Nitrate is a crucial environmental pollutant,and its risk on ecosystem keeps increasing.Photocatalytic conversion of nitrate to ammonia can simultaneously achieve the commercialization of environmental hazards and rec...Nitrate is a crucial environmental pollutant,and its risk on ecosystem keeps increasing.Photocatalytic conversion of nitrate to ammonia can simultaneously achieve the commercialization of environmental hazards and recovery of valuable ammonia,which is green and sustainable for the planet.However,due to the thermodynamic and kinetic energy barriers,photocatalytic nitrate reduction usually involves a higher selectivity of the formation of nitrogen that largely limits the ammonia synthesis activity.In this work,we reported a green and facile synthesis of novel metallic ruthenium particle modified graphitic carbon nitride photocatalysts.Compare with bulk graphitic carbon nitride,the optimal sample had 2.93-fold photocatalytic nitrate reduction to ammonia activity(2.627 mg/h/gcat),and the NH3 selectivity increased from 50.77%to 77.9%.According to the experimental and calculated results,the enhanced photocatalytic performance is attributed to the stronger light absorption,nitrate adsorption,and lower energy barrier for the generation of ammonia.This work may provide a facile way to prepare metal modified photocatalysts to achieve highly efficient nitrate reduction to ammonia.展开更多
Potassium titanate nanostructures were synthesised by hydrothermal treatment of TiO2 (P25) in KOH and H2O2. As-produced powders were characterised by scanning electron microscopy, energy-dispersive X-ray spectroscop...Potassium titanate nanostructures were synthesised by hydrothermal treatment of TiO2 (P25) in KOH and H2O2. As-produced powders were characterised by scanning electron microscopy, energy-dispersive X-ray spectroscopy, transmission electron microscopy, X-ray diffraction, and nitrogen adsorption-desorption methods. Longitudinally-oriented-wire-like structures with a length up to several micrometres and diameters ranging from 10 to 30 nm were obtained. Larger size fibrous nanowires resulting from the hydrotherrnal treatment showed high affinity in adsorbing crystal violet (CV), which was mainly due to their high surface area. The photocatalytic bleaching of CV solution revealed that the wires are photoactive under ultraviolet light irradiation. Macroporous nanowires are considered as effective adsorbents of CV, capable of photocatalvtic degradation, and they can be easily separated from the solution by settling.展开更多
Agriculture is the largest consumer of freshwater.Desalinated seawater is an important alternative water source for sustainable irrigation.However,some issues of the current desalination technology hinder its use for ...Agriculture is the largest consumer of freshwater.Desalinated seawater is an important alternative water source for sustainable irrigation.However,some issues of the current desalination technology hinder its use for agriculture irrigation,including low boron removal and high energy consumption.This study systematically explored the feasibility of employing fertilizer drawn forward osmosis(FDFO)as an alternative to 2nd pass reverse osmosis(RO)by considering the boron removal performance and specific energy consumption(SEC).Different operating conditions were investigated,such as the boron and NaCl concentrations in feed solution(FS),draw solution(DS)concentration,pH,the volume ratio of FS to DS,membrane orientation,flow rate,and operating temperature.The results indicated that a low boron concentration in FS and high DS pH(pH=11.0)decreased the boron solute flux,and led to low final boron concentration in the DS.The other operating conditions had negligible influence on the final DS boron concentration.Also,a lower flow rate and higher specific water flux with certain permeate water volumes were conducive to reducing the SEC of the FDFO process.Overall,our study paves a new way of using FDFO in irrigation,which avoids the phytotoxicity and human health risk of boron.The results show the potential of FDFO as an alternative to 2nd pass RO for irrigation water production.展开更多
Octanoic acid(OA) was selected to represent fatty acids in effluent organic matter(EOM). The effects of feed solution(FS) properties, membrane orientation and initial permeate flux on OA fouling in forward osmo...Octanoic acid(OA) was selected to represent fatty acids in effluent organic matter(EOM). The effects of feed solution(FS) properties, membrane orientation and initial permeate flux on OA fouling in forward osmosis(FO) were investigated. The undissociated OA formed a cake layer quickly and caused the water flux to decline significantly in the initial 0.5 hr at unadjusted p H 3.56; while the fully dissociated OA behaved as an anionic surfactant and promoted the water permeation at an elevated p H of 9.00. Moreover, except at the initial stage, the sudden decline of water flux(meaning the occurrence of severe membrane fouling) occurred in two conditions: 1.0.5 mmol/L Ca2+, active layer facing draw solution(AL-DS) and 1.5 mol/L Na Cl(DS); 2. No Ca2+,active layer-facing FS(AL-FS) and 4 mol/L Na Cl(DS). This demonstrated that cake layer compaction or pore blocking occurred only when enough foulants were absorbed into the membrane surface, and the water permeation was high enough to compact the deposit inside the porous substrate. Furthermore, bovine serum albumin(BSA) was selected as a co-foulant.The water flux of both co-foulants was between the fluxes obtained separately for the two foulants at p H 3.56, and larger than the two values at p H 9.00. This manifested that, at p H 3.56,BSA alleviated the effect of the cake layer caused by OA, and OA enhanced BSA fouling simultaneously; while at p H 9.00, the mutual effects of OA and BSA eased the membrane fouling.展开更多
基金an Australian Research Council(ARC)Future Fellowship(FT160100195)the National Key Research and Development Program of China(2016YFA0602900)+4 种基金the National Natural Science Foundation of China(21673220)Department of Science and Technology of Sichuan Province(2017GZ0051)Jilin Province Science and Technology Development Program(20190201270JC,20180101030JC)Part of the computational time is supported by the High Performance Computing Center of Jilin University and Jilin Province,as well as Network and Computing Center of Changchun Institute of Applied ChemistryDerek Hao acknowledges the technical support of Beijing NBET Technology Co.,Ltd.The authors also acknowledge the Sydney Analytical(USYD),CTWW,MAU,and Chem Lab of UTS for the lab supports.
