Catalytic performance improvement of volatile organic compounds oxidation over MnO_(x) and GdMnO_(3) composite oxides from spent lithium-ion batteries:Effect of acid treatment

In this work,cathode materials of spent lithium-ion ternary batteries are recovered and used as metal precursor to prepare multi-metal oxides MnO_(x)(SY)and GdMnO_(3)(SY)via combustion method and sol-gel method,respectively.Furthermore,a series of MnO_(x)(SY)-n and GdMnO_(3)(SY)-n(n=0.05,0.10,1.00,4.00,n represents the dilute HNO_(3) concentration)catalysts are fabricated by acid treatment of MnO_(x)(SY)and GdMnO_(3)(SY)samples and catalytic activities of oxygenated VOCs oxidation over all the prepared catalysts are investigated.Catalytic evaluation results show that acid-treated MnO_(x)(SY)-0.10 and GdMnO_(3)(SY)-0.05 samples perform the optimum VOCs removal efficiency respectively,which may be attributed to their obvious enhancement of physicochemical properties.In detail,Mn O_(x)(SY)-0.10 and GdMnO_(3)(SY)-0.05 samples exhibit the larger specific surface area,bigger amount of surface high-valence metal ions(Mn^(4+),Co^(3+),Ni^(3+)),more abundant adsorbed oxygen species and better low-temperature reducibility,which can play a crucial role in the significant improvement of VOCs oxidation.In situ DRIFTS results imply that the possible main intermediates are-OCO,-COO and-C-O species produced during VOCs oxidation.Possible by-products are further determined via TD/GC-MS analysis.

Target the neglected VOCs emission from iron and steel industry in China for air quality improvement

Recent years have witnessed significant improvement in China’s air quality.Strict environmental protection measures have led to significant decreases in sulfur dioxide(SO2),nitrogen oxides(NOx),and particulate matter(PM)emissions since 2013.But there is no denying that the air quality in 135 cities is inferior to reaching the Ambient Air Quality Standards(GB 3095–2012)in 2020.In terms of temporal,geographic,and historical aspects,we have analyzed the potential connections between China’s air quality and the iron and steel industry.The non-target volatile organic compounds(VOCs)emissions from iron and steel industry,especially from the iron ore sinter process,may be an underappreciated index imposing a negative effect on the surrounding areas of China.Therefore,we appeal the authorities to pay more attention on VOCs emission from the iron and steel industry and establish new environmental standards.And different iron steel flue gas pollutants will be eliminated concurrently with the promotion and application of new technology.

Evaluation of 1,4-naphthoquinone derivatives as antibacterial agents:activity and mechanistic studies

The diverse and large-scale application of disinfectants posed potential health risks and caused ecological damage during the 2019-nCoV pandemic,thereby increasing the demands for the development of disinfectants based on natural products,with low health risks and low aquatic toxicity.In the present study,a few natural naphthoquinones and their derivatives bearing the 1,4-naphthoquinone skeleton were synthesized,and their antibacterial activity against selected bacterial strains was evaluated.In vitro antibacterial activities of the compounds were investigated against Escherichia coli and Staphylococcus aureus.Under the minimum inhibitory concentration(MIC)of≤0.125μmol/L for juglone(1a),5,8-dimethoxy-1,4-naphthoquinone(1f),and 7-methyl-5-acetoxy-1,4-naphthoquinone(3),a strong antibacterial activity against S.aureus was observed.All 1,4-naphthoquinone derivatives exhibited a strong antibacterial activity,with MIC values ranging between 15.625 and 500μmol/Land ECso values rangingbetween10.56 and248.42μmol/L.Most of the synthesized compounds exhibited strong antibacterial activities against S.aureus.Among these compounds,juglone(la)showed the strongest antibacterial activity.The results from mechanistic investigations indicated that juglone,a natural naphthoquinone,caused cell death by inducing reactive oxygen species production in bacterial cells,leading to DNA damage.In addition,juglone could reduce the self-repair ability of bacterial DNA by inhibiting RecA expression.In addition to having a potent antibacterial activity,juglone exhibited low cytotoxicity in cell-based investigations.In conclusion,juglone is a strong antibacterial agent with low toxicity,indicating that its application as a bactericidal agent may be associated with low health risks and aquatic toxicity.

