Wenhong Pu

Rapid cultivation of aerobic granular sludge in a pilot scale sequencing batch reactor.

Aerobic granular sludge which had good performance to pollutants removal was successfully cultivated within 18 days in a pilot scale sequencing batch reactor, about 25% mature aerobic granular sludge was inoculated when the setting time of activated sludge was reduced to 10 min. Anaerobic biological selector was implemented to inhibit filamentous bacteria overgrowth, where the maximum COD could reach to 1703.74 mg/L. The cultivated aerobic granular sludge was irregular and pale yellow, average particle size, SVI, SV₃₀/SV₅, PN/PS, EPS and water content were 1.58 mm, 67.64 mL/g, 0.91, 2.17, 268.90 mg EPS/g MLVSS and 98.16% on the 18th day. Mechanism of rapid granulation mainly included crystal nucleus hypothesis and selection pressure hypothesis. The inoculated aerobic granules could maintain stable under short setting time environment, making it directly as the crystal nucleus and the carriers for new particles without obvious disintegration, which eventually shortened the granulation time greatly.

Removal of benzotriazole by heterogeneous photoelectro-Fenton like process using ZnFe2O4 nanoparticles as catalyst.

ZnFe2O4 nanoparticles (ZFNPs) were developed as catalyst for the degradation of benzotriazole (BTA) by heterogeneous photoelectro-Fenton (PE-Fenton) like process. ZFNPs were prepared by a co-precipitation process and then characterized with transmission electron microscopy (TEM), X-ray fluorescence (XRF), X-ray diffraction (XRD) and BET surface area. Using such ZFNPs as catalyst, the degradation of BTA was investigated. Due to the high catalytic activity of ZFNPs, PE-Fenton like process showed efficient degradation of BTA. The influencing factors such as pH, dosage of ZFNPs, applied potential and initial concentration of BTA were systematically investigated. Under the optimum conditions, 91.2% of BTA was removed after 180 min treatment.

Simulation of the performance of aerobic granular sludge SBR using modified ASM3 model.

The activated sludge model No. 3 (ASM3) was modified to describe the biological reactions in aerobic granular sludge SBR. The simultaneous storage and growth, nitrification and denitrification were all accounted for in modified model. The sensitivities of effluent COD, NH(4)(+) -N, and TN toward the stoichiometric and kinetic coefficients were analyzed. A standard set of parameters obtained from a combination of literature data was chosen for the model. The experimental results for the time profile of COD, NH(4)(+) -N, and TN in a typical cycle were used to verify the ASM3 model. The verification results show the model established is applicable for simulating the perfo rmance of an aerobic granule-based SBR. A comparison of the measured and predicted values of substrate removal for both the modified ASM3 and the original ASM3 was also performed. The verification and comparison results show the modified ASM3 model describes the aerobic granule-based SBR better and more mechanistically.

The Influence of Gold Nanoparticles on Simultaneous Determination of Uric Acid and Ascorbic Acid

A three-dimensional L-cysteine (L-cys) monolayer assembled on gold nanoparticles (GNP) providing simultaneous detection of uric acid (UA) and ascorbic acid (AA) was studied in this work. The cyclic voltammetry demonstrated that, at a bare glassy carbon electrode (GCE) or planar gold electrode, the mixture of UA and AA showed one overlapped oxidation peak; whereas when the electrode was modified with GNP, the oxidation peaks for UA and AA were separated. While a GNP modified electrode was further modified with L-cys monolayer (L-cys/GNP/GCE), namely, three-dimensional L-cys monolayer, a better separation for UA and AA response was obtained. Interestingly, the L-cys monolayer-modified planar gold electrode presented a block effect on the oxidation of AA, which was facilitated by the three-dimensional L-cys monolayer attributed to its distinct structure. The pH of solution presented a noticeable effect on the separation of UA and AA at GNP modified electrodes with or without L-cys monolayer. Wide concentration ranges from 2 × 10−6−1 × 10−3 M to UA and 2 × 10−6−8 × 10−4 M to AA could be obtained at L-cys/GNP/GCE.

Three dimensional monolayer of 3-mercaptopropionic acid assembled on gold nanoparticles for electrochemical determination of trace Cu(II)

Abstract The electrochemical behavior of Cu(II) was investigated on three‐dimensional 3‐mercaptopropionic acid (MPA) assembled on gold nanoparticle‐modified glassy carbon (GNP/GC) electrode. The results demonstrated that the MPA monolayer inhibited the charging current while promoted the response of accumulated Cu(II) on GNP/GC electrode. The effects of pH, scan rate, and accumulation time on the voltammetric behavior of Cu(II) on the MPA/GNP/GC electrode were studied. The MPA modified electrode presented a voltammetric response linearly proportional to the Cu(II) concentration from 0.1 µg/l to 100 µg/l, with a detection limit of 3.2 ng/l. Moreover, this electrode was successfully applied to the determination of Cu(II) in tap water.

