Engineering of Defect-Rich Cu2WS4 Nano-homojunctions Anchored on Covalent Organic Frameworks for Enhanced Gaseous Elemental Mercury Removal.

Fabricating two-dimensional transition-metal dichalcogenide (TMD)-based unique composites is an effective way to boost the overall physical and chemical properties, which will be helpful for the efficient and fast capture of elemental mercury (Hg0) over a wide temperature range. Herein, we constructed a defect-rich Cu2WS4 nano-homojunction decorated on covalent organic frameworks (COFs) with abundant S vacancies. Highly well-dispersed and uniform Cu2WS4 nanoparticles were immobilized on COFs strongly via an ion pre-anchored strategy, consequently exhibiting enhanced Hg0 removal performance. The saturation adsorption capacity of Cu2WS4@COF composites (21.60 mg·g-1) was 9 times larger than that of Cu2WS4 crystals, which may be ascribed to more active S sites exposed in hybrid interfaces formed in the Cu2WS4 nano-homojunction and between Cu2WS4 nanoparticles and COFs. More importantly, such hybrid materials reduced adsorption deactivation at high temperatures, having a wide operating temperature range (from 40 to 200 °C) owing to the thermostability of active S species immobilized by both physical confined and chemical interactions in COFs. Accordingly, this work not only provides an effective method to construct uniform TMD-based sorbents for mercury capture but also opens a new realm of advanced COF hybrid materials with designed functionalities.

Tire pyrolysis wastewater treatment by a combined process of coagulation detoxification and biodegradation.

Recycling waste tires through pyrolysis technology generates refractory wastewater, which is harmful to the environment if not disposed properly. In this study, a combined process of coagulation detoxification and biodegradation was used to treat tire pyrolysis wastewater. Organics removal characteristics at the molecular level were investigated using electrospray ionization (ESI) coupled with Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR MS). The results showed that nearly 90% of the organic matter from the wastewater was removed through the process. Preference of the two coagulants for different classes of organics in tire pyrolysis wastewater was observed. The covalently bound inorganic-organic hybrid coagulant (CBHyC) used in this work had a complementary relationship with biodegradation for the organics removal: this coagulant reduced toxicity and enhanced the biodegradation by preferentially removing refractory substances such as lignin with a high degree of oxidation (O/C > 0.3). This study provides molecular insight into the organics of tire pyrolysis wastewater removed by a combined treatment process, supporting the advancement and application of waste rubber recycling technology. It also contributes to the possible development of an effective treatment process for refractory wastewater.

Interpenetrating network nanoarchitectonics of antifouling poly(vinylidene fluoride) membranes for oil-water separation.

Poly(vinylidene fluoride) (PVDF) membranes are a commonly used cheap material and have been widely used in wastewater treatment. In this study, a simple strategy was proposed to construct PVDF-g-PEG membranes with an interpenetrating network structure by simulating plant roots for the treatment of oil/water emulsion. Meanwhile, the hydrophilicity, antifouling, and mechanical properties of the membrane were improved. A series of chemical and physical characterization methods were used to verify the successful formation of a PVDF-g-PEG layer on the membrane surface. The effects of graft modifier content on the crystallization behavior, microstructure, and membrane permeability were studied. When the optimized membrane (m-PVDF-2) was applied to the treatment of oily wastewater, its separation performance was significantly better than that of the blank PVDF membrane, and the oil removal rate was over 99.3%. BSA and oil contamination were nearly reversible, and excellent oil resistance to high-viscosity oil was also observed. The method reported in this article is a one-step, simple method for constructing hydrophilic and oil-resistant PVDF membranes without any intermediate additives and harmful or costly catalysts. They can be used as an ideal material for preparing efficient oil-water separation membranes.

Treatment of ammonia-embodied wastewater by a transition-metal-based photochemical catalysis strategy.