The ignored emission of volatile organic compounds from iron ore sinter process

Iron ore sintering is a major source of gaseous and particulate pollutants emission in iron smelt plant. The aim of present study is to characterize the volatile organic compounds(VOCs) emission profiles from iron ore sintering process. Both sinter pot test and sinter simulation experiment were conducted and compared. Out results showed that sinter process produced large quantity of VOCs together with NOxand SO_2. VOCs and NO were produced simultaneously in sinter pot test from 3 to 24 min after ignition, flowed by SO_2 production from 15 min to the end of sintering. Total VOCs(TVOC) concentration in sinter flue gas was affected by the coal and coke ratio in sinter raw material. The maximum TVOC concentration was 34.5 ppm when using 100% coal as fuel. Sinter simulation experiments found that the number of VOCs species and their concentrations were found by sinter temperature. The largest VOCs species varieties were obtained at 500 °C. Benzene, toluene,xylene and ethylbenzene were major VOCs in sinter flue gas based on the results from both simulation test and sinter pot. It thus demonstrated that in addition to NO_x, SO_2 and metal oxide particles, sinter flue gas also contained significant amount of VOCs whose environmental impact cannot be ignored. Based on our work, it is timely needed to establish a new VOC emission standard for sinter flue gas and develop advanced techniques to simultaneously eliminate multi-pollutants in iron ore sinter process.

Secondary battery inspired ɑ-nickel hydroxide as an efficient Ni-based heterogeneous catalyst for sulfate radical activation

Highly reactive radical species play an important role in syn-thetic chemistry, industrial processes, and environmental remedi-ation applications [1,2]. The radicals can be formed by eitherthermal decomposition of highly active oxidants or by catalyticactivation of stable oxidants under mild conditions [2]. Recently,the sulfate radical （.504） with its advantages of strong oxidizingpower, selective reactivity, and stability over a broad range of pHhas emerged as an excellent and versatile oxidant for a variety ofapplication [5].

Photodeposited FeOOH vs electrodeposited Co-Pi to enhance nanoporous BiVO4 for photoelectrochemical water splitting

Co-Pi and FeOOH cocatalysts were in-situ deposited on the surface of nanoporous BiVO4 photoelectrodes.The FeOOH cocatalyst has little effect on the BiVO4 samples＇ morphologies,while the electrodeposited CoPi cocatalyst seems to affect the surface of BiVO4 The impedance intensity modulated photocurrent spectroscopy（IMPS）,Mott-Schottky（M-S） techniques characterize BiVO4 samples photoelectrochemical performance with the deposition of Co-Pi and FeOOH.The Co-Pi/BiVO4 shows better photoelectrochemical performance than the FeOOH/BiVO4,but the FeOOH/BiVO4 exhibited the better stabilities.The flat band potential and slope of M-S plotof FeOOH/BiVO4 have little variations compared with BiVO4.In contrast,Co-Pi/BiVO4 exhibited the down shifted flat band potential,which is beneficial for the photoelectrochemical water oxidation.The electron transfer measurements revealed that the deposition of FeOOH and Co-Pi onto BiVO4 significantly enhanced the photoelectrochemical performance via reducing the interface resistance and promoting the electron transport.Furthermore,Co-Pi cocatalysts can further pin the transport-limiting traps and significantly facilitate the electron transport.

