[Degradation of SMX with Peracetic Acid Activated by Nano Core-shell Co@NC Catalyst].

Peracetic acid (PAA), as a new oxidant, has attracted increasing attention in the treatment of refractory organic pollution in sewage. In this study, the nano core-shell Co@NC catalyst was prepared via etching and used to activate PAA to degrade sulfamethoxazole (SMX) in sewage. The results indicated that the degradation rate of SMX reached 98%, and its reaction rate constant was 0.80 min-1 under optimal conditions (catalyst dosage=0.02 g·L-1, PAA concentration=0.12 mmol·L-1, pH=7, SMX concentration=10 µmol·L-1). With the increase in PAA concentration and core-shell Co@NC dosage, the degradation efficiency of SMX increased. The study found that the core-shell Co@NC/PAA system had the best degradation effect on SMX under near-neutral conditions (pH 6.0-8.0), and both acidic and alkaline environments were not conducive to SMX degradation. HCO3- and humic acid showed significant inhibition on the degradation of SMX, whereas Cl- showed weak inhibition. In addition, through a free radical quenching experiment and electron paramagnetic resonance (EPR) detection, acetoxy radical (CH3CO2CO3·) were the main active species for the degradation of organic pollutants in the system. Transformation products (TPs) of SMX were analyzed by U-HPLC-Q-Exactive Orbitrap HRMS, and a possible degradation path of SMX was proposed. At the same time, the catalyst recycling experiment showed that the nano core-shell Co@NC catalyst had good stability and reusability.

Enhancing Astaxanthin Accumulation in Haematococcus pluvialis by Coupled Light Intensity and Nitrogen Starvation in Column Photobioreactors.

Natural astaxanthin mainly derives from a microalgae producer, Haematococcus pluvialis. The induction of nitrogen starvation and high light intensity is particularly significant for boosting astaxanthin production. However, the different responses to light intensity and nitrogen starvation needed to be analyzed for biomass growth and astaxanthin accumulation. The results showed that the highest level of astaxanthin production was achieved in nitrogen starvation, and was 1.64 times higher than the control group at 11 days. With regard to the optimization of light intensity utilization, it was at 200 µmo/m²/s under nitrogen starvation that the highest astaxanthin productivity per light intensity was achieved. In addition, both high light intensity and a nitrogen source had significant effects on multiple indicators. For example, high light intensity had a greater significant effect than a nitrogen source on biomass dry weight, astaxanthin yield and astaxanthin productivity; in contrast, nitrogen starvation was more beneficial for enhancing astaxanthin content per dry weight biomass. The data indicate that high light intensity synergizes with nitrogen starvation to stimulate the biosynthesis of astaxanthin.

Conversion of kraft lignin under hydrothermal conditions.

The aim of this study is to explore hydrothermal conversion of kraft lignin for value-added products. With ranging between 5.4% and 10.6%, total oil yield decreased with the increase of temperature (130, 180, and 230°C), the longer reaction time (15-60min) led to increased total oil yield. Main compound of oils characterized by GC-MS was guaiacol (2-methoxy phenol) in the range of 19-78% of oil depending on different reaction conditions. Residual kraft lignins were characterized by GPC and FTIR with respect to the conversion mechanism of kraft lignin by this process. The conversion of kraft lignin under hydrothermal conditions had something to do with the degradation of ß-O-4 linkages, hydroxyl groups, carbonyl groups, aromatic rings resulting in the increased amount of phenolic OH groups in kraft lignin.

Developmental toxicity of diclofenac and elucidation of gene regulation in zebrafish (Danio rerio).

