Research progress of CO_(2) capture and mineralization based on natural minerals

Natural minerals,such as kaolinite,halloysite,montmorillonite,attapulgite,bentonite,sepiolite,forsterite,and wollastonite,have considerable potential for use in CO_(2) capture and mineralization due to their abundant reserves,low cost,excellent mechanical prop-erties,and chemical stability.Over the past decades,various methods,such as those involving heat,acid,alkali,organic amine,amino sil-ane,and ionic liquid,have been employed to enhance the CO_(2) capture performance of natural minerals to attain high specific surface area,a large number of pore structures,and rich active sites.Future research on CO_(2) capture by natural minerals will focus on the full utiliza-tion of the properties of natural minerals,adoption of suitable modification methods,and preparation of composite materials with high specific surface area and rich active sites.In addition,we provide a summary of the principle and technical route of direct and indirect mineralization of CO_(2) by natural minerals.This process uses minerals with high calcium and magnesium contents,such as forsterite(Mg_(2)SiO_(4)),serpentine[Mg_(3)Si_(2)O(OH)_(4)],and wollastonite(CaSiO_(3)).The research status of indirect mineralization of CO_(2) using hydro-chloric acid,acetic acid,molten salt,and ammonium salt as media is also introduced in detail.The recovery of additives and high-value-added products during the mineralization process to increase economic benefits is another focus of future research on CO_(2) mineralization by natural minerals.

Genome-Wide Analysis of the F3′5′H Gene Family in Blueberry(Vaccinium corymbosum L.)Provides Insights into the Regulation of Anthocyanin Biosynthesis

The F3′5′H gene family plays an important role in regulating anthocyanin biosynthesis,abiotic stress,and hormone signaling.In this study,14 F3′5′H genes were identified from the blueberry genome.The chromosomal distribution,physicochemical properties,F3′5′H domain,conserved motifs,cis-acting elements,and intron/exon compositions were analyzed.The functional prediction analysis of these VcF3′5′Hs indicated that their biological functions included light response and other secondary metabolites.The results of qRT-PCR showed that VcF3′5′Hs(especially VcF3′5′H4)were highly expressed at the ripening stage.Subcellular localization revealed that VcF3′5′H4 may be located in the endoplasmic reticulum.Co-expression analysis showed that the VcF3′5′H gene family was related to anthocyanin.This research provides an overview of the blueberry F3′5′H family and helps verify the role of these genes in regulating anthocyanin biosynthesis.

Performance and mechanism of La-Fe metal-organic framework as a highly efficient adsorbent for fluoride removal from mine water

Water fluoride pollution has caused non-negligible harm to the environment and humans,and thus it is crucial to find a suitable treatment technology.In this study,La-Fe@PTA adsorbent was synthesized for the defluoridation of mine water.The results showed that the optimum conditions for defluoridation by La-Fe@PTA were p H close to 7.0,the initial F-concentration of 10 mg/L,the dosage of 0.5 g/L and the adsorption time of 240 min.Compared with SO_4^(2-),Cl^(-),NO_(3)^(-),Ca^(2+)and Mg^(2+),CO_(3)^(2-)and HCO_(3)^(-)presented severer inhibition on fluoride uptake by La-Fe@PTA.The adsorption process fits well with the pseudo-second-order kinetic model and Freundlich model,and the maximum adsorption capacity of Langmuir model was 95 mg/g.Fixed-bed adsorption results indicated that fluoride in practical fluorinated mine water could be effectively removed from 3.6 mg/L to less than 1.5 mg/L within130 bed volume(BV)by using 1.5 g La-Fe@PTA.Furthermore,the adsorbent still had good adsorption capacity after regeneration,which confirms the great application potential of La-Fe@PTA as a fluoride ion adsorbent.The mechanism analysis showed that La-Fe@PTA adsorption of fluorine ions is a physicochemical reaction driven by electrostatic attraction and ion exchange.

Weight change and all-cause and cause-specific mortality:A 25-year follow-up study