Risk Factors and Pregnancy Outcome in Women with a History of Cesarean Section Complicated by Placenta Accreta

Objective:To explore the risk factors and pregnancy outcomes in women with a history of cesarean section complicated by placenta accreta(PA).Methods:This case-control study included clinical data from singleton mothers with a history of cesarean section in 11 public tertiary hospitals in seven provinces of China between January 2017 and December 2017.According to the intraoperative findings after delivery,the study population was divided into PA and non-PA groups.We compared the pregnancy outcomes between the two groups,used multivariate logistic regression to analyze the risk factors for placental accreta.Results:For this study we included 11,074 pregnant women with a history of cesarean section;and of these,869 cases were in the PA group and 10,205 cases were in the non-PA group.Compared with the non-PA group,the probability of postpartum hemorrhage(236/10,205,2.31%vs.283/869,32.57%),severe postpartum hemorrhage(89/10,205,0.87%vs.186/869,21.75%),diffuse intravascular coagulation(3/10,205,0.03%vs.4/869,0.46%),puerperal infection(33/10,205,0.32%vs.12/869,1.38%),intraoperative bladder injury(1/10,205,0.01%vs.16/869,1.84%),hysterectomy(130/10,205,1.27%vs.59/869,6.79%),and blood transfusion(328/10,205,3.21%vs.231/869,26.58%)was significantly increased in the PA group(P<0.05).At the same time,the neonatal birth weight 3250.00(2950.00–3520.00)g vs.2920.00(2530.00–3250.00)g),the probability of neonatal comorbidities(245/10,205,2.40%vs.61/869,7.02%),and the rate of neonatal intensive care unit admission(817/10,205,8.01%vs.210/869,24.17%)also increased significantly(P<0.05).Weight(odds ratio)(OR)=1.03,95%confidence interval(CI):1.01–1.05)),parity(OR=1.18,95%CI:1.03–1.34),number of miscarriages(OR=1.31,95%CI:1.17–1.47),number of previous cesarean sections(OR=2.57,95%CI:2.02–3.26),history of premature rupture of membrane(OR=1.61,95%CI:1.32–1.96),previous cesarean-section transverse incisions(OR=1.38,95%CI:1.12–1.69),history of placenta previa(OR=2.44,95%CI:1.50–3.96),and the combination of prenatal hemorrhage(OR=9.95,95%CI:8.42–11.75)and placenta previa(OR=91.74,95%CI:74.11–113.56)were all independent risk factors for PA.Conclusion:There was an increased risk of adverse outcomes in pregnancies complicated by PA in women with a history of cesarean section,and this required close clinical attention.Weight before pregnancy,parity,number of miscarriages,number of previous cesarean sections,history of premature rupture of membranes,past transverse incisions in cesarean sections,a history of placenta previa,prenatal hemorrhage,and placenta previa were independent risk factors for pregnancies complicated with PA in women with a history of cesarean section.These independent risk factors showed a high value in predicting the risk for placentab accreta in pregnancies of women with a history of cesarean section.

Temperature sensitivity of organic compound destruction in SCWO process

To study the temperature sensitivity of the destruction of organic compounds in supercritical water oxidation process （SCWO）, oxidation effects of twelve chemicals in supercritical water were investigated. The SCWO reaction rates of different compounds improved to varying degrees with the increase of temperature, so the highest slope of the temperature-effect curve （/max） was defined as the maximum ratio of removal ratio to working temperature. It is an important index to stand for the temperature sensitivity effect in SCWO. It was proven that the higher imax is, the more significant the effect of temperature on the SCWO effect is. Since the high-temperature area of SCWO equipment is subject to considerable damage from fatigue, the temperature is of great significance in SCWO equipment operation. Generally, most compounds （/max 〉 0.25） can be completely oxidized when the reactor temperature reaches 500~C. However, some compounds （/max 〉 0.25） need a higher temperature for complete oxidation, up to 560~C. To analyze the correlation coefficients between/max and various molecular descriptors, a quantum chemical method was used in this study. The structures of the twelve organic compounds were optimized by the Density Functional Theory B3LYP/6-311G method, as well as their quantum properties. It was shown that six molecular descriptors were negatively correlated to imax while other three descriptors were positively correlated to imax. Among them, dipole moment had the greatest effect on the oxidation thermodynamics of the twelve organic compounds. Once a correlation between molecular descriptors and imax is established, SCWO can be run at an appropriate temperature according to molecular structure.

