Wanpeng Zhu

Tsinghua University, Peping, Beijing, China

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Publications (38)65.86 Total impact

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    ABSTRACT: The photocatalytic decomposition and mineralization of p-chlorobenzoic acid (p-CBA), 4-chlorophenol (4-CP), hydroquinone and 4-nitrophenol (4-NP) in aqueous solution were investigated using two kinds of low-pressure mercury lamps: one was UV (ultraviolet) lamp emitting at 254 nm and the other was VUV (vacuum ultraviolet) lamp emitting at both 254 and 185 nm. VUV irradiation led to the most efficient degradation of the organics. The validation of calculation shows the effect of bubble on radiation scattering was little. The evolution of the radiation absorbance of the reaction solutions suggests the radiation adsorption of the intermediates was negligible. Based on these results simple reaction kinetic models were established with the pseudo-first order reaction rate constants relating to incident radiation intensity. The reaction rate constants of photolysis and photocatalysis (kPD and KPCD) were calculated through the numerical simulation of the models. Using the calculated kPD and KPCD of p-CBA (0.1 and 11.0 min−1, respectively), the removals of p-CBA in TiO2/UV photocatalysis were predicted, which were almost the same as the measured removals. With the calculated kPD and KPCD of 4-NP (0.011 and 4.8 min−1, respectively), the removals of 4-NP in TiO2/UV photocatalysis process in a big reactor under the different gas flow rates were also predicated, which agreed well with the measured results.
    Separation and Purification Technology 01/2014; 122:105–111. · 2.89 Impact Factor
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    ABSTRACT: The development of highly active carbon material catalysts in catalytic wet air oxidation (CWAO) has attracted a great deal of attention. In this study different carbon material catalysts (multi-walled carbon nanotubes, carbon fibers and graphite) were developed to enhance the CWAO of phenol in aqueous solution. The functionalized carbon materials exhibited excellent catalytic activity in the CWAO of phenol. After 60 min reaction, the removal of phenol was nearly 100% over the functionalized multi-walled carbon, while it was only 14% over the purified multi-walled carbon under the same reaction conditions. Carboxylic acid groups introduced on the surface of the functionalized carbon materials play an important role in the catalytic activity in CWAO. They can promote the production of free radicals, which act as strong oxidants in CWAO. Based on the analysis of the intermediates produced in the CWAO reactions, a new reaction pathway for the CWAO of phenol was proposed in this study. There are some differences between the proposed reaction pathway and that reported in the literature. First, maleic acid is transformed directly into malonic acid. Second, acetic acid is oxidized into an unknown intermediate, which is then oxidized into CO2 and H2O. Finally, formic acid and oxalic acid can mutually interconvert when conditions are favorable.
    Journal of Environmental Sciences. 01/2014;
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    ABSTRACT: Ruthenium catalysts on various activated carbon (AC) supports were prepared using conventional calcination and microwave irradiation. Their activity in the catalytic ozonation of dimethyl phthalate was studied. The relationship between the structure and activity was investigated. All the supports and catalysts increased total organic carbon removal. The activity order was Ru/coal-AC > nutshell-AC > Ru/nutshell-AC > Ru/coconut-AC ≈ coal-AC > coconut-AC. The supported Ru particles diffused into the macropores, which increased mass transfer resistance in catalytic ozonation and decreased the probability that the reactants can contact the active phase on the interior surface. This was one reason why the activity of nutshell-AC and Ru/nutshell-AC was lower than that of Ru/coal-AC. A difference in Ru dispersion on the surface of the catalyst also caused the activity difference. The active phase on the surface of nutshell-AC can be changed by microwave irradiation, which caused Ru/nutshell-AC to even be less active than the corresponding support. As compared to the use of conventional calcination, the use of microwave irradiation enhanced the metal dispersion and catalytic activity of Ru/coal-AC.摘要采用传统焙烧和微波辐射制备了不同活性炭 (AC) 负载 Ru 催化剂, 并用于催化臭氧氧化降解邻苯二甲酸二甲酯 (DMP) 反应中, 探讨了催化剂的构效关系. 结果表明, 所有 AC 和催化剂均能提高臭氧氧化 DMP 过程中 TOC (总有机碳) 去除率, 其活性顺序为 Ru/coal-AC > nutshell-AC > Ru/nutshell-AC > Ru/coconut-AC ≈ coal-AC > coconut-AC. 负载的 Ru 颗粒扩散到 AC 大孔中, 增加了反应的传质阻力, 使得反应物与 AC 内表面的活性位和金属 Ru 的接触机会减少, 这是 Ru/nutshell-AC 和 Ru/coconut-AC 活性低于 Ru/coal-AC 的一个原因; 催化剂表面 Ru 分散度也是导致其活性差别的原因之一. 微波加热引起 nutshell-AC 表面活性官能团发生变化, 从而导致其负载的 Ru 催化活性降低. 相对于传统焙烧, 微波辐射热处理能够提高 coal-AC 表面 Ru 的分散度, 从而提高催化剂活性.
