Hong Yong Xie

Degradation of Artificial Sweetener Saccharin Sodium by Advanced Oxidation Technology

In this paper, the advanced oxidation processes of photocatalytic oxidation and Photo-Fenton oxidation were used in degradation of emerging pollutants saccharin sodium. The concentration of saccharin sodium was determined by HPLC. The results showed both photocatalytic oxidation and Photo-Fenton oxidation had an effective degradation of saccharin sodium. The degradation process was followed the first-order reaction. The best conditions of photocatalytic oxidation system: 500W mercury lamp, 0.04 g TiO2, pH=7 and the best ratio of photo-Fenton was SAC:H2O2:Fe2+=5:60:1. The total organic carbon (TOC) of sample has significantly reduced to about 93% by the two systems.

Controllable Imprinted Polymer Layer Coated Silica-Gel for S-1-(1-Naphthyl) Ethylamine Recognition by ATRP

Controlled grafting of S-1-(1-naphthyl) Ethylamine-imprinting polymer layer on the silica-gel was carried out by the surface-initiated atom transfer radical polymerization (ATRP). Polymerization time was used as the independent variable to manipulate the amount of grafted imprinting polymer on the silica-gel. For comparison, molecularly imprinted polymers (MIPs) without silica-gel also prepared at the same condition. SEM, FT-IR and UV spectrum were used to study the structural morphology and selectivity of polymers and probe the incorporation of imprinted polymer layer on the surface of substrates. Results indicate that the integration of ATRP and molecularly imprinted polymerization realize preparation of molecular selective polymers and it is possible to tune selectivity and morphology in rational way by changing polymerization times. Meanwhile, we achieve a reference strategy for the development of molecularly imprinting polymer for drugs and to handle forms in certain applications such as chromatographic stationary phases for chiral separations.

Photodegradation of Toluene by TiO2 Nanoparticles by Flame CVD Process

Photo-degradation of toluene at ppb levels by mixed-phase TiO2 nanoparticles, synthesized by the oxidation of TiCl4 in propane/air flame chemical vapor deposition (CVD) process, has been investigated experimentally by using a tubular photoreactor with thin TiO2 films coated on the reactor wall by sedimentation. Effects of toluene at initial concentration at ppb levels, rutile mass fraction and photoluminescence (PL) spectra of TiO2 nanoparticles on degradation degree have been investigated under the conditions of 5.7 seconds of residence time, 70% relative humidity, 38mg/cm2 of TiO2 loading, 25mW/cm2 of irradiation with main wavelength of 254nm.

A Model of Batch Grinding of Talc Powders

Grinding of talc powders has been studied both theoretically and experimentally. The specific rates of breakage of talc powders were measured based on the first-order breakage kinetics model and the cumulative breakage distribution parameters of talc powders were measured from primary breakage products. Based on the measurement results, the specific rate of breakage and cumulative breakage distribution functions were correlated with particle size asand , repectively. A differential-integral equation was thus build to describe grinding as a rate process and was integrated numerically. Comparisons on size distribution showed that the specific rate of breakage of talc powders increased with grinding time at an increase rateabout 0.0066min-2.

Investigation on Dissolution of Brominated Epoxy Resin Using Ionic Liquid [Bmim]Cl from Waste Printed Circuit Boards

Treatment technology of brominated epoxy resin (BER) is still a big challenge to waste printed circuit boards (PCBs) recycling. In order to make full use of the materials, ionic liquid 1-butyl-3-methyl imidazole chloride ([Bmim]Cl) was used to dissolve BER to separate glass fibers from PCB nonmetallic powders. The effects of dissolving parameters including temperature, time and solid/ liquid ratio on the dissolution rate of BER were investigated. The dissolved BER were regenerated and were characterized by FTIR and thermal analysis. Results showed that [Bmim]Cl was a good direct solvent for BER dissolution and at a suitable condition of 170°Cfor 6 hours with solid/liquid ratio of 1: 20 (g/g), nearly 90% of BER in original powders were dissolved. The possible dissolution mechanism was also discussed.

Determination of Retardation Factor of Perchloroethylene in Low Organic Carbon Aquifer

The retardation factor (R) expression was deduced for amended double-mode sorption isotherm of perchloroethylene (PCE) in low organic carbon content (0.080~0.090%) aquifer. The retardation effect varied with the solute concentration, the higher the concentration was, the lower the retardation factor. The values of R were determined and compared with the estimation values based on octanol-water partition coefficient (Kow), solubility data of a particular compound and Linear Free-Energy Relationships (LFER). It indicated that there were obvious discrepancy of R among the determinations and estimations. Although how to determine the exact value of R is still questioned, it may be advisable and feasible to understand the retardation effect using batch sorption tests in studying the transport of pollutant in aquifer, especially in mathematical simulation study.

Saturation Concentration of Gas Pollutants in Photocatalysis

Saturation behavior in photocatalysis is investigated for volatile organic carbons (VOCs) and ammonia by using a tubular photoreactor and TiO2 nanoparticles, synthesized by a flame chemical vapor deposition (CVD) process. Degradation degree versus initial concentration shows that saturation behavior occurs at different initial concentrations for different gas pollutants. The saturation concentration is obtained by taking as the intersection of the level off part and the tangential line to the rapid change part from the curve of degradation degree versus initial concentration. The saturation concentration for benzene is as low as 0.063 mg/m3, and is up to 720mg/m3 for formaldehyde for TiO2 nanoparticles synthesized by a flame CVD process.

CO2 Sequestration in Mixtures of Sodium Humate and Waste Gypsum

A novel process of CO2 sequestration in mixtures of sodium humate (HA-Na) and waste gypsum was proposed. Experiments investigated the CO2 absorption properties for HA-Na solution. HA-Na solution shows great performance in CO2 absorption, and the CO2 absorption amount reaches to 0.96 mol for 3 hours with 100 mL HA-Na solution (0.04 g/mL), at the condition of 15 °C, gas flow rate of 40 mL/h. the CO2 sequestration mechanism by HA-Na and desulfurization gypsum (DG) was analyzed. CaSO4 plays a key role in the CO2 absorption by HA-Na solution. A permanent method of CO2 sequestration is achieved by the mixtures of HA-Na and waste gypsum.

Remediation of Perchloroethylene Contaminated Groundwater by Zero-Valent Iron Integrated with Anaerobic Microbial Community

Previous study using batch method showed that an integrated technique using a combination of zero-valent iron and an anaerobic microbial community (FeMB) showed good degradation efficiency for perchloroethylene (PCE). In this study, a permeable reaction barrier (PRB) with FeMB as reactive media was simulated in remediation columns. It was proved that PCE was retardation adsorption and degraded in remediation columns. A mathematical model was developed and used to simulate the transport and transformation of PCE in remediation columns, and was also used to predict the fate of PCE in groundwater in different conditions. Results showed that FeMB PRB might be an environmentally desirable technology and the model could describe successfully the transport and transformation of PCE in remediation columns.

COD Removal of Textile Printing and Dyeing Wastewater by Photocatalysis

Degradation of printing and dyeing wastewater after aerobic biochemical treatment by photocatalysis is studied by using a rotating photoreactor and TiO2 photocatalyst of Degussa P25. Effects of irradiation time and pH value on removing efficiency are investigated. The results show that the COD down to about 80mg/L can be achieved at the irradiation time of about 4-5 hours at mild pH values. At the pH value from 1.5 to 3.2, the COD down to about 80mg/L can be achieved at the irradiation time less than 1 hour, and the COD down to about 20mg/L could be achieved at the irradiation time of about 4 hours at a pH value of about 3.2.