改性活性炭对硫氰酸钠膜分离浓水脱杂过程的影响因素

为解决东北某湿法腈纶生产厂中回收NaSCN(硫氰酸钠)效果欠佳的现状,采用不同改性方法制备了10%-H-GAC(氧化改性活性炭)、1M-Na-GAC(还原改性活性炭)和600-N₂-GAC(高温改性活性炭),并探讨了改性方法、吸附时间、投加量以及初始pH对NaSCN膜分离浓水脱杂过程的影响. 结果表明:10%-H-GAC较其他改性活性炭对浓水中NH₃-N、COD_Cr、TOC和盐度的去除率要好. 以10%-H-GAC为吸附剂,吸附时间为180 min,投加量为12.0 g/L,初始pH为6.0时,NH₃-N、COD_Cr、TOC和盐度去除率分别可达35.1%、32.3%、34.9%、25.4%,表明该处理技术能很好地去除硫氰酸钠膜分离浓水中的污染物. 采用Fruendlich吸附等温模型对10%-H-GAC的吸附行为进行拟合,得到的NH₃-N、COD_Cr、TOC及盐度拟合方程的相关系数均在0.92以上. 准二级动力学方程能更好地描述废水中杂质在活性炭上的吸附行为,反映吸附过程. 研究显示,10%-H-GAC能有效去除硫氰酸钠膜分离浓水中的杂质,达到回收硫氰酸钠的目的. 

Influence Factors Analysis on the Treatment of NaSCN Concentrated Effluent by Modified Activated Carbon

In order to improve recovery of sodium thiocyanate from wet-spun acrylic fiber in northeastern China, a diverse modified technique for fabricating oxidative, reductive and high temperature activated carbon was adopted. This study investigated methods of modification of the activated carbon, adsorption time, dosage and initial pH values of membrane separation of sodium thiocyanate (MSST) concentration water effects of removal noise processing. The result showed that, after being modified by 10% HNO₃ oxidation of activated carbon, TOC and salinity removal rates were better than any other modification methods on concentration of NH₃-N, COD_Cr. With activated carbon adsorption time of 180 min, dosage of 12.0 g/L and initial pH of 6.0, the removal rates of NH₃-N, COD_Cr, TOC and salinity in the concentration water were up to about 35.1%, 32.3%, 34.9% and 25.4%. The processing could remove the impurities of MSST concentration water. Moreover, the study also analyzed the thermodynamics and kinetics in the adsorbed process by nitrate modified activated carbon. Freundlich isothermal adsorption model was used to represent the substance in the concentrated solution adsorbed on activated carbon, and NH₃-N, COD_Cr, TOC and salinity in the wastewater were measured; their correlation was more than 0.92. In addition, the second order kinetics equation could better describe the act of impurities in wastewater by adsorption on activated carbon, and it could better reflect the adsorption process. The study showed that the oxidative modified activated carbon could effectively remove the impurity in the MSST, and achieved the purpose of recovery of sodium thiocyanate.