Inspired by the self-purification process and a low nitrogen content of the ocean, and the fact that the driving-force behind ecological cycle is solar irradiation, a novel photochemical strategy was designed to spontaneously remove inorganic ammonia nitrogen from wastewater with solar irradiation. This strategy is based on the principles of green chemistry and energy efficiency, and meanwhile the prevention from the introduction of accompanying pollution. In our strategy, a photo-Fe (or Mn)-O2 system was built to remove ammonia-nitrogen from its aqueous solution. The results show that with full band solar irradiation at a range of 10-30 mW cm-2, in weak alkaline condition, more than 90% of ammonia-nitrogen can be effectively removed from NH4Cl aqueous solution by the new strategy, with a residual concentration as low as 2 mg L-1. Mn(III) was proved to be a better catalyst than Fe(III). The catalytic mechanism of N-removal is the generation of •OH during the process of the photoreduction of transition metal hydroxides. DFT theory had been applied to help explaining the mechanism. Different from general knowledge, in our strategy, an alkaline environment, where the generation rate of radicals was relatively slow and comparable to oxidation rate of transition metal ions, can guarantee the stability and persistency of the catalytic reaction. No NOx was produced in this strategy. This new strategy provides a new possibility of cost-efficient and environmental-friendly wastewater treatment, and has certain meaning of understanding how self-purification works in nature.

Using ESI FT-ICR MS to Characterize Dissolved Organic Matter in Salt Lakes with Different Salinity.

Dissolved organic matter (DOM) composition in salt lakes is critical for water quality and aquatic ecology, and the salinization of salt lakes affects the DOM composition. To the best of our knowledge, no study has explored the effects of salinity on salt lake DOM composition at the molecular level. In this work, we selected Qinghai Lake (QHL) and Daihai Lake (DHL) as typical saline lakes. The two lakes have similar geographical and climatic conditions, and the salinity of QHL is higher than that of DHL. Fourier transform ion cyclotron resonance mass spectrometry coupled with electrospray ionization was applied to compare the DOM molecular composition in the two lakes. At higher salinity, the DOM showed larger average molecular weight, higher oxidation degree, and lower aromaticity. Moreover, the proportion of DOM that is vulnerable to microbial degradation (e.g., lipids), photo-degradation (e.g., aromatic structures), or both processes (e.g., carbohydrates and unsaturated hydrocarbons) reduced at higher salinity. On the contrary, compounds that are refractory to microbial degradation (e.g., lignins/CRAM-like structures and tannins) or photo-degradation (e.g., aliphatic compounds) accumulated. Our study provides a useful and unique method to study DOM molecular composition in salt lakes with different salinity and is helpful to understand DOM transformation during the salinization of salt lakes.

Molecular Characterization of Organics Removed by a Covalently Bound Inorganic-Organic Hybrid Coagulant for Advanced Treatment of Municipal Sewage.

Coagulation is an important process to remove organics from water. The molecular composition and structure of organic matter influence water quality in many ways, and the lack of information regarding the organics removed by different coagulants makes it challenging to optimize coagulation processes and ensure reclaimed water safety. In this paper, we investigated coagulation of secondary biological effluent from a municipal sewage treatment plant with different coagulants. We emphasized investigation of organics removal characteristics at the molecular level using Fourier transform-ion cyclotron resonance mass spectrometry (FT-ICR MS) coupled with electrospray ionization (ESI). We found that conventional coagulants can only partially remove condensed polycyclic aromatics and polyphenols with low H/C (H/C < 0.7) and highly unsaturated and phenolic compounds and aliphatic compounds with high O/C (O/C > 0.6). A new coagulant, CBHyC, had better removal efficiencies for all organics with different element compositions and molecular structures, especially organics that are resistant to conventional coagulants such as highly unsaturated and phenolic compounds and aliphatic compounds located in 0.3 < O/C < 0.8 and 1.0 < H/C < 2.0 regions and sulfur-containing compounds with higher O/C (e.g., anionic surfactants and their metabolites or coproducts). This study provides molecular insights into the organics removed by different coagulants and provides data supporting the possible optimization of advanced wastewater treatment processes.

Molecular insights into the mechanism and the efficiency-structure relationship of phosphorus removal by coagulation.

