Expanded graphite （r-;G） shows higher adsorption capacity for oils than for dyes. To illustrate the different adsorption mechanism of EG for these pollutants, adsorption capacities of dyes and oil on EG were firs...Expanded graphite （r-;G） shows higher adsorption capacity for oils than for dyes. To illustrate the different adsorption mechanism of EG for these pollutants, adsorption capacities of dyes and oil on EG were firstly studied. And then stepwise adsorption for oils was carried out with EG which has been saturated firstly by dyes, the difference between adsorbance of oil on EG was checked with deviation analysis. Scanning electronic microscopy （SEM） analysis was used to show structure difference of EG adsorbed different adsorbates. These used adsorbates were SD300 oil, basic fuchsine, Auramine lake yellow O and acid brilliant red 3B. The adsorption isotherm of dyes on EG is type 11 or type 1, and their equilibrium adsorbances are less than 1.0 g/g. While, adsorbance for SD300 oil can reach 104.5 g/g. Deviation analysis for stepwise adsorbances of oil shows no statistical significance. EG saturated firstly by dyes, still has an average adsorption capacity of 35 g/g for SD300 oil, and it does not change with the initial dyes concentration. SEM photos illustrate the adsorption of oil on EG is mainly filling, In the adsorption of dyes, there is severe breakage of the V-type pore and shrinkage of the particle. Kinetic difference is analyzed also.展开更多
Polymeric membranes with the integration of various functional performances toward wastewater treatment are urgently required.However,most of the polymeric membranes only exhibit a single function of highly efficientl...Polymeric membranes with the integration of various functional performances toward wastewater treatment are urgently required.However,most of the polymeric membranes only exhibit a single function of highly efficiently removing one kind of pollutants.In this work,a biomimetic modification method was introduced to tailor the chemical and topological structure of the porous poly(vinylidene fluoride)(PVDF)fibers prepared by electrospinning.The polydopamine(PDA)nanoparticles were homogeneously introduced onto the surface of PVDF porous fibers via precisely tailoring the concentration of dopamine,which endowed the fibers with more polar groups and bigger roughness but did not destroy the crystalline structures.The fibrous membranes exhibited switchable superhydrophilicity and superlipophilicity characteristics,excellent adsorption abilities toward organic dyes,heavy metal ions and oils.The highest adsorption capacities achieved 917.4 mg/g toward methylene blue(MB),42.6 mg/g toward Cr(VI)and 74.6 g/g toward silicone oil,respectively.Specifically,the membrane could rapidly remove the trace MB when water flowed through the membrane.The membrane also exhibited excellent sterilization performances,and the bacterial eliminating rate achieved 99.9%for the E.coli and S.aureus.The excellent light-to-heat conversion ability endowed the membrane with the selfheating ability,furtherly intensifying the wastewater treatment efficiency.This work confirms that the PDA nanoparticles-decorated PVDF porous fibers might be the new generation adsorbents used in wastewater treatment.展开更多
文摘Expanded graphite （r-;G） shows higher adsorption capacity for oils than for dyes. To illustrate the different adsorption mechanism of EG for these pollutants, adsorption capacities of dyes and oil on EG were firstly studied. And then stepwise adsorption for oils was carried out with EG which has been saturated firstly by dyes, the difference between adsorbance of oil on EG was checked with deviation analysis. Scanning electronic microscopy （SEM） analysis was used to show structure difference of EG adsorbed different adsorbates. These used adsorbates were SD300 oil, basic fuchsine, Auramine lake yellow O and acid brilliant red 3B. The adsorption isotherm of dyes on EG is type 11 or type 1, and their equilibrium adsorbances are less than 1.0 g/g. While, adsorbance for SD300 oil can reach 104.5 g/g. Deviation analysis for stepwise adsorbances of oil shows no statistical significance. EG saturated firstly by dyes, still has an average adsorption capacity of 35 g/g for SD300 oil, and it does not change with the initial dyes concentration. SEM photos illustrate the adsorption of oil on EG is mainly filling, In the adsorption of dyes, there is severe breakage of the V-type pore and shrinkage of the particle. Kinetic difference is analyzed also.
基金financially supported by the National Natural Science Foundation of China(No.51473137)the Youth Science and Technology Innovation Team of Sichuan Province of Functional Polymer Composites(No.2021JDTD0009)the Sichuan Science and Technology Program(No.2020YFG0099)。
文摘Polymeric membranes with the integration of various functional performances toward wastewater treatment are urgently required.However,most of the polymeric membranes only exhibit a single function of highly efficiently removing one kind of pollutants.In this work,a biomimetic modification method was introduced to tailor the chemical and topological structure of the porous poly(vinylidene fluoride)(PVDF)fibers prepared by electrospinning.The polydopamine(PDA)nanoparticles were homogeneously introduced onto the surface of PVDF porous fibers via precisely tailoring the concentration of dopamine,which endowed the fibers with more polar groups and bigger roughness but did not destroy the crystalline structures.The fibrous membranes exhibited switchable superhydrophilicity and superlipophilicity characteristics,excellent adsorption abilities toward organic dyes,heavy metal ions and oils.The highest adsorption capacities achieved 917.4 mg/g toward methylene blue(MB),42.6 mg/g toward Cr(VI)and 74.6 g/g toward silicone oil,respectively.Specifically,the membrane could rapidly remove the trace MB when water flowed through the membrane.The membrane also exhibited excellent sterilization performances,and the bacterial eliminating rate achieved 99.9%for the E.coli and S.aureus.The excellent light-to-heat conversion ability endowed the membrane with the selfheating ability,furtherly intensifying the wastewater treatment efficiency.This work confirms that the PDA nanoparticles-decorated PVDF porous fibers might be the new generation adsorbents used in wastewater treatment.
