Co-metabolic and biochar-promoted biodegradation of mixed PAHs by highly efficient microbial consortium QY1

Polycyclic aromatic hydrocarbons(PAHs), typical representatives of the persistent organic pollutants(POPs), have become ubiquitous in the environment.In this study, a novel microbial consortium QY1 that performed outstanding PAHs-degrading capacity has been enriched.The degradation characteristics of single and mixed PAHs treated with QY1 were studied, and the effect of biochar on biodegradation of mixed PAHs and the potential of biochar in PAHs-heavy metal combined pollution bioremediation were also investigated.Results showed that, in single substrate system, QY1 degraded 94.5% of 500 mg/L phenanthrene(PHE) and 17.8% of 10 mg/L pyrene(PYR) after 7 days, while in PHE-PYR mixture system, the biodegradation efficiencies of PHE(500 mg/L) and PYR(10 mg/L) reached 94.0%and 96.2%, respectively, since PHE served as co-metabolic substrate to have significantly improved PYR biodegradation.Notably, with the cooperation of biochar, the biodegradations of PHE and PYR were greatly accelerated.Further, biochar could reduce the adverse impact of heavy metals(Cd^(2+), Cu^(2+), Cr_(2)O_(7)^(2-)) on PYR biodegradation remarkably.The sequencing analysis revealed that Methylobacterium, Burkholderia and Stenotrophomonas were the dominant genera of QY1 in almost all treatments, indicating that these genera might play key roles in PAHs biodegradation.Overall, this study provided new insights into the efficient bioremediation of PAHs-contaminated site.

Quorum sensing regulation methods and their effects on biofilm in biological waste treatment systems: A review

Quorum sensing (QS) plays an important role in microbial aggregation control. Recently, the optimization of biological waste treatment systems by QS regulation gained an increasing attention. The effects of QS regulation on treatment performances and biofilm were frequently investigated. To understand the state of art of QS regulation, this review summarizes the methods of QS enhancement and QS inhibition in biological waste treatment systems. Typical QS enhancement methods include adding exogenous QS molecules, adding QS accelerants and cultivating QS bacteria, while typical QS inhibition methods include additions of quorum quenching (QQ) bacteria, QS-degrading enzymes, QS-degrading oxidants, and QS inhibitors. The specific improvements after applying these QS regulation methods in different treatment systems are concluded. In addition, the effects of QS regulation methods on biofilm in biological waste treatment systems are reviewed in terms of biofilm formation, extracellular polymeric substances production, microbial viability, and microbial community. In the end, the knowledge gaps in current researches are analyzed, and the requirements for future study are suggested.

Concentrations of phthalates metabolites in blood and semen and the potential effects on semen concentration and motility among residents of the Pearl River Delta region in China

Exposure to phthalate acid esters(PAEs)has been found to have adverse effects on reproduction of human and animal.However,the effects on the semen quality are controversial.In this study,we have collected paired blood and sperm samples from patients(n=103)at a medical clinic in Guangzhou,China,to determine the concentrations of eight phthalate metabolites∑8m-PAEs).The concentration ranges of P8m-PAEs were 2.7-55 and 0.99-17 ng/mL in blood and semen samples,respectively.MEHP(median,3.6 ng/mL in blood and 0.55 ng/mL in semen)and MnOP(median,3.4 ng/mL in blood and 0.69 ng/mL in semen)were the predominant analytes in both blood and semen samples.However,analytes were not correlated in paired blood and semen.Semen motility was significantly associated to the concentrations of∑8m-PAEs in semen,but it did not associate to the concentrations of PAEs in blood.Multi-linear regression analysis,including concentrations of PAEs in both blood and semen,as well as BMI,occupation,living habits,suggested that exposure to PAEs at current environmental levels had very limited effects on semen quality of population in Guangzhou,China.