Types and structures of phosphorus compounds influence the removal of phosphorus by coagulation. Until now, the molecular-level interaction between coagulants and phosphorus (especially organophosphates) and the relationship between removal efficiency and phosphorus structure have not been clear. This work investigated the removal of phosphorus with different structures using conventional coagulants (poly aluminum chloride (PACl) and polymerized ferric sulfate (PFS)) and a novel covalently-bound inorganic-organic hybrid coagulant (CBHyC). CBHyC removed more than 98% of phosphate and most of organophosphates, had more stable performance than PACl and PFS, and was less affected by pH, initial phosphorus concentration, and co-occurring materials. Molecular dynamics simulation demonstrated that CBHyC removed phosphorus mainly through electrostatic attraction and hydrophobic interaction. Furthermore, this work established QSAR (quantitative structure activity relationship) models for removal efficiency and organophosphate structure for the first time. The model showed that atomic charges of phosphorus atoms (QP) and hydrogen atoms (QH+) in the system and the energy gap (ΔEMO) affected electronegativity and hydrophobicity, thus influencing organophosphate removal efficiency. The model had high fitting precision and good predictive ability and has the potential to greatly reduce the cost of optimizing processes and conditions for phosphorus removal.

Electro-oxidation of perfluorooctanoic acid by carbon nanotube sponge anode and the mechanism.

As an emerging persistent organic pollutant (POPs), perfluorooctanoic acid (PFOA) exists widely in natural environment. It is of particular significance to develop efficient techniques to remove low-concentration PFOA from the contaminated waters. In this work, we adopted a new material, carbon nanotube (CNT) sponge, as electrode to enhance electro-oxidation and achieve high removal efficiency of low-concentration (100µgL(-1)) PFOA from water. CNT sponge was pretreated by mixed acids to improve the surface morphology, hydrophilicity and the content of carbonyl groups on the surface. The highest removal efficiencies for low-concentration PFOA electrolyzed by acid-treated CNT sponge anode proved higher than 90%. The electro-oxidation mechanism of PFOA on CNT sponge anode was also discussed. PFOA is adsorbed on the CNT sponge rapidly increasing the concentration of PFOA on anode surface. When the potential on the anode is adjusted to more than 3.5V, the adsorbed PFOA undergoes electrochemically oxidation and hydrolysis to produce shorter-chain perfluorocarboxylic acids with less CF2 unit. The efficient electro-oxidation of PFOA by CNT sponge anode is due to the combined effect of adsorption and electrochemical oxidation. These findings provide an efficient method to remove actual concentration PFOA from water.

Preparation and antibacterial activity of lysozyme and layered double hydroxide nanocomposites.

It is necessary to develop "green" disinfection technology which does not produce disinfection by-products. Lysozyme-layered double hydroxide nanocomposites (LYZ-LDHs) were prepared by intercalating LYZ in LDH for the first time. Their antibacterial activity was evaluated using staphylococcus aureus as a target. The bacteria removal mechanism was also studied. Characterization of LYZ-LDHs by X-ray diffraction and Fourier transform infrared spectroscopy indicated that LYZ was successfully intercalated in LDH, compressed and deformed without secondary structural change. LYZ-LDHs showed excellent bactericidal effectiveness against staphylococcus aureus. The antibacterial performance of LYZ-LDHs was found to be affected by the LYZ/LDH ratio and the pH of the bacteria-containing water. The bacteria removal efficiency of LYZ-LDHs with LYZ/LDH mass ratio of 0.8 was consistently above 94% over the pH range of 3-9. LYZ-LDHs adsorbed bacteria to their surface by LDH and then killed them by the immobilized LYZ. This new material integrated the bactericidal ability of LYZ and adsorption ability of LDH. Moreover, the antibacterial ability of LYZ-LDHs was persistent and not limited by the adsorption capacity.

Arsenite removal from aqueous solution by a microbial fuel cell-zerovalent iron hybrid process.

