In order to inhibit the swelling of the clay minerals in the in-situ leaching process of weathered crust elution-deposited rare earth ores(WCE-DREO),diallyl dimethyl ammonium chloride(DMDACC)was introduced as an anti-...In order to inhibit the swelling of the clay minerals in the in-situ leaching process of weathered crust elution-deposited rare earth ores(WCE-DREO),diallyl dimethyl ammonium chloride(DMDACC)was introduced as an anti-swelling agent and combined with(NH_(4))_(2)SO_(4)as a novel composite leaching agent.It can be found that the novel composite leaching agent exhibits a good anti-swelling performance and leaching capacity of rare earth,and has great potential on the actual exploitation of WCE-DREO.The antiswelling mechanism of DMDACC was studied by characterization analysis.The results show that DMDACC with positive charges can be adsorbed on the clay particles by the electrostatic attraction and hydrogen bonds,and neutralize the negative charge of the clay particles.The double electrical layers are suppressed and the repulsion force between clay sheets decreases.It causes the clay particles prone to aggregate.Moreover,DMDACC can enter the interlayer and expel out the water molecules in interlayer.The interlayer spacing is decreased and the hydration swelling of the clay particles is weakened.It can provide a theoretical basis for the development of novel anti-swelling agents.展开更多
基金Project supported by the National Natural Science Foundation of China(U2002215,51734001)。
文摘In order to inhibit the swelling of the clay minerals in the in-situ leaching process of weathered crust elution-deposited rare earth ores(WCE-DREO),diallyl dimethyl ammonium chloride(DMDACC)was introduced as an anti-swelling agent and combined with(NH_(4))_(2)SO_(4)as a novel composite leaching agent.It can be found that the novel composite leaching agent exhibits a good anti-swelling performance and leaching capacity of rare earth,and has great potential on the actual exploitation of WCE-DREO.The antiswelling mechanism of DMDACC was studied by characterization analysis.The results show that DMDACC with positive charges can be adsorbed on the clay particles by the electrostatic attraction and hydrogen bonds,and neutralize the negative charge of the clay particles.The double electrical layers are suppressed and the repulsion force between clay sheets decreases.It causes the clay particles prone to aggregate.Moreover,DMDACC can enter the interlayer and expel out the water molecules in interlayer.The interlayer spacing is decreased and the hydration swelling of the clay particles is weakened.It can provide a theoretical basis for the development of novel anti-swelling agents.
基金funding from the Strategic Priority Research Program of the Chinese Academy of Sciences(CAS,XDB0450401)the National Natural Science Foundation of China(22278387 and 22321001)+4 种基金CAS Project for Young Scientists in Basic Research(YSBR-070)the National Key Research and Development Program of China(2022YFA1203601)the Natural Science Foundation of Anhui Province(2208085QB60)Anhui Provincial Innovation Project Funding Program for Overseas Students(2022LCX006)USTC Research Funds of the Double First Class Initiative(YD2060002022).
文摘传统二维纳米片膜在分子和离子分离领域具有巨大潜力,然而在实际污水处理中不可避免地会出现溶胀和易氧化的问题.本研究利用一种新型二维纳米片AgCrSe_(2),采用聚多巴胺(PDA)原位交联策略,成功构筑了高稳定性二维AgCrSe_(2)-PDA膜.该膜能够耐受酸性、碱性介质以及氧化性溶液(0.3 wt%过氧化氢),展现出优异的抗溶胀和抗氧化稳定性.此外,该膜对带负电的染料和乙二胺四乙酸(EDTA)络合的重金属离子的截留率接近100%,通量约为5.0 L m^(−2) h^(−1) bar^(−1).值得注意的是,经过140小时的错流过滤,尽管膜通量略有下降,但该膜对CuEDTA的截留率仍保持在90%左右.这种高稳定性的膜结构源自于PDA与AgCrSe_(2)纳米片之间的配位相互作用.本研究为开发高稳定性的二维膜提供了有效的策略,为工业污水净化提供了新型膜材料.
