In this paper, fouling mechanisms of mullite ceramic membranes for treatment of oily wastewaters in hybrid coagulation-microfiltration （MF） process presented. Hermia＇s models for cross flow filtration were used to ...In this paper, fouling mechanisms of mullite ceramic membranes for treatment of oily wastewaters in hybrid coagulation-microfiltration （MF） process presented. Hermia＇s models for cross flow filtration were used to investigate the fouling mechanisms of membranes with various coagulating chemicals concentrations. Four coagu lating chemicals （FeC12.4H20, FeSO4.7H20, A1C13-6H20 and A12（SO4）3.18H20） plus Ca（OH）2 of the same concen- tration were evaluated in the coagulation-MF hybrid process with different concentrations （0, 50 mg.L-1, 100 mg.L-1 and 200 mg.L-1）. To determine whether the data agree with models under consideration, the coefficients of determination （R2） of all models were compared with one another. In addition, average prediction errors of models were calculated. The results showed that cake filtration model can be applied for prediction of permeation flux decline for MF and coagulation-（MF） hybrid process with the best average error equal to 0.09%. Results indicated that pore blocking behavior changes as time of filtration increases, and one model cannot predict pore blocking behavior in all filtration time with very good precision.展开更多
Global changes such as atmospheric CO_(2)enrichment often facilitate exotic plant invasions and alter soil arbuscular mycorrhizal fungi(AMF)community.However,it is still unclear whether the effects of CO_(2)enrichment...Global changes such as atmospheric CO_(2)enrichment often facilitate exotic plant invasions and alter soil arbuscular mycorrhizal fungi(AMF)community.However,it is still unclear whether the effects of CO_(2)enrichment on exotic plant invasions are associated with its effects on root-AMF symbiosis of invasive and native plants.To address this issue,the annual invasive plant Xanthium strumarium and two phylogenetically related annual natives were compared under ambient and elevated CO_(2)concentrations for three consecutive years.Atmospheric CO_(2)enrichment increased AMF colonization rates for the species only in few cases,and the invader did not benefit more from CO_(2)enrichment in terms of AMF colonization.Under ambient CO_(2)concentration,however,the invader had a higher AMF colonization rate than the natives in the first year of the study,which disappeared in the second and third year of the study due to the increase of AMF colonization rates in the natives but not in the invader.The influences of species,CO_(2)concentrations and planting year on AMF colonization were associated with their effects on both soil nutrient and AMF community,and the former may be more important as it also influenced the latter.Our results indicate that the invader could more quickly form symbiosis with soil AMF,contributing to adaptation and occupation of new habitats,and that it is necessary to consider the roles of AMF and the effects of time when determining the effects of global changes such as atmospheric CO_(2)enrichment on exotic plant invasions.展开更多
文摘In this paper, fouling mechanisms of mullite ceramic membranes for treatment of oily wastewaters in hybrid coagulation-microfiltration （MF） process presented. Hermia＇s models for cross flow filtration were used to investigate the fouling mechanisms of membranes with various coagulating chemicals concentrations. Four coagu lating chemicals （FeC12.4H20, FeSO4.7H20, A1C13-6H20 and A12（SO4）3.18H20） plus Ca（OH）2 of the same concen- tration were evaluated in the coagulation-MF hybrid process with different concentrations （0, 50 mg.L-1, 100 mg.L-1 and 200 mg.L-1）. To determine whether the data agree with models under consideration, the coefficients of determination （R2） of all models were compared with one another. In addition, average prediction errors of models were calculated. The results showed that cake filtration model can be applied for prediction of permeation flux decline for MF and coagulation-（MF） hybrid process with the best average error equal to 0.09%. Results indicated that pore blocking behavior changes as time of filtration increases, and one model cannot predict pore blocking behavior in all filtration time with very good precision.
基金supported by the National Natural Science Foundation of China(31971557,31670545 and 31470575)the National Key R&D Program of China(2017YFC1200101).
文摘Global changes such as atmospheric CO_(2)enrichment often facilitate exotic plant invasions and alter soil arbuscular mycorrhizal fungi(AMF)community.However,it is still unclear whether the effects of CO_(2)enrichment on exotic plant invasions are associated with its effects on root-AMF symbiosis of invasive and native plants.To address this issue,the annual invasive plant Xanthium strumarium and two phylogenetically related annual natives were compared under ambient and elevated CO_(2)concentrations for three consecutive years.Atmospheric CO_(2)enrichment increased AMF colonization rates for the species only in few cases,and the invader did not benefit more from CO_(2)enrichment in terms of AMF colonization.Under ambient CO_(2)concentration,however,the invader had a higher AMF colonization rate than the natives in the first year of the study,which disappeared in the second and third year of the study due to the increase of AMF colonization rates in the natives but not in the invader.The influences of species,CO_(2)concentrations and planting year on AMF colonization were associated with their effects on both soil nutrient and AMF community,and the former may be more important as it also influenced the latter.Our results indicate that the invader could more quickly form symbiosis with soil AMF,contributing to adaptation and occupation of new habitats,and that it is necessary to consider the roles of AMF and the effects of time when determining the effects of global changes such as atmospheric CO_(2)enrichment on exotic plant invasions.
