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Background: Building upon the socioecological perspective, this study examines prospective associations linking leisure activity participation with alcohol purchasing and consumption in early adolescence.Methods: A total of 1763 seventh graders (age 12-13 years) were recruited from middle schools in urban Taiwan via multi-stage sampling and followed-up 1.5 years later during ninth grade. Information about leisure activities, covariates (i.e., gender, puberty development, family structure, parental educational attainment, monthly allowance, peer drinking, and childhood alcohol experience), and two outcome variables (i.e., alcohol purchasing and drinking behaviors) was gathered via web-based self-administered questionnaires. Data concerning alcohol outlets and recreational resource for each community district were retrieved from official statistics and commercial sources. Two-level hierarchical generalized linear models were used to evaluate association estimates.Findings: Five percent of ninth graders ever purchased alcohol and nearly one in seven drank alcohol on three or more occasions (i.e., occasional drinking) in the past year. Sports, unstructured, and organized leisure activities were not linked with illegal alcohol purchasing when community contexts were statistically adjusted; a higher community on-premised alcohol outlet density increased alcohol purchasing by 94% (95% CI = 1.24-3.06). In contrast, unstructured leisure activity participation at 7th grade predicted occasional drinking (adjusted Odds Ratio [aOR] = 5.52; 95% CI = 3.13-9.74). Sports participation was associated with reduced risk of occasional drinking in the communities with high unregulated alcohol outlets (aOR for interaction = 0.58; P < .001).Conclusion: Our research provides insights to differential roles of leisure activity participation in shaping adolescents' commercial alcohol access and occasional drinking. Macro-social contexts should be considered in the efforts to reduce underage drinking problems through leisure activities. [ABSTRACT FROM AUTHOR]

Livestock wastewater can contain high levels of phosphates and trace amounts of various ionic species harming the environment and human health. These ions can be successfully removed from livestock effluent and recovered in a non-toxic crystal form via crystallization. The fluidized bed homogeneous crystallization (FBHC) technology is a cutting-edge pretreatment method that removes phosphate and ammonium by crystallizing struvite. The findings demonstrated a 37% removal for ammonium solutions alone, 38% with copper, 35% with zinc, and 33% when copper and zinc were present, while the crystallization efficiency was achieved at 35%, 33% with copper, 28% with zinc, and 26% with copper and zinc. For phosphate-containing solutions, 95% was removed, 81% with copper, 96% with zinc, and 88% with copper and zinc. Similarly, crystallization efficiency was attained at 87%, 60% with copper, 94% with zinc, and 81% when copper and zinc were combined with phosphates. For ammonium solutions, copper and zinc reduced the removal and crystallization efficiency at constant pH and increased at increasing pH. For phosphate solutions, the removal and crystallization efficiencies increased at increasing pH. However, zinc ions resulted in the highest removal, and crystallization efficiency for phosphate solutions was attained. Based on SEM, EDS, XRD, and XPS analyses, the peaks revealed the presence of struvite in the form of magnesium ammonium phosphate. [Display omitted] • Struvite crystal was recovered as ammonium and phosphate at 94% in the presence of zinc ions. • The best pH of 9.0 of the effluent affected the ammonium and phosphate removal and crystallization. • The removal was best for phosphate ions in the presence of zinc at 95% and 94% for the crystallization. [ABSTRACT FROM AUTHOR]

[Display omitted] • Industrial processes produce excess nickel, risking public and ecological health. • Bi-pH in the fluidized-bed granulation process improved nickel granulation. • Molar ratio and initial concentrations directly affect saturation and nucleation. • Co-compounds slightly affected Ni2+ removal but reduced granulation efficiency. Anthropogenic activities and industrial processes generate large amounts of nickel in effluent, posing a threat to public and ecological health. Several processes have been developed to remove nickel and adhere to environmental limits. The fluidized-bed non-seeded granulation process has proven effective in removing and recovering metals including nickel. In this study, nickel was precipitated using phosphate while investigating bi-pH operation. The study compared single-pH and bi-pH and found that bi-pH was better. The effects of molar ratio ([Ni2+]:[PO 4 3-]), initial nickel concentration, copper ion concentrations, and other co-existing chemical compounds were then investigated under bi-pH operation. The optimal conditions were observed at bi-pH 7.5 and 9.0, molar ratio of 1:1.3, and 300 mg/L initial nickel concentration. The results showed that bi-pH improved the granulation process by generating heterogeneous granulation through observed bi-layers. The effects of molar ratio and initial nickel concentrations were attributed to changes in the predominant saturation condition, dictating primary and secondary nucleation. Co-existing compounds had no significant effect on total nickel removal but reduced granulation efficiency due to nickel complexation, ionic competition, and precipitate dissolution. [ABSTRACT FROM AUTHOR]

Advanced oxidation processes (AOPs) are promising technologies to mineralize organic pollutants and reduce chemical oxygen demand (COD) from water effluents. Unfortunately, treatment of real industrial effluents is barely reported in literature and actual application is rare. One of the technology transfer limitations is associated to the identification of the most suitable stage for AOPs implementation in existing water treatment facilities of industry manufacturers. Here, we report a complete study where the most suitable stage for Fenton treatment implementation for a screw manufacture industry water treatment facility is identified. Actual wastewater effluent was collected, characterized and treated by means of Fluidized-bed Fenton (FBF) treatment to reduce COD levels. Fenton’s reagents feeding mode is evaluated to better understand influence on continuous flow operational FBF performance and efficiency. [ABSTRACT FROM AUTHOR]

Chlorophenols are extensively used in the anthroposphere, and their fates in the atmosphere, hydrosphere, biosphere and lithosphere and their degradations under natural light of great interests. The homogeneous photocatalytic degradation of 2-chlorophenol (2-CP) in titanium dioxide suspensions containing copper ions or/and sulfates has been well examined. In this study, TiO 2 is directly doped with copper sulfate by a sol-gel method to promote its visible light activity (VLA) following a post-calcination step. The effects of three parameters of synthesis (calcination temperature, amounts of dopant and nitric acid) on 2-CP degradations were experimentally investigated using a three-factor, two-level factorial design in the first stage. Catalysts of the most significant synthetic parameters were further synthesized at five calcined temperatures and characterized in the second stage. 2-CP was completely removed using catalysts that were doped 0.21 mol.% CuSO 4 with 0.1 vol.% nitric acid and then calcined at 300 °C for 6 h. Morphological variations with doping amount are observed from scanning electron micrographs. XRD patterns demonstrated a transformation from amorphous to the anatase phase, with replacement of Ti 4+ by Cu 2+ in the crystal structure of TiO 2 . UV–visible light diffuse reflectance spectra of the doped catalysts exhibited red-shifts, revealing their VLA. Surface areas, measured by the BET method, decreased as the calcination temperatures increased, and the pore sizes increased. Moreover, effect of three operational parameters, including: (del) initial concentration of 2-CP, initial pH and the photocatalyst dosage, under visible-light irradiation were investigated to simulate the scenarios of degradation in the natural and artificial conditions. Optimal operational parameters were obtained at a catalyst dosage of 3 g·dm −3 , an initial 2-CP concentration of 20 ppm and a solution pH of 5.5. The pH zpc of the undoped and CuSO 4 -doped TiO 2 were determined to be 3.5 and 3.84. [ABSTRACT FROM AUTHOR]