    Chinese Journal of Catalysis 02/2013; 34(2):313–321. · 1.30 Impact Factor
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    ABSTRACT: The cellular responses, biodegradation and bioaccumulation of four endocrine disrupting chemicals, including nonylphenols (NPs), bisphenol A (BPA), 17alpha-ethynylestradiol (EE2), and estradiol (E2), in the marine diatom Navicula incerta, were investigated through the 96-h exposure test. The 50% effective concentration (EC(50)) values in the algal growth inhibition test for NPs, BPA, EE2 and E2 were 0.20mgL(-1), 3.73mgL(-1), 3.21mgL(-1) and >10mgL(-1), respectively. With the increase of test concentrations, the cellular contents of polysaccharides and protein were reduced but the lipid content was increased, while the levels of chlorophyll a and total chlorophyll c were not affected by target EDCs. The activities of superoxidase dismutase and glutathione-S-transferase were stimulated by EDCs. The activities of peroxide dismutase were inhibited by NPs, BPA, and EE2, but were enhanced by E2. The bioaccumulation and biodegradation of target EDCs were inhibited with the increasing exposure concentrations. Nevertheless, the toxic and inhibitory effects of these EDCs on the diatom at their environmental relevant concentrations were relatively low. At the environmental relevant concentration (0.001mgL(-1)), 20.69% of NPs, 37.78% of BPA, 31.26% of EE2 and 52.26% of E2 were removed from the seawater in 96h via biodegradation, and the respective 96-h bioconcentration factor (BCF) values were 2077, 261, 470, and 39. These results showed that among the four target EDCs, NPs would be most problematic as reflecting by their low biodegradation and high BCF in the diatom, suggesting that the NPs would accumulate within the algal cell and pose threats to organisms at higher tropic levels, especially the larvae feeding on the diatom.
    Chemosphere 05/2010; 80(5):592-9. · 3.14 Impact Factor
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    ABSTRACT: The kinetic process of pressure-induced gelation of whey protein isolate (WPI) solutions was studied using in situ light scattering. The relationship of the logarithm of scattered light intensity (I) versus time (t) was linear after the induced time and could be described by the Cahn-Hilliard linear theory. With increasing time, the scattered intensity deviated from the exponential relationship, and the time evolution of the scattered light intensity maximum Im and the corresponding wavenumber qm could be described in terms of the power-law relationship as Im~fβ and qm~f−α, respectively. These results indicated that phase separation occurred during the gelation of WPI solutions under high pressure.
    Journal of Physics Conference Series 04/2010; 215(1):012169.
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    ABSTRACT: Occurrence and distribution of three typical endocrine-disrupting chemicals (EDCs), nonylphenol mixture (NPs), bisphenol A (BPA), and 17α-ethynilestradiol (EE2), were investigated in the seawater, suspended solid, and sediment around the coastline of Shenzhen city. Field surveys were conducted in both dry season and rainy season to access the influence of rainfall and basic water quality parameters on the distribution of target EDCs. In the seawater, NPs, BPA, and EE2 ranged from 31 to 1,777ng/l, from 11 to 777ng/l, and from 10 to 269ng/l, respectively. In the suspended solid, NPs, BPA, and EE2 were in the range from 3 to 289ng/l, from 1 to 75ng/l, and from 1 to 29ng/l, respectively. In the sediment, NPs, BPA, and EE2 varied from 9 to 355ng/g dry weight (dw), from 3 to 156ng/g dw, and from 7 to 144ng/g dw, respectively. With the increasing rainfall, the concentrations of target EDCs decreased in seawater and sediment and increased in suspended solid at all the sampling locations. Among the six measured basic water quality parameters, the volatile suspended solid value was positively related with the partition property of target EDCs between suspended solid and seawater. Based on the results of principal component analysis, dissolved organic carbon, total nitrogen, and total phosphorous had close relationships with the distribution of target EDCs in the seawater. Temperature and dissolved oxygen had little relationship with the distribution of target EDCs in the coastal area. KeywordsCoastal pollution-Endocrine-disrupting chemicals-Rainfall-Basic water quality parameters-Principal component analysis
    Water Air and Soil Pollution 01/2010; 209(1):333-343. · 1.75 Impact Factor
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    ABSTRACT: Effects of aluminum on water distribution system and human health mainly attribute to its speciation in drinking water. Laboratory experiments were performed to investigate factors that may influence aluminum speciation in water supply system. The concentration of soluble aluminum and its transformation among other aluminum species were mainly controlled by kinetics processes of related reactions. Total aluminum concentration had a notable effect on the concentrations of mononuclear and soluble aluminum in the first 4 day; then its effect became weak. At pH above 7.50, both fluoride and orthophosphate had little effect on aluminum speciation; while, when the solution pH was below 7.50, the concentrations of mononuclear and soluble aluminum were proportional to the concentration of fluoride and inversely proportional to the concentration of orthophosphate. Both mononuclear and polynuclear silicic acids could complex with mononuclear aluminum by forming soluble aluminosilicates. In addition, the adding sequence of orthophosphate and aluminum into drinking water would also affect the distribution of aluminum species in the first 4 day. In order to minimize aluminum bioavailability in drinking water, it was suggested that orthophosphate should be added prior to coagulant process, and that the concentrations of fluoride and silicic acids should be controlled below 2.0 and 25 mg/L, respectively, prior to the treatment. The solution pH in coagulation and filtration processes should be controlled in the range of 6.50-7.50.