Rapidly and mildly transferring anatase phase of graphene-activated TiO2 to rutile with elevated Schottky barrier:Facilitating interfacial hot electron injection for Vis-NIR driven photocatalysis

Visible and even infrared(IR)light-initiated hot electrons of graphene(Gr)catalysts are a promising driven power for green,safe,and sustainable H2O2 synthesis and organic synthesis without the limitation of bandgap-dominated narrow light absorption to visible light confronted by conventional photocatalyst.However,the life time of photogenerated hot electrons is too short to be efficiently used for various photocatalytic reactions.Here,we proposed a straightforward method to prolong the lifetime of photogenerated hot electrons from graphene by tuning the Schottky barrier at Gr/rutile interface to facilitate the hot electron injection.The rational design of Gr-coated TiO2 heterojunctions with interface synergy-induced decrease in the formation energy of the rutile phase makes the phase transfer of TiO2 support proceed smoothly and rapidly via ball milling.The optimized Gr/rutile dyad could provide a H2O2 yield of 1.05 mM·g-1·h-1 under visible light irradiation(λ≥400 nm),which is 30 times of the state-of-the-art noble-metal-free titanium oxide-based photocatalyst,and even achieves a H2O2 yield of 0.39 mM·g-1·h-1 on photoexcitation by near-infrared-region light(~800 nm).

Indicating landfill stabilization state by using leachate property from Laogang Refuse Landfill

Variation and evolution process of leachate can be applied as a reference for landfill stabilization phase. In this work, leachates with different ages were collected from Laogang Refuse Landfill, and characterized with 14 key parameters. Simultaneously, principal component analysis （PCA） was applied to develop a synthetic parameter-F based on these 14 parameters, and a logarithm equation was simulated for the landfill stabilization process finally. It was predicted that leachates would meet Class I and Class II in standard for pollution control on the landfill site of municipal solid waste （GB 16889-1997） after 32 years and 22 years disposal under the natural attenuation in the humid and warm southern areas of China, respectively. The predication of landfill state would be more accurate and useful according to the synthetic parameter F of leachate from a working landfill.

A Polyimide-Based Photocatalyst for Continuous Hydrogen Peroxide Production Using Air and Water under Solar Light

Hydrogen peroxide(H_(2)O_(2))is a clean disinfectant,bleaching agent,and value-added fuel in various systems and is industrially produced through multistep energy-intensive hydrogenation/oxidation using H_(2)and O_(2).The exploitation of metal-free catalysts for alternative H_(2)O_(2)photoconversion is limited by their limited activity and selectivity,especially for the continuous H_(2)O_(2)production using only air,water,and solar light.Now,a cheap and robust polymer,poly(4,4′,4″-(1,3,5-triazine-2,4,6-triyl)triphenyl pyromellitimide)(PTTPI)was rationally synthesized by thermal structure-defect control under relatively low temperature(80-190℃),and the resulting metal-free material with a concisely refined band structure functioned as an efficient and ultra-stable photocatalyst for H_(2)O_(2)production over a wide pH range.The PTTPI photocatalyst with an optimized defective degree(0.51)and moderate bandgap(2.3 eV)exhibited a H_(2)O_(2)production yield rate of 16.6μg h^(−1) mg_(cat)^(−1) and a high apparent quantumefficiency of 16.2%.By merging the well-designed PTTPI catalyst with the water transport path of natural cotton,a zero-emission and sunlightonly input system is constructed for continuous H_(2)O_(2)production from air and water in the natural environment.The design of the polyimide-based catalyst reveals a sustainable future toward efficient H_(2)O_(2)synthesis with sunlight-only energy input,enabling its implementation in other photocatalytic systems and on-site processing communities.