The removal of antibiotic pollutants remaining in the environmental media has been a big challenge nowadays.Herein,we report a facile and green approach to fabricate an eco-friendly composite membrane without addition...The removal of antibiotic pollutants remaining in the environmental media has been a big challenge nowadays.Herein,we report a facile and green approach to fabricate an eco-friendly composite membrane without addition of any toxic polymers or chemical cross-linking agents to effectively remove the tetracycline hydrochloride in Water.Firstly,the sulfated cellulose nanocrystalline(CNC) was obtained via hydrolysis of sulfuric acid by using microcrystalline cellulose(MCC) as raw material under ultrasonic condition.The as-prepared CNC has a nanowhisker dimension with 200.2 ± 110.2 nm in length,15.7 ± 9.3 nm in width,and 7.2 ± 3.1 nm in height.The obtained CNC is cellulose type I as determined by X-ray diffraction(XRD),while its crystallinity index(Crl) can reach 82.3%.Then,the composite membrane derived from the obtained CNC and commercial mixed cellulose ester(MCE)membrane was facilely prepared through vacuum dewatering process,which is applied to remove tetracycline hydrochloride(Th) in solution.The results showed that the removal efficiency of Th through the neat MCE was only28 ± 4%,while it could be improved to 58 ± 5% and 89 11%,respectively,by filtering through composite membranes with different contents of CNC deposition.Such effect is derived from the combine factors based on both steric hindrance(sieving) and electrostatic interaction(Donnan) effect of the composite membranes.The development of related CNC materials and composite fabrication processes is in favor of cost-effective and "green"polymer composites for the remediation of increasing antibiotic pollution and the purification of contaminated water nowadays.展开更多
Chitosan/Cellulose (CTS/CL) composite membranes were prepared by cross-linking reaction with 3-methy- lglutaric anhydride (3MGA). The cross-linked membranes with CTS/CL were obtained at different CTS con- tents in var...Chitosan/Cellulose (CTS/CL) composite membranes were prepared by cross-linking reaction with 3-methy- lglutaric anhydride (3MGA). The cross-linked membranes with CTS/CL were obtained at different CTS con- tents in variations from 50 to 100 wt%, and these membranes were applied in the dehydration of ethanol/wa- ter mixtures. Especially, it was observed that in the case of a composite membrane containing chitosan 80% (CTS/CL-80/20) showed a performance with a separation factor of α = 17.1 and a total permeation flux of J = 326 g/(m2h). It was observed that the total permeation flux decreased when the cross-linking increased and the increase in the ethanol content in the feed solution showed an increase in the separation factor. The CTS/ CL-80/20 showed excellent performance with good mechanical strength and dehydration performance in the ethanol/water mixture separation.展开更多
Freshwater scarcity is a critical challenge that human society has to face in the 21st century.Desalination of seawater by reverse osmosis(RO)membranes was regarded as the most promising technology to overcome the cha...Freshwater scarcity is a critical challenge that human society has to face in the 21st century.Desalination of seawater by reverse osmosis(RO)membranes was regarded as the most promising technology to overcome the challenge given that plenty of potential fresh water resources in oceans.However,the requirements for high desalination efficiency in terms of permeation flux and rejection rate become the bottle-neck which needs to be broken down by developing novel RO membranes with new structure and composition.Cellulose acetate RO membranes exhibited long durability,chlorine resistance,and outstanding desalination efficiency that are worthy of being recalled to address the current shortcomings brought by polyamide RO membranes.In terms of performance enhancement,it is also important to use new ideas and to develop new strategies to modify cellulose acetate RO membranes in response to those complex challenges.Therefore,we focused on the state of the art cellulose acetate RO membranes and discussed the strategies on membrane structural manipulation adjusted by either phase separation or additives,which offered anti-fouling,anti-bacterial,anti-chlorine,durability,and thermo-mechanical properties to the modified membranes associated with the desalination performance,i.e.,permeation flux and rejection rate.The relationship between membrane structure and desalination efficiency was investigated and established to guide the development of cellulose acetate RO membranes for desalination.展开更多
