Degradation mechanism of BPA under VUV irradiation: efficiency contribution and DFT calculations.

Bisphenol A (BPA) is regarded as a hazardous pollutant that exists widely in aquatic environments, posing a severe threat to human health. In this study, a vacuum ultraviolet (VUV) lamp emitting a hybrid of 254 nm and 185 nm light was used to degrade BPA. Results indicated that photolysis via 254 nm wavelength accounted for 24.93% for BPA decay, while indirect oxidation was responsible for 52.27% of decay. Results confirmed that the degradation of BPA under VUV illumination mainly occurred via photo-excited degradation and ·OH electrophilic addition reactions based on average local ionization energy (ALIE) calculation and density functional theory (DFT) calculations. Therefore, only light with a wavelength of 254 nm was able to induce the first three excited states of BPA, forming the electron transition type of n → π* from O atom to a single benzene ring and π → π* in the single benzene ring. Indirect oxidation by ·OH occurred as it preferentially attacked the C6 atom in BPA ring A. Moreover, the energy required for photo-excited degradation was about twofold than that of ·OH electrophilic addition reactions.

Occurrence of Iodophenols in Aquatic Environments and the Deiodination of Organic Iodine with Ferrate(VI).

Toxic and odorous iodophenols are commonly identified as disinfection by-products (DBPs) in drinking water. Herein, ng/L levels of iodophenols were identified in river water, wastewater treatment plant effluent, and medical wastewater, with the simultaneous identification of µg/L to mg/L levels of iodide (I-) and total organic iodine (TOI). Oxidation experiment suggested that the I-, TOI, and iodophenols could be oxidized by ferrate [Fe(VI)], and more than 97% of TOI had been transformed into stable and nontoxic IO3-. Fe(VI) initially cleaved the C-I bond of iodophenols and led to the deiodination of iodophenols. The resulted I- was swiftly oxidized into HOI and IO3-, with the intermediate phenolic products be further oxidized into lower molecular weight products. The Gibbs free energy change (ΔG) of the overall reaction was negative, indicating that the deiodination of iodophenols by Fe(VI) was spontaneous. In the disinfection of iodine-containing river water, ng/L levels of iodophenols and chloro-iodophenols formed in the reaction with NaClO/NH2Cl, while Fe(VI) preoxidation was effective for inhibiting the formation of iodinated DBPs. Fe(VI) exhibited multiple functions for oxidizing organic iodine, abating their acute toxicity/cytotoxicity and controlling the formation of iodinated DBPs for the treatment of iodide/organic iodine-containing waters.

Application of vacuum-ultraviolet (VUV) for phenolic homologues removal in humic acid solution: Efficiency, pathway and DFT calculation.

Vacuum-ultraviolet (VUV) photo-initiated oxidation of phenolic homologues in simulative natural water were investigated, including phenol, o-dihydroxybenzene (ODB), m-dihydroxybenzene (MDB), p-dihydroxybenzene (PDB), paranitrophenol (PNP) and o-chlorophenol (OCP). Results showed the phenolic homologues removal rate reached at least 90% in pure water, which was dependent on temperature, pH, concentration of HA, and functional group of HA. Experimental results indicated that 0.2 mg/L HA might be a critical point. Additionally, the rate constant of the six phenolic homologues reduced by 76.85%, 77.81%, 71.91%, 79.15%, and 55.69%, respectively in the MDB solution, and 79.73%, 82.80%, 95.36%, 80.38%, and 92.64%, respectively in the benzoic acid (BA) solution, compared to the rate constant in pure water. Moreover, quantum chemistry calculation indicated that the variances between phenolic compounds in removal rate were attributed to the substituent on the benzene ring. And, to some extent, the carboxy group of HA was supposed to arose the suppression for phenolic homologues removal rate. Mechanism involved phenolic homologues degradation using vacuum-ultraviolet (VUV) was summarized, where it underwent the formation of quinone structures, ring opening, short-chain organic acid, even eventually the transformation into NO3- and Cl- of PNP and OCP.

[Analysis of Storage Sludge Composition Characteristics and Evolutionary Regularity in the Hunhe River Basin].

With the acceleration of urbanization, the accumulation of storage sludge in the Hunhe River Basin has increased year by year, creating a potential and long-term threat to the environment. In order to realize the resource-saving and harmless treatment of storage sludge, the composition of storage sludge and the evolvement rule were analyzed and researched. The basic physicochemical properties (water content, pH, volatile organic compounds (VS), and total alkalinity), nutrient index (TC, TN, C/N, TK, and TP), microbial composition, and heavy metal contents and fraction were analyzed. The results showed the VS and various nutrient element contents decreased with the prolongation of storage time, and changes in water content were not obvious, which was independent of the storage time and only relevant to natural conditions. The pH was maintained at around 7, and the bacteria predominated in microorganisms, accounting for about 90%. The content of anaerobic microorganisms increased. The contents and fractions of Cu, Zn, Cr, Ni, Pb, Cd, As, and Hg did not change significantly, but the content of Cu was higher than the Chinese standard for agricultural utilization (GB 4284-1984). Therefore, there is a larger risk of storage sludge for agricultural use. Therefore, the analysis of the composition and evolution of storage sludge in the Hunhe River Basin is of great significance for further resource treatment of sludge.

Nitrogen removal and microbial community shift in an aerobic denitrification reactor bioaugmented with a Pseudomonas strain for coal-based ethylene glycol industry wastewater treatment.