Currently, the aluminum industry is facing a major problem in the disposal of highly alkaline bauxite wastewater. It contains the red mud that is formed during alumina extraction via Bayer process. Approximately, 1.5 t/y of bauxite residue per ton of alumina were produced and continuously increasing up to 150 Mt/y. In this study, the simulated bauxite wastewater was treated using a non-seeded fluidized-bed homogeneous granulation technology. The effect of effluent pH, molar ratio of [Ca +2 ] in /[C 2 O 4 −2 ] in (1.00, 1.25, 1.50, and 1.75), and influent flow rates (15, 25, and 35 mL min −1 ) were evaluated in terms of oxalate removal and granulation efficiency. Increasing the pH of effluent tend to increase the oxalate removal and granulation efficiency. The best effluent pH with highest removal of 87.6% was 5.5 ± 0.05 and for the granulation of 81.7% was 3.75 ± 0.05. Increasing the molar ratio of [Ca +2 ] in /[C 2 O 4 −2 ] in up to 1.75 exhibits a reduction of oxalate concentration in the bauxite wastewater. This results to the highest oxalate removal of 87.6% and granulation efficiency of 85.6%. At 35 mL min −1 influent flow rate, the highest oxalate removal of 86.6% and 84.6% granulation efficiency was achieved. A firm and rigid structures of micro fragments of the granules formed was analyzed using SEM and validated by XRD analysis as calcium oxalate monohydrate (COM-CaC 2 O 4 ·H 2 O). [ABSTRACT FROM AUTHOR]

This study determined the removal of nickel from a synthetic Watts bath electroplating composition (NiCl 2 ·6H 2 O, NiSO 4 ·6H 2 O, and H 3 BO 3 ) by homogeneous fluidized-bed granulation process. The effects of adding calcium ions present in an electroplating bath while varying influent nickel concentration (200 mg·L −1 , 300 mg·L −1 , and 400 mg·L −1 ), [CO 3 2− :Ni 2+ ] molar ratio (1.0, 1.5 and 2.0) and pH of carbonate precipitant (10.5, 10.8, and 11.0) were evaluated. Calcium ion addition was varied at 20 mg·L −1 , 50 mg·L −1 , and 100 mg·L −1 . The best operating conditions were at 300 mg·L −1 influent nickel concentration, [CO 3 2− :Ni 2+ ] molar ratio of 1.5, and pH of 10.8 of the precipitant from different types of water source. The removal of nickel from synthetic Watts bath electroplating wastewater using tapwater was 84.93%, and 92.66% with the addition of Ca 2 + ion at 20 mg·L −1 . For the synthetic Watts bath electroplating wastewater using reverse osmosis water, nickel removal was 97.08% and 98.51% when pure nickel ion in the solution was used. The characterized granules has low symmetry that confirmed the characteristics of a nullaginite mineral of Ni 2 (CO 3 )(OH) 2 . [ABSTRACT FROM AUTHOR]

Acetaminophen (ACT) is a mild analgesic commonly used for relief of fever, headache and some minor pains. It had been detected in both fixed factory-discharged wastewaters, and diverse sources, e.g. surface waters during festival events. Degradation of such trace emergent pollutants by titanium dioxide (TiO 2 ) photocatalysts is a common approach; however, the band gap that can be utilized in the UV range is limited. In order to extend downward the energy required to excite the photocatalytic material, doping with potassium peroxodisulfate (K 2 S 2 O 8 ) by a sol-gel method was done in this work. The visible-light active photocatalyst was tested on the degradation of ACT under four parameters including: initial ACT concentration, catalyst dose, initial pH, and system temperature. Optimal conditions, which achieved 100% ACT degradation, were obtained by using 0.1 mM ACT initial concentration, catalyst dose of 1 g L −1 , initial pH of 9.0 and system temperature of 22 °C at the end of 9-h irradiation. Meanwhile, three types of degradation kinetic models (i.e. zero, pseudo first and second order) were tested. The feasible model followed a pseudo-first order model with the computed constant (k app ) of 7.29 × 10 −3 min −1 . The present study provides a better photocatalytic degradation route by K 2 S 2 O 8 -modified TiO 2 in comparison with pristine TiO 2 , in wastewater treatment dealing with ACT and other persistent organic pollutants. [ABSTRACT FROM AUTHOR]

In this study, the electro-Fenton process was used to treat synthetic and actual TFT-LCD wastewaters. TFT-LCD wastewater contains high amounts of organic solvents mainly dimethyl sulfoxide (DMSO). For the simulated TFT-LCD wastewater, response surface methodology (RSM) was used to fit experimental data to empirical models with the responses, %DMSO removal and H 2 O 2 efficiency (Δ[H 2 O 2 ]/Δ[DMSO]). Among the studied independent variables that affect DMSO degradation efficiency, Fe 2+ loading was found to be the most dominant, then pH and, H 2 O 2 loading being the least significant. DMSO removal and H 2 O 2 efficiency improved with high Fe 2+ loading, low H 2 O 2 loading and low solution pH. The observed decrease in pH was attributed to the production of acidic degradation intermediates of DMSO. At 5 mM DMSO loading, treatment efficiency reached 100% DMSO removal. The electro-Fenton technology was also applied to real TFT-LCD wastewater resulting in TOC and COD removals of 68% and 79%, respectively. [ABSTRACT FROM AUTHOR]

Highlights: [•] The seed had a significant effect on the initial rate of phosphate removal. [•] The types of seed affect the removal rate and efficiency of phosphate. [•] Surface nucleation reached at a maximum of phosphate removal efficiency. [•] The inorganic ions present had no significant impact on phosphate removal. [•] Several magnesium phosphate species were formed for all FBR experiments. [Copyright &y& Elsevier]

