Preparation and characterization of clay based ceramic porous membranes and their use for the removal of lead ions from synthetic wastewater with an insight into the removal mechanism.

The present study explores the use of local clay from the United Arab Emirates (UAE) to prepare porous ceramic membranes (flat disk shape) for the purpose of removing toxic heavy metals from contaminated water. Four distinct ceramic membranes, crafted from locally sourced clay and incorporated with activated carbon and graphite, underwent careful and thorough preparation. The initial set of membranes was subjected to open-air sintering, resulting in the creation of mACA and mGrA membranes.

Facile Coaxial Electrospinning Synthesis of Polyacrylonitrile/Cellulose Acetate Nanofiber Membrane for Oil-Water Separations.

Oil-contaminated water and industrial oily wastewater discharges have adversely affected aquatic ecosystems and human safety. Membrane separation technology offers a promising solution for effective oil-water separation. Thus, a membrane with high surface area, hydrophilic-oleophobic properties, and stability is a promising candidate.

Novel composites of activated carbon and layered double oxide for the removal of sulfate from synthetic and brackish groundwater.

Sulfate (SO) is a major water and environmental concern that causes severe diarrhea, death of invertebrates and plant species, and clogging of industrial pipes. In the current work, treatment of SO from synthetic and real groundwater having 3901 mg(SO)/L was investigated for the first time using Zn-Al and Mg-Al layered double oxides doped granular activated carbon (GAC/Mg-Al LDO and GAC/Zn-Al LDO). The co-precipitation method was followed to synthesize the GAC/LDO composites using an Mg or Zn to Al molar ratio of 3:1.

Synthesis and Biocompatibility Evaluation of PCL Electrospun Membranes Coated with MTA/HA for Potential Application in Dental Pulp Capping.

This study aimed to develop polycaprolactone (PCL) electrospun membranes coated with mineral trioxide aggregate/hydroxyapatite (MTA/HA) as a potential material for dental pulp capping. Initially, the PCL membrane was prepared by an electrospinning process, which was further surface coated with MTA (labeled as PCLMTA) and HA (labeled as PCLHA). The physico-chemical characterization of the fabricated membranes was carried out using field emission scanning electron microscopy (FE-SEM)/Energy dispersive X-ray (EDX), X-ray diffraction (XRD), Raman spectroscopy, and contact angle analysis.

Carbide-derived carbon as an extraordinary material for the removal of chromium from an aqueous solution.

In the present work, the adsorptive removal of chromium (Cr) from water by carbide-derived carbon (CDC) was investigated. The morphology and structure of the CDC were characterized by using FTIR, SEM, TEM, XRD, and N adsorption-desorption measurements. The effect of adsorption parameters including contact time, initial Cr concentration, temperature, initial solution pH, and CDC dosage was examined on the removal of Cr ions.

Tribological Behavior of Aluminum Hybrid Nanocomposites Reinforced with Alumina and Graphene Oxide.

Due to rapid technological advancements, the demand for lightweight materials with improved tribo-mechanical properties is continuously growing. The development of composite materials is one of the routes taken by researchers to meet these target properties. Aluminum (Al) is one of the most suitable materials used for developing composites for a wide range of applications because of its light weight, high conductivity, and high specific strength.

Mechanical and Thermal Evaluation of Aluminum Hybrid Nanocomposite Reinforced with Alumina and Graphene Oxide.

Aluminum matrix composites are among the most widely used metal matrix composites in several industries, such as aircraft, electronics, automobile, and aerospace, due to their high specific strength, durability, structural rigidity and high corrosion resistance. However, owing to their low hardness and wear resistance, their usage is limited in demanding applications, especially in harsh environments. In the present work, aluminum hybrid nanocomposite reinforced with alumina (AlO) and graphene oxide (GO) possessing enhanced mechanical and thermal properties was developed using spark plasma sintering (SPS) technique.

Monolayer Graphene Transfer onto Hydrophilic Substrates: A New Protocol Using Electrostatic Charging.

In the present work, we developed a novel method for transferring monolayer graphene onto four different commercial hydrophilic micro/ultra-filtration substrates. The developed method used electrostatic charging to maintain the contact between the graphene and the target substrate intact during the etching step through the wet transfer process. Several measurement/analysis techniques were used in order to evaluate the properties of the surfaces and to assess the quality of the transferred graphene.

Fouling control in reverse osmosis for water desalination & reuse: Current practices & emerging environment-friendly technologies.

Reverse Osmosis (RO) is becoming increasingly popular for seawater desalination and wastewater reclamation. However, fouling of the membranes adversely impacts the overall process efficiency and economics. To date, several strategies and approaches have been used in RO plants and investigated at the laboratory-scale for their effectiveness in the control of different fouling types.

Graphene Oxide-Based Membranes for Water Purification Applications: Effect of Plasma Treatment on the Adhesion and Stability of the Synthesized Membranes.

The adhesion enhancement of graphene oxide (GO) and reduced graphene