SO32-/HSO5-体系去除印染生化尾水溶解性有机污染物

Removal of soluble organic containments from dyeing biochemical effluent by SO32-/HSO5- system optimized

印染废水常规生化处理尾水中仍残余一定浓度的溶解性有机污染物(DOM)和新标准严格管控的苯胺.采用亚硫酸钠活化过硫酸氢钾复合盐(SO 3^2-/HSO^5-)产硫酸根自由基(SO^4-)高级氧化体系对尾水进行深度处理,并基于响应面法优化初始pH值、反应温度、SO 3^2-/HSO^5-物质的量比和HSO 5-投加量对COD和苯胺去除效果的单独及交互影响.结果表明该体系对苯胺具有非常显著的去除效果,同时对COD亦有一定的降解能力.影响因子对COD和苯胺降解效果贡献排序分别为:温度>n(SO 3^2-)/n(HSO^5-)>n(HSO^5-)>初始pH值和n(HSO^5-)>n(SO3^2-)/n(HSO^5-)/初始pH值>温度.在实验优化后得到的最佳条件下(pH=6.8,温度为53℃,SO 3^2-/HSO 5-物质的量比为1.6,HSO5-投加量为37.1mmol/L)反应10min,出水的COD和苯胺去除率分别达到33%和90%.进一步分析了印染生化尾水处理前后DOM的荧光和分子特性,三维荧光光谱(3DEEMs)发现芳香族蛋白质和溶解性微生物代谢产物是原尾水中DOM的主要组分,经不同氧化条件下出水中DOM的荧光强度明显降低且性质发生改变,荧光区域标准体积削减了42.03%~77.67%;同时观察到氧化出水中类色氨酸(Ex/Em=230~225nm/340~330nm)峰值发生了5~10nm的蓝移,推测尾水中稠环芳烃分解为小分子,共轭基团和芳香环数量减少;凝胶渗透色谱(GPC)结果表明DOM中大分子(0.45 m^100kDa)物质比例为41%,中等分子(12~100kDa)物质的比例为48.9%,峰值分子量(Mp)为56.324kDa,Mw/Mn=2.168,处理后的出水Mp主要分布在12.28~17.56kDa范围内,小分子物质数量增多,结构和种类发生变化;气相色谱质谱(GC-MS)进一步揭示氧化出水中的烷烃类物质含量明显降低,主要副产物为一些酯类、醇类和脂肪酸物质,为后续进一步生化处理创造了条件.

The conventional biochemical treatment effluent of dyeing wastewater(BREDW)still contains a certain concentration of dissolved organic pollutants(DOM)and Aniline strictly controlled by the new standard.Sodium bisulfite-activated potassium bisulfate complex salt(SO3^2-/HSO5-)advanced oxidation system was used to produce sulfate radical(SO4^-·)for the advanced treatment of BREDW.The effects of initial pH value,reaction temperature,SO3^2-/HSO5-molar ratio and HSO5-dosage on the removal of COD and aniline were optimized based on response surface methodology.COD and aniline can be removed by the system remarkably.The contribution order of influencing factors to COD and aniline treatment were as follows:temperature>n(SO3^2-)/n(HSO^5-)>n(SO3^2-)>initial pH value and n(HSO^5-)>n(SO3^2-)/n(HSO5-)/initial pH value>temperature.The removal rates of COD and aniline were 33%and 90%respectively under the experimental conditions by the experiment optimization:pH of 6.8,temperature of 53℃,concentration molar ratio SO3^2-to HSO^5-of 1.6 and HSO5-dosage of 37.1mmol/L.Further studies were made on the changes of fluorescence and molecular properties of the main DOMs before and after dyeing effluent treatment.3DEEMs found that aromatic proteins and soluble microbial metabolites were the main components of DOM in the BREDW.The fluorescent DOM content in the oxidized effluent decreased significantly under different conditions,and the fluorescent area volume was reduced by 42.03%~77.67%.At the same time,the peak value of tryptophan(Ex/Em=230~225nm/340nm^330nm)in the oxidized effluent was observed to blue shift of 5~10nm.Polycyclic aromatic hydrocarbons in BREDW are decomposed into small molecules,the number of conjugated groups and aromatic rings decreases;GPC revealed that the proportion of macromolecules(0.45μm^100kDa)was 41%,that of medium molecules(12~100kDa)was 48.9%,that of peak molecular weight(Mp)was 56.324kDa,and that of Mw/Mn=2.168.After treatment,the effluent Mp mainly distributes in the range of 12.28~17.56kDa,with more small molecular substances,more structures and species.GC-MS synchronously reveals that the alkanes in the oxidized effluent are greatly reduced,and the main by-products are esters,alcohols and fatty acids,which can create conditions for further biochemical treatment.