An aerobic denitrification system, initially bioaugmented with Pseudomonas strain T13, was established to treat coal-based ethylene glycol industry wastewater, which contained 3219 ± 86 mg/L total nitrogen (TN) and 1978 ± 14 mg/L NO3--N. In the current study, a stable denitrification efficiency of 53.7 ± 4.7% and nitrite removal efficiency of 40.1 ± 2.7% were achieved at different diluted influent concentrations. Toxicity evaluation showed that a lower toxicity of effluent was achieved when industry wastewater was treated by stuffing biofilm communities compared to suspended communities. Relatively high TN removal (~50%) and chemical oxygen demand removal percentages (>65%) were obtained when the influent concentration was controlled at below 50% of the raw industry wastewater. However, a further increased concentration led to a 20-30% decrease in nitrate and nitrite removal. Microbial network evaluation showed that a reduction in Pseudomonas abundance was induced during the succession of the microbial community. The napA gene analysis indicated that the decrease in nitrate and nitrite removal happened when abundance of Pseudomonas was reduced to less than 10% of the overall stuffing biofilm communities. Meanwhile, other denitrifying bacteria, such as Paracoccus, Brevundimonas, and Brucella, were subsequently enriched through symbiosis in the whole microbial network.

Improved interfacial oxygen reduction by ethylenediamine tetraacetic acid in the cathode of microbial fuel cell.

In this study, ethylenediamine tetraacetic acid (EDTA) was investigated as a new kind of non-polymeric catalyst binder to improve interfacial oxygen reduction reaction (ORR) for the cathode of microbial fuel cell (MFC). The electrochemical analysis and MFC tests show negative correlation between ORR activity and molar concentration of EDTA applied during electrode preparation. In particular, the 0.02mol/L-EDTA yields higher ORR activity than other binder materials like Nafion, water, 0.1mol/L-EDTA and 0.2mol/L-EDTA, as indicated by the strongest response of ORR current and the smallest charge-transfer resistance. Accordingly, the MFC with cathode of 0.02mol/L-EDTA produced a maximum power density of 722mW/m(2), accounting for a value approximately 42% higher than that of commercial Nafion binder (5wt%, 507mW/m(2)). The improved ORR activity should be attributed to the enhanced proton transfer from phosphate ions to EDTA-involved three-phase boundary as a result of dipole ion bonds on nitrogen atoms having unshared pair of electrons in EDTA molecule.

[Effect of various factors on ozone inactivating Giardia in water].

In order to study the effect of O3 inactivating Giardia in water, different factors (CT value, pH, temperature, turbidity, organic content and inorganic ions) which might influence the inactivation were investigated by using fluorescence staining method. The results indicated that the whole process of O3 inactivating Giardia could be divided into two periods, the inactivated rate in log phase was significantly faster than it in the slow phase [k1 = (5.64 +/- 0.023) x 10(-1) mg x min, k2 = (2.72 +/- 0.002) x 10(-2) mg x min, k1 >> k2]. When the turbidity was 0.1 to 20. 0NTU, temperature was 5 to 35 degrees C, pH was 6.0 to 9.0, HA content was 0.5 to 10.0 mg/L, the turbidity was lower, the higher inactivating ratio could be received. With the increasing of temperature, the inactivating effect was decreased. The ability of O3 inactivating Giardia was stronger under acidic condition than it was in alkali circumstance. When the reaction system contained higher concentration of organics, the competition reaction might take place between Giardia and organics with O3, which might reduce inactivation ratio. The sequence of affecting disinfectant ability of O3 was NO3- > None > SO4(2-) > HCO3-, while inorganic cations (Ca2+, Mg2+ and Cu2+) promoted the inactive reaction to a certain extent. If the CT value of O3 was more than 15.0 min x mg/L, the ratio of inactivation could exceed 99.0% during disinfecting drinking water.

Effect of aridification on the replacement of zonic species, Stipa baicalensis Roshev., by azonic species, Leymus chinensis Tzvel., in the steppe of China.

The perennial grass Stipa baicalensis is the zonic species in the steppe of China, but is currently being replaced by the azonic species of Leymus chinensis. In this area, aridification is on the increase; therefore, we hypothesize that water competition plays a significant role in this succession. The limit of osmotic adjustment in S. baicalensis (13.94%-16.30% PEG) was much lower than that in L. chinensis (17.20%-24.50% PEG) in response to drought. The synoptic causal model accounted for most of the variation in the process of physiological regulation as indicated by the small residual effect (0.121-0.161). These results demonstrated that the two species dealt with drought in different ways. Stomata of L. chinensis acted more directly on transpiration, and the advantage in water competition resulted from the powerful stomatal control. On the other hand, S. baicalensis was more easily affected by non-stomatal limitation which was physiologically inactive in response to drought. Results supported the hypothesis above. S. baicalensis was more susceptible to the damage of aridification and was less competitive to water than L. chinensis.

[Interaction between p53 and HSP70 in human hepatocellular carcinoma tissues].

AIM: To investigate the interaction between p53 and heat shock protein70 (HSP70) in human hepatocellular carcinoma tissues. METHODS: HSP70 and p53-double positive samples were screened by imunohistochemical staining from twelve human hepatocellular carcinoma tissues, and the tissue homogenate was prepared. Coimmunoprecipitation was performed by using either anti-HSP70 mAb or anti-p53 mAb. The immunoprecipitate was analysed by SDS-PAGE and Western blot. RESULTS: Immunohistochemical staining detection showed that three samples out of twelve cases were double positive for both HSP70 and p53. p53 protein existed in the immunoprecipitate of anti-HSP70 mAb, while there was HSP70 protein in the immunoprecipitate of anti-p53 mAb. CONCLUSION: HSP70 and p53 exist as a complex in human hepatocellular carcinoma tissues, which will provide a new route for studying the pathogenesis and immunotherapy of human hepatocellular carcinoma.