Background:Whether the dynamic weight change is an independent risk factor for mortality remains controversial.This study aimed to examine the association between weight change and risk of all-cause and cause-specific mortality based on the Linxian Nutrition Intervention Trial(NIT)cohort.Methods:Body weight of 21,028 healthy residents of Linxian,Henan province,aged 40-69 years was measured two times from 1986 to 1991.Outcome events were prospectively collected up to 2016.Weight maintenance group(weight change<2 kg)or stable normal weight group was treated as the reference.Cox proportional hazard model was performed to calculate hazard ratios(HRs)and 95%confidence intervals(95%CIs)to estimate the risk of mortality.Results:A total of 21,028 subjects were included in the final analysis.Compared with the weight maintenance group,subjects with weight loss≥2 kg had an increased risk of death from all-cause(HR_(All-cause)=1.14,95%CI:1.09-1.19,P<0.001),cancer(HR_(Cancer)=1.12,95%CI:1.03-1.21,P=0.009),and heart disease(HR_(Heart diseases)=1.21,95%CI:1.11-1.31,P<0.001),whereas subjects with weight gain≥5 kg had 11%(HR_(Cancer)=0.89,95%CI:0.79-0.99,P=0.033)lower risk of cancer mortality and 23%higher risk of stroke mortality(HR_(Stroke)=1.23,95%CI:1.12-1.34,P<0.001).For the change of weight status,both going from overweight to normal weight and becoming underweight within 5 years could increase the risk of total death(HR_(Overweight to normal)=1.18,95%CI:1.09-1.27;HR_(Becoming underweight)=1.35,95%CI:1.25-1.46)and cancer death(HR_(Overweight to normal)=1.20,95%CI:1.04-1.39;HR_(Becoming underweight)=1.44,95%CI:1.24-1.67),while stable overweight could increase the risk of total death(HR_(Stable overweight)=1.11,95%CI:1.05-1.17)and death from stroke(HR_(Stable overweight)=1.44,95%CI:1.33-1.56).Interaction effects were observed between age and weight change on cancer mortality,as well as between baseline BMI and weight change on all-cause,heart disease,and stroke mortality(all P_(interaction)<0.01).Conclusions:Weight loss was associated with an increased risk of all-cause,cancer,and heart disease mortality,whereas excessive weight gain and stable overweight were associated with a higher risk of stroke mortality.Efforts of weight management should be taken to improve health status.Trial registration:https://classic.clinicaltrials.gov/,NCT00342654.

Can perfluorooctanoic acid be effectively degraded usingβ-PbO_(2)reactive electrochemical membrane?

Aqueous perfluorooctanoic acid(PFOA)elimination has raised significant concerns due to its persistence and bioaccumulation.Althoughβ-PbO_(2)plate anodes have shown efficient mineralization of PFOA,it remains unclear whether PFOA can be effectively degraded usingβ-PbO_(2)reactive electrochemical membrane(REM).Herein,we assessed the performance of Ti/SnO_(2)-Sb/La-PbO_(2)REM for PFOA removal and proposed a possible degradation mechanism.At a current density of 10 mA/cm2and a membrane flux of 8500(liters per square meter per hour,LMH),the degradation efficiency of 10 mg/L PFOA was merely8.8%,whereas the degradation efficiency of 0.1 mg/L PFOA increased to 96.6%.Although the porous structure of theβ-PbO_(2)REM provided numerous electroactive sites for PFOA,the generated oxygen bubbles in the pores could block the pore channels and adsorb PFOA molecules.These hindered the protonation process and significantly impeded the degradation of high-concentration PFOA.Quenching experiments indicated that·OH played dominant role in PFOA degradation.The electrical energy per order to remove 0.1 mg/L PFOA was merely 0.74 Wh/L,which was almost an order of magnitude lower than that of other anode materials.This study presents fresh opportunities for the electrochemical degradation of low-concentration PFOA usingβ-PbO_(2)REM.

Review on recent progress in on-line monitoring technology for atmospheric pollution source emissions in China

Emissions from mobile sources and stationary sources contribute to atmospheric pollution in China,and its components,which include ultrafine particles(UFPs),volatile organic compounds(VOCs),and other reactive gases,such as NH3and NOx,are the most harmful to human health.China has released various regulations and standards to address pollution from mobile and stationary sources.Thus,it is urgent to develop online monitoring technology for atmospheric pollution source emissions.This study provides an overview of the main progress in mobile and stationary source monitoring technology in China and describes the comprehensive application of some typical instruments in vital areas in recent years.These instruments have been applied to monitor emissions from motor vehicles,ships,airports,the chemical industry,and electric power generation.Not only has the level of atmospheric environment monitoring technology and equipment been improving,but relevant regulations and standards have also been constantly updated.Meanwhile,the developed instruments can provide scientific assistance for the successful implementation of regulations.According to the potential problem areas in atmospheric pollution in China,some research hotspots and future trends of atmospheric online monitoring technology are summarized.Furthermore,more advanced atmospheric online monitoring technology will contribute to a comprehensive understanding of atmospheric pollution and improve environmental monitoring capacity.

