The search for a simple, affordable, and rapidly separation method for oil-water mixtures is one of the most serious challenges that the world is facing today. Superhydrophobic, or superoleophilic, materials and surfaces are promising choices for these types of separations. In the present work, pre-wetting of river sand, sea sand and desert sand have been used in a gravity-driven separation of an oil–water mixture. The superoleophobicity properties of these pre-wetted sand materials were found to be good, with a maximum and minimum oil contact angle of about 141.1° for desert sand and 113.8° for sea sand. Also, the relationship between the porosity of the respective sand layer and the water phase separation rate was constructed. As a result of a simple particle size screening, the highest separation rate of sea sand (24.3±2.4 mm/s) was obtained. And this is the highest oil-water separation rate that has ever been achieved for a sand material. In addition to the particle size of sand, the effect by the number of separation cycles, thickness of sand layer, temperature, pH value, salt concentration, and different oil-water mixtures, have also been investigated.
Solid-state nanopores have become a prominent tool in the field of single-molecule detection. Conventional solid-state nanopores are thick, which affects the spatial resolution of the detection results. Graphene is the thinnest 2D material and has the highest spatial detection resolution. In this study, a graphene membrane chip was fabricated by combining a MEMS process with a 2D material wet transfer process. Raman spectroscopy was used to assess the quality of graphene after the transfer. The mechanism behind the influence of the processing dose and residence time of the helium ion beam on the processed pore size was investigated. Subsequently, graphene nanopores with diameters less than 10 nm were fabricated via helium ion microscopy. DNA was detected using a 5.8 nm graphene nanopore chip, and the appearance of double-peak signals on the surface of 20 mer DNA was successfully detected. These results serve as a valuable reference for nanopore fabrication using 2D material for DNA analysis.
A series of nanopores with diameters ranging from 2.5 to 63 nm are fabricated on a reduced $\mathrm{S}{\mathrm{i}}_{3}{\mathrm{N}}_{4}$ membrane by focused ion beam and high energy electron beam. Through measuring the blocked ionic currents for DNA strands threading linearly through those solid-state nanopores, it is found that the blockade ionic current is proportional to the square of the hydrodynamic diameter of the DNA strand. With the nanopore diameter reduced to be comparable with that of DNA strands, the hydrodynamic diameter of the DNA becomes smaller, which is attributed to the size confinement effects. The duration time for the linear DNA translocation events increases monotonically with the nanopore length. By comparing the spatial configurations of DNA strands through nanopores with different diameters, it is found that the nanopore with large diameter has enough space to allow the DNA strand to translocate through with complex conformation. With the decrease of the nanopore diameter, the folded part of the DNA is prone to be straightened by the nanopore, which leads to the increase in the occurrence frequency of the linear DNA translocation events. Reducing the diameter of the nanopore to 2.5 nm allows the detection and discrimination of three nucleotide ``G'' and three nucleotide ``T'' homopolymer DNA strands based on differences in their physical dimensions.
In recent years, oil-water separation has been widely researched to reduce the influences of industrial wastewater and offshore oil spills. A filter membrane with special wettability can achieve the separation because of its opposite wettability for water phase and oil phase. In the field of filter membrane with special wettability, porous metal filter membranes have been much investigated because of the associated high efficiency, portability, high plasticity, high thermal stability, and low cost. This article provides an overview of the research progress of the porous metal filter membrane fabrication and discusses the future developments in this field.
Nanoparticle drug delivery systems are currently one of the hottest topics in the field of medicine. They can precisely deliver drugs to the parts of the patient that need treatment, with the goal of improving patient effectiveness and reducing drug toxicity. Gold nanoparticles (AuNPs) are considered one of the most promising nanomaterials due to their unique optical, electronic, sensing, and biochemical properties. By combining AuNPs with different ligands, functionalized gold nanoparticle (F-AuNPs) drug delivery systems can be obtained, which have broad application prospects in the field of medicine. This article focuses on the different ligand connection types of F-AuNPs and reviews the research progress of F-AuNPs drug delivery systems in the field of medicine in recent years.
'/%3e%3cuse xlink:href='%23a' transform='rotate(23.036 .093 25.536)'/%3e%3cuse xlink:href='%23a' transform='rotate(45.87 1.273 16.18)'/%3e%3cuse xlink:href='%23a' transform='rotate(69.945 .996 12.078)'/%3e%3cuse xlink:href='%23a' transform='rotate(20.66 -19.689 31.932)'/%3e%3c/svg%3e)
'/%3e%3c/defs%3e%3cpath fill='%23012169' d='M0 0h10080v5040H0z'/%3e%3cpath stroke='%23fff' stroke-width='.6' d='m0 0 6 3m0-3L0 3' clip-path='url(%23b)' transform='scale(840)'/%3e%3cpath stroke='%23e4002b' stroke-width='.4' d='m0 0 6 3m0-3L0 3' clip-path='url(%23c)' transform='scale(840)'/%3e%3cpath stroke='%23fff' stroke-width='840' d='M2520 0v2520M0 1260h5040'/%3e%3cpath stroke='%23e4002b' stroke-width='504' d='M2520 0v2520M0 1260h5040'/%3e%3cg fill='%23fff'%3e%3cuse xlink:href='%23d' x='2520' y='3780'/%3e%3cuse xlink:href='%23a' x='7560' y='4200'/%3e%3cuse xlink:href='%23a' x='6300' y='2205'/%3e%3cuse xlink:href='%23a' x='7560' y='840'/%3e%3cuse xlink:href='%23a' x='8680' y='1869'/%3e%3cuse xlink:href='%23e' x='8064' y='2730'/%3e%3c/g%3e%3c/svg%3e)
