Decolorization of anthraquinone dye Reactive Blue 19 by the combination of persulfate and zero-valent iron.

Decolorization of anthraquinone dye Reactive Blue 19 (RB19) with sulfate radicals generated in situ from persulfate and zero-valent iron (ZVI) was investigated. The effects of initial solution pH, initial concentration of RB19, ZVI and persulfate, reaction temperature and common dissolved anions were studied. 100% color removal efficiency and 54% TOC removal efficiency were achieved in 45 min with an initial RB19 concentration of 0.1 mM under typical conditions (pH 7.0, 0.8 g L(-1) ZVI, 10 mM persulfate and 30 C). The decolorization efficiency of RB19 increased with higher iron dosage, higher initial persulfate concentration, and higher reaction temperature. It is also an acid driven process. The decolorization process followed pseudo-first order kinetics and the activation energy was 98.1 kJ mol-1. RB19 decolorization was inhibited by common dissolved anions such as CL-, NO3-, H2PO4- and HCO3- since they reacted with sulfate radicals that retarded the oxidation process. The experiment demonstrated that the combination of persulfate and ZVI was a promising technology for the decolorization of dye wastewater.

Global review of phthalates in edible oil: An emerging and nonnegligible exposure source to human.

This work investigated the presence of seven major phthalates in nine different kinds of edible oils (i.e. olive, rapeseed, peanut, sesame, tea seed, corn, soybean, sunflower, and blended oil) and their potential impacts on human. The respective total average phthalates concentrations in the oils studied were found to be 6.01, 2.79, 2.63, 2.03, 1.73, 1.66, 1.57, 1.26, and 0.72 mg/kg. On the other hand, the seven main phthalates in the edible oils with the average concentration ranked from high to low were in order of DiNP, DEHP, DiDP, DBP, DiBP, DEP, and BBP, with 0.90, 0.81, 0.79, 0.71, 0.22, 0.17, and 0.10 mg/kg, respectively. The estimated maximum human daily intakes (EDI) of DEHP, DBP, DiBP, DiNP, BBP, DEP, and DiDP via edible oils were determined to be 552, 2996, 121, 356, 268, 66, and 563 µg/p/d, respectively. It was further revealed that the maximum human EDI of DEHP, DBP, BBP, and DiBP through consumption of edible oils were 2.92, 6.79, 1.24, and 1.06 times higher than those via bottled water. The calculated average estrogenic equivalence (EEQ) values of the seven major phthalates in edible oils fell into the range of 2.7-958.1 ng E2/L, which were 45-396 times of those in bottled water. With published works, the complete distributions of 15 phthalates in nine kinds of edible oils were established and assessed for the health risks based on EDI and EEQ. This work provided the first evidence that edible oil is a potential source of phthalates, thus the potential adverse estrogenic effects on human health should need to be assessed in a holistic manner.

Trace determination of sulfonamide antibiotics and their acetylated metabolites via SPE-LC-MS/MS in wastewater and insights from their occurrence in a municipal wastewater treatment plant.

Antibiotics have drawn much attention as their wide usage in humans and animals may result in microbial resistance, which is a huge threat to humans' health. Studies on the occurrence and removals of antibiotics in wastewater treatment plants have been widely performed, but very few covered their main acetylated metabolites. This study developed an effective analytical method for the trace determination of four sulfonamides and three acetylated metabolites in municipal wastewaters, which was validated by linearity (R2 > 0.995), sensitivity (limit of quantification, LOQ < 0.78 ng/L), recovery (77.7%-148.1%) and precision (relative standard deviation, RSD < 9.6%). All sulfonamides and their acetylated metabolites were detected in municipal wastewaters including influent, primary settling tank and effluent. Removal performances of sulfapyridine (SP), sulfadiazine (SDZ), sulfamethoxazole (SMZ), and N4-acetyl sulfadiazine (AC-SDZ) in the municipal wastewater treatment plant were moderate or excellent, whereas the corresponding removals of sulfamethazine (SM2), N4-acetyl sulfapyridine (AC-SP), and N4-acetyl sulfamethazine (AC-SM2) were poor. The calculated poor removal of SM2 might be attributed to its fluctuation in raw wastewater, whereas the poor removals of AC-SP and AC-SM2 may be due to re-transformation from their parent sulfonamides. Our results showed that monitoring of acetylated sulfonamides in municipal wastewater is important for two reasons. One is that acetylated metabolites are good biomarkers for wastewater-based epidemiology when they are combined with their corresponding parent sulfonamides. The other is that the potential risk of sulfonamides in effluent to the natural environment cannot be accurately evaluated unless their acetylated metabolites are also accounted. This report is the first to address the potential risk of acetylated sulfonamides in effluent of wastewater treatment plants.

