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The ultrasonic method developed to measure the dispersed phase holdups in dispersion systems is based on the fact that the velocity of ultrasound in the dispersion is different from that in the liquid. The relationships between velocity differences in the term of transmission time differences of ultrasound and gas holdup in a gas‐liquid system and solid holdup in a liquid‐solid system were derived. The holdups became linearly dependent on the time differences, which is in agreement with the experimental data. Based on those relations, a model for simultaneous measurement of gas and solid holdups in three‐phase systems is proposed. The model permits measurement of the dispersed phase holdups by measuring the transmission time of ultrasound transmitted through the dispersions in two frequencies. It allows investigation of local holdups distributions in a bubble column and in a suspended bubble column.

The oxidation of surfactant (polyoxyethylene alkyl ether, C 14 H 29 O(CH 2 CH 2 ) 7 H, hereafter referred to as SS-70) induced by high power ultrasound is examined. The influences of aeration, bubble distribution, and frequency on the degradation rate are investigated. SS-70 is decomposed totally in a few hours. The optimum frequency for the degradation is observed. The decomposition rate of the surfactant is enhanced by the aeration and depends on the shape of the reactor. The optimum condition for the degradation process of ultrasonic oxidation is discussed.

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Monolithic columns for analytical applications have attracted the researcher's attention. In this work, the laboratory-made organic-polymer monolithic column is modified with trypsin and further applied as a nanobiocatalyst microreactor and a stationary phase for separating chiral compounds by liquid chromatography. The monolith was synthesized by in-situ copolymerization of glycidyl methacrylate (GMA) and ethylene glycol dimethacrylate (EDMA) or trimethylolpropane trimethacrylate (TRIM) as a crosslinking agent, with porogen of 1,4-butanediol/propanol/water (4:7:1 v/v) and AIBN as the radical polymerization initiator inside PEEK and silicosteel tubings (1.0 mm i.d  100 mm) at 60 C for 12 h. A total monomer ratio (%T) and crosslinking agent (%C) of 40:25 and 28:12 were applied to prepare poly-(GMA-co-EDMA) and poly-(GMA-co-TRIM), respectively. The produced monoliths were further modified by introducing trypsin (10 mg/L) through the ring-opening reaction of the epoxide group existing in the monolithic column. The trypsin-immobilized poly-(GMA-co-EDMA) monolithic column was applied as the nanobiocatalyst microreactor for online/flow-through and rapid digestion of β-casein sample into its peptide fragments. The trypsin-immobilized poly-(GMA-co-TRIM) column has potential application to be used as the HPLC stationary phase for the separation of R/S-citronellal enantiomers.