Environmental pollution by emerging contaminants, e.g. pharmaceuticals, has become a matter of widespread concern in recent years. We investigated the membrane transport of diclofenac and its toxic effects on gene expression and the development of zebrafish embryos. The association of diclofenac with the embryos conformed to the general partition model at low concentration, the partition coefficient being 0.0033 ml per embryo. At high concentration, the interaction fitted the Freundlich model. Most of the diclofenac remained in the extracellular aqueous solution with less than 5% interacting with the embryo, about half of which was adsorbed on the membranes while the rest entered the cytoplasm. Concentrations of diclofenac over 10.13 µM were lethal to all the embryos, while 3.78 µM diclofenac was teratogenic. The development abnormalities at 4 day post treatment (dpt) include shorter body length, smaller eye, pericardial and body edema, lack of liver, intestine and circulation, muscle degeneration, and abnormal pigmentation. The portion of the diclofenac transferred into the embryo altered the expression of certain genes, e.g. down-regulation of Wnt3a and Gata4 and up-regulation of Wnt8a. The alteration of expression of such genes or the regulation of downstream genes could cause defects in the cardiovascular and nervous systems.

Sorption-desorption and transport of trimethoprim and sulfonamide antibiotics in agricultural soil: effect of soil type, dissolved organic matter, and pH.

Use of animal manure is a main source of veterinary pharmaceuticals (VPs) in soil and groundwater through a series of migration processes. The sorption-desorption and transport of four commonly used VPs including trimethoprim (TMP), sulfapyridine, sulfameter, and sulfadimethoxine were investigated in three soil layers taken from an agricultural field in Chongming Island China and two types of aqueous solution (0.01 M CaCl2 solution and wastewater treatment plant effluent). Results from sorption-desorption experiments showed that the sorption behavior of selected VPs conformed to the Freundlich isotherm equation. TMP exhibited higher distribution coefficients (K d = 6.73-9.21) than other sulfonamides (K d = 0.03-0.47), indicating a much stronger adsorption capacity of TMP. The percentage of desorption for TMP in a range of 8-12 % is not so high to be considered significant. Low pH (

Polychlorinated dibenzo-p-dioxins and polychlorinated dibenzofuran concentrations in Xingyun Lake sediment close to the pulp mill region of Jiangchuan (China): a typical case study.

Sediment cores from Xingyun Lake close to the pulp mill region of Jiangchuan (China), earlier found to be highly contaminated by pulping at least from the 1990s, were analyzed by HRGC/HRMS for the concentrations of 17 polychlorinated dibenzo-p-dioxins and polychlorinated dibenzofurans (PCDD/Fs). Regarding the contribution of individual congeners, PCDD/F levels ranged from ND (non-detectable) to 82.05 pg g(-1) dw (from ND to 0.16 pg WHO-TEQ g(-1) dw) in 0-20 cm of sediment and from ND to 45.61 pg g(-1) dw (from ND to 0.67 WHO-TEQ g(-1) dw) in 20-40 cm of sediment for 17 PCDD/Fs (WHO-TEQ: WHO-endorsed toxic equivalents). Major PCDD/Fs identified and confirmed were high-chlorinated congeners including OCDD/Fs and HpCDD/Fs in the two depths. For high-chlorinated PCDD/Fs such as O, Hp-CDD/Fs across the depth of sediment, sediment had a higher proportion in 0-20 cm than that in 20-40 cm. On the contrary, for low-chlorinated PCDD/Fs such as T, Pe, Hx-CDD/Fs, the lower proportion was found in 0-20 cm. The results demonstrated that PCDD/Fs loads in the sediment of Xingyun Lake were very low compared to loads in the other regions about 8 years after closedown of a majority of pulp production with chlorine, which indicated that pulp production was an important emission source of dioxins.

Sorption of carbamazepine from water by magnetic molecularly imprinted polymers based on chitosan-Fe3O4.

A novel magnetic-molecularly imprinted polymer (MMIP) based on chitosan-Fe3O4 has been synthesized for fast separation of carbamazepine (CBZ) from water. During polymerization, the modified chitosan-Fe3O4 was used not only as supporter but also as functional monomer. The properties of obtained MMIP were characterized by scanning electron and transmission electron microscopy, X-ray diffraction, Fourier transform infrared spectra, thermo-gravimetric analysis and so on. The sorption equilibrium data was well described by Freundlich isotherm model and the increase in the temperature generated an increase in the sorption amount, indicating endothermic nature of adsorption process. Sorption kinetics followed the pseudo-second-order model. The feasibility of selective sorption of CBZ from real water by the MMIP was analyzed by using spiked real water samples. The result showed that the sorption capacity of MMIP has no obvious decrease in different water samples whereas there was obvious decline in the sorption amount of the MNIP.

