大孔树脂对对硝基苯胺的吸附行为及其应用研究

研究了溶液中无机盐、pH值对氨基修饰超高交联大孔树脂NDA-99、氧修饰超高交联大孔树脂NDA-150和大孔树脂XAD-4吸附对硝基苯胺的影响。结果表明,无机盐对吸附影响不大;NDA-99、NDA-150在中性范围吸附量最大,XAD-4的吸附量随pH增大而增大;3种树脂的吸附等温线都能很好的利用Freundlich方程进行拟合,吸附皆为放热反应且为优惠吸附;3种树脂的饱和吸附量大小依次为NDA-150>NDA-99>XAD-4。依据上述结论,采用NDA-150处理对硝基苯胺生产母液废水,每批次处理量为40BV,废水中对硝基苯胺浓度由2130mg/L降至9.6mg/L,去除率达99.5%,吸附后的树脂采用95%的乙醇可完全再生,高浓度对硝基苯胺乙醇再生溶液经蒸馏可回收对硝基苯胺和脱附剂,实现了废水治理与资源化的统一。

ADSORPTION BEHAVIOR OF P-NITROANILINE ON MACROPOROUS POLYMER AND ITS APPLICATION

P-nitroaniline adsorption onto three polymeric adsorbents including an aminated hyper-cross-linked polymer NDA-99, an oxygenated hyper-cross-linked polymer NDA-150, and a macroporous polymer XAD-4 was compared. Experimental results indicated that NaCl in solution takes a negligible effect on p-nitroanilien adsorption. NDA-99 and NDA-150 exhibited a maximum capacity at neutral solution pH, while the capacity of XAD-4 was increased as solution pH increased. All the adsorption isotherms can be well represented by Freundlich equation. Adsorption capacity of the adsorbents follows the sequence as NDA-150>NDA-99> XAD-4. Subsequently, NDA-150 was employed for treatment of p-nitroaniline manufacturing wastewater. P-nitroaniline concentration in the wastewater was decreased from 1450mg/L to 43.5mg/L after NDA-150 adsorption with the corresponding removal efficiency of about 97%. The spent NDA-150 could be readily regenerated with 95% ethanol for repeated use. p-nitroaniline would be subsequently recovered from the high concentrated regenerant solution by distillation.