壳聚糖和PDMDAAC改性膨润土用于处理含油废水的研究

含油废水污染范围广,对人类和生态环境危害大。采用常规方法(如浮选法、絮凝法、电化学法、膜分离法和生物法)处理的除油率不高于91%,成本较高,因此急需开发一种高效低廉的吸附剂。膨润土是一种优良的吸附剂,但用其直接处理含油废水的效果较低。本文选用壳聚糖和PDMDAAC两种有机物作为改性剂,对钠基膨润土改性,使膨润土能有效地处理含油废水。通过实验比较了两种有机改性膨润土处理含油废水的最佳去除条件,探讨了表征对其吸附性能的影响。去油效果结果表明:壳聚糖改性膨润土的除油率可达87.8%,PDMDAAC改性膨润土的除油率可达89.3%,处理所需时间少于15 min;除油效率和处理时间都优于常规方法。吸附性能表征结果显示,两种改性剂均以负载的方式和钠基膨润土颗粒结合,吸附性能良好;相比而言,PDMDAAC改性膨润土的处理效果比壳聚糖改性膨润土更好。PDMDAAC应用于含油废水的处理,具有成本低、效率高、操作简单的特点,在含油废水处理领域具有较好的应用前景。

Study of Oil-bearing Wastewater Treatment by Chitosan-bentonite and PDMDAAC-bentonite

Oil-bearing wastewater pollution has noxious effects on human health and the ecological environment. Oil-bearing wastewater treatments are less efficient by traditional methods (flotation method, flocculation technology, electrochemistry method, membrane separation and biological method) which yield than 91% recovery. Therefore, it is urgent to develop a new kind of high efficiency and cheap adsorbent. Bentonite is an excellent adsorbent, but the effect to oil-bearing wastewater treatment could be improved significantly. The main purpose of this study is to prepare a high efficient modified bentonite for oil-bearing wastewater treatment. Chitosan and PDMDAAC as modifiers were used respectively to prepare a series of cationic polymer modified bentonite. The optimal conditions and properties for modified bentonite to adsorb oil in oil-bearing wastewater were investigated and compared. Experimental results show that removing rates were improved to 87.8% and 89.3% by using chitosan-bentonite and PDMDAAC-bentonite, respectively. The processing time is shorter than 15 min. Compared with the traditional method, the new method is less time-consuming and has a higher efficiency. With Fourier Transform Infrared Spectroscopy (FT-IR), X-ray Diffraction (XRD) and Scanning Electron Microscope (SEM), the results show that chitosan and PDMDAAC is coated as Na⁺-bentonite. Comparisons of adsorption performance show that PDMDAAC-bentonite is an improvement on chitosan-bentonite. PDMDAAC-bentonite has high efficiency, low cost and is easy to operate, and can be used in wastewater treatment extensively.