was S element.The sulfide oxidation by sodium pyrosulfite followed the second-order reaction kinetics under the optimal conditions and the coefficient of determination was 0.9819.The apparent second-order rate constant was k = 0.0063 L/(mg·min).