In-situ decoration of metallic Bi on BiOBr with exposed(110)facets and surface oxygen vacancy for enhanced solar light photocatalytic degradation of gaseous n-hexane

Photocatalytic degradation of gaseous pollutants on Bi-based semiconductors under solar lightirradiation has attracted significant attention.However,their application in gaseous straight-chainalkane purification is still rare.Here,a series of Bi/BiOBr composites were solvothermally synthe-sized and applied in solar-light-driven photocatalytic degradation of gaseous n-hexane.The charac-terization results revealed that both increasing number of functional groups of alcohol solvent(from methanol and ethylene glycol to glycerol)and solvothermal temperature(from 160 and 180to 200℃)facilitated the in-situ formation of metallic Bi nanospheres on BiOBr nanoplates withexposed(110)facets.Meanwhile,chemical bonding between Bi and BiOBr was observed on theseexposed facets that resulted in the formation of surface oxygen vacancy.Furthermore,the synergis-tic effect of optimum surface oxygen vacancy on exposed(110)facets led to a high visible light re-sponse,narrow band gap,great photocurrent,low recombination rate of the charge carriers,andstrong·O2-and h*formation,all of which resulted in the highest removal efficiency of 97.4%within120 min of 15 ppmv of n-hexane on Bi/BiOBr.Our findings efficiently broaden the application ofBi-based photocatalysis technology in the purification of gaseous straight-chain pollutants emittedby the petrochemical industry.

Impacts of n-alkane concentration on soil bacterial community structure and alkane monooxygenase genes abundance during bioremediation processes

Petroleum hydrocarbons,mainly consisting of n-alkanes and polycyclic aromatic hydrocarbons(PAHs),are considered as priority pollutants and biohazards in the environment,eventually affecting the ecosystem and human health.Though many previous studies have investigated the change of bacterial community and alkane degraders during the degradation of petroleum hydrocarbons,there is still lack of understanding on the impacts of soil alkane contamination level.In the present study,microcosms with different n-alkane contamination(1%,3%and 5%)were set up and our results indicated a complete alkane degradation after 30 and 50 days in 1%-and 3%-alkane treatments,respectively.In all the treatments,alkanes with medium-chain length(C_(11)-C_(14))were preferentially degraded by soil microbes,followed by C27-alkane in 3%and 5%treatments.Alkane contamination level slightly altered soil bacterial community,and the main change was the presence and abundance of dominant alkane degraders.Thermogemmatisporaceae,Gemmataceae and Thermodesulfovibrionaceae were highly related to the degradation of C_(14)-and C_(27)-alkanes in 5%treatment,but linked to alkanes with medium-chain(C11-C18)in 1%treatment and C21-alkane in 3%treatment,respectively.Additionally,we compared the abundance of three alkane-monooxygenase genes,e.g.,alk_A,alk_P and alk_R.The abundance of alk_R gene was highest in soils,and alk_P gene was more correlated with alkane degradation efficiency,especially in 5%treatment.Our results suggested that alkane contamination level showed non-negligible effects on soil bacterial communities to some extents,and particularly shaped alkane degraders and degrading genes significantly.This study provides a better understanding on the response of alkane degraders and bacterial communities to soil alkane concentrations,which affects their biodegradation process.

Synthesis of 2-[^2H]-2-（1-methylalkyl）succinic acids

We describe a specific procedure for the synthesis of deuterium-labelled 2-（1-methylalkyl）succinate established via alkylation of diethyl malonate, Krapcho decarboxylation reaction with D20 and hydrolysis reaction. Two novel compounds, 2-[^2H]-2-ethylsuccinic acid and 2-[^2H]-2-（1-methylhep- tyl）succinic acid were prepared via this synthetic route and characterized by mass spectrometry and ^1H NMR. The results showed that the 2-（1-methylalkyl）succinic acids were deuterated at the β-position, which is considered as an important reaction centre in the anaerobic degradation of n-alkanes.