Strategies of selective electroreduction of aqueous nitrate to N_(2) in chloride-free system:A critical review

Electroreduction of nitrate has been gaining wide attention in recent years owing to it's beneficial for converting nitrate into benign N_(2) from the perspective of electrocatalytic denitrification or into value-added ammonia from the perspective of electrocatalytic NH_(3) synthesis.By reason of the undesired formation of ammonia is dominant during electroreduction of nitrate-containing wastewater,chloride has been widely used to improve N_(2) selectivity.Nevertheless,selective electroreduction of nitrate to N2 gas in chloride-containing system poses several drawbacks.In this review,we focus on the key strategies for efficiently enhancing N_(2) selectivity of electroreduction of nitrate in chloride-free system,including optimal selection of elements,combining an active metal catalyst with another metal,manipulating the crystalline morphology and facet orientation,constructing core–shell structure catalysts,etc.Before summarizing the strategies,four possible reaction pathways of electro-reduction of nitrate to N_(2) are discussed.Overall,this review attempts to provide practical strategies for enhancing N2 selectivity without the aid of electrochlorination and highlight directions for future research for designing appropriate electrocatalyst for final electrocatalytic denitrifi-cation.

Ordered mesoporous materials for water pollution treatment:Adsorption and catalysis

To meet the growing emission of water contaminants,the development of new materials that enhance the efficiency of the water treatment system is urgent.Ordered mesoporous materials provide opportunities in environmental processing applications due to their exceptionally high surface areas,large pore sizes,and enough pore volumes.These properties might enhance the performance of materials concerning adsorption/catalysis capability,durability,and stability.In this review,we enumerate the ordered mesoporous materials as adsorbents/catalysts and their modifications in water pollution treatment from the past decade,including heavy metals(Hg^(2+),Pb^(2+),Cd^(2+),Cr^(6+),etc.),toxic anions(nitrate,phosphate,fluoride,etc.),and organic contaminants(organic dyes,antibiotics,etc.).These contributions demonstrate a deep understanding of the synergistic effect between the incorporated framework and homogeneous active centers.Besides,the challenges and perspectives of the future developments of ordered mesoporous materials in wastewater treatment are proposed.This work provides a theoretical basis and complete summary for the application of ordered mesoporous materials in the removal of contaminants from aqueous solutions.

In-situ construction of abundant active centers on hierarchically porous carbon electrode toward high-performance phosphate electrosorption: Synergistic effect of electric field and capture sites

Phosphate removal is crucial for eutrophication control and water quality improvement.Electro-assisted adsorption,an eco-friendly elec-trosorption process,exhibited a promising potential for wastewater treatment.However,there are few works focused on phosphate electro-sorption,and reported electrodes cannot attach satisfactory removal capacities and rates.Herein,electro-assisted adsorption of phosphate via in-situ construction of La active centers on hierarchically porous carbon(LaPC)has been originally demonstrated.The resulted LaPC composite not only possessed a hierarchically porous structure with uniformly dispersed La active sites,but also provided good conductivity for interfacial electron transfer.The LaPC electrode achieved an ultrahigh phosphate electrosorption capability of 462.01 mg g^(-1) at 1 V,outperforming most existing electrodes.The superior phosphate removal performance originates from abundant active centers formed by the coupling of electricfield and capture sites.Besides,the stability and selectivity toward phosphate capture were maintained well even under comprehensive conditions.Moreover,a series of kinetics and isotherms models were employed to validate the electrosorption process.This work demonstrates a deep understanding and promotes a new level of phosphate electrosorption.

Lightweight Si_(3)N_(4)@SiO_(2) ceramic foam for thermal insulation and electromagnetic wave transparency

Increasing porosity is one of the most direct ways to improve the thermal insulation and dielectric properties of materials.Until now,many wet methods for preparing Si_(3)N_(4) ceramic foams usually face the problems of complex rheology,long period,and expensive cost,and the reported pore sizes of Si_(3)N_(4) ceramic foams are typically micron-grade,resulting in a lack of competitiveness in thermal insulation and wave-transparent applications.In this paper,the Si_(3)N_(4)@SiO_(2) ceramic foams were prepared using an efficient dry-method,which combined three processes of low temperature chemical vapor deposition(LTCVD),template,and isostatic pressing.The method has the advantages of simple operation and short preparation period,and can realize near-net size molding and mass production.In addition,the evolution mechanisms of honeycomb microstructure and composition of Si_(3)N_(4)@SiO_(2) ceramic foam during sintering were studied by chemical reaction thermodynamics.The as-prepared Si_(3)N_(4)@SiO_(2) ceramic foam possesses low density(0.377 g·cm^(-3)),high compressive strength(7.5 MPa),low thermal conductivity(0.0808 W·m^(-1)·K^(-1)),and excellent dielectric properties(ε<1.32,tanδ<0.009)in the frequency range of 8-18 GHz,and its maximum working temperature in air can reach up to 1100℃.It will be recommended to be applied in the interlayer of Si_(3)N_(4) ceramic radome to improve its thermal insulation and electromagnetic wave transparency performances.

Adsorption of Quaternary Ammonium Compounds onto Activated Sludge

The performance of activated sludge in the removal of tetradecyl benzyl dimethyl ammonium chloride (C14BDMA) by adsorption from aqueous solution was investigated with different PH, contact time, ionic strength and temperature. Equilibrium was achieved within 2 h of contact time. The adsorption capacity increased largely with increasing solution pH and remained constant above pH 9. The ionic strength had a negative effect on C14BDMA removal. The adsorption isotherms were analyzed by Langmuir and Freundlich isotherm models, and equilibrium partitioning data was described well by both models. Kinetics data was best described by the pseudo second-order model. Experimental results indicated that the adsorption was favorable at lower temperatures. Thermodynamic parameters, including the Gibbs free energy (ΔG0), enthalpy (ΔH0), and entropy (ΔS0), were also calculated. These parameters indicated that adsorption of C14BDMA onto activated sludge was feasible, spontaneous and exothermic in the temperature range of 15-35℃. The activated sludge was shown to be an effective adsorbent for C14BDMA.

Long-term survival of esophageal squamous cell carcinoma after surgical treatment in a large-scale retrospective study from a single cancer center

Purpose To analyze the long-term overall survival(OS)and influencing factors of patients with esophageal squamous cell cancer(ESCC)under surgical treatment.Method We collected patients with ESCC who received surgical treatment in Sichuan Cancer Hospital&institute from January 2010 to December 2017,and selected 2,766 patients with thoracic esophageal carcinoma with relatively complete follow-up results as the objects of this study.We analyzed the characteristics,postoperative complications and long-term OS results of those patients.Results Of the 2766 patients,81.6%were male,midthoracic esophageal cancer accounted for 53.5%.McKeown was used in 72.0%of patients and Ivor-Lewis was used in 26.4%of patients.About 47.8%of patients received minimally invasive esophagectomy(MIE).The overall complication rate was 25.8%.The 1-year,3-year and 5-year OS rates were 86.2%,57.5%and 46.8%,respectively.McKeown had a better long-term OS rate than Ivor-Lewis(49.5%vs 41.2%,P<0.001),and MIE is superior to open surgery(51.8%vs 42.5%,P<0.001).Conclusion McKeown has advantages over Ivor-Lewis.MIE results in better long-term survival outcomes for patients.But more prospective randomized controlled trials with large samples are needed.