Drinking water treatment sludge,characterized as accumulated suspended solids and organic and inorganic matter,is produced in large quantities during the coagulation process.The proper disposal,regeneration or reuse o...Drinking water treatment sludge,characterized as accumulated suspended solids and organic and inorganic matter,is produced in large quantities during the coagulation process.The proper disposal,regeneration or reuse of sludge is,therefore,a significant environmental issue.Reused sludge at low temperatures is an alternative method to enhance traditional coagulation efficiency.In the present study,the recycling mass of mixed sludge and properties of raw water （such as pH and turbidity） were systematically investigated to optimize coagulation efficiency.We determined that the appropriate dosage of mixed sludge was 60 mL/L,effective initial turbidity ranges were below 45.0 NTU,and optimal pH for DOMs and turbidity removal was 6.5-7.0 and 8.0,respectively.Furthermore,by comparing the flocs characteristics with and without recycling sludge,we found that floc structures with sludge were more irregular with average size growth to 64.7 μm from 48.1 μm.Recycling sludge was a feasible and successful method for enhancing pollutants removal,and the more irregular flocs structure after recycling might be caused by breakage of reused flocs and incorporation of powdered activated carbon into larger flocs structure.Applied during the coagulation process,recycling sludge could be significant for the treatment of low temperature and micro-polluted source water.展开更多
导电水凝胶作为可穿戴式传感器满足了机械灵活性和智能感应的基本要求.然而,它们往往遇到一些问题,如良好的机械性能和高导电性之间的不相容性、较差的抗菌能力和难以回收.在此,我们通过简单的冻融方法开发了高导电性物理交联的聚乙烯醇...导电水凝胶作为可穿戴式传感器满足了机械灵活性和智能感应的基本要求.然而,它们往往遇到一些问题,如良好的机械性能和高导电性之间的不相容性、较差的抗菌能力和难以回收.在此,我们通过简单的冻融方法开发了高导电性物理交联的聚乙烯醇/壳聚糖-植酸(PVA/CS-PA)水凝胶.PA与CS和PVA基质之间的氢键和静电作用不仅赋予了水凝胶适宜的机械性能和良好的延展性,而且还使其具备有意义的可回收特性.此外,由于PA分子的离子传导性和抗菌能力,该水凝胶表现出卓越的导电性(~0.125 S cm^(-1))和抗菌活性.这些特殊的性能使基于该水凝胶的可穿戴传感器表现出应变敏感的特性(在200%-420%的应变下,应变系数为7.21),可以监测人体的各种活动.此外,PVA/CSPA溶胶墨水可以在冰浴环境下转变为凝胶状态,这将满足柔性电路的需要,并使可穿戴式传感器更加便携.展开更多
Urban mining is essential for continued natural resource extraction. The recovery of rare and precious metals （RPMs） from urban mines has attracted increasing attention from both academic and industrial sectors, bec...Urban mining is essential for continued natural resource extraction. The recovery of rare and precious metals （RPMs） from urban mines has attracted increasing attention from both academic and industrial sectors, because of the broad application and high price of RPMs, and their low content in natural ores. This study summarizes the distribution characteristics of various RPMs in urban mines, and the advantages and shortcomings of various technologies for RPM recovery from urban mines, including both conventional （pyrometallurgical, hydrometallurgical, and biometallurgical processing）, and emerging （electrochemical, supereritieal fluid, mechanochemical, and ionic liquids processing） technologies. Mechanical/physical technologies are commonly employed to separate RPMs from nonmetallic components in a pre-treatment process. A pyrometallurgical process is often used tbr RPM recovery, although the expensive equipment required has limited its use in small and medium-sized enterprises. Hydrometallurgical processing is effective and easy to operate, with high selectivity of target metals and high recovery efficiency of RPMs, compared to pyrometallurgy. Biometallurgy, though, has shown the most promise for leaching RPMs from urban mines, because of its low cost and environmental friendliness. Newly developed technologies electrochemical, supercritical fluid, ionic liquid, and mechanochemical have offered new choices and achieved some success in laboratory experiments, especially as efficient and environmentally friendly methods of recycling RPMs. With continuing advances in science and technology, more technologies will no doubt be developed in this field, and be able to contribute to the sustainability of RPM mining.展开更多