Conventional zerovalent iron (ZVI) technology has low arsenic removal efficiency because of the slow ZVI corrosion rate. In this study, microbial fuel cell (MFC)-zerovalent iron (MFC-ZVI) hybrid process has been constructed and used to remove arsenite (As(III)) from aqueous solutions. Our results indicate that the ZVI corrosion directly utilizes the low-voltage electricity generated by MFC in the hybrid process and both the ZVI corrosion rate and arsenic removal efficiency are therefore substantially increased. The resultant water qualities are compliant with the recommended standards of EPA and WHO. Compared to the ZVI process alone, the H2O2 generation rate and output are dramatically improved in MFC-ZVI hybrid process. Strong oxidants derived from H2O2 can rapidly oxidize As(III) into arsenate (As(V)), which helps to improve the As(III) removal efficiency. The distribution analysis of As and Fe indicates that the As/Fe molar ratio of the flocs in solution is much higher in the MFC-ZVI hybrid process. This phenomenon results from the different arsenic species and hydrous ferric oxides species in these two processes. In addition, the electrosorption effect in the MFC-ZVI hybrid process also contributed to the arsenic removal by concentrating As(V) in the vicinity of the iron electrode.

Mechanisms for the direct electron transfer of cytochrome c induced by multi-walled carbon nanotubes.

Multi-walled carbon nanotube (MWCNT)-modified electrodes can promote the direct electron transfer (DET) of cytochrome c (Cyt c). There are several possible mechanisms that explain the DET of Cyt c. In this study, several experimental methods, including Fourier transform infrared spectroscopy, circular dichroism, ultraviolet-visible absorption spectroscopy, and electron paramagnetic resonance spectroscopy were utilized to investigate the conformational changes of Cyt c induced by MWCNTs. The DET mechanism was demonstrated at various nano-levels: secondary structure, spatial orientation, and spin state. In the presence of MWCNTs, the secondary structure of Cyt c changes, which exposes the active site, then, the orientation of the heme is optimized, revolving the exposed active center to the optimum spatial orientation for DET; and finally, a transition of spin states is induced, providing relatively high energy and a more open microenvironment for electron transfer. These changes at different nano-levels are closely connected and form a complex process that promotes the electron transfer of Cyt c.

Removal of Acid Orange 7 in simulated wastewater using a three-dimensional electrode reactor: removal mechanisms and dye degradation pathway.

The removal of Acid Orange 7 (AO7) in simulated wastewater was experimentally investigated using a three-dimensional electrode reactor with granular activated carbon as the particle electrode, ACF (activated carbon fiber)/Fe as the anode, and ACF/Ti as the cathode. Particular attention was paid to the reaction mechanisms and the dye degradation pathway in the system. The removal of AO7 in the system was mainly dependent on the oxidation by the produced active substances (()OH, etc.) and the coagulation by Fe(II) or Fe(III) dissolved from the anode. The former mechanism was predominant. A possible pathway for AO7 degradation was proposed by monitoring the temporal evolution of intermediates in the solution, with the use of some techniques including GC/MS, FTIR and HPLC. The AO7 molecule was observed to be firstly decomposed to aromatic intermediates, further degraded to ring opening products and finally mineralized to CO(2), H(2)O and inorganic salts. The intermediates increased the biodegradability of the wastewater, which was proved by the increase of the BOD/COD value after electrolysis treatment. The three-dimensional electrode method can be considered an effective alternative to dye wastewater pretreatment prior to the biological process.

Factors affecting the performance of microbial fuel cells for sulfide and vanadium (V) treatment.

Sulfide and vanadium (V) are pollutants commonly found in wastewaters. A novel approach has been investigated using microbial fuel cell (MFC) technologies by employing sulfide and V(V) as electron donor and acceptor, respectively. This results in oxidizing sulfide and deoxidizing V(V) simultaneously. A series of operating parameters as initial concentration, conductivity, pH, external resistance were carefully examined. The results showed that these factors greatly affected the performance of the MFCs. The average removal rates of about 82.2 and 26.1% were achieved within 72 h operation for sulfide and V(V), respectively, which were accompanied by the maximum power density of about 614.1 mW m(-2) under all tested conditions. The products generated during MFC operation could be deposited, resulting in removing sulfide and V(V) from wastewaters thoroughly.

[Performance of a single chamber microbial fuel cell utilizing Dioscorea zingiberensis C. H. Wright wastewater].