Bisphenol A concentrations in human urine, human intakes across six continents, and annual trends of average intakes in adult and child populations worldwide: A thorough literature review.

Bisphenol A (BPA) is an important industrial raw material that is widely applied in daily products. BPA is also an endocrine-disrupting chemical that may adversely affect humans. This review thoroughly collected data on BPA concentration in human urine and determined main influencing factors. The average BPA intake of humans across six continents or the average value worldwide was calculated based on a simple model. Results showed that the average BPA intake was ranked from high to low as follows: Oceania, Asia, Europe, and North America in the child population and Oceania, Europe, Asia, and North America in the adult population. The annual trend of the average BPA intake was similar between the adult and child populations. The BPA intake in the two populations evidently decreased from 2000 to 2008 and then slightly increased from 2008 to 2011. The BPA intake in the child population started to decrease again from 2011, whereas the corresponding intake in the adult population continued to increase. The distinct difference likely contributed to the wide prohibition of the use of BPA in food-related products for children in many countries since 2009; the bans effectively decreased the total BPA exposure in the child population.

Migration and potential risk of trace phthalates in bottled water: A global situation.

Increasing attention has been dedicated to trace phthalates in bottled water due to the serious concerns on public health, while there is still a lack of systematic analysis and assessment of current global situation. Through analyzing five representative phthalates in bottled water over 20 countries, this work clearly revealed the phthalates-associated potential risks in both human daily intake and estrogenic effect. In the risk assessment, the kinetic models were also developed to describe and predict phthalates migration. In more than three hundred brands of bottled waters from twenty one countries, the detection frequency of the five targeted phthalates was found to be in the order of dibutyl phthalate (DBP, 67.6%), di-2-(ethyl hexyl) phthalate (DEHP, 61.7%), diethyl phthalate (DEP, 47.1%), benzyl butyl phthalate (BBP, 36.9%), and dimethyl phthalate (DMP, 30.1%). Among the countries studied relating concentrations of DEHP in bottled waters, the top five countries ranked in the order of high to low were Thailand, Croatia, Czech Republic, Saudi Arabia and China with an average level of 61.1, 8.8, 6.3, 6.2 and 6.1 µg/L, respectively. The average levels of BBP, DBP, DMP and DEP in bottled water from Pakistan were high, in which DEP and DMP were ranked 1st among all countries with the average levels of 22.4 and 50.2 µg/L, while BBP and DBP were ranked 2nd and 3rd with the average levels of 7.5 and 17.8 µg/L, respectively. The human daily intake-based risk assessment revealed that phthalates in bottled waters studied would not pose a serious concern on public health. However, the adverse estrogenic effects of phthalates in bottled water from some countries appeared to be significant. This study just shed light on global situation of phthalates in bottled water, and more efforts should be needed to systematically examine the phthalates-related safety of bottled water.

[Biorecovery of Palladium from Simulated Wastewaters and Its Catalytic Property for Methylene Blue].

By using Enterococcus faecalis Z5 strain (CCTCC M2012445) as a microbial resource, this study explored the possibility of recovering palladium (Pd) in the form of nanoparticles by adding an electron donor; investigated the Pd biorecovery efficiency of three kinds of simulated wastewaters including industrial waste processing leachates (IW) , printed circuit board scrap (PCBS) , and spent automotive catalyst (SAC); and analyzed the effect of other metal ions contained in simulated wastewater on Pd biorecovery efficiency. The results showed that the E. faecalis Z5 could recover Pd(Ⅱ) as palladium nanoparticles from the three simulated wastewaters. X-ray diffraction and transmission electron microscopy analysis indicated that the recovered product was Pd nanoparticles that were about 10 nm in size and mainly distributed in the periplasm of the cells. The order of Pd(Ⅱ) biorecovery efficiency from the three kinds of wastewaters was IW> SAC> PCBS. The biosorption efficiencies for IW, SAC, and PCBS were 99.8% (6 h), 99.7% (8 h), and 90.3% (12 h), respectively, and the bioreduction efficiencies were 99.9% (4 h), 99.9% (6 h), and 80.4% (36 h). Other metal ions contained in the simulated wastewaters such as Pt(Ⅳ), Au(Ⅲ), Ag(Ⅰ), Cu(Ⅱ), and Fe(Ⅱ) affected both the biosorption and bioreduction processes. The degree of matrix effects on the Pd(Ⅱ) bioreduction efficiency were in the order Au(Ⅲ)> Pt(Ⅳ)> Cu(Ⅱ)> Ag(Ⅰ)> Fe(Ⅱ). Further doping the recovered Pd nanoparticles with ferriferous oxide enabled the products to catalyze the degradation of methylene blue in heterogeneous Fenton reactions, which showed 96.7% degradation rate of methyl blue within 80 min.

[Bio-inspired Recovery of Platinum Nanoparticle and Its Mechanism].