Highlights: [•] The effect of UV light on acetaminophen degradation was investigated. [•] Pseudo-first order degradation rate constant of acetaminophen was obtained. [•] Applying UV light for first stage increased the acetaminophen degradation. [ABSTRACT FROM AUTHOR]

Highlights: [•] The DMSO degradation was compared by different Fenton processes. [•] The effect of current density on the DMSO degradation was insignificant. [•] The DMSO degradation efficiency improved at chloride ion concentration was low. [•] Inorganic ions inhibited the DMSO degradation in the following sequence: >F− >Cl−. [Copyright &y& Elsevier]

Abstract: Ferromagnetic elements Fe, Ni and Co were immobilized on the porous SiO2 to catalyze the hydrogen generation from aqueous alkaline NaBH4 (sodium borohydride). The porous SiO2 was prepared by silica-surfactant self-assembly and the ferromagnetic catalyst was prepared by chemical reduction. The ferromagnetic catalysts were characterized using TG/DTA (Thermogravimetry/differential thermal analysis), BET, XRD (X-ray powder diffraction), ESEM/EDS (environmental scanning electron microscope/energy dispersive spectroscopy), XPS (x-ray photoelectron spectroscopy) and VSM (vibration sample magnetometer) measurements. The surface area of porous SiO2 was affected by the molecular weight of surfactant. The relative catalytic activities in the generation of hydrogen from alkaline NaBH4 solution follow the order Co/SiO2 > Ni/SiO2 > Fe/SiO2. The rates of hydrogen generation using Co/SiO2, Ni/SiO2 and Fe/SiO2 catalysts in 20 ml of 5 wt.% NaBH4 solution at 313 K were 8701, 307 and 130 ml min−1 g−1-metal, respectively. It is found that the degree of metal-oxidation and crystal structure affected the catalytic activity. The hydrogen generation of NaBH4 in alkaline solution increased with increasing cobalt loading, of which the activation energy was 59 ± 2 kJ mol−1. [Copyright &y& Elsevier]

Abstract: Synthetic wastewater containing monoethanolamine (MEA) and phosphate, which was generated during the cleaning and etching processes for thin-film transistor liquid crystal displays (TFT-LCDs) was treated using a novel process. Degradation of MEA was studied and compared using the Fenton and fluidized-bed Fenton processes. Comparison results show that the Fe2+ concentration was an important factor for MEA and chemical oxygen demand (COD) removal in the fluidized-bed Fenton process. The degradation of MEA followed pseudo-first-order reaction kinetics. The MEA, COD and total organic carbon (TOC) removal efficiencies by the fluidized-bed Fenton process after 60min were 15–26% higher than those by the Fenton process. The phosphate removal rate followed a first-order reaction. Phosphate removal was optimized by selecting sand grains sized (0.24–0.5mm) and a molar ratio of Fe2+/P of 1.3 at pH 7. In the two stages, optimized conditions were Fe2+/P=1.3 at pH 7 using 100g SiO2 for phosphate removal, and 3mM Fe2+ and 50mM H2O2 at pH 3 for MEA removal; phosphate removal efficiency was 45% and MEA removal efficiency was 76%. [Copyright &y& Elsevier]

Abstract: This study investigated the degradation of acetaminophen (ACTP) in the Fenton and electro-Fenton processes in an aerator reactor. The influences of important parameters on acetaminophen degradation were studied and described in details. The experimental results show that the Fenton and electro-Fenton processes had maximum ACTP degradation efficiencies of 99% and 100%, respectively. The ACTP degradation efficiency of Fenton process and electro-Fenton process were apparently increased at pH 2 and 4, respectively; ACTP degradation efficiency increased 72% at pH 2 in the Fenton process and 74% at pH 4 in the electro-Fenton process when fixed H2O2 dosage (15mM) and Fe2+ dosage was increased from 0.01 to 0.1mM. The Box–Behnken design results indicated that the relative effects of the studied parameters on ACTP degradation in Fenton and electro-Fenton processes were Fe2+ >H2O2 >pH. The initial rate of ACTP degradation (r) and ACTP degradation efficiency in the electro-Fenton process were apparently higher than those in the Fenton process at pH 2, as a high H2O2-to-Fe2+ molar ratio (1500) was used. The COD and TOC obtained by electro-Fenton process were 12% and 65% higher, respectively, than those in the Fenton process. [Copyright &y& Elsevier]

Abstract: A recyclable and reusable Ru/Al2O3 catalyst is prepared for hydrogen generation from the hydrolysis process of alkaline sodium borohydride (NaBH4) solution. The hydrogen generation rate by the hydrolysis and methanolysis of alkaline NaBH4 was explored as a function of NaOH concentration. Meantime, the byproducts derived from the spent alkaline NaBH4 solution were characterized by X-ray diffraction (XRD), scanning electro microscope/energy dispersive spectrometer (SEM/EDS) and NMR (Nuclear Magnetic Resonance). The effect of NaOH concentration on the hydrogen generation from the hydrolysis of NaBH4 significantly depends on the type of catalysts. With increasing NaOH concentration, the hydrogen generation rates decrease when using ruthenium (Ru) composite as a catalyst. The hydrogen generation rate of the methanolysis of NaBH4 is significantly inhibited in the presence of NaOH as compared with the hydrolysis of NaBH4. The durability test of the Ru/Al2O3 catalyst shows that the hydrogen generation rate decreases with recycling and reuse. The XRD and NMR analysis results show that the borate hydrate (NaBO2 H2O) was derived from the hydrolysis of 20 wt% and 30 wt% NaBH4. [Copyright &y& Elsevier]

Abstract: Acetaminophen is a widely used drug worldwide and is one of the most frequently detected in bodies of water making it a high priority trace pollutant. This study investigated the applicability of the electro-Fenton and photoelectro-Fenton processes using a double cathode electrochemical cell in the treatment of acetaminophen containing wastewater. The Box–Behnken design was used to determine the effects of initial Fe2+ and H2O2 concentrations and applied current density. Results showed that all parameters positively affected the degradation efficiency of acetaminophen with the initial Fe2+ concentration being the most significant parameter for both processes. The acetaminophen removal efficiency for electro-Fenton was 98% and chemical oxygen demand (COD) removal of 43% while a 97% acetaminophen removal and 42% COD removal were observed for the photoelectro-Fenton method operated at optimum conditions. The electro-Fenton process was only able to obtain 19% total organic carbon (TOC) removal while the photoelectro-Fenton process obtained 20%. Due to negligible difference between the treatment efficiencies of the two processes, the electro-Fenton method was proven to be more economically advantageous. The models obtained from the study were applicable to a wide range of acetaminophen concentrations and can be used in scale-ups. Thirteen different types of intermediates were identified and a degradation pathway was proposed. [Copyright &y& Elsevier]

