[Molecular Signatures of Dissolved Organic Matter in the Paihe River and Its Tributaries].

Dissolved organic matter (DOM) is an abundant and critical component of aquatic ecosystems, participating in many physicochemical and biogeochemical processes. The Paihe River is the only inflow river in the Jianghuai section of "Yangtze-Huaihe water diversion" clear water gallery project; however, its DOM molecular composition information and characteristics are still unclear. In this study, the molecular characterization of DOM in the Paihe River and Guangming Dayan River was determined using Orbitrap mass spectrometry. The Pearson's correlation and principal component analysis (PCA) were used to study the relationship between molecular composition information, characteristics, and sources of DOM in two rivers. The results showed that the molecular weight and oxygen content of DOM molecules in the Paihe River were relatively low; the molecular weight, aromaticity, and unsaturation of DOM molecules in the Guangming Dayan River were relatively high. From the element composition and compound composition of the two rivers' DOM, both rivers were mainly composed of CHO-compounds, lignin, and tannins derived from land plants, which indicates that both rivers were severely affected by terrestrial input. There were high percentages of CHOS, protein, and lipid compounds of DOM in the Paihe River. According to the results of the Pearson's correlation and PCA analyses, the DOM molecules of the Paihe River were also influenced by wastewater from sewage treatment plants, urbanization processes, and microbial activity. Molecular composition information and characteristics of DOM can provide a detailed reference to improve the theoretical support for the Paihe River clear water gallery project.

Superior degradation of phenolic contaminants in different water matrices via non-radical Fenton-like mechanism mediated by surface-disordered WO3.

Heterogeneous Fenton-like catalysis mediated by solid catalyst is a promising oxidation technology for water purification. The redox reactivity, cost-effectiveness, and environmental compatibility of solid catalyst play governing roles in oxidant activation, radical generation, and pollutant degradation. Herein, the surface-disordered WO3 (D-WO3) functionally engineered by the unique crystalline-amorphous core-shell structure is proven to be a superior solid catalyst of heterogeneous Fenton-like catalysis for peroxymonosulfate (PMS) activation and pollutant degradation in various water matrices. Six typical phenolic and dye pollutants are effectively and selectively degraded in the D-WO3/PMS system with much reduced matrix effects. Both radical identifying and scavenging tests elucidate the important role of non-radical 1O2 and mediated electron transfer during PMS activation on the D-WO3 surface. The superior Fenton-like activity of D-WO3 can be mainly attributed to the surface and sub-surface distorted lattice sites with finely tailored atomic and electronic structures and surface chemistry. These distorted lattice sites can thermodynamically serve as the key reactive centers of dissociative adsorption and catalytic activation for both PMS and pollutant, with high adsorption energy, strong structural activation, and smooth electron transfer. Our findings provide a new chance for heterogeneous Fenton-like catalysis mediated by transition metal oxides with high capacity, low cost, and no toxicity for promising water purification.

Non-radical activation of H2O2 by surface-disordered WO3 for efficient and selective pollutant degradation with weak matrix effects.

Heterogeneous catalysis is promising for water treatment. Solid catalysts play governing roles. Herein, the surface-disordered WO3, D-WO3, engineered with surface and sub-surface defective sites from NaBH4 reduction was proven to be an effective catalyst for H2O2 activation. The defective degree and defects amount on WO3 were regulated by NaBH4. More than 95% of two typical azo dyes, RhB and MG, were selectively degraded in D-WO3/H2O2 system during 3.0 h, while no significant activity was observed for MO as well as bisphenol A, roxarsone, phenol, 4-chlorophenol, p-nitrophenol, o-aminophenol, urea, and 2,4-dichlorophenol in comparison under the identical conditions (mainly less than 20%). Both ESR and radical scavenging tests indicated the minor role of ·OH from H2O2 activation on D-WO3. The superior activity of D-WO3 could be mainly attributed to the surface and sub-surface defects with finely tailored local atomic configurations and electronic structures of central metal sites. Surface and sub-surface defective sites could serve as the reactive sites of interfacial adsorption, dissociative activation, and catalytic decomposition for both oxidant and pollutants, with high adsorption energy, strong structural activation, and superior catalytic activity. Our findings provided a new chance for non-selective radical catalysis based on transition metal oxides and a promising catalyst with high performance, low cost, and no toxicity for pollutant degradation with weak matrix effects in wastewater and surface water.

The Neuroprotective Effect of Amitriptyline on Radiation-Induced Impairment of Hippocampal Neurogenesis.

The radioprotective effect of amitriptyline, an inhibitor of acid sphingomyelinase (ASMase), on radiation-induced impairment of hippocampal neurogenesis, loss of interneuron, and animal weight changes was investigated in BALB/c mice by immunostaining of biomarkers for cell division (Ki67), immature neurons (doublecortin or DCX), and interneurons (parvalbumin or PV) in the dentate gyrus (DG) of hippocampus. The results indicated that preirradiation (with 10 mg/kg, 2 times per day, for 7 consecutive days) or postirradiation (with 10 mg/kg, 2 times per day, for 14 consecutive days) treatment (pretreatment or posttreatment) with intraperitoneal injection of amitriptyline prevented the loss of newly generated neurons, proliferating cells, and interneurons in the subgranular zone of the DG. At the molecular level, pretreatment or posttreatment inhibited the expression of sphingomyelin phosphodiesterase 1 (SMPD1) gene which codes for ASMase. The pretreatment for 7 days also prevented radiation-induced weight loss from 2 to 3 weeks, but not within 1 week after irradiation. On the other hand, the posttreatment with amitriptyline for 14 days could improve animal weight gain from 4 to 6 weeks after irradiation. The present study suggests that amitriptyline may be a promising candidate radio-neuroprotective drug to improve radiation-induced impairment of hippocampal neurogenesis and relevant neurological and neuropsychological disorders.