This paper illustrated an approach of using a self-isolated bacterium Enterococcus faecalis Z5(CCTCC M2012445) to recover platinum nanoparticles from aqueous solution, and exploring its possibility under the condition of providing an exogenous electron donor. At the same time, the impacts of initial Pt concentration, biomass, temperature and pH on recovery process were researched to explore the possible mechanism of recovery process. The results showed that Enterococcus faecalis Z5 could recover platinum nanoparticles and there were two steps:bio-sorption and bio-reduction. And the initial Pt concentration 286.46 mg·L-1, biomass 3.2 g·L-1, temperature 50℃ and pH 6 for biorecovering were optimized. The TEM and XRD results indicated that the reduction products were platinum nanoparticles, of which most were distributed on the periplasm and the diameters were about 5 nm. Moreover, as shown by XPS figures, Pt (Ⅳ) was firstly reduced to Pt (Ⅱ), then further reduced to Pt (0) and nanoparticles were formed. The reduction of Pt (Ⅱ) to Pt (0) was a rate-limiting step. And the FTIR result showed the corresponding peaks of hydroxyl and amide group changes on the bacterium before and after reduction, probably playing an important role in the reduction process.

[Synthesis of Fe/nitrogen-doped Carbon Nanotube/Nanoparticle Composite and Its Catalytic Performance in Oxygen Reduction].

The cathode catalyst plays an important role in the electricity generation of microbial fuel cells (MFCs). In order to achieve the large-scale application of MFCs, cathode catalyst with low cost and high oxygen reduction reaction (ORR) has great sense to substitute the precious catalyst of Pt/C. Here chemical vapor deposition (CVD) method was utilized accompanied with melamine as a nitrogen and carbon precursor, oxidized carbon powder (Black Pearls 2000 or Acetylene Black) as carbon precursor and iron acetate as an iron precursor so as to synthesize two kinds of Fe and nitrogen doped carbon nanotube/nanoparticle composites (FeNCB and FeNCC) as MFCs cathode catalysts. The cyclic voltammetry and rotating ring-disk electrode were applied to analyze the ORR activity discrepancies of FeNCB, FeNCC, and Pt/C (20%), which was confirmed by MFC operation. The results showed that the ORR performance of FeNCB was slightly better than Pt/C and dramatically better than FeNCC. Moreover, the catalysis of ORR by FeNCB was through a four-electron transfer pathway. Besides, the performance of MFC-FeNCB was higher than MFC-Pt/C and observably higher than MFC-FeNCC which was a contribute to promote the scale of MFC. MFC-FeNCB achieved the maximum power output density of 1212.8 mW x m(-2), an open circuit potential of 0.875 V, and a stabilized voltage of (0.500 +/- 0.025) V. Further analysis via X-ray diffraction, X ray photoelectron spectroscopy, and Raman exhibited that the diameter of carbon nanotube, the types of N and Fe as well as the concentration of nitrogen, iron and oxygen was the reason for the discrepancies of ORR characteristics for the prepared catalysts.

[Analysis and Characterization of Multi-modified Anodes via Nitric Acid and PPy/AQDS in Microbial Fuel Cells].

The properties of anode material are crucial for high performances in microbial fuel cells (MFCs). Hereby, a biocompatible, conductive, and high electron transfer ability anode was fabricated by electrodepositing polypyrrole/anthraquinone-2, 6-disulphonic disodium salt (PPy/AQDS) onto nitric acid-soaked carbon felt. The results showed that the multi-modified anode outperformed the pristine one in biomass, electrical conductivity, and exchange current density with between 2.4 and 3.3 times better performance. The multi-modified anode (applied with 0.12 C·cm-2 total charge density) showed the highest peak current density (2.86 mA), the largest amount of biomass loading (0.44 mg·cm-2), the most favoured electrical conductivity (0.33 S·cm-1), and exchange current density (3.65×10-3 A·m-2), as a result, the maximum power density of the MFC equipped with the anode delivered a 2.2-fold increase over that of the control (1060.7 mW·m-2vs. 477.6 mW·m-2), and thus has great potential to be used as an anode for high-power MFCs. Further investigation revealed that the increased energy output might be attributed to the bridging of the carbon fibers by electrically conductive PPy/AQDS composite films, which provided a uniform connection throughout the nitric treated carbon felt as well as the synergetic effects between the newly formed functional groups like pyrrolic N and PPy/AQDS. It was proposed that integrating biocompatibility (BCB) with electrical conductivity (EC) and electron transfer efficiency (ETE) through multi-modification could form high-performance anode. Future efforts to be made for realizing more extraordinary high-performance MFCs anodes were also outlined. This work may also provide a novel universal approach for the development of other types of anode for high-performance MFCs through integrating the BCB with EC and ETE simultaneously.