    Journal of Environmental Sciences 01/2010; 22(1):47-55. · 1.77 Impact Factor
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    ABSTRACT: This article focused on the influences of fulvic acid and humic acid on aluminum speciation in drinking water. Factors including the concentration of residual chlorine and pH value had been concerned. Aluminum species investigated in the experiments included inorganic mononuclear, organic mononuclear, mononuclear, polymer, soluble, and suspended forms. It was found that the effects of fulvic acid and humic acid on aluminum speciation depended mainly on their molecular weight. Fulvic acid with molecular weight less than 5000 Dalton had little influence on aluminum speciation; while fulvic acid with molecular weight larger than 5000 Dalton and humic acid would increase the concentration of soluble aluminum significantly even at concentration below 0.5 mg/L (calculated as TOC). Aluminum species, in the present of fulvic acid with molecular weight larger than 5000 Dalton and humic acid, were more stable than that in the present of fluvic acid with molecular mass less than 5000 Dalton, and varied little with reaction time. Within pH range 6.5-7.5, soluble aluminum increased notably in water with organic matter. As the concentration of residual chlorine increased, the effects of fulvic acid and humic acid became weak. The reactions between humic acid, fulvic acid with large molecular weight, and aluminum were considered to be a multi-dentate coordination process. With the consideration of aluminum bioavailability, reducing the concentration of fulvic acid and humic acid and keeping the pH value among 6.5-7.5 were recommended during drinking water treatment.
    Journal of Environmental Sciences 01/2010; 22(2):211-7. · 1.77 Impact Factor
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    ABSTRACT: In this paper, the experimental results on the effects of a magnetic field on water are reported. Purified water was circulated at a constant flow rate in a magnetic field. After this treatment, the physicochemical properties of water were changed, shown as the decrease of surface tension and the increase of viscosity over the treatment time. The water is more stable by magnetic treatment with less molecular energy and more activation energy, as shown from the calculation based on the results. The correlation time τc was calculated in terms of spin–lattice relaxation time of proton NMR, which verified that the rotational motions got slow down after magnetic treatments. A two-phase model was set up to prove that the proportion of free water molecules was reduced. The results suggested that the average size of water clusters became larger by magnetic treatments.
    Journal of Molecular Structure 01/2009; · 1.40 Impact Factor
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    ABSTRACT: Catalytic ozonation of dimethyl phthalate (DMP) in aqueous solution (5mg/L) under various reactions was performed to examine the effect of catalyst dosage, catalyst particle size, ozone dosage, and gas flow rate on the mineralization of DMP. The mineralization of DMP can be achieved via ozonation and the presence of Ru/AC could greatly accelerate the mineralization rate of DMP in ozonation process. In the continuous experiment of the Ru/AC catalyzed ozonation of DMP, total organic carbon (TOC) removals were kept stable around 75% during 42 h reaction. No leaching of ruthenium was observed in the treated water samples. The treatment of natural water using Ru/AC+O(3), Ru/AC+O(2) and ozonation alone was studied. In the Ru/AC+O(3) process, TOC removals, the reductions of the haloacetic acid formation potentials (HAAFPs), and the reductions of the trihalomethane formation potentials (THMFPs) of 11 water samples were 22-44%, 39-61% and 50-65%, respectively. Ru/AC+O(3) process was much more effective than ozonation alone for TOC removal and the reduction of disinfection by-product formation potential (DBPFP) in the treatment of natural water. It is a promising water treatment technology.
