The suspended TiO2 powder enjoys free contact with pollutant molecule in a photocatalytic reactor; it can generally achieve better efficiency than the immobilized TiO2 catalysts. However, the separation and reuse of this catalyst powder from treated water often limit its application in practice. An adsorptive activated carbon-supported titanium dioxide photocatalyst TiO2/AC was prepared using nanosized titanium dioxide (anatase) immobilized on activated carbon powder by a novel preparation technique with polyacrylic ester emulsion. Meanwhile, the heterogeneous photocatalytic decomposition of aqueous hydroquinone over the ultraviolet irradiated TiO2/AC photocatalyst was carried out with high decomposition efficiencies in a slurry photocatalytic reactor (SPCR), which provided the effective contact of TiO2/AC photocatalyst and reactant. The pH value, the ratio of TiO2/hydroquinone, the aerating, and the concentration of H2O2 on photocatalytic decomposition of hydroquinone were discussed in detail. Experimental results showed that not only did the photocatalyst have a high adsorption performance and a good photocatalytic activity for hydroquinone but also the catalyst was easily separated from SPCR and recycled as well. Moreover, it was found that the reaction kinetic fixed the pseudo-first-order kinetic equation, which provided a detailed kinetic understanding of photocatalytic degradation of hydroquinone in SPCR.

Addition of urea-based antifreeze admixtures during cement mixing in construction of buildings has led to increasing indoor air pollution because of continuous transformation and emission of urea to gaseous ammonia on indoor concrete walls. To control ammonia pollution from indoor concrete walls, a circulated photocatalytic reactor (CPCR) was designed to intensify the performance for the decomposition of gaseous ammonia in the present study and TiO 2 film photocatalysts were prepared by the sol-gel method and coating onto the inner wall of this reactor using a bonder of polyacrylic ester emulsion, which was characterized by FTIR, TEM, and SEM. In particular, the influences of initial concentration of ammonia on the degradation conversion (D p ), apparent reaction rate constants (k r ), initial degradation rate (r), deactivation, and regeneration of catalyst in CPCR were investigated. Furthermore, a designed equation of surface catalytic kinetics was developed for describing the decomposition of ammonia in CPCR. The total number of adsorption sites available for the gas molecules N T and the adsorption equilibrium constant K ads values were determined through a linearfitting method. Finally, undesirable NO 2 and NO 3 were detected as the intermediates in the process of photodegradation at different initial concentration of ammonia, which was detected by catalytic kinetic spectrophotometry. The results indicated that the degradation conversion (D p ), initial degradation rate (r), degraded products, and half-life (t 1/2 ) were closely correlated to the initial concentration of ammonia. It was found that the reaction kinetics fixed the pseudofirst-order kinetic equation of photocatalytic degradation of gaseous ammonia in CPCR, and the kinetic results are discussed in terms of adsorption of ammonia and products degraded.

Self-emulsified water-borne epoxy curing agent of nonionic type was prepared using triethylene tetramine (TETA) and derivative of epoxy resin as a capping agent, which was synthesized by liquid epoxy resin (E51) and polyethylene glycol (PEG), and the curing agent possessed emulsification and curing properties at the same time. The curing agent with good property of emulsifying liquid epoxy resin could be obtained under the condition of the molar ratio of PEG : E51 : TETA as 0.8 : 1 : 3.5 at 80 C for 5 h. The mean particle size of the emulsion liquid was about 220 nm with the prepared curing agent and epoxy resin at the mass ratio of 1 : 3. The structure of the emulsion-type curing agent was confirmed by FTIR and 1 H NMR spectra, and the mechanism of cured film formation was also analyzed by SEM photographs. The cured film prepared by the emulsion-type curing agent and epoxy resin under ambient cure conditions showed good properties even at high staving temperature. This study provides useful suggestions for the application of the water-borne epoxy resins in coating industry.