A simple strategy to refine Cu2O photocatalytic capacity for refractory pollutants removal: Roles of oxygen reduction and Fe(II) chemistry.

Visible-light-driven photocatalysis is a promising technology for advanced water treatment, but it usually exhibits a low efficiency. Cu2O is a low-cost semiconductor with narrow band gap, high absorption coefficient and suitable conduction band, but suffers from low charge mobility, poor quantum yield and weak catalytic performance. Herein, the Cu2O catalytic capacity for refractory pollutants degradation is drastically improved by a simple and effective strategy. By virtue of the synergistic effects between photocatalysis and Fenton, a novel and efficient photocatalysis-driven Fenton system, PFC, is originally proposed and experimentally validated using Cu2O/Nano-C hybrids. The synergistic PFC is highly Nano-C-dependent and exhibits a significant superiority for the removal of rhodamine B and p-nitrophenol, two typical refractory pollutants in wastewater. The PFC superiority is mainly attributed to: (1) the rapid photo-electron transfer driven by Schottky-like junction, (2) the selective O2 reduction mediated by semi-metallic Nano-C for efficient H2O2 generation, (3) the specific H2O2 activation and large OH generation catalyzed by Haber-Weiss Fenton mechanism, and (4) the accelerated Fe2+/Fe3+ cycling and robust Fe2+ regeneration via two additional pathways. Our findings might provide a new chance to overcome the intrinsic challenges of both photocatalysis and Fenton, as well as develop novel technology for advanced water treatment.

Wire-cylinder dielectric barrier discharge induced degradation of aqueous atrazine.

The wire-cylinder dielectric barrier discharge reactor was adopted for removal of aqueous atrazine. The effect of different parameters on the degradation efficiency of atrazine was investigated, and the degradation mechanism of atrazine was studied. The experimental results showed that when the discharge power was 50 W and the air flow rate was 140 L h(-1), 93.7% of atrazine was degraded after 18 min of discharge time. The concentrations of generated O3 and H2O2 increased with increasing discharge time. The pH decreased from 6.80 to 2.50, 12.7% of TOC was removed after 18 min. The concentrations of generated Cl(-) and NO3(-) increased significantly during the degradation process of atrazine, and the decreasing toxicity trend was observed for the treated atrazine solution. The degradation byproducts of atrazine were identified using liquid chromatography-time-of-flight mass spectrometry (LC-TOF-MS), which might be formed mainly in dechlorination hydroxylation, alkyl oxidation, dechlorination hydroxylation combined with alkyl oxidation and demethylation oxidation reactions.

[Speciation distribution characters of heavy metals in waste printed circuit boards].

The environmental availability of heavy metals from the waste printed circuit boards (PCBs) were studied through BCR's three-stage extraction procedures from EU and Tessier's five sequential extraction procedures. The results show that the heavy metal extraction rates with BCR's procedures are higher than that with Tessier's from waste PCBs. There are significant differences in fraction distributions of heavy metals in PCBs. The speciation of Ni in the PCBs exists mainly in residual forms and has little effect on the environment. The percentage of acidic extractable forms with BCR's method and the total amount of exchangeable and carbonate which bound for Tessier's procedure of Pb and Zn are high, in the South China, the two metals are more easily released by acid rain. Acidic extractable forms of Cu is the main speciation in PCBs with BCR's extraction procedures, while the percentage of Fe-Mn oxides- bound of Cu is the highest with Tessier's procedures, though the result is not agree consistent, due to the high content of Cu in PCBs, the harm of Cu from PCBs could not be neglected.

Treatment of tannery wastewater by electrocoagulation.

Treatment of tannery wastewater by electrocoagulation with low cell current (< or = 1A) and soluble electrodes (mild steel electrodes and aluminum electrodes) was studied. Compared with aluminum electrodes, mild steel electrodes were more effective for the removal of sulfide, with a removal efficiency of over 90%. But during the treatment process, black color precipitate typical to iron(II) sulfides was produced. While aluminum electrodes were effective to eliminate the colority of the effluent, the removal efficiency of sulfide was lower than 12%. The mechanisms of the removal of chemical oxygen demand, ammonia, total organic carbon, sulfide and colority with the two soluble electrodes (mild steel and aluminum electrodes) were discussed in detail. In order to exert the predominance of diffenent types of electrodes, the tannery wastewater was treated using mild steel electrodes first followed by the filter and finally by the aluminum electrodes, the elimination rates of chemical oxygen demand, ammonia, total organic carbon, sulfide and colority were 68.0%, 43.1%, 55.1%, 96.7% and 84.3%, respectively, with the initial concentrations 2413.1 mg/L, 223.4 mg/L, 1000.4 mg/L, 112.3 mg/L and 256 dilution times, respectively. The absorbance spectra and energy consumption during electrocoagulation process were also discussed.