低温结晶法对染料中间体磺化工艺母液的资源化利用

Resourceful Utilization of Dye Intermediate Mother Liquor from Sulfonation Processes by Low-Temperature Crystallization

用低温结晶法处理4种染料中间体磺化工艺母液,研究温度、pH、碱种类等对处理效果的影响。实验表明,模拟废水的化学需氧量(COD)去除率均随着温度的降低而升高;添加氢氧化钾调节pH对2-萘酚-6,8-二磺酸二钾盐(G盐)模拟废水处理效果较好;在酸性条件下,β-萘磺酸钠盐(β盐)模拟废水处理效果随着pH的升高而下降。在对实际废水处理中,G盐废母液经过-12℃冷冻12h,COD去除率为55%,其结晶固体主要成分为2-萘酚-3,6-二磺酸二钠盐(R盐);用氢氧化钾调节过滤液pH至7.0,在-16℃冷冻12h,COD去除率进一步达62%,其结晶固体主要成分为G盐;β盐母液COD去除率可达78.8%,可回收部分β盐。结果表明,通过低温结晶法对G盐母液和β盐母液中有机成分进行资源化回收是有效可行的。

Four dye intermediate mother liquors from sulfonation processes were treated by lowtemperature crystallization,and the influences of temperature,pH and the kind of alkali were investigated.The results showed that the removal of chemical oxygen demands（COD）of simulated wastewater increased with decreasing temperature. Adjusting pH of simulated 2-naphthalene-6,8-disulfonic acid dipotassium salt（G salt）wastewater by adding KOH improved the performance of treatment,while the effect of treatment for simulated 2-naphthalenesulfonic acid sodium salt（βsalt）wastewater decreased with increasing pH under acidic condition.The real G salt mother liquor was frozen for 12hat-12 ℃,and reached the removal of COD of 55% with the main production of 2-naphthol-3,6-disulfonic acid disodium salt（R salt）.Then the pH of G salt filtering medium was adjusted to 7.0,and frozen 12hat-16 ℃,the removal of COD increased to 62% while the main component of crystal production was G salt.The removal of COD ofβsalt mother liquor reached 78.8%,andβsalt was partly recovered.The recovery of organic components in G salt andβsalt mother liquors by low-temperature crystallization was feasible.