    Journal of hazardous materials 12/2008; 166(1):502-7. · 4.14 Impact Factor
  • Fei Teng, Yuntao Guan, Wanpeng Zhu
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    ABSTRACT: Fe inhibition to PCR can be overcome by adding greatly excessive EDTA first, and then the same amount Mg(2+) as EDTA to PCR mix. By this method impure DNA was amplified successfully. DNA samples containing metals whose complexation constant with EDTA was much higher than Mg(2+) can also be amplified.
    Journal of Microbiological Methods 07/2008; 75(2):362-4. · 2.16 Impact Factor
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    ABSTRACT: CeO2-TiO2 catalysts are prepared by coprecipitation method, and the activity and stability in the catalytic wet air oxidation (CWAO) of phenol are investigated in a batch reactor and packed-bed reactor. CeO2-TiO2 mixed oxides show the higher activity than pure CeO2 and TiO2, and CeO2-TiO2 1/1 catalyst displays the highest activity in the CWAO of phenol. In a batch reactor, COD and TOC removals are about 100% and 77% after 120 min in the CWAO of phenol over CeO2-TiO2 1/1 catalyst at reaction temperature of 150 degrees C, the total pressure of 3 MPa, phenol concentration of 1000 mg/L, and catalyst dosage of 4 g/L. In a packed-bed reactor using CeO2-TiO2 1/1 particle catalyst, over 91% COD and 80% TOC removals are obtained at the reaction temperature of 140 degrees C, the air total pressure of 3.5 MPa, the phenol concentration of 1000 mg/L for 100 h continue reaction. Leaching of metal ions of CeO2-TiO2 1/1 particle catalyst is very low during the continuous reaction. CeO2-TiO2 1/1 catalyst exhibits the excellent activity and stability in the CWAO of phenol.
    Journal of Hazardous Materials 06/2008; 153(3):1248-53. · 3.93 Impact Factor
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    ABSTRACT: Multi-walled carbon nanotubes (MWCNTs), with no supported metal, were used as catalysts in the wet air oxidation of phenol. The MWCNTs were chemically modified using HCl or HNO3–H2SO4. They were characterized by BET, SEM, TEM, FT-IR and Raman spectroscopy. The functionalized MWCNTs exhibited both high activity and good stability in the wet air oxidation of phenol. At 160 °C and 2.0 MPa with an initial phenol concentration of 1000 mg/L, 100% phenol conversion and 76% total organic carbon abatement could be achieved after 120 min reaction. Upon reaction, the short chain carboxylic acids mainly maleic/fumaric, malonic, oxalic, formic and acetic acid were produced. Surface functional groups (–COOH) were shown to play a key role in the high activity of the functionalized MWCNTs. A mechanism for the CWAO of phenol was proposed.
    Carbon. 01/2008;
  • Yunrui Zhou, Wanpeng Zhu, Xun Chen
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    ABSTRACT: In this paper, factors influencing the mineralization of dimethyl phthalate (DMP) during catalytic ozonation with a cerium-doped Ru/Al2O3 catalyst were studied. The catalytic contribution was calculated through the results of a comparison experiment. It showed that doping cerium significantly enhanced catalytic activity. The total organic carbon (TOC) removal over the doped catalyst at 100 min reached 75.1%, 61.3% using Ru/Al2O3 catalyst and only 14.0% using ozone alone. Catalytic activity reached the maximum when 0.2% of ruthenium and 1.0% of cerium were simultaneously loaded onto Al2O3 support. Results of experiments on oxidation by ozone alone, adsorption of the catalyst, Ce ion’s and heterogeneous catalytic ozonation confirmed that the contribution of heterogeneous catalytic ozonation was about 50%, which showed the obvious effect of Ru-Ce/Al2O3 on catalytic activity.
    Frontiers of Environmental Science & Engineering in China 01/2008; 2(3):354-357. · 0.75 Impact Factor
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    ABSTRACT: The pelletized ruthenium catalysts were prepared by impregnation of different pelletized supports: CeO2 and ZrO2-CeO2. Their mechanical strength, specific surface area, pore size distribution and adsorption capacity for phenol were studied. Catalytic wet air oxidation of phenol with pelletized catalyst of Ru/ZrO2-CeO2 was performed in a continuous packed-bubble column reactor. The fresh and used Ru/ZrO2-CeO2 catalysts were compared. It shows that introduction of ZrO2 into Ru/CeO2 increased the mechanical strength, specific surface area and adsorption capacity of pelletized catalyst. In the experiment of wet air oxidation of phenol with Ru/ZrO2-CeO2 for 100 h, phenol and TOC removal stabilized around 100 and 96%, respectively. The concentrations of intermediates were low. The leaching concentrations of active species during the reaction were also low. After reaction, the textures, morphologies, microcosmic crystal pattern of catalyst and oxidation state of catalytic active phase of zirconium, cerium, ruthenium and oxygen did not change much, but the carbonaceous deposits on the surface of used catalyst were observed, and they would be fully oxidized at about 300 °C. The pelletized catalyst of Ru/ZrO2-CeO2 possesses the possibility of practical use.