The stability of aerobic granular sludge treating municipal sludge deep dewatering filtrate in a bench scale sequencing batch reactor

Inoculated with mature aerobic granular sludge in a sequencing batch reactor, gradually increasing the proportion of municipal sludge deep dewatering filtrate in influent, aerobic granular sludge was domesticated after 84 days and maintained its structure during the operation. The domesticated AGS was yellowish-brown, dense and irregular spherical shape, average size was 1.49 mm, water content and specific density were 98.13% and 1.0114, the SVI and settling velocity were 40 ml/g and 46.5m/h. After 38 days, NO3(-)-N accumulated obviously in the reactor as lack of carbon sources. When adding 1-3g solid CH3COONa at 4.5 and 5.5h of each cycle from the 57th day, the removal rate of TN rose to above 90% after 20 days, where effective COD removal and denitrification were realized in a single bioreactor. Finally, the removal rates of COD, TP, TN and NH4(+)-N were higher than 95%, 88%, 96% and 99%.

Comparative Study of the Influence of Photoluminescence Quantum Yield and Molecular Orientation of Wide-Energy-Gap Small Molecules on the Performance of Organic Schottky Junctions

In this paper, we comparatively investigate the influence of absolute photoluminescence quantum yield (PLQY) and molecular orientation of a series of wide-energy-gap donors, which are usually used in organic light-emitting diodes, on the performance of organic Schottky junctions (OSJs) with low donor concentration. This work shows that PLQY of donors plays a crucial role on the photocurrent and fill factor of these types of OSJs. The PLQY of donors demonstrates a negative effect on the short-circuit current (JSC) of OSJs. The molecular orientation of donors also influences the OSJ performance for both linearor planar-shaped molecules, and horizontal orientation helps to achieve a higher JSC. The influencing priority of molecule characteristics of donors is PLQY>orientation.

The treatment of solvent recovery raffinate by aerobic granular sludge in a pilot-scale sequencing batch reactor

Mature aerobic granular sludge (AGS) was inoculated for the start-up of a pilot-scale sequencing batch reactor for the treatment of high concentration solvent recovery raffinate (SRR). The proportion of simulated wastewater (SW) (w/w) in the influent gradually decreased to zero during the operation, while volume of SRR gradually increased from zero to 10.84 L. AGS was successfully domesticated after 48 days, which maintained its structure during the operation. The domesticated AGS was orange, irregular, smooth and compact. Sludge volume index (SVI), SV30/SV5, mixed liquor volatile suspended solids/mixed liquor suspended solids (MLVSS/MLSS), extracellular polymeric substances, proteins/polysaccharides, average particle size, granulation rate, specific oxygen utilization rates (SOUR)H and (SOUR)N of AGS were about 38 mL/g, 0.97, 0.52, 39.73 mg/g MLVSS, 1.17, 1.51 mm, 96.66%, 47.40 mg O2/h g volatile suspended solids (VSS) and 8.96 mg O2/h g VSS, respectively. Good removal effect was achieved by the reactor. Finally, the removal rates of chemical oxygen demand (COD), total inorganic nitrogen (TIN), NH4+-N and total phosphorus (TP) were more than 98%, 96%, 97% and 97%, respectively. The result indicated gradually increasing the proportion of real wastewater in influent was a useful domestication method, and the feasibility of AGS for treatment of high C/N ratio industrial wastewater.

Immobilization of Hemoglobin on Platinum Nanoparticles-Modified Glassy Carbon Electrode for H2O2 Sensing

This work described an amperometric hydrogen peroxide (H2O2) biosensor based on immobilization of hemoglobin (Hb) on a glassy carbon (GC) electrode modified by platinum nanoparticles, which was prepared by an in situ chemical reductive growth method. The electrochemical impedance measurements confirmed that the Hb was immobilized on the platinum nanoparticles-modified glassy carbon surface and has a synergistic effect with platinum nanoparticles in improving the catalytic reduction of H2O2. The Hb immobilized platinum nanoparticles-modified GC (Hb/Pt/GC) electrode displays an effective catalytic response to the reduction of H2O2. A linear dependence of the catalytic current versus H2O2 concentration was obtained in the range of 5.0×10−6 to 4.5×10−4 mol·L−1 with a detection limit (S/N=3) of 7.4×10−7 mol·L−1.

Utilization of anaerobic granular sludge for chromium (VI) removal from wastewater: optimization by response surface methodology

In this study, anaerobic granular sludge (AGS) was used as a novel adsorbent for hexavalent chromium (Cr (VI)) removal from aqueous solutions. Factor experiments were conducted to find out the effects of different variables on the biosorption process. Among these terms, the impact of three main independent variables (contact time, initial pH and AGS dosage) on the removal efficiency of Cr (VI) was modeled using a well-fitting polynomial equation (R2 = 0.9044), by conducting 20 batch experiments designed by a central composite. The experimental isotherm data were successfully described by the Freundlich isotherm and the pseudo-second-order kinetic model was more suitable for explaining the kinetics process of adsorption. The AGS can be disposed using 0.1 M NaOH with 96.4% desorption efficiency. The results of the analyses (X-ray photoelectron spectroscopy and Fourier transformed infrared spectroscopy) suggested that Cr (VI) adsorption most likely involved electrostatic adsorption, redox reaction and complexation.