The possibility of electricity generation in a single chamber microbial fuel cell fed with Dioscorea zingiberensis C. H. Wright wastewater was demonstrated, and the effects of COD and SO4(2-) concentration on MFC performance were investigated. Under the same conductivity and COD concentration, the power density generated from wastewater equaled to 80.3% of that from glucose. At low COD concentration, the electricity generation increased with increasing COD loading rates, and the maximum power density was 322 mW/m2; while the COD concentration was enhanced over 2766 mg/L, the stable times for electricity generation was reduced and the MFC could not recover to previous performance as refueling. That indicates high COD loading rates would inhibit microbial activity. The COD removal rates varied from 68.2% to 84.8%, and it decreased when COD concentration climbed up. The power density was enhanced with SO4(2-) concentration increasing up to 7716 mg/L (Conductivity > 8.19 mS/cm) after which no further improvements in power density were observed. The maximum power density of the wastewater containing SO4(2-) was lower by 14.5% on average than that of the wastewater which removed SO4(2-). And its coulombic efficiencies declined substantially as SO4(2-) concentration increasing, which imply that the SO4(2-) is deoxidized as the electron acceptor, which takes the MFC efficiency down.

[Species distribution and coagulation behavior of covalent bonded aluminum-silicon hybrid flocculants].

Covalent bonded aluminum-silicon hybrid flocculants were synthesized by employing tetraethylorthosilicate (TEOS) and two silane coupling agents [diethoxydimethylsilane (DEDMS), gamma-aminopropylmethyldiethoxysilane (APDES)] as silicon sources, respectively. The distribution of Al species was investigated by 27Al NMR method and the coagulation behavior was evaluated by treating synthetic water containing humic acid. The results of 27Al NMR show that silicon source, Si/Al molar ratio and basicity (B) exhibit effect on the Al species distribution. In the products with APDES as silicon source, the highest content of Al13 was obtained and its amount increases with the rise of Si/Al molar ratio. The effect of B value on the Al species is similar for the three sets of flocculants. The content of monomeric species decreases with the rise of B value. At Si/Al = 0.4, there are no Al13 observed throughout the B value range in the products with TEOS as silicon source. Al13 starts to appear at a higher B value of 1.5 for the products with DEDMS as silicon source and a lower B value of 0.5 for that with APDES as silicon source, respectively. The coagulation results show that, in acidic conditions, the best dosage range of the flocculants with APDES as silicon source is the widest of the three, resulting in the best coagulation efficiency. In alkaline conditions, the coagulation efficiency of the products with TEOS as silicon source is slightly better than the other two.

Defluoridation of drinking water by combined electrocoagulation: effects of the molar ratio of alkalinity and fluoride to Al(III).

The defluoridation efficiency (epsilon(F)) of electrocoagulation (EC) is closely related to the pH level of the F(-)-containing solution. The pH level usually needs to be adjusted by adding acid in order to obtain the highest epsilon(F) for the F(-)-containing groundwater. The use of combined EC (CEC), which is the combination of chemical coagulation with EC, was proposed to remove fluoride from drinking water for the first time in this study. The optimal scheme for the design and operation of CEC were obtained through experiments on the treatment of F(-)-containing groundwater. It was found, with OH(-) being the only alkalinity of the raw water, that the highest efficiency would be obtained when the molar ratio of alkalinity and fluoride to Al(III) (gamma(Alkalinity+F)) was controlled at 3.0. However, when the raw water contained HCO(3)(-) alkalinity, a correction coefficient was needed to correct the concentration of HCO(3)(-) to obtain the optimal defluoridation condition of gamma(Alkalinity+F)=3.0 for CEC. The correction coefficient of HCO(3)(-) concentration was concluded as 0.60 from the experiment. For the practical F(-)-containing groundwater treatment, CEC can achieve similar epsilon(F) as an acid-adding EC process. The consumption of aluminum electrode was decreased in CEC. The energy consumption also declined greatly in CEC, which is less than one third of that in the acid-adding EC process.

Study on treatment of coking wastewater by biofilm reactors combined with zero-valent iron process.