    Applied Catalysis B: Environmental. 01/2008; 78:30-37.
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    ABSTRACT: Ruthenium catalysts were prepared by impregnation of different supports: ZrO2, CeO2, TiO2, ZrO2–CeO2 and TiO2–CeO2. Their activities for acetic acid oxidation in aqueous solution were investigated in a stirred reactor at a reaction temperature of 200°C and total pressure of 4MPa. The order of the catalyst activity obtained was RuO2/ZrO2–CeO2>RuO2/CeO2>RuO2/TiO2–CeO2>RuO2/ZrO2>RuO2/TiO2, which corresponds to surface concentration of non-lattice oxygen (defect-oxide or hydroxyl-like group) of these catalysts. The non-lattice oxygen on the catalyst surface plays an important role in the catalytic activity.
    Catalysis Communications - CATAL COMMUN. 01/2008; 9(13):2163-2167.
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    ABSTRACT: Multi-walled carbon nanotubes (MWNTs) were used as a catalyst for catalytic wet air oxidation (CWAO) of phenol in a batch reactor. SEM, TEM and FT-IR technique were applied to investigate the microstructure and the surface functional group of the MWNTs. When the carboxylic groups (–COOH) are grafted onto the surface of the MWNTs, the functionalized MWNTs exhibit a good catalytic activity in CWAO of phenol. At a reaction temperature of 160 °C, oxygen pressure of 2.0 MPa and a phenol concentration of 1000 mg/L, 100% phenol and 76% TOC are removed after 120 min reaction.
    Catalysis Communications 01/2007; 8(12):2059-2063. · 2.92 Impact Factor
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    ABSTRACT: The UV/O3-BAC (biological activated carbon) process was employed to treat secondary effluents and compared to the O3-BAC process. The effects of ozone dosage and empty bed contact time (EBCT) in BAC unit on dissolved organic carbon (DOC) removal were investigated. The results showed that the presence of UV improved ozone utilization and biodegradability of the effluent. DOC removal increased with ozone dosage and EBCT in BAC, however, 3 mg/L ozone dosage with 15 min oxidation time and 15 min EBCT in BAC were more economical and efficient. The synergetic effect in UV/O3-BAC process is more than that in O3-BAC process for DOC removal. Except for organic pollutants with MW >10,000 Da, those of other MW range were decomposed much more by UV/O3 process than by O3 process. GC/MS analysis showed dibutyl phthalate, bis(2-ethylhexyl) phthalate, 4-bromo-3-chloroaniline and other phenol derivatives were prevalent organic pollutants found in the secondary effluent. After UV/O3 treatment, some aromatic compounds including 2,4-dichloro-benzenamine, 4-bromo-3-chloroaniline and 3,5-dimethoxy-acetophenone disappeared and some small molecules were formed, but the kinds and concentration of organic pollutants including phthalate esters were greatly reduced by the subsequent BAC unit.
    Desalination. 01/2007;
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    Tsinghua Science & Technology 01/2007; 47(9):1481-1484.
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    ABSTRACT: release of pollutants in Agricultural Runoff (AR) from a plastic canopy (PC) region in eastern Dianchi Catchment of China was investigated. The daily variation coefficients of water quantity in 2002 and 2003 were 15.9 and 7.6 respectively. From May 2002 to September 2003, local farmland had discharge of 2.9–3.2 l m<sup align="right"> 2 </sup> d<sup align="right"> 1 </sup>. Pollutant loads from research area to Dianchi Lake from October to April were 10.7 kgTN d<sup align="right"> 1 </sup>, 2.91 kgNH<sub align="right"> 3 </sub>-N d<sup align="right"> 1 </sup> and 0.18 kgTP d<sup align="right"> 1 </sup>. Dissolved Total Phosphorus (DTP) was the major form of TP. PCs changed the pollutant release mode of farmland, and farmland discharge mainly entered groundwater.
    International Journal of Environment and Pollution - INT J ENVIRON POLLUTION. 01/2007; 31.