Rare earth elements(lanthanum,cerium and erbium)doped black oxygen deficient Bi_(2)O_(3)-Bi_(2)O_(3-x) as novel photocatalysts enhanced photocatalytic performance

Novel black oxygen deficient bismuth oxide(Bi_(2)O_(3)-Bi_(2)O_(3-x))photocatalytic material was successfully prepared by a two zone temperature controlled muffle furnace method.The lanthanum,cerium and erbium ions are successfully doped into Bi_(2)O_(3)-Bi_(2)O_(3-x) with the average contents of 10.77 wt%,7.62 wt%and 8,14 wt%,respectively.The re sults show that a large number of oxygen vacancies exist in Bi_(2)O_(3)-Bi_(2)O_(3-x).La^(3+)Ce^(3+)and Er^(3+)act as electron acceptors to temporarily trap the photo-generated electrons.The XPS spectrum show Bi-O band in Bi_(2)O_(3)-Bi_(2)O_(3-x) and the O 1s peak of Ce/Bi_(2)O_(3)-Bi_(2)O_(3-x) move toward the direction of low binding energy.These phenomena fully prove that the separation of photogenerated electron-hole pairs will be more effectual,so as to reduce the possibility of charge carrier recombination.The radical scavenging experiments and electron spin resonance detections confirm that the conduction band of the original Bi_(2)O_(3)can easily receive photogenerated electrons,while the valence band of the modified Bi_(2)O_(3)-Bi_(2)O_(3-x) tends to accept photogenerated holes and then forms the circulation system.Therefore,Ce/Bi_(2)O_(3)-Bi_(2)O_(3-x) can degrade tetracycline hydrochloride up to 90.15%.This research provides some new insights into developing green and recyclable photocatalysts for the remediation of antibiotic contamination.

Experimental and theoretical insights into copper phthalocyanine-based covalent organic frameworks for highly efficien radioactive iodine capture

Exploring efficient materials for capturing radioactive iodine in nuclear waste is of great significance for the progress of nuclear energy as well as the protection of ecological environment.Covalent organic frameworks(COFs)have emerged as promising adsorbents because of their predesignable and functionalizable skeleton structures.However,it remains a grand challenge to achieve large scale preparation of COFs.In this work,we developed a mild and efficient microwave irradiation method instead of the traditional solvothermal method to prepare copper phthalocyanine-based covalent organic frameworks(Cu_(x)Pc-COFs)within only 15 min.The nitrogen-rich 1,2,4,5-tetracarbonitrilebenzene(TCNB)was selected as the solely organic ligand to construct copper phthalocyanine-based 2D conjugated COFs.The resultant Cu_(x)Pc-COFs exhibited excellent iodine enrichment with 2.99 g/g for volatile iodine and 492.27 mg/g for iodine-cyclohexane solution,respectively,outperforming that of many porous materials.As indicated by spectroscopic analysis and DFT calculations,this impressive adsorption performance can be attributed to the charge transfer arising from nitrogen-rich phthalocyanine structures and electron-richπ-conjugated systems with iodine molecules.Moreover,the strong electrostatic interaction between Cu(Ⅱ)on chelate centers and polyiodide anions(I_(x)^(-))also play an important role in the firmly trapping radioactive iodine.Therefore,this study provides a facile and intelligent approach to implement metal-based COFs for the remediation of toxic radioactive iodine.

垂直交错且具有可控电子结构的NiFeP/MXene电催化剂用于高效析氧反应

具有良好析氧反应(OER)活性的层状双氢氧化物(LDHs)在储能/转化领域得到了广泛的研究.然而,导电性差、易团聚、本征活性低等特点限制了其实际应用.通过改善NiFeLDHs的本征活性和稳定性(如引入杂原子或与其他导电基质结合)以提高全解水性能,受到越来越多的关注.本文通过水热和煅烧磷化两步反应,成功合成了在碳化钛二维薄片上的垂直交错的三元相磷化镍/铁杂化物(NiFeP/MXene).优化后的NiFe P/MXene在电流密度为10 mA cm^(-2)时仅有286 mV的低过电位和较低的塔菲尔斜率35 mV dec^(-1),超过了许多现有的NiFe基催化剂的性能.进一步将NiFeP/MXene应用于碱性电解质中全解水的阳极,仅需要1.61 V的电池电压就能达到10 mA cm^(-2)的电流密度.密度函数理论(DFT)计算结果表明,无论是MXene还是磷化,都能有效调整电催化剂表面的电子结构和密度,提升d带中心的能级,从而实现对OER性能的提升.该研究为设计高性能的OER催化剂提供了新的思路.