[Copper recovery from artificial bioleaching lixivium of waste printed circuit boards].

The key step to realize metal recovery from bioleaching solutions is the recovery of copper from bioleaching lixivium of waste printed circuit boards in high-grade form. The influences of cathode material, current density, initial pH and initial copper ion concentration on the efficiency and energy consumption of copper recovery from artificial bioleaching lixivium under condition of constant current were investigated using an electro-deposition approach. The results showed that the larger specific surface area of the cathode material (carbon felt) led to the higher copper recovery efficiency (the recovery efficiencies of the anode and the cathode chambers were 96.56% and 99.25%, respectively) and the smaller the total and unit mass product energy consumption (the total and unit mass product energy consumptions were 0.022 kW x h and 15.71 kW x h x kg(-1), respectively). The copper recovery efficiency and energy consumption increased with the increase of current density. When the current density was 155.56 mA x cm(-2), the highest copper recovery efficiencies in the anode and cathode chambers reached 98.51% and 99.37%, respectively. Accordingly, the highest total and unit mass product energy consumptions were 0.037 kW x h and 24.34 kW x h x kg(-1), respectively. The copper recovery efficiency was also significantly affected by the initial copper ion concentration. The increase of the initial copper ion concentration would lead to faster decrease of copper ion concentration, higher total energy consumption, and lower unit mass product consumption. However, the initial pH had no significant effect on the copper recovery efficiency. Under the optimal conditions (carbon felt for cathode materials, current density of 111.11 mA x cm(-2), initial pH of 2.0, and initial copper ion concentration of 10 g x L(-1)), the copper recovery efficiencies of the anode and cathode chambers were 96.75% and 99.35%, and the total and unit mass product energy consumptions were 0.021 kW x h and 14.61 kW x h x kg(-1), respectively. The deposited copper on the cathode material was fascicularly distributed and no oxygen was detected.

[Influence of carboxylic carbon nanotube supported platinum catalyst on cathode oxygen reduction performance of MFC].

The cathodic catalyst plays an important role in the electricity generation of the microbial fuel cell (MFC). In order to evaluate the efficiency of oxygen reduction on the carbon nanotube (CNT) functionalized with different carboxylic groups supported Pt, carboxylic CNTs under the conditions of 80 degrees C and 95 degrees C were prepared, respectively. Pt/CNT catalysts (Pt/CNT-80 and Pt/CNT-95) was prepared by the dipping-precipitation method and their oxygen reduction efficiency was tested in the MFC (MFC-80, MFC-95 and MFC-C) with the air cathode. The results showed that the maximum power output densities of the MFC-95 and MFC-80 were 568.8 mWx m(-2) and 412.8 mWx m(-2), internal resistances were 204.7 omega and 207.7 omega, and open circuit potentials were 0.719 V and 0.651 V, respectively. However, the maximum power output density of the control MFC-C was only 5.4 mW x m(-2), and its internal resistance was 826.2 omega. XPS and XRD analysis results demonstrate that the efficiency of Pt/CNT-95 catalyst is better than Pt/CNT-80 may result from the surface of carboxylic CNT in the 95 degrees C introduced rich oxygen containing groups.

[Role of layered double hydroxide (LDH) in the protection of herring testis DNA from heavy metals].

The role of layered double hydroxide (LDH) in the protection of herring testis DNA from heavy metals Cd2+ and Pb2+ was studied by X-ray diffraction ( XRD) spectra, Fourier transform infrared (FTIR) spectra, Scanning Electron Microscopy (SEM), Cyclic Voltammetry and Ultraviolet Spectrometry. Size expansion of the basal spacing (003) from 0. 76 nm in LDH to 2. 30 nm was observed in the resulting DNA-LDH nanohybrids and it gave peaks corresponding to C=O (1 534 cm(-1) and 1488 cm(-1)) in skeleton and bases, C-O stretching vibration (1228 cm(-1)), and P-O symmetrical stretching vibration (1096 cm(-1)) in functional groups of DNA, indicating that DNA were intercalated into the LDH by the ion exchange. However, the displacement of NO3(-) was not fully complete (partial intercalation of DNA). The DNA outside LDH interlayers was absorbed on the surface of LDH. The cyclic voltammetric curves showed that DNA in the composites exhibited a very similar peaks, which corresponded to the two reduction current peaks (E(P) = - 1.2 mV and E(P) = -2.4 mV) of free DNA. Also there was no cathode sag emerging in cyclic voltammetric curves, suggesting that both Cd2+ and Pb2+ cannot insert into the groove of DNA to associate with base pairs or other groups when DNA was bound on LDH. The results showed that, on the one hand, both Cd2+ and Pb2+ were absorbed on the external surface of LDH for immobilization, on the other hand, the layer of LDH provided ideal space for DNA by the action of protecting DNA molecules from Cd2+ and Pb2+.