Nanopore-Based Strategy for Sequential Separation of Heavy-Metal Ions in Water

Abstract

Developing novel methods for the removal of heavy-metal ions from wastewater with low costs, special selectivity and high efficiency is quite important in water restoration and comprehensive ecological improvement. In this work, a nanopore-based strategy was suggested and related segregation apparatus was built to separate multiple heavy-metal ions in water by selective complexation. The results indicated that the prioritization of the selecting order for the complexing agent (thiacalix[4]arene- p-tetrasulfonate (TCAS)) to heavy-metal ions was Cu(II) > Cd(II) > Pb(II) > Ba(II). Meanwhile, higher driven voltage corresponded to a faster separation speed, while it could cause the decomposition of complexed heavy-metal ions when excessed the threshold. On the other hand, pH value would affect the hydrolysis of heavy-metal ions, the complexation of the calixarene to the heavy-metal ions and the speed of the electroosmotic flow. In our experiments, the maximum separation efficiency was achieved when the driven voltage was 1.5 V and the pH value was 5.0, corresponding to the best separation rate of 94.8%, 95.2%, 92.8%, 93.6%, for Cu(II), Cd(II), Pb(II) and Ba(II), respectively.

Nanopore Detection of Metal Ions: Current Status and Future Directions

“…Then, TCAS would selectively and sequentially react with Cd(II), Pb(II), and Ba(II) one by one in the permeation cell to form metal–TCAS chelates, which allowed them to be separated from each other using the same device. [ 107 ]…”

Removal of Various Hazardous Materials Using a Multifunctional Biomass-Derived Hydroxyapatite (HAP) Catalyst and Its Antibacterial Effects

“…The elimination of heavy metals is of particular interest to scientists and engineers because of the negative impact of these pollutants on a wide range of living organisms [14,15]. As a result, various techniques for heavy metal removal from wastewater, such as ion exchange, chemical precipitation, membrane separation, and adsorption, have been developed [16,17]. Precipitation accompanied by a chemically or externally mediated transition to non-labile forms is a popular method for removing metals from water and wastewater.…”

Low‐voltage efficient electroosmotic pumps with ultrathin silica nanoporous membrane

“…So far, a variety of nanoporous membranes have been developed, such as track‐etched polymer membranes , anodic aluminum oxide (AAO) membranes , carbon nanotube (CNT) membranes , porous silicon membranes , and silica nanoporous membranes . These EOPs based nanoporous membranes have been applied into various fields, like separation and detection , drug delivery , mixers , self‐electroosmotic pumps , and micro‐nanofluidic microchips and so on. However, each of them has certain weakness in their preparation and structure.…”

“…Supplying a high voltage often has several drawbacks, such as the need of special power supplies, complicated operation conditions, and the generation of Joule heat, which limit the practical applications of EOPs . The development of low‐voltage EOPs is important and necessary in order to work under certain wild conditions .…”

“…Supplying a high voltage often has several drawbacks, such as the need of special power supplies, complicated operation conditions, and the generation of Joule heat, which limit the practical applications of EOPs [4]. The development of lowvoltage EOPs is important and necessary in order to work under certain wild conditions [5][6][7][8].Ultrathin, flow-through nanoporous membranes are attractive materials for the fabrication of low-voltage EOPs. The ultrathin thickness allows EOPs to work in a relative low…”