Abstract: Photocatalytic titanium dioxide was synthesized by an acid-catalyzed sol–gel process with titanium n-butoxide as the precursor. Several factors including adsorption, wavelength, aniline concentration, and pH were examined to measure their impact on the photocatalytic activity of synthetic TiO2, using aniline as the target compound under visible light irradiation by light-emitting diodes. Under blue-light illumination, the as-synthesized TiO2 exhibited photocatalytic activity of whereas commercial TiO2 (Degussa P-25) displayed no photoreaction under the same conditions. This photoactivity was more pronounced under blue, green, yellow, and red light, and that corresponded very well with the adsorption spectrum of as-synthesized TiO2. As the initial aniline concentration increased from 0.047 to 0.80mM, the degradation efficiency of aniline decreased from 72% to 18% after irradiation for 4h with 1g/L TiO2. The reaction followed the Langmuir–Hinshelwood kinetic model with the adsorption equilibrium and rate constant having values of 15.89 1/mM and 9.96×10−4/(mMmin), respectively. For the photocatalysis of aniline by this visible-light-activated TiO2, the optimum pH was 7 in the range 4–10. [Copyright &y& Elsevier]

Abstract: A Box–Behnken design (BBD) statistical experimental design was used to investigate the degradation of o-toluidine by the electro-Fenton process. This method can be used to determine the optimal conditions in multivariable systems. Fe2+ concentration (0.2–1.0mM), H2O2 concentration (1–5mM), pH (2–4), and current (1–4A) were selected as independent variables. The removal efficiencies for o-toluidine and chemical oxygen demand (COD) were represented by the response function. Result by 2-level factorial design show that the pH and the Fe2+ and H2O2 concentrations were the principal parameters. Among the main parameters, the removal efficiencies for o-toluidine and COD were significantly affected by pH and Fe2+ concentration. From the Box–Behnken design predictions, the optimal conditions in the electro-Fenton process for removing 90.8% of o-toluidine and 40.9% of COD were found to be 1mM of Fe2+ and 4.85mM of H2O2 at pH 2. Under these optimal conditions, the experimental data showed that the removal efficiencies for o-toluidine and COD in the electro-Fenton process and the photoelectro-Fenton process were more than 91% and 43%, respectively, after 60min of reaction. The removal efficiencies for o-toluidine and COD in the Fenton process are 56% and 27%, respectively. [Copyright &y& Elsevier]

Abstract: This study investigated the treatment of textile industrial wastewater from a dyeing and finishing mill by the fluidized-bed Fenton process. Operating variables, such as the pH, concentrations of H2O2 and Fe2+, are used to explore the respective effects on the oxidation and decolorization of the textile wastewater. The experimental results were estimated in terms of chemical oxygen demand (COD) and color reductions to examine the treatment efficiency. The optimum pH was observed to be around 3. The decolorization and the oxidation efficiencies could achieve 92% and 49%, respectively, in only 2min of reaction under the concentration ratio of [COD]:[Fe2+]:[H2O2]=1:0.95:3.17. By using this process, the oxidation of textile wastewater increased with increasing H2O2 dosage. The highest level of oxidation was 87%. [Copyright &y& Elsevier]

Abstract: Novel composites of porous SiO2-LP and SiO2-HP supports are synthesized by the silica–polyethylene glycol monooleyl ether surfactant self-assembly method to obtain a large surface area. Cobalt is immobilized in the supports by incipient wetness impregnation. A stable and active Co/SiO2 catalyst is examined using FE-SEM, BET and XRD. Further, the catalyst is tested for catalytic hydrolysis of alkaline sodium borohydride (NaBH4) solution: the rate of hydrogen generation is found to increase with increasing cobalt loading of the Co/SiO2 catalyst. The hydrogen generation rates increase dramatically when the temperature is increased from 17 to 40°C. The highest hydrogen generation rates of Co/SiO2 catalyst are obtained at 2513mLmin−1 g−1 in 20mL of 5wt.% NaBH4 solution containing 5wt.% NaOH at 40°C. [Copyright &y& Elsevier]

Abstract: The competitive kinetics technique is shown to be a useful and reliable tool for determining rate constants. Regardless of the conditions of the reaction and the operation mode, the intrinsic second-order rate constants of 2,6-dimethyl-aniline and hydroxyl radicals were 1.65×1010, 1.60×1010, and 1.71×1010 M−1 s−1 in the absence of SiO2 under complete-mix conditions, in the presence of SiO2 under complete-mix conditions, and in a fluidized-bed Fenton reactor with SiO2 as the media, respectively, demonstrating that the rates are comparable under a variety of reaction conditions. The average intrinsic second-order rate constant of o-toluidine and hydroxyl radicals obtained in a homogeneous system under various conditions was 7.36×109 M−1 s−1, indicating that o-toluidine is less susceptible to hydroxyl radicals than 2,6-dimethyl-anilne. Hydroxyl radicals primarily attacked the amine group rather than the methyl group of the o-toluidine to form o-cresol and 2-nitrotoluene, which sequentially transformed to carboxylic acids including acetic, oxalic, lactic, and maleic acids after the collapse of the benzene ring. [Copyright &y& Elsevier]

Abstract: In this study, the electro-Fenton and fluidized-bed Fenton processes under the given conditions were used to oxidize aniline. Factors such as feeding mode and concentration of the hydrogen peroxide were explored. Results showed that the feeding mode of H2O2 did not significantly affect the aniline oxidation in the electro-Fenton process. However, the aniline oxidation slightly decreased with the two-step addition of H2O2 in the fluidized-bed Fenton process. Presumably the decline of remaining Fe2+ led to destitute hydrogen radicals from the Fe2+-catalyzed H2O2. In addition, the removal efficiency of aniline was maintained at a maximum as H2O2 concentration was higher than 0.04M in the electro-Fenton process. Meanwhile, the almost exhausted H2O2 would increase the amount of Fe2+ in the solution for the electro-Fenton process. This is because the Fe2+ is regenerated through the reduction of Fe3+ on the cathode. The electro-Fenton process has a stronger oxidative ability with regard to the production of the oxalic acid than fluidized-bed Fenton process which was attributed to a higher consumption of H2O2. Therefore, in the aspect of H2O2 depletion, the mineralization efficiency of the fluidized-bed Fenton process was higher than that of the electro-Fenton process. [Copyright &y& Elsevier]