Removal of carbamazepine and clofibric acid from water using double templates-molecularly imprinted polymers.

A novel double templates-molecularly imprinted polymer (MIP) was prepared by precipitation polymerization using carbamazepine (CBZ) and clofibric acid (CA) as the double templates molecular and 2-vinylpyridine as functional monomer. The equilibrium data of MIP was well described by the Freundlich isotherm model. Two kinetic models were adopted to describe the experimental data, and the pseudo second-order model well-described adsorption of CBZ and CA on the MIP. Adsorption experimental results showed that the MIP had good selectivity and adsorption capacity for CBZ and CA in the presence of competitive compounds compared with non-imprinted polymer, commercial powdered activated carbon, and C18 adsorbents. The feasibility of removing CBZ and CA from water by the MIP was demonstrated using tap water, lake water, and river water.

Comparative study of the degradation of carbamazepine in water by advanced oxidation processes.

Degradation of carbamazepine (CBZ) using ultraviolet (UV), UV/H2O2, Fenton, UV/Fenton and photocatalytic oxidation with TiO2 (UV/TiO2) was studied in deionized water. The five different oxidation processes were compared for the removal kinetics of CBZ. The results showed that all the processes followed pseudo-first-order kinetics. The direct photolysis (UV alone) was found to be less effective than UV/H2O2 oxidation for the degradation of CBZ. An approximate 20% increase in the CBZ removal efficiency occurred with the UV/Fenton reaction as compared with the Fenton oxidation. In the UV/TiO2 system, the kinetics of CBZ degradation in the presence of different concentrations of TiO2 followed the pseudo-first order degradation, which was consistent with the Langmuir-Hinshelwood (L-H) model. On a time basis, the degradation efficiencies ofCBZ were in the following order: UV/Fenton (86.9% +/- 1.7%) > UV/TiO2 (70.4% +/- 4.2%) > Fenton (67.8% +/- 2.6%) > UV/H2O2 (40.65 +/- 5.1%) > UV (12.2% +/- 1.4%). However, the lowest cost was obtained with the Fenton process.

[Simultaneous determination of 10 sulfonamide antibiotics in water by solid-phase extraction and high performance liquid chromatography].

A solid-phase extraction (SPE)-high performance liquid chromatography (HPLC) method has been developed for simultaneous determination of 10 sulfonamide antibiotics in water. The analytes were first enriched and purified through a PEP solid-phase extraction column, and eluted with acetonitrile-dichloromethane solution (2: 1, V/V), then detected by a HPLC with a UV detector. The detection wavelength was 268 nm and the column temperature was 33 degrees C, using gradient elution process with acetonitrile - 0.4% acetic acid/water (V/V) as the mobile phase to achieve baseline separations of these 10 analytes. The linearity range was 10 - 2 000 microg x L(-1). The recovery ranges of standard addition for deionized water and real water samples were 73.4% - 95.6% and 70.2% - 92.5%, respectively (except for sulfonamide, were 8.5% and 8.0%). The limit of detection was 1.42-7.25 ng x L(-1). Application of this method for parts of Huangpu River in Shanghai, surface water and groundwater in Chongming Island showed that sulfonamide antibiotics were detected in different frequencies in different aqueous environments, with the concentration range of 13.3 - 241.5 ng x L(-1), proving this method is easy, rapid, sensitive and efficient to meet the needs of actual work.

Enhanced anaerobic treatment of CSTR-digested effluent from chicken manure: The effect of ammonia inhibition.

