Environmental Effects of Micro- and Ultra-microchannel Structures of Natural Minerals

The micro-channels usually refers to structural channels of minerals with aperture in the range of 0.3 nm to 2.0 nm. Such microchannels include, Mn-O octahedron channel filled by K in cryptomelane, and channel constructed by Si-O and AI-O tetragonal molecular sieve filled by Na and Ca in zeolite, and effectively have the function of molecular sieve. Here we point out that ultramicrochannels of natural minerals have apertures below 0.3 nm with the features of ionic sieves. The ultra-microchannels of mineral feldspar, accounting for half mass of the Earth＇s crust, have been largely ignored because the aperture is too small. In this work, we present that feldspar displays a certain degree of ion exchange and owns a feature of channel structure under both high and low temperatures. At high temperature, Na^＋ can enter the channels of feldspars. The content of Na2O in feldspar increases up to 15.9%. At middle temperature, Pb^2＋ can also enter the channels of feldspar as the result of ion exchange, leading thus to the formation of Pb-feldspar. At room temperature, about 97.94% Cd^2＋ can be removed and Cd-feldspar can be obtained. These phenomena indicate typical effects of ultra-microchannels of feldspar, which may be suggested as a potential for the treatment of heavy metal pollution and nuclear waste. The ultra-microchannels of natural minerals have played special role in migration and exchange of geomaterials. The molecular sieves of microchannels of a few natural minerals have the property of purifying molecular gas pollution. And the ionic sieves of ultramicrochannels of most natural minerals can purify ionic water contaminates.

Liquid Phase Exfoliation of 2D Materials and Its ElectrochemicalApplications in the Data-Driven Future

The electrochemical properties of 2D materials,particularly transition metal dichalcogenides(TMDs),hinge ontheir structural and chemical characteristics.To be practicallyviable,achieving large-scale,high-yield production is crucial,ensuring both quality and electrochemical suitability forapplications in energy storage,electrocatalysis,and potentialbasedionic sieving membranes.A prerequisite for success is a deepunderstanding of the synthesis process,forming a critical linkbetween materials synthesis and electrochemical performance.Thisreview extensively examines the liquid-phase exfoliation technique,providing insights into potential advancements and strategies tooptimize the TMDs nanosheet yield while preserving theirelectrochemical attributes.The primary goal is to compiletechniques for enhancing TMDs nanosheet yield through direct liquid-phase exfoliation,considering parameters like solvents,surfactants,centrifugation,and sonication dynamics.Beyond addressing the exfoliation yield,the review emphasizes the potentialimpact of these parameters on the structural and chemical properties of TMD nanosheets,highlighting their pivotal role inelectrochemical applications.Acknowledging evolving research methodologies,the review explores integrating machine learning anddata science as tools for understanding relationships and key characteristics.Envisioned to advance 2D material research,includingthe optimization of graphene,MXenes,and TMDs synthesis for electrochemical applications,this compilation charts a coursetoward data-driven techniques.By bridging experimental and machine learning approaches,it promises to reshape the landscape ofknowledge in electrochemistry,offering a transformative resource for the academic community.

Integrated ionic sieving channels from engineering ordered monolayer two-dimensional crystallite structures

Atomically thin solid-state channels enabling selective molecular transport could potentially be used in a variety of separation and energy conversion applications.The density of channels,their height,distance and edge structure are the key factors that dramatically impact the selective transport performance.However,such channels with small constrictions and atomic precision have been limited to proof-ofconcept demonstrations based on microscale two-dimensional(2D)crystal stripes.Here,we report the engineering of highly ordered,scalable monolayer graphene crystallite arrays by chemical vapor deposition(CVD)method with a modified anisotropic etching approach.The size,shape,distance and edge structure of the graphene crystallite arrays in a large area could be delicately controlled through tailoring the synthetic parameters.This array structure can act as pillars to prop up a smooth single-crystal graphene film,and the fabricated integrated angstrom-size(3.4A)channels allow water transport but exclude hydrated ions,demonstrating potential in selective ionic sieving and nanofiltration practice.