Abstract: This study investigated the effects of inorganic ions including chloride ions, dihydrogen phosphate ions and nitrate ions on the oxidation of nitrobenzene by the fluidized-bed Fenton process. The nitrobenzene degradation decreased with increasing chloride, dihydrogen phosphate and nitrate concentrations. Dihydrogen phosphate and chloride ions significantly inhibited nitrobenzene degradation. However, the inhibition caused by chloride ions could be overcome by extending the reaction time if the concentration of chloride ions was low. Nitrate did not have significant effect on nitrobenzene removal. The inhibition effect of each inorganic ion on the nitrobenzene degradation was in the order: H2PO4 − ≫Cl− >NO3 −. In addition, the results also show that the removal efficiency of nitrobenzene by fluidized-bed Fenton process was higher than traditional Fenton process. [ABSTRACT FROM AUTHOR]

Abstract: o-Toluidine is used primarily in the manufacture of dyestuffs, and also in the production of rubber, chemicals, and pesticides and as a curing agent for epoxy resin systems. It is considered to be toxic and carcinogenic. This study uses the Box–Behnken statistical experiment design to investigate the degradation of o-toluidine by the photo-Fenton process. The effects of ferrous ion dosage, hydrogen peroxide concentration and UVA irradiation were selected as factors in the Box–Behnken design experiment, while, o-toluidine and COD removal efficiency were considered as response functions. Results show that ferrous ion and hydrogen peroxide concentrations were the main parameters affecting the o-toluidine and COD removal, while the number of UVA lamps had a slight effect on the reaction. From the Box–Behnken statistical design prediction, the optimum condition for removing 100% of o-toluidine and 74% of COD was 1.2mM of ferrous ion, 8mM of hydrogen peroxide and UVA 85.7W/m3 at pH 3. [Copyright &y& Elsevier]

This research investigated the nitrobenzene oxidation and iron removal by fluidized-bed Fenton process using metal oxide as the carriers. It was found that the removal efficiency of nitrobenzene was not affected in the presence of metal oxide. However, metal oxide could retard the degradation rate of nitrobenzene with Fenton process due to ferrous adsorption/complexation onto its surface leaving insufficient free Fe2+ to catalyze the decomposition of H2O2. Nonetheless, as the free Fe2+ was sufficient, nitrobenzene was oxidized at the same rate as that by the conventional Fenton process. Fenton''s reagent and nitrobenzene concentrations have an impact on nitrobenzene oxidation rate. The empirical kinetic equation for nitrobenzene oxidation by the fluidized-bed Fenton process under the conditions of 0.667–5mM of Fe2+, 10–50mM of H2O2, 5–12.5mM of nitrobenzene, 76.9g/l of metal oxide, and pH 2.8±0.2, can be described as:Considering on iron removal performance, it was found that the fluidized-bed Fenton process could remove 30–65% of iron via iron crystallization onto the carriers’ surface which could lead to a significant reduction in ferric hydroxide sludge production. H2O2 played an important role in iron crystallization and once it was exhausted, the re-dissolution of iron occurred. In addition, it was found that the metal oxide could be repeatedly used up to 5 cycles without any significant deterioration in its surface activity. Hence, it implies that the metal oxide can be used successfully in the fluidized-bed Fenton process operated under a continuous mode. [Copyright &y& Elsevier]

Cartap is a carbamate insecticide intended to protect crops such as rice, tea, and sugarcane. Cartap in the environment presents a serious threat to non-target organisms through direct exposure or via biomagnification. Electro-assisted Fenton technology taps the potential of Fenton reagents to degrade cartap. Electrochemical reduction of iron accelerates catalyst regeneration. Cartap degradation was first investigated by varying reaction pH, as well as the initial H 2 O 2 and Fe2+ dosage, followed by optimization studies using central composite design. Parametric results indicate the highest cartap removal of 98.10% was achieved at 1.6 pH, 3.0 mM Fe2+ , and 40 mM H 2 O 2 at I = 1.0 A and t = 30 min. These results notoriously surpass conventional Fenton that only achieved 53.8% cartap removal under similar conditions. The hybridization of Fenton process through electrochemical regeneration enhances removal and increases degradation kinetic up to a pseudo-first-order rate constant value of 21.30 × 10–4 s−1. Effects of coexisting inorganic salts PO 4 3–, NO 3 –, and Cl– at 1 mM and 10 mM concentrations were investigated. These results demonstrate that Fenton electrification as process intensification alternative can enhance the performance and competitiveness of conventional Fenton by ensuring higher availability of iron catalyst while minimizing sludge production. [Display omitted] • Electro-assisted Fenton process increases Fenton performance by over 2-fold. • Response surface methodology shows a strong correlation between operational variables. • Complete abatement of pesticide cartap is attained by electro-assisted Fenton process. • Process intensification shows benefit for pesticide decontamination. [ABSTRACT FROM AUTHOR]

• Copper granules were recovered using unseeded fluidized-bed granulation process. • The presence of 186 mg·L–1 of EDTA reached 93% copper removal and 54–78% granulation. • The presence of 0.019 mg·L–1 CH 2 O attained 99% copper removal and 90% granulation. • The presence of both EDTA and CH 2 O achieved 94% copper removal and 84% granulation. • Copper granules formed are similar to that of Azurite based on FTIR and XRD peaks. Copper-contaminated industrial wastewaters are usually treated by large-footprint conventional technologies that generate high-moisture sludge. These disadvantages led to the development of the unseeded fluidized-bed granulation process (UFBGP), an innovative green technology with potential to simultaneously remove copper from electroless copper plating spent rinse waters and recover them as high-quality granules. Electroless copper plating rinse water is a complex aqueous matrix containing copper ions and organic additives such as ethylenediaminetetraacetic acid (EDTA) and formaldehyde (CH 2 O) as complexing and reducing agents, respectively. Herein, we investigated copper removal and granulation from simulated electroless copper plating spent rinse waters containing EDTA and CH 2 O via the unseeded fluidized-bed granulation process. Results showed that copper removal and granulation from simulated spent rinse waters containing 186 mg L–1 EDTA reached 93% and 78%, respectively. On the other hand, copper removal and granulation from simulated spent rinse waters with 0.019 mg L–1 CH 2 O were 99% and 90%, respectively. However, simulated spent rinse waters containing both EDTA and CH 2 O had copper removal and granulation of 94% and 84%, respectively. Scanning electron microscope images of the recovered granules showed clusters of irregularly-shaped spherical solids while the X-ray diffractograms of the solids revealed crystalline properties identical to those of the mineral azurite. Overall, the study demonstrated the effectiveness of the UFBGP in recovering high-quality copper granules from simulated industrial wastewaters. [ABSTRACT FROM AUTHOR]