The effect of ammonia inhibition was evaluated during the enhanced anaerobic treatment of digested effluent from a 700m(3) chicken-manure continuous stirred tank reactor (CSTR). A 12.3L internal circulation (IC) reactor inoculated with an anaerobic granular sludge and operated at 35±1°C was employed for the investigation. With a corresponding organic loading rate of 1.5-3.5kg-COD/m(3)d over a hydraulic retention time of 1.5d, a maximum volumetric biogas production rate of 1.2m(3)/m(3)d and TCOD (total COD) removal efficiency ranging from 70% to 80% was achieved. However, the continual increase in the influent TAN content led to ammonia inhibition in the methanogenesis system. The SCOD/TAN (soluble COD/total ammonia nitrogen) ratio was presented to be the key controlling factor for the anaerobic treatment of semi-digested chicken manure, and further validation through shock loading and ammonia inhibition experiments was conducted. The threshold value of the SCOD/TAN ratio was determined to be 2.4 (corresponding to a TAN of 1250mg/L) at an influent pH of 8.5-9.

Synthesis by precipitation polymerization of molecularly imprinted polymer for the selective extraction of diclofenac from water samples.

A molecularly imprinted polymer (MIP) was synthesized by precipitation polymerization using diclofenac (DFC) as a template, 2-vinylpyridine (2-VP) as functional monomer, ethylene glycol dimethacrylate (EGDMA) as cross-linker, and toluene as porogen. The MIP showed outstanding affinity toward DFC in aqueous solution with a binding site capacity (Q(max)) of 324.8 mg/g (1.09 mmol/g) and was used as solid-phase extraction (SPE) material for the quantitative enrichment of DFC in environmental water samples and off-line coupled to a reversed-phase HPLC/DAD. Various parameters including washing solvent, elution solvent and breakthrough volume affecting the extraction efficiency of the polymers have been evaluated to achieve the selective preconcentration of DFC from water samples and to reduce non-specific interactions. Recoveries of DFC extracted from tap water, river water and wastewater samples were higher than 95%, and no significant DFC recovery difference was obtained among the different water matrix. The stability of MIP was tested by consecutive percolation of water sample, and it was shown that the performance of the MIP did not vary even after 30 adsorption and desorption cycles. Furthermore, the MISPE was used for the analysis of DFC in river water and wastewater samples and revealed DFC concentrations of 0.69±0.002 µg/L (n=3) and 0.31±0.004µg/L (n=3), respectively. The results were in good agreement with corresponding LC-MS/MS data.

Selective removal of diclofenac from contaminated water using molecularly imprinted polymer microspheres.

A molecularly imprinted polymer (MIP) was synthesized by precipitation polymerization using diclofenac (DFC) as a template. Binding characteristics of the MIP were evaluated using equilibrium binding experiments. Compared to the non-imprinted polymer (NIP), the MIP showed an outstanding affinity towards DFC in an aqueous solution with a binding site capacity (Q(max)) of 324.8 mg/g and a dissociation constant (K(d)) of 3.99 mg/L. The feasibility of removing DFC from natural water by the MIP was demonstrated by using river water spiked with DFC. Effects of pH and humic acid on the selectivity and adsorption capacity of MIP were evaluated in detail. MIP had better selectivity and higher adsorption efficiency for DFC as compared to that of powdered activated carbon (PAC). In addition, MIP reusability was demonstrated for at least 12 repeated cycles without significant loss in performance, which is a definite advantage over single-use activated carbon.

Performance evaluation and application of molecularly imprinted polymer for separation of carbamazepine in aqueous solution.

A molecularly imprinted polymer (MIP) for selective adsorption of carbamazepine (CBZ) in aqueous solution was synthesized by precipitation polymerization using CBZ as a template molecule and methacrylic acid (MAA) as a functional monomer. The performance of the CBZ-MIP was evaluated in terms of selectivity, adsorption capacity, binding characteristics, loading volume, and elution volume. The CBZ-MIP exhibited a high affinity for CBZ over the competitive compound (Diclofenac) and was more suitable to remove low concentrations of CBZ in large-volume water samples. A binding performance experiment indicated that the adsorption of CBZ-MIP was characterized by both specific and non-specific binding interactions. Moreover, the regenerability of the MIP was affirmed in ten sequential cycles of adsorption/desorption without a significant loss in recovery. Finally, the CBZ-MIP was applied to enrich CBZ in environmental water samples, and the CBZ concentrations were subsequently determined using HPLC-UV. The results were in good agreement with corresponding LC-MS/MS data.

CFD optimization of continuous stirred-tank (CSTR) reactor for biohydrogen production.

