基于低压UV引发的壳聚糖基絮凝剂定位改性及其除乳化油机理研究

As the development of industrialization, oily wastewater sourced from various industries has increased year after year, and oil contamination has becoming urgent water environment problems. There are several problems for oily wastewater treatment by using traditional flocculants, such as high dosage, poor selectivity and pH adaptability, and secondary pollution. Thus, develop a new environment-friendly flocculant with high efficiency and low consumption is imperative. Research shows that it is favorable for improving selectivity and pH adaptability of flocculant in oil removal by introduction of hydrophobic and charged groups through molecular orientate modification, which is the key to achieve high efficient removal of oil from wastewater. Chitosan as an important green environment-friendly flocculants substrate material provides a favorable condition for functional orientate modification because of amino and hydroxyl groups with high reactivity. Previous studies found that low-pressure UV initiation can realize modification of organic flocculants in order to improve flocculation performance in water treatment, and presents advantages of environment-friendly, low energy consumption, and easy industrial application compared with traditional thermal initiation and high-pressure UV initiation. Therefore, a new method of low-pressure initiation will be employed in this project, and introducing hydrophobic and charged groups into chitosan through molecular orientate modification will achieve high efficient removal of emulsified oil from water. On this basis, structure-activity relationship between structural modification and oil removal will be deeply analyzed, and the influence factors, variety discipline and flocculation mechanism of oil removal through flocculation will be studied.

随着工业化发展，含油废水量逐年增加，油污染成为亟待解决的水环境问题。传统絮凝剂对含油废水处理存在用量高、选择性与pH适应性差、二次污染等问题，开发新型高效低耗、绿色环保的絮凝剂势在必行。研究表明，通过分子定位改性引入疏水与带电基团，能够提升絮凝剂除油的选择性与pH适应性，是实现含油废水高效去除的关键。壳聚糖作为重要的绿色环保絮凝剂基材，分子中的氨基与羟基的反应活性高，为功能定位改性创造了有利条件。前期研究发现，低压紫外光（UV）引发能够实现有机絮凝剂的改性以提高水处理絮凝性能，而且比传统的热引发、高压UV引发具有绿色环保、能耗低、易于产业化等优点。因此，本项目拟采用低压UV引发的新方式，通过分子定位改性技术将疏水与带电基团引入壳聚糖分子中，实现对水中乳化油的高效去除。在此基础上，深入分析结构改性与絮凝除油性能之间的构-效关系，并研究絮凝剂对含油废水絮凝处理的影响因素、变化规律及去除机理。

针对传统絮凝剂处理含油废水存在的用量高、选择性与pH适应性差、二次污染的问题，本项目建立起低压紫外光引发絮凝剂改性制备方法体系，在绿色絮凝剂基材壳聚糖分子链活性氨基与羟基中定位接枝引入疏水基团与阳离子带电基团，制备出绿色环保型改性壳聚糖絮凝剂，实现了对乳化油废水高效低耗、高pH适应性的絮凝处理。并揭示了不同疏水与阳离子基团改性壳聚糖絮凝剂与除乳化油性能间的构-效关系及其絮凝除油机理。在此基础上，通过硅烷偶联剂在改性壳聚糖分子中引入磁性纳米四氧化三铁，获得结构稳定的磁性共价键改性壳聚糖絮凝剂，大幅度提升了油水分离速度与提高絮凝剂的重复利用效率，并阐述了乳化油颗粒与改性壳聚糖、磁性共价键改性壳聚糖絮凝剂的结合机理，分析了乳化油复杂组分与改性壳聚糖絮凝剂的相互作用关系，以及在钢铁冶金行业热轧乳化油废水处理中验证和优化了磁性共价键改性壳聚糖絮凝剂的除油与重复利用性能。总体上，本项目完成了预定研究内容与目标，项目的实施为绿色环保、高效低耗、高适应性除油絮凝剂的开发提供了新的思路，为后续乳化油工业废水絮凝处理工程化奠定理论基础。