以提取的玉米秸秆纤维素为原料制备羧甲基纤维素,在其中添加甘油和不同浓度的AgNO_(3)后制得改性复合膜。通过扫描电子显微镜(SEM)、X射线衍射(XRD)、X射线光电子能谱(XPS)、热重分析(TGA)、傅里叶红外光谱(FT-IR)对改性复合膜进行结构...以提取的玉米秸秆纤维素为原料制备羧甲基纤维素,在其中添加甘油和不同浓度的AgNO_(3)后制得改性复合膜。通过扫描电子显微镜(SEM)、X射线衍射(XRD)、X射线光电子能谱(XPS)、热重分析(TGA)、傅里叶红外光谱(FT-IR)对改性复合膜进行结构和形貌表征,结果表明:改性复合膜质地均匀,部分Ag^(+)以单质银的形式与膜中的成分相互作用,膜热稳定性良好,满足保鲜材料要求。改性复合膜对大肠杆菌(E.coli)及白色葡萄球菌(S.albus)的抑制情况进一步证明了其中存在单质Ag粒子,对S.albus的抑制能力更强。用改性复合膜包裹蓝莓,存储10 d后的失重率低于7%、颜色几乎没有变化;可溶性固形物损失小于3%、可滴定酸下降不明显,当加入1 mL 0.01 mol/LAgNO_(3)时,改性复合膜的保鲜性能相对较好。展开更多
基金financially supported by the Tianjin Science and Technology Committee Major Project Program(18ZXJMTG00070)
文摘The removal of antibiotic pollutants remaining in the environmental media has been a big challenge nowadays.Herein,we report a facile and green approach to fabricate an eco-friendly composite membrane without addition of any toxic polymers or chemical cross-linking agents to effectively remove the tetracycline hydrochloride in Water.Firstly,the sulfated cellulose nanocrystalline(CNC) was obtained via hydrolysis of sulfuric acid by using microcrystalline cellulose(MCC) as raw material under ultrasonic condition.The as-prepared CNC has a nanowhisker dimension with 200.2 ± 110.2 nm in length,15.7 ± 9.3 nm in width,and 7.2 ± 3.1 nm in height.The obtained CNC is cellulose type I as determined by X-ray diffraction(XRD),while its crystallinity index(Crl) can reach 82.3%.Then,the composite membrane derived from the obtained CNC and commercial mixed cellulose ester(MCE)membrane was facilely prepared through vacuum dewatering process,which is applied to remove tetracycline hydrochloride(Th) in solution.The results showed that the removal efficiency of Th through the neat MCE was only28 ± 4%,while it could be improved to 58 ± 5% and 89 11%,respectively,by filtering through composite membranes with different contents of CNC deposition.Such effect is derived from the combine factors based on both steric hindrance(sieving) and electrostatic interaction(Donnan) effect of the composite membranes.The development of related CNC materials and composite fabrication processes is in favor of cost-effective and "green"polymer composites for the remediation of increasing antibiotic pollution and the purification of contaminated water nowadays.
文摘Chitosan/Cellulose (CTS/CL) composite membranes were prepared by cross-linking reaction with 3-methy- lglutaric anhydride (3MGA). The cross-linked membranes with CTS/CL were obtained at different CTS con- tents in variations from 50 to 100 wt%, and these membranes were applied in the dehydration of ethanol/wa- ter mixtures. Especially, it was observed that in the case of a composite membrane containing chitosan 80% (CTS/CL-80/20) showed a performance with a separation factor of α = 17.1 and a total permeation flux of J = 326 g/(m2h). It was observed that the total permeation flux decreased when the cross-linking increased and the increase in the ethanol content in the feed solution showed an increase in the separation factor. The CTS/ CL-80/20 showed excellent performance with good mechanical strength and dehydration performance in the ethanol/water mixture separation.
基金the National Natural Science Foundation of China(51673011).
文摘Freshwater scarcity is a critical challenge that human society has to face in the 21st century.Desalination of seawater by reverse osmosis(RO)membranes was regarded as the most promising technology to overcome the challenge given that plenty of potential fresh water resources in oceans.However,the requirements for high desalination efficiency in terms of permeation flux and rejection rate become the bottle-neck which needs to be broken down by developing novel RO membranes with new structure and composition.Cellulose acetate RO membranes exhibited long durability,chlorine resistance,and outstanding desalination efficiency that are worthy of being recalled to address the current shortcomings brought by polyamide RO membranes.In terms of performance enhancement,it is also important to use new ideas and to develop new strategies to modify cellulose acetate RO membranes in response to those complex challenges.Therefore,we focused on the state of the art cellulose acetate RO membranes and discussed the strategies on membrane structural manipulation adjusted by either phase separation or additives,which offered anti-fouling,anti-bacterial,anti-chlorine,durability,and thermo-mechanical properties to the modified membranes associated with the desalination performance,i.e.,permeation flux and rejection rate.The relationship between membrane structure and desalination efficiency was investigated and established to guide the development of cellulose acetate RO membranes for desalination.
文摘以提取的玉米秸秆纤维素为原料制备羧甲基纤维素,在其中添加甘油和不同浓度的AgNO_(3)后制得改性复合膜。通过扫描电子显微镜(SEM)、X射线衍射(XRD)、X射线光电子能谱(XPS)、热重分析(TGA)、傅里叶红外光谱(FT-IR)对改性复合膜进行结构和形貌表征,结果表明:改性复合膜质地均匀,部分Ag^(+)以单质银的形式与膜中的成分相互作用,膜热稳定性良好,满足保鲜材料要求。改性复合膜对大肠杆菌(E.coli)及白色葡萄球菌(S.albus)的抑制情况进一步证明了其中存在单质Ag粒子,对S.albus的抑制能力更强。用改性复合膜包裹蓝莓,存储10 d后的失重率低于7%、颜色几乎没有变化;可溶性固形物损失小于3%、可滴定酸下降不明显,当加入1 mL 0.01 mol/LAgNO_(3)时,改性复合膜的保鲜性能相对较好。
