Rhubarb, a well-known Chinese herbal medicine, is also used in Europe and other places of the world. Anthraquinones derivatives are thought to be the major active components. A pressurized liquid extraction (PLE) and capillary zone electrophoresis (CZE) separation were developed for simultaneous determination of five anthraquinones including aloe-emodin, emodin, chrysophanol, physcion, and rhein in Rhubarb. The effects of the experimental variables on PLE and CZE have been optimized. The optimum conditions of PLE were: solvent, methanol; temperature, 140 degrees C; particle size, 0.13-0.2 mm; static extraction time, 5 min; pressure, 1500 psi; and one extraction. The best separation of the five anthraquinones could be obtained using 50 mM borate buffer (pH 8.2) containing 25% isopropyl alcohol and 25% acetontrile as modifier, while the separation voltage was 25 kV and the temperature was at 20 degrees C. The method developed is accurate, simple, and reproducible, and could be used for quality control of Rhubarb and its medical preparations.
The aging oily wastewater (AOW) from Tarim oilfield in China was treated by demulsification/flocculation. A novel sewage treatment agent (YL-7) was developed using a cationic surfactant (LY) and flocculants (polydimethyl diallyl ammonium chloride (PDMDAAC)/polyaluminum chloride (PAC)). At an YL-7 dosage of 320 mg L(-1) at 323 K for 90 min, the oil content of AOW was reduced from 728.8 mg L(-1) to 23.7 mg L(-1), and oil removal efficiency reached 96.7%. Microorganism flocs (extracted from AOW) with high negative zeta potential enhanced the stability of oil/water emulsion. LY and PDMDAAC neutralized the negative charge on the oil droplet surface. PDMDAAC and PAC mainly bridged and swept flocs during the flocculation process. YL-7 was found to be a suitable sewage treatment agent in removing oil from AOW.
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