文摘Nitrate is a crucial environmental pollutant,and its risk on ecosystem keeps increasing.Photocatalytic conversion of nitrate to ammonia can simultaneously achieve the commercialization of environmental hazards and recovery of valuable ammonia,which is green and sustainable for the planet.However,due to the thermodynamic and kinetic energy barriers,photocatalytic nitrate reduction usually involves a higher selectivity of the formation of nitrogen that largely limits the ammonia synthesis activity.In this work,we reported a green and facile synthesis of novel metallic ruthenium particle modified graphitic carbon nitride photocatalysts.Compare with bulk graphitic carbon nitride,the optimal sample had 2.93-fold photocatalytic nitrate reduction to ammonia activity(2.627 mg/h/gcat),and the NH3 selectivity increased from 50.77%to 77.9%.According to the experimental and calculated results,the enhanced photocatalytic performance is attributed to the stronger light absorption,nitrate adsorption,and lower energy barrier for the generation of ammonia.This work may provide a facile way to prepare metal modified photocatalysts to achieve highly efficient nitrate reduction to ammonia.
基金funded by an Australian Research Council-Linkage Project (No. LP0991544)a UTSAustralian Postgraduate Award scholarship
文摘Potassium titanate nanostructures were synthesised by hydrothermal treatment of TiO2 (P25) in KOH and H2O2. As-produced powders were characterised by scanning electron microscopy, energy-dispersive X-ray spectroscopy, transmission electron microscopy, X-ray diffraction, and nitrogen adsorption-desorption methods. Longitudinally-oriented-wire-like structures with a length up to several micrometres and diameters ranging from 10 to 30 nm were obtained. Larger size fibrous nanowires resulting from the hydrotherrnal treatment showed high affinity in adsorbing crystal violet (CV), which was mainly due to their high surface area. The photocatalytic bleaching of CV solution revealed that the wires are photoactive under ultraviolet light irradiation. Macroporous nanowires are considered as effective adsorbents of CV, capable of photocatalvtic degradation, and they can be easily separated from the solution by settling.
基金supported by the National Key Research and Development Program of China(No.2018YFC040800202)the National Natural Science Foundation of China(Grant No.21878177)+1 种基金the Natural Science Foundation of Shandong Province(No.ZR2019LFG003)the grants from the Tai Shan Scholar Foundation(No.ts201511003)。
文摘Agriculture is the largest consumer of freshwater.Desalinated seawater is an important alternative water source for sustainable irrigation.However,some issues of the current desalination technology hinder its use for agriculture irrigation,including low boron removal and high energy consumption.This study systematically explored the feasibility of employing fertilizer drawn forward osmosis(FDFO)as an alternative to 2nd pass reverse osmosis(RO)by considering the boron removal performance and specific energy consumption(SEC).Different operating conditions were investigated,such as the boron and NaCl concentrations in feed solution(FS),draw solution(DS)concentration,pH,the volume ratio of FS to DS,membrane orientation,flow rate,and operating temperature.The results indicated that a low boron concentration in FS and high DS pH(pH=11.0)decreased the boron solute flux,and led to low final boron concentration in the DS.The other operating conditions had negligible influence on the final DS boron concentration.Also,a lower flow rate and higher specific water flux with certain permeate water volumes were conducive to reducing the SEC of the FDFO process.Overall,our study paves a new way of using FDFO in irrigation,which avoids the phytotoxicity and human health risk of boron.The results show the potential of FDFO as an alternative to 2nd pass RO for irrigation water production.
文摘Octanoic acid(OA) was selected to represent fatty acids in effluent organic matter(EOM). The effects of feed solution(FS) properties, membrane orientation and initial permeate flux on OA fouling in forward osmosis(FO) were investigated. The undissociated OA formed a cake layer quickly and caused the water flux to decline significantly in the initial 0.5 hr at unadjusted p H 3.56; while the fully dissociated OA behaved as an anionic surfactant and promoted the water permeation at an elevated p H of 9.00. Moreover, except at the initial stage, the sudden decline of water flux(meaning the occurrence of severe membrane fouling) occurred in two conditions: 1.0.5 mmol/L Ca2+, active layer facing draw solution(AL-DS) and 1.5 mol/L Na Cl(DS); 2. No Ca2+,active layer-facing FS(AL-FS) and 4 mol/L Na Cl(DS). This demonstrated that cake layer compaction or pore blocking occurred only when enough foulants were absorbed into the membrane surface, and the water permeation was high enough to compact the deposit inside the porous substrate. Furthermore, bovine serum albumin(BSA) was selected as a co-foulant.The water flux of both co-foulants was between the fluxes obtained separately for the two foulants at p H 3.56, and larger than the two values at p H 9.00. This manifested that, at p H 3.56,BSA alleviated the effect of the cake layer caused by OA, and OA enhanced BSA fouling simultaneously; while at p H 9.00, the mutual effects of OA and BSA eased the membrane fouling.