Developing high-quality g-C_(3)N_(4) film electrode for the photoelectrocatalytic degradation of methylene blue in water

Developing a high-quality photoelectrode for photoelectrochemical applications is still an ongoing challenge. In this study, we prepared the g-C_(3)N_(4) film on the indium tin oxide(ITO) glass through conventional coating, liquid-based growth, in-situ calcination, and vapor deposition methods, respectively. These electrodes were characterized and used as photoanodes to degrade methylene blue(MB) in water. Among these methods, the in-situ calcination method was most appropriate for preparing the continuous and organized g-C_(3)N_(4) film electrodes with uniform g-C_(3)N_(4) coverage and strong adhesion to the ITO substrate.It also had the highest activity in the photocatalytic(PC), electrochemical(EC), and photoelectrocatalytic(PEC) degradation processes of MB. In the PEC reaction, at an applied potential of 1.0 V and a light intensity of 0.96 W/cm^(2), the removal rate of MB was 62.5%, which was much higher than those in the PC and EC reactions. The high degradation rate was due to the synergistic effect of PEC degradation, wherein the PC and EC reactions promote and optimize each other. In the PC reaction, MB was degraded by-CH_(3) elimination, while the EC degradation pathway mainly included the conversion of sulfhydryl into sulfoxide and the opening of the central aromatic ring. Both methyl loss and aromatic ring opening occurred in the PEC reaction. Moreover, some monocyclic compounds were formed, and MB showed more complete degradation in the PEC reaction.

改性粉煤灰对沙土物理特性改良效果研究

针对内蒙古锡盟地区粉煤灰堆存量大、利用率低以及当地土壤荒漠化严重等系列问题,本工作提出利用粉煤灰改良荒漠土壤的新思路。首先用硫酸对惰性的粉煤灰进行表面活化改性,采用SEM和XRD等分析测试手段研究粉煤灰结构变化,采用XPS和TG分析方法分别对粉煤灰表面羟基定性分析和定量计算,以期明晰粉煤灰表面羟基化效果;其次,使用改性前后粉煤灰分别作为土壤加固剂,以现场采集沙土为加固对象,研究改性粉煤灰对砂土稳定性的影响。结果表明,使用1.5 mol/L的硫酸溶液预改性后,颗粒表面羟基数量较原始粉煤灰增大4倍。按质量比1:9将酸改性前后的粉煤灰分别与沙土复配并静置15天后对复配土的力学强度进行测定,结果显示原始沙土间的黏聚力为0.29 kPa,改性前粉煤灰-沙土复配土的黏聚力为0.88kPa,而改性后粉煤灰-沙土复配土的黏聚力提高到3.51 kPa。

Adsorptive removal of antibiotics from water using magneticion exchange resin

The occurrence of antibiotics in the environment has recently raised serious concern regarding their potential threat to aquatic ecosystem and human health. In this study, the magnetic ion exchange（MIEX） resin was applied for removing three commonly-used antibiotics, sulfamethoxazole（SMX）, tetracycline（TCN） and amoxicillin（AMX） from water.The results of batch experiments show that the maximum adsorption capacities on the MIEX resin for SMX, TCN and AMX were 789.32, 443.18 and 155.15 μg/m L at 25°C,respectively, which were 2–7 times that for the powdered activated carbon. The adsorption kinetics of antibiotics on the MIEX resin could be simulated by the pseudo-second-order model（R^2= 0.99）, and the adsorption isotherm data were well described by the Langmuir model（R^2= 0.97）. Solution p H exhibited a remarkable impact on the adsorption process and the absorbed concentrations of the tested antibiotics were obtained around the neutral p H.The MIEX resin could be easily regenerated by 2 mol/L Na Cl solution and maintained high adsorption removal for the tested antibiotics after regeneration. Anion exchange mechanism mainly controlled the adsorption of antibiotic and the formation of hydrogen binding between the antibiotic and resin can also result in the increase of adsorption capacity. The high adsorption capacity, fast adsorption rate and prominent reusability make the MIEX resin a potential adsorbent in the application for removing antibiotics from water.

Catalytic wet air oxidation of phenol with functionalized carbon materials as catalysts:Reaction mechanism and pathway

The development of highly active carbon material catalysts in catalytic wet air oxidation（CWAO）has attracted a great deal of attention. In this study different carbon material catalysts（multi-walled carbon nanotubes,carbon fibers and graphite） were developed to enhance the CWAO of phenol in aqueous solution. The functionalized carbon materials exhibited excellent catalytic activity in the CWAO of phenol. After 60 min reaction,the removal of phenol was nearly100% over the functionalized multi-walled carbon,while it was only 14% over the purified multi-walled carbon under the same reaction conditions. Carboxylic acid groups introduced on the surface of the functionalized carbon materials play an important role in the catalytic activity in CWAO. They can promote the production of free radicals,which act as strong oxidants in CWAO. Based on the analysis of the intermediates produced in the CWAO reactions,a new reaction pathway for the CWAO of phenol was proposed in this study. There are some differences between the proposed reaction pathway and that reported in the literature. First,maleic acid is transformed directly into malonic acid. Second,acetic acid is oxidized into an unknown intermediate,which is then oxidized into CO2 and H2O. Finally,formic acid and oxalic acid can mutually interconvert when conditions are favorable.