There has been little work on the optimal configuration of biohydrogen production reactors. This paper describes three-dimensional computational fluid dynamics (CFD) simulations of gas-liquid flow in a laboratory-scale continuous stirred-tank reactor used for biohydrogen production. To evaluate the role of hydrodynamics in reactor design and optimize the reactor configuration, an optimized impeller design has been constructed and validated with CFD simulations of the normal and optimized impeller over a range of speeds and the numerical results were also validated by examination of residence time distribution. By integrating the CFD simulation with an ethanol-type fermentation process experiment, it was shown that impellers with different type and speed generated different flow patterns, and hence offered different efficiencies for biohydrogen production. The hydrodynamic behavior of the optimized impeller at speeds between 50 and 70 rev/min is most suited for economical biohydrogen production.

[Novel phosphorus and nitrogen removal process for municipal sewage treatment: performance evaluation and design optimization].

A novel modified A2/O process (MMAO) was developed for nitrogen and phosphorus removal of municipal sewage. Bench-scale study was conducted to evaluate the performance of the MMAO process treating practical municipal sewage at normal temperature. Activated sludge model (ASM2D) was used to simulate the MMAO process and optimize its design and operation. It was found that the average treatment efficiency of COD, TN, NH4+-N and TP achieved by MMAO were up to 85.7%, 66.8%, 97.35% and 78.1%, respectively. When influent COD concentration of the system was more than 300 mg/L, a better nitrogen and phosphorus removal efficiency of 70% and 90% were achieved. After being calibrated and validated by the experimental results, the activated sludge model of MMAO could simulate the biological reactions occurred in the systems excellently. Optimization design and operational parameters could be accomplished by the mechanical activated sludge modeling. Furthermore, the model could also evaluate the process performance under peak load and low temperature and presented a whole scheme toward the unit combination and operation control. The effluent quality of MMAO process under stable operating could reach the first (B) standard of Municipal Sewage Treatment Plant Pollutants Discharge Standards (GB 18918-2002). The effluent of anaerobic unit was pumped directly into the anoxic unit to supply carbon source for denitrification instead of internal recirculation of mixture liquid, which would save operation cost significantly. The total hydraulic retention time of MMAO was lower than traditional biological organic removal system, so it was very suitable for the improvement of existing plant.

[Effect and mechanism of heavy metal stabilization treatment of sediment in Jinshan Lake].

The heavy metal stabilization treatment (by mixture of CaO, CaO2, CaO and CaO2) of sediment in Jinshan Lake were investigated through soil column experiment, including the transport and transformation of heavy metal in sediment after stabilization, and the mechanism of heavy metal stabilization treatment technology. In the simulated acid rain experiment under a pH of 2.9, Zn in the sediment stabilized by CaO, CaO+ CaO2, CaO2, respectively, transferred to the third layer with the first layer's migrating quantities of 96, 97 and 93 mg/kg, while in another experiment under a pH of 5.0, Zn transferred to the third layer with the first layer's migrating quantities of 87, 90 and 89 mg/kg, respectively. In the blank experiments under pH 2.9 and 5.0, Zn transferred to the sixth and fifth layer with the first layer migrating quantities of 128 and 112 mg/kg, respectively. The above results were concluded to be: 1) both migrating velocity and first layer's migrating quantity of Zn decreased in stabilized sediment; 2) the three tested ways could reduce it migrating capability in soil; 3) pH of leached solution could affect the migrating capability of Zn and high Ph would lead to the decrease of Zn in soil. For Ni and Cd, the similar conclusion could also be gained. The results of metal transporting mechanism experiments with CaO, CaO + CaO2, CaO2 showed that: 1) pH of the sediment increased from 6.76 to 8.33, 8.15 and 8.21; 2) TOC content decreased with a range of 5%, 10.9% and 13.1%; 3) fixedness part contents of Zn, Ni and Cd increased 10.6%, 1.7% and 4.5%, respectively, which is the important reason leading to the decrease of metal transporting capability. The transformation proportion of heavy metal from labilization to stabilization showed that the stabilization capability of heavy metal followed the sequence: Zn > Cd > Ni.