基金supported by the Important Project of Science and Technology for Water Pollution Control and Treatment (No:2009ZX07424-005-01)
文摘Drinking water treatment sludge,characterized as accumulated suspended solids and organic and inorganic matter,is produced in large quantities during the coagulation process.The proper disposal,regeneration or reuse of sludge is,therefore,a significant environmental issue.Reused sludge at low temperatures is an alternative method to enhance traditional coagulation efficiency.In the present study,the recycling mass of mixed sludge and properties of raw water （such as pH and turbidity） were systematically investigated to optimize coagulation efficiency.We determined that the appropriate dosage of mixed sludge was 60 mL/L,effective initial turbidity ranges were below 45.0 NTU,and optimal pH for DOMs and turbidity removal was 6.5-7.0 and 8.0,respectively.Furthermore,by comparing the flocs characteristics with and without recycling sludge,we found that floc structures with sludge were more irregular with average size growth to 64.7 μm from 48.1 μm.Recycling sludge was a feasible and successful method for enhancing pollutants removal,and the more irregular flocs structure after recycling might be caused by breakage of reused flocs and incorporation of powdered activated carbon into larger flocs structure.Applied during the coagulation process,recycling sludge could be significant for the treatment of low temperature and micro-polluted source water.
基金supported by the Science and Technology Department of Jilin Province(20210101067JC and 20230101353JC)。
文摘导电水凝胶作为可穿戴式传感器满足了机械灵活性和智能感应的基本要求.然而,它们往往遇到一些问题,如良好的机械性能和高导电性之间的不相容性、较差的抗菌能力和难以回收.在此,我们通过简单的冻融方法开发了高导电性物理交联的聚乙烯醇/壳聚糖-植酸(PVA/CS-PA)水凝胶.PA与CS和PVA基质之间的氢键和静电作用不仅赋予了水凝胶适宜的机械性能和良好的延展性,而且还使其具备有意义的可回收特性.此外,由于PA分子的离子传导性和抗菌能力,该水凝胶表现出卓越的导电性(~0.125 S cm^(-1))和抗菌活性.这些特殊的性能使基于该水凝胶的可穿戴传感器表现出应变敏感的特性(在200%-420%的应变下,应变系数为7.21),可以监测人体的各种活动.此外,PVA/CSPA溶胶墨水可以在冰浴环境下转变为凝胶状态,这将满足柔性电路的需要,并使可穿戴式传感器更加便携.
文摘Urban mining is essential for continued natural resource extraction. The recovery of rare and precious metals （RPMs） from urban mines has attracted increasing attention from both academic and industrial sectors, because of the broad application and high price of RPMs, and their low content in natural ores. This study summarizes the distribution characteristics of various RPMs in urban mines, and the advantages and shortcomings of various technologies for RPM recovery from urban mines, including both conventional （pyrometallurgical, hydrometallurgical, and biometallurgical processing）, and emerging （electrochemical, supereritieal fluid, mechanochemical, and ionic liquids processing） technologies. Mechanical/physical technologies are commonly employed to separate RPMs from nonmetallic components in a pre-treatment process. A pyrometallurgical process is often used tbr RPM recovery, although the expensive equipment required has limited its use in small and medium-sized enterprises. Hydrometallurgical processing is effective and easy to operate, with high selectivity of target metals and high recovery efficiency of RPMs, compared to pyrometallurgy. Biometallurgy, though, has shown the most promise for leaching RPMs from urban mines, because of its low cost and environmental friendliness. Newly developed technologies electrochemical, supercritical fluid, ionic liquid, and mechanochemical have offered new choices and achieved some success in laboratory experiments, especially as efficient and environmentally friendly methods of recycling RPMs. With continuing advances in science and technology, more technologies will no doubt be developed in this field, and be able to contribute to the sustainability of RPM mining.