Experiments were conducted to investigate the behavior of the integrated system with biofilm reactors and zero-valent iron (ZVI) process for coking wastewater treatment. Particular attention was paid to the performance of the integrated system for removal of organic and inorganic nitrogen compounds. Maximal removal efficiencies of chemical oxygen demand (COD), ammonia nitrogen (NH(3)-N) and total inorganic nitrogen (TIN) were up to 96.1, 99.2 and 92.3%, respectively. Moreover, it was found that some phenolic compounds were effectively removed. The refractory organic compounds were primarily removed in ZVI process of the integrated system. These compounds, with molecular weights either ranged 10,000-30,000 Da or 0-2000 Da, were mainly the humic acid (HA) and hydrophilic (HyI) compounds. Oxidation-reduction and coagulation were the main removal mechanisms in ZVI process, which could enhance the biodegradability of the system effluent. Furthermore, the integrated system showed a rapid recovery performance against the sudden loading shock and remained high efficiencies for pollutants removal. Overall, the integrated system was proved feasible for coking wastewater treatment in practical applications.

[Al species distribution of organic silicate aluminum hybrid flocculants by Al-ferron complexation timed spectrophotometric method].

New types of organic silicate aluminum hybrid flocculants were prepared by employing Tetraethylorthosilicat (TEOS), Diethoxydimethylsilane (DEDMS), gamma-Aminopropylmethyldiethoxysilane (APDES) as silicon source. The Al species distribution in these new products was investigated by Al-Ferron complexation timed spectrophotometric method. The results show that silicon source, basicity (B) and Si/Al molar ratio have effect on the Al species distribution. Among them, basicity has greater effect, three sets of products have similar characteristics. The content of Al(a) declines with the rise of B value, while the contents of Al(b) and Al(c) increase. Al(c) is the dominant Al species in the products with TEOS as silicon source. DEDMS has little contribution to the distribution of Al species. In the products with APDES as silicon source, Al(c) is the dominant Al species while the content increases with the rise of Si/Al molar ratio.

[Effect of cathode material on electrolytic treatment of Acid Orange 7 by a three-phase three-dimensional electrode reactor].

The simulative wastewater containing Acid Orange 7 (AO7) of 300 mg/L was electrolytically treated by a three-phase three-dimensional electrode reactor. Particular attention was paid on the comparison of treatment efficiency of different cathodes in the system. Intermediate products and concentration of *OH and H2O2 were further investigated using HPLC, UV-Vis scan and GC-MS, with the purpose of investigating the electrolysis behavior of AO7 with different cathodes. Results showed that activated carbon fiber (ACF) cathode was more effective than graphite or stainless steel cathode. Despite all of the three investigated cathodes showed high efficiency in the decolorization of AO7 (more than 96% after 60 min of electrolysis under 20 V), the TOC removal ratio of ACF system (57.4%) was much higher than those of the other two. Although the generation of *OH and H2O2 were both found in the three systems, the concentration in the system with ACF as the cathode was much higher than those in the other two, which resulted in the better mineralization ability. Moreover, the same degradation route of AO7 was found in the three systems, which involved the generation of ketone and naphthol compounds.

Mentality and behavior of children with congenital heart diseases / 中华心血管病杂志

<p><b>OBJECTIVE</b>The present study was designed to investigate the influence of Congenital Heart Disease (CHD) on the mentality and behavior in children, and to compare post operative mentality and behavior in children receiving interventional therapy and congenital heart surgery.</p><p><b>METHOD</b>Mentality and behavior of 232 children suffering from CHD were examined with Achenbach Child Behavior Checklist (CBCL) edited by XU Tao-yuan in 1992 and 100 sex, age, education and achievement-matched children with pneumonia were enrolled as controls.</p><p><b>RESULTS</b>The mentality and behavior abnormal rates of the boys and girls suffering from CHD were significantly higher than those of controls (P < 0.01, P < 0.05). The behavior abnormities of the boys presented as depression, social flinch, physical complains, assault and violate rules. Whereas the girls presented as depression, social flinch, physical complains and violate rules. The total cursory mark of postoperative check result of the interventional and surgical children, both in girls and in boys, were significantly lower than those of the preoperative children (P < 0.05). The total and assault cursory mark of postoperative check result of children treated with interventional therapy were significantly lower than those of children treated with the surgical operations (P < 0.05). The abnormal rates of mentality and behavior positively correlated with the disease course.</p><p><b>CONCLUSIONS</b>CHD is associated with increased abnormal mentality and behavior of the children. Early treatment, especially the interventional therapy can significantly improve the mentality and behavior of the children with CHD.</p>