A Cu-TiO2/Ti dual rotating disk photocatalytic (PC) reactor has been developed based on our single rotating disk photoelectrocatalytic (PEC) reactor (Y. Xu, et. al, Environ. Sci. Technol. 2008, 42, 2612-2617), and successfully applied to the treatment of laboratory and industrial dye wastewater. Round TiO2/Ti and Cu disks of the same size are connected by a Cu wire and fixed parallel on an axis continually rotating at 90 rpm. High treatment efficiency is obtaineddueto direct photooxidation on the TiO2/Ti photoanode as well as additional degradation on the Cu cathode, which is speculated via indirect hydrogen peroxide (H2O2) oxidation and direct electro-reduction of dye on cathode. The mechanism of the Cu-TiO2/Ti dual rotating disk PC reactor was investigated. In a 20 mg L-1 Rhodamine B (RB) solution, approximately 100mV of potential and 10μA of current were measured between the Cu and TiO2/Ti electrode during PC treatment. Such phenomenon was explained by spontaneous electron transfer based on the same principle of establishing a Schottky barrier. On the Cu electrode surface, the photoelectrons either reduced dye molecules directly or reacted with dissolved oxygen (DO) to form H2O2. Rotation of electrodes out of the solution enhanced the mass transfer of target compound and kept the aqueous film fresh. The Cu-TiO2/Ti dual rotating disk PC reactor is a simple and effective device for the treatment of RB dye wastewater.

A TiO2/Ti rotating disk photoelectrocatalytic (PEC) reactor has been developed and successfully applied to degrade Rhodamine B (RB) and other dyes in textile effluents. The innovative concept behind the reactor design is to simultaneously perform two processes on one electrode. These two processes are (1) highly effective thin-film PEC, in which the upper half of the round disk photoanode was coated with a thin layer of wastewater and exposed to UV radiation in air; and (2) the conventional PEC, in which the other half of the disk was immersed in bulk wastewater and irradiated by the same light source. The average aqueous film thickness was about 75μm. The disk electrode was kept rotating at 90 rpm to continuously refresh the thin aqueous film for the upper side of the electrode and to promote the mass transfer of the target pollutants and the degradation products on the lower part of the disk. Using 20-150 mg L-1 RB solutions as a model system, thin-film PEC removed total color and total organic carbon (TOC) by 27-84% and 7-48%, respectively, within 1 h,muchhigher than 3-55% and 0-30% removal by conventional PEC under the same treatment conditions. Results also suggest that the thinfilm process was especially superior for treating high concentration solutions. Application of the rotating disk PEC reactor in industrial textile effluents showed a satisfactory result. The recycle experiments demonstrated excellent stability and reliability of the rotating disk PEC electrode. This study proposed a new concept for designing a PEC reactor applicable to industrial wastewater treatment.

The high energy cost of an electrochemical method is the fatal drawback that hinders its large scale application in wastewater treatment. In traditional single-chamber electrolysis cell, only direct oxidation at an anode exists. Although a small amount of hydrogen peroxide is produced at the cathode by reduction, it is transferred to the anode and destroyed there without adding much benefit to organic decomposition. A two-chamber electrolytic cell, connected with an electrolyte bridge, was developed in this work. In this new reactor, direct oxidation at anode and indirect oxidation by hydrogen peroxide at cathode can occur simultaneously. Therefore "dual electrodes oxidation" in one electrochemical reactor was achieved successfully. Compared to a traditional one cell reactor, this reactor cuts the energy cost by 50%, and thus might lead to reconsideration of the electrochemical role in wastewater treatment. A Pt/C gas diffusion electrode (GDE) is fabricated and used as a cathode fed with oxygencontaining gases to produce hydrogen peroxide. When purified air diffuses through the active layer on the GDE, oxygen is reduced to hydrogen peroxide with a high yield to decompose organics. It has been found that the direct oxidation process at an anodic zone is slightly affected by factors such as pH variation, Fe (Ⅱ) existence and aeration, while indirect oxidation at the cathodic zone is strongly affected. Dye used as a model pollutant was oxidized into small organic acids in both anode and cathode regions in this electrolytic reactor. GC-MS and IR spectrum were employed to analyze the intermediates formed during the degradation. Twenty intermediates have been detected, including 14 esters, 3 acids and 3 compounds with NO2 or N-OH groups. Thereafter, the degradation pathways of dye Acid Red B are proposed.

A novel solid-phase microextraction (SPME) setup, circulating cooling solid-phase microextraction (CC-SPME), is developed for determining organochlorine pesticides (OCPs) in water. The linearity area of this method is 0.5-120g/l, its RSD value is less than 10% and detection limit is in the low ng/l when it is used to detect-hexachlorocyclohexane, which is better than traditional headspace SPME (HS-SPME) and direct immersion SPME (DI-SPME) methods. The influence of factors such as pH, ionic intensity, adsorption time, and adsorption temperature were also investigated, respectively.

A surfactant-bound monolithic stationary phase based on the co-polymerization of 11-acrylaminoundecanoic acid (AAUA) is designed for capillary high performance liquid chromatography (HPLC). Using D-optimal design, the effect of the polymerization mixture (concentrations of monomer, crosslinker and porogens) on the chromatographic performance (resolution and analysis time) of the AAUA-EDMA monolithic column was evaluated. The polymerization mixture was optimized using three proteins as model test solutes. The D-optimal design indicates a strong dependence of chromatographic parameters on the concentration of porogens (1, 4-butanediol and water) in the polymerization mixture. Optimized solutions for fast separation and high resolution separation, respectively, were obtained using the proposed multivariate optimization. Differences less than 6.8% between the predicted and the experimental values in terms of resolution and retention time indeed confirmed that the proposed approach is practical. Using the optimized column, fast separation of proteins could be obtained in 2.5min, and a tryptic digest of myoglobin was successfully separated on the high resolution column. The physical properties (i.e., morphology, porosity and permeability) of the optimized monolithic column were thoroughly investigated. It appears that this surfactant-bound monolith may have a great potential as a new generation of capillary HPLC stationary phase.