Treatment of coking wastewater using oxic-anoxic-oxic process followed by coagulation and ozonation

An oxic-anoxic-oxic(O-A-O)system followed by coagulation and ozonation processes was used to study the treatment of coking wastewater.In the O-A-O process,the removals of NH4+-N,total nitrogen and COD were 91.5-93.3%,91.3-92.6%and 89.1-93.8%,respectively when employing hydraulic residence times of 60 h for the biochemical system.High removal of NH4+-N was obtained due to the placement of an aerobic tank in front of A-O system which can mitigate the inhibitory effect of toxic compounds in coking wastewater on nitrifying bacteria.Addition of methanol into the anoxic reactor greatly increased the removal of total nitrogen,indicating that denitrifiers can hardly use organic compounds in coking wastewater as carbon source for denitrification.COD values of the effluent from the O-A-O system were still higher than 260 mg/L even with a prolonged time of 160 h mainly due to the high refractory properties of residual compounds in the effluent.The subsequent coagulation and ozonation processes resulted in the COD removal of 91.5%-93.3%and reduced the relative abundance of large molecular weight(MW)organics(>1 kDa)from 55.8%to 20.93%with the ozone,PAC and PAM dosages of 100,150 and 4 mg/L respectively.Under these conditions,the COD value and concentration of polycyclic aromatic hydrocarbons in the final effluent were less than 80 and 0.05 mg/L,respectively,which meet the requirement of the Chinese emission standard.These results indicate that the combined technology of O-A-O process,coagulation and ozonation is a reliable way for the treatment of coking wastewater.

Catalytic ozonation of organic compounds in water over the catalyst of RuO2/ZrO2-CeO2

This research investigates the performances of RuO2/ZrO2-CeO2 in catalytic ozonation for water treatment. The results show that RuO2/ZrO2-CeO2 was active for the catalytic ozonation of oxalic acid and possessed higher stability than RuO2/Al2O3 and Ru/AC. In the catalytic ozonation of dimethyl phthalate （DMP）, RuO2/ZrO2-CeO2 did not enhance the DMP degradation rate but significantly improved the total organic carbon （TOC） removal rate. The TOC removal in catalytic ozonation was 56% more than that in noncatalytic ozonation. However this does not mean the catalyst was very active because the contribution of catalysis to the overall TOC removal was only 30%. The adsorption of the intermediates on RuO2/ZrO2-CeO2 played an important role on the overall TOC removal while the adsorption of DMP on it was negligible. This adsorption difference was due to their different ozonation rates. In the catalytic ozonation of disinfection byproduct precursors with RuO2/ZrO2-CeO2, the reductions of the haloacetic acid and trihalomethane formation potentials （HAAFPs and THMFPs） for the natural water samples were 38%–57% and 50%–64%, respectively. The catalyst significantly promoted the reduction of HAAFPs but insignificantly improved the reduction of THMFPs as ozone reacts fast with the THMs precursors. These results illustrate the good promise of RuO2/ZrO2-CeO2 in catalytic ozonation for water treatment.

Enhanced triallyl isocyanurate(TAIC)degradation through application of an 03/UV process:Performance optimization and degradation pathways

Triallyl isocyanurate(TAIC,C12H15N3O3)has featured in wastewater treatment as a refractory organic compound due to the significant production capability and negative environmental impact.TAIC degradation was enhanced when an ozone(O3)/ultraviolet(UV)process was applied compared with the application of an independent O3 process.Although 99%of TAIC could be degraded in 5 min during both processes,the O3/UV process had a 70%mineralization rate that was much higher than that of the independent O3 process(9%)in 30 min.Four possible degradation pathways were proposed based on the organic compounds of intermediate products identified during TAIC degradation through the application of independent 03 and O3/UV processes.pH impacted both the direct and indirect oxidation processes.Acidic and alkaline conditions preferred direct and indirect reactions respectively,with a pH of 9 achieving maximum Total Organic Carbon(TOC)removal.Both CO32-and HCO3-decreased TOC removal,however only CO32-negatively impacted TAIC degradation.Effects of Cl-as a radical scavenger became more marked only at high concentrations(over 500 mg/L Cl-).Particulate and suspended matter could hinder the transmission of ultraviolet light and reduce the production of HO·accordingly.