The era of industrialization has caused the drastic increase in atmospheric carbon dioxide concentrations that now require various remediation strategies such as CO 2 capture and storage. In this study, calcium carbonate granulation is proposed as a new conversion route for CO 2 trapped in water matrices into dense solids. Herein, we demonstrate the effectiveness of the fluidized-bed reactor to produce compact calcium carbonate pellets from captured CO 2 via a granulation reaction at different pH conditions and in the absence of seed materials. Constant values of calcium-to-carbonate ratio, influent carbonate concentration and influx flow rate were used while operating pH was varied from 8.5 to 11.0. Optimal operating condition with carbonate removal and granulation efficiencies of 92% and 90%, respectively was found at pH of 10.0 ± 0.2, where the lowest daily effluent concentration of carbonate ions was measured at 16.6 mg L−1 via the alkalinity test. At optimum operating pH, large compact granules ranging from 1 – 2 mm in diameter (∼93.6 g) were obtained with overall particle size distribution leaning towards bigger sizes. Morphological analyses of the granules revealed their smooth surfaces and subrounded shapes, while crystalline and elemental analyses identified these as high purity calcium carbonate. Moreover, spontaneous homogeneous nucleation, particle aggregation, crystal growth and granulation are proposed as the main mechanisms of calcium carbonate granulation. Image 1 • Aqueous potassium carbonate was the form of trapped CO 2 used. • Dissolved potassium carbonate was converted to dense calcium carbonate granules in a fluidized bed reactor. • Operating pH affected effluent alkalinity. • Operating pH influenced carbonate removal and granulation. • Morphology, structure and elemental composition of granules were examined. [ABSTRACT FROM AUTHOR]

• Carbon dioxide capture, utilization and storage in the form of calcium carbonate. • Calcium carbonate homogeneous granulation in a fluidized-bed reactor. • The kinetic analysis revealed that the pseudo-second order best fitted the results. • Calcium-is-to-carbonate molar ratio directly affects the granule characteristics. • High purity of calcium carbonate-aragonite granules were produced. The granulation of calcium carbonate (CaCO 3) exhibited high industrial demand due to its wider application and importance in cement, paper, glass and steel manufacturing. This paper investigated the granulation kinetics of CaCO 3 through the fluidized-bed homogeneous granulation (FBHG) process during the homogenous nucleation stage. The CaOH solution was used as source of Ca2+ reactant, while K 2 CO 3 solution as source of CO 3 2− precipitant. The mechanism followed the pseudo-second order kinetics. The calcium cation attracts the carbonate anion to form CaCO 3 through a double displacement chemical reaction. The calcium-is-to-carbonate molar ratio ([Ca2+]/[CO 3 2−]) was varied into 1.25 to 2.50, with constant values of pH = 10 ± 0.2, influent carbonate concentration = 10 mM and total influx flow rate = 60 mL min−1. The ideal [Ca2+]/[CO 3 2−] condition was found to be at 1.50 that means the precipitation of CaCO 3 grew and stayed inside the reactor. At the same condition, granules of diameter size of 1 mm to 2 mm were collected with a subrounded shape and smooth surface as shown by its surface morphology. The characterization analysis also verified the high purity of CaCO 3 -aragonite granules precipitated through the FBHG process. [ABSTRACT FROM AUTHOR]

Green and sustainable strategies aim for the development of manufacturing processes that maximize the use of resources instigating semiconductor industry to adopt zero-liquid discharge policies. Complexity and variations of semiconductor wastewater effluents opens an opportunity for resource recovery (i.e. copper from chemical-mechanical polishing) including heavy metals and inorganic ions (i.e. phosphate from acid cleaning). This present work demonstrates the capabilities of fluidized-bed homogeneous crystallization as treatment technology to process water effluents for industrial reuse while simultaneously recovering precious resources such as copper and phosphate. Operational variables have been optimized considering the combination of both effluents to produce high quality copper phosphate granules. The optimum copper percentage removal and crystallization efficiency were 99% and 96.07% respectively obtained at pH e 6.0–6.5, 1.25 [PO 4 −3] in /[Cu2+] in at hydraulic retention time 22.5 min with 0.51 kg Cu2+/m2 h and fixed [Cu2+] in loading of 4.5 mM. The recovered crystals have an average particle diameter of ∼1 mm and were characterized identifying libethenite (Cu 2 PO 4 OH) as main recovered products. [ABSTRACT FROM AUTHOR]

With the rapid growth of the world's informatics innovation, printed circuit boards (PCBs) processing produces wastewaters with copper and nickel ions. This study aims to remove and recover copper and nickel ions from synthetic PCB wastewater using a fluidized-bed homogeneous granulation process (FBHGP). FBHGP is an advanced green technology that removes copper and nickel and transforms the sludge into a hard granule. The impacts on the removal and granulation of copper and nickel of the initial operating pH, molar ratio (MR) of precipitant to metal, and precipitant flow rate have been evaluated. The highest copper removal was attained at 97% at pH of 6.5 and 98% copper removal at an MR of 2.0 and 10 mL·min -1 . A 93% copper granulation was achieved at the same pH, while a 94% copper granulation was also achieved at the same MR and precipitant flow rate. At a pH of 7.5, 85% nickel removal and 74% granulation were attained for a nickel. At an MR of 1.75, 82% and 74% were the highest removal and granulation. While at 25 mL·min -1 , the highest removal was 83%, and 73% nickel granulation was achieved. Copper has been successfully recovered from synthetic PCB wastewater using FBHGP. At the same time, nickel needs a multi-step FBR, which is more suitable for the recovery of nickel under the same conditions applied during the same period., (© 2021. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

Desulfurization of liquid fuels mitigates the amount of noxious sulfur oxides and particulates released during fuel combustion. Existing literature on oxidative-adsorptive desulfurization technologies focus on sulfur-in-fuel removal by various materials, but very little information is presented about their desorption kinetics and thermodynamics. Herein, we report for the first time, the mechanism of sulfur desorption from neutral activated alumina saturated with dibenzothiophene sulfone. Batch experiments were conducted to examine the effects of agitation rate, desorption temperature, sulfur content, and eluent type on sulfur desorption efficiencies. Results show enhanced desorption capacities at higher agitation rate, desorption temperature, and initial sulfur content. Desorption efficiency and capacity of acetone were found to be remarkably superior to ethanol, acetone:ethanol (1:1), and acetone:isopropanol (1:1). Desorption kinetics reveal excellent fit of the nonlinear pseudo-second-order equation on desorption data, indicating chemisorption as the rate-determining step. Results of the thermodynamics study show the spontaneous (ΔG° ≤ -2.08 kJ mol -1 ) and endothermic (ΔH° = 32.35 kJ mol -1 ) nature of sulfur desorption using acetone as eluent. Maximum regeneration efficiency was attained at 93% after washing the spent adsorbent with acetone followed by oven-drying. Scanning electron microscopy, Fourier transform infrared, and X-ray diffraction spectroscopy analyses reveal the intact and undamaged structure of neutral activated alumina even after adsorbent regeneration. Overall, the present work demonstrates the viability of neutral activated alumina as an efficient and reusable adsorbent for the removal of sulfur compounds from liquid fossil fuels., (© 2021. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

This study investigated the air quality improvement in terms of bacterial and fungal contamination in an exercise room of a fitness center under normal operating conditions. Environmental conditions including air conditioning, ventilation, moisture, CO 2 , particulate matters, and total number of users were also recorded. In addition, fungal and bacterial load were assessed and disinfection on sports equipment surface was also examined. Background bacteria and fungi densities in bioaerosols were in the range of 249 ± 65 to 812 ± 111 CFU/m 3 and 226 ± 39 to 837 ± 838 CFU/m 3 in the exercise room of the fitness center and 370 ± 86 to 953 ± 136 CFU/m 3 and 465 ± 108 to 1734 ± 580 CFU/m 3 in the outdoor air, respectively. Chlorine dioxide and weak acid hypochlorous water aerosols could remove both bacteria and fungi much better than water scrubbing. Contact time of 15 min was sufficient to control both bacteria and fungi to comply with the official air quality standards. User density and carbon dioxide deteriorated both bacteria and fungi disinfection performance whereas temperature was only statistically significant on fungi disinfection. Other factors including relative humidity, airflow velocity, and particulate matters did not have any statistically significant effect on microbial inactivation. Apart from bioaerosol disinfection, inactivation of microorganisms on surfaces of sports equipment was also conducted using chlorine dioxide, zinc oxide, weak acid hypochlorous water, and commercial disinfectant. The surfaces of bicycle handle, dumbbell, and sit-up bench were found to be contaminated with bacteria. Overall bacterial load was 390 to 3720 CFU/cm 2 with Escherichia coli specifically 550 to 1080 CFU/cm 2 . Chlorine dioxide and zinc oxide were noticeably better than weak acid hypochlorous water and commercial disinfectant in terms of bacteria inactivation whereas all tested disinfectants had comparable effectiveness on E. coli disinfection. Targeted microorganisms on the sports equipment surface were sufficiently inactivated within 2 min after the application of disinfectant., (© 2021. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

Cartap is a thiocarbamate pesticide widely-used to protect rice crops, one of the most mass-produced cereals worldwide. Effluents containing cartap pose serious environment and health risks due to the acute toxicity of this emerging contaminant. This work evaluates the capabilities of the Fenton process to efficiently remove cartap from water matrices. Process parameters such as hydrogen peroxide dosage, ferrous ion concentration and operating pH were optimized using Box-Behnken design. Results showed complete cartap removal with Fenton oxidation in a fluidized-bed reactor while eliminating sludge generation during treatment. Fluidized-bed Fenton process had improved reduction in chemical oxygen demand and total organic carbon due to the contribution of heterogeneous Fenton catalysis to the overall degradation of cartap species compared to conventional Fenton in a batch reactor. Furthermore, competitive reactions and scavenging effects in complex natural water matrices were simulated with the use of inorganic ions such as nitrate, chloride, and phosphate. Results demonstrated the detrimental effect of phosphate ions on Fenton oxidation due to the precipitation of soluble catalysts as iron phosphates, which stops the catalytic Fenton cycle and thus the production of oxidants for contaminant degradation., (© 2020. Springer-Verlag GmbH Germany, part of Springer Nature.)

The disinfection efficiencies of two chemical disinfectants, chlorine dioxide and weak acid hypochlorous water (WAHW), were examined in the soiled room and dishwashing room of a hospital infectious disease ward in Taiwan. The investigations were conducted in two seasons, namely winter and summer, in order to examine the correlation between the bioaerosol concentration and the environmental factors. In addition, a single-daily disinfection mode (SM) and a twice-daily disinfection mode (TM) were applied in this study. The results showed that the bacteria and fungi colony counts were strongly correlated with the temperature. Both disinfectants reduced the bacteria and fungi concentrations in the considered rooms. However, of the two disinfectants, the ClO 2 showed a stronger disinfection effect than the WAHW. It means that when using ClO 2 as the disinfectant, the disinfection efficiency of the TM treatment mode is significantly better than that of the SM treatment mode. But, when using WAHW as the disinfectant, no significant difference is found between the disinfection efficiencies of the two methods. Overall, the results showed that the application of ClO 2 twice daily provided the most effective means of satisfying the Taiwan EPA guidelines for the indoor air quality of hospital medical wards., (© Springer Nature B.V. 2020.)

Photocatalysis is one of the most promising advanced oxidation processes due to the capability of solid catalyst to continuously produce oxidant species under light irradiation. The use of conventional UV lamps is high cost intensive, which undermines the possible implementation in developing countries. Visible light active photocatalysts can overcome these challenges and find a market opportunity for competitive technology implementation. This work proposes the synthesis of visible light active catalyst following a facile sol-gel synthesis that introduces CuSO 4 as dopant in TiO 2 . Results present complete abatement of methylene blue in 120 min of treatment under 50 mW cm -2 of blue light (λ = 450 nm), while commercial P25 TiO 2 presented null abatement under identical conditions. Synthesis parameters including dopant level and calcination temperature allowed defining optimum synthesis conditions based on material characteristics modification and catalytic activity enhancement. A doping level of 0.21 mol% CuSO 4 was identified as optimum condition to enable visible light photocatalysis of doped TiO 2 catalysts calcined at 300 °C. Finally, operational parameters were evaluated defining a wide range of pH operation under 3.0 g L -1 of catalyst dose to treat up to 20 g L -1 of highly recalcitrant phenothiazine dye. These optimum conditions allowed complete dye removal under visible light after 120 min of treatment.

The present study investigates the influence of calcination temperature on the properties and photoactivity of multi-element doped TiO 2 . The photocatalysts were prepared by incorporating silver (Ag), fluorine (F), nitrogen (N), and tungsten (W) into the TiO 2 structure via the sol-gel method. Spectroscopic techniques were used to elucidate the correlation between the structural and optical properties of the doped photocatalyst and its photoactivity. XRD results showed that the mean crystallite size increased for undoped photocatalysts and decreased for the doped photocatalysts when calcination was done at higher temperatures. UV-Vis spectra showed that the absorption cut-off wavelength shifted towards the visible light region for the as-synthesized photocatalysts and band gap narrowing was attributed to multi-element doping and calcination. FTIR spectra results showed the shifting of OH-bending absorption bands towards increasing wave numbers. The activity of the photocatalysts was evaluated in terms of gaseous formaldehyde removal under visible light irradiation. The highest photocatalytic removal of gaseous formaldehyde was found at 88%. The study confirms the effectiveness of multi-element doped TiO 2 to remove gaseous formaldehyde in air by visible light photocatalysis and the results have a lot of potential to extend the application to other organic air contaminants.

As with all indoor public spaces in Taiwan, the stack rooms in public libraries should meet the air quality guidelines laid down by the Taiwan Environmental Protection Administration. Accordingly, utilizing a university library in Taiwan for experimental purposes, this study investigates the efficiency of gaseous chlorine dioxide (ClO2) as a disinfection agent when applied using three different treatment modes, namely a single-daily disinfection mode (SIM), a twice-daily disinfection mode (TWM), and a triple-daily disinfection mode (TRM). For each treatment mode, the ClO2 is applied using an ultrasonic aerosol device and is performed both under natural lighting conditions and under artificial lighting conditions. The indoor air quality is evaluated before and after each treatment session by measuring the bioaerosol levels of bacteria and fungi. The results show that for all three disinfection modes, the application of ClO2 reduces the indoor bacteria and fungi concentrations to levels lower than those specified by the Taiwan EPA (i.e., bacteria <1500 CFU/m(3), fungi <1000 CFU/m(3)), irrespective of the lighting conditions under which the disinfection process is performed. For each disinfection mode, a better disinfection efficiency is obtained under natural lighting conditions since ClO2 readily decomposes under strong luminance levels. Among the three treatment modes, the disinfection efficiencies of the TWM and TRM modes are very similar under natural lighting conditions and are significantly better than that of the SIM mode. Thus, overall, the results suggest that the TWM treatment protocol represents the most cost-effective and efficient method for meeting the indoor air quality requirements of the Taiwan EPA.

In this study, the target compound is dimethyl sulfoxide (DMSO), which is used as a photoresist stripping solvent in the semiconductor and thin-film transistor liquid crystal display (TFT-LCD) manufacturing processes. The effects of the operating parameters (pH, Fe(2+) and H2O2 concentrations) on the degradation of DMSO in the fluidized-bed Fenton process were examined. This study used the Box-Behnken design (BBD) to investigate the optimum conditions of DMSO degradation. The highest DMSO removal was 98 % for pH 3, when the H2O2 to Fe(2+) molar ratio was 12. At pH 2 and 4, the highest DMSO removal was 82 %, when the H2O2 to Fe(2+) molar ratio was 6.5. The correlation of DMSO removal showed that the effect of the parameters on DMSO removal followed the order Fe(2+) > H2O2 > pH. From the BBD prediction, the optimum conditions were pH 3, 5 mM of Fe(2+), and 60 mM of H2O2. The difference between the experimental value (98 %) and the predicted value (96 %) was not significant. The removal efficiencies of DMSO, chemical oxygen demand (COD), total organic carbon (TOC), and iron in the fluidized-bed Fenton process were higher than those in the traditional Fenton process.

An unsymmetrical star-shaped pi-system (1) with an isotruxene core and three fluorene arms has been synthesized, and its photophysical, electrochemical, and thermochemical properties have been investigated and compared with the corresponding symmetrical truxene derivatives 2a-d (Kanibolotsky, A. L.; Berridge, R.; Skabara, P. J.; Perepichka, I. F.; Bradley, D. D. C.; Koeberg, M. J. Am. Chem. Soc. 2004, 126, 13695-13702). Stronger electronic couplings between the arms in 1 vs 2a-d lead to lower optical band gap, larger splitting in oxidation potentials, and superior thermostability. [structure: see text]

A high activity isoflavone-glucosidase, which hydrolysis glycosides, was obtainde using liquid fermentation from Absidia sp. R strain. The isoflavone-glucosidase was purified 11 folds with yielding rate of 10.9% after ammonium sulfate precipitation and DEAE-Cellocuse (DE-52) ion exchange chromatography. SDS-PAGE results showed that the molecular weight is 53kD. And the optimum temperature, the optimum pH, Km and pI of the enzyme are 50 deegrees C, 5.0, 1.3 x 10(-2) mol/L and 3.2, respectively. The isoflavone-glucosidase is also rather stable under 60 degrees C and in pH range from 5.0 to 7.0. The enzyme can be activated by Co2+ and Ca2+, and be inhibited by Ag+ and Cu2+.

This work presents a photocatalysis-based method to treat and purify air because of its broad applicability to common, oxidizable air contaminants. The effect of oxygen content, temperature, water vapor, and acetone concentration on the photooxidation of acetone on TiO2 surface was investigated. The photocatalytic decomposition reaction of acetone obeyed the first-order equation. The decomposition rate increased with increasing the oxygen content. The rate of acetone oxidation increased when water vapor increased from 18.7 to 417 microM and decreased at higher than 417 microM. The conversion and mineralization of acetone decreased at higher than 138 degrees C. The initial rate of acetone degradation can be well described by the Langmuir-Hinshelwood rate form. The specific reaction rate constant and the equilibrium adsorption are 15.8 microM/min and 0.0671 L/microM, respectively. The difference between observed and estimated half-lives became larger when the initial concentration of acetone was increased. It is assumed that the intermediates competed with parent compound so that delayed the half-life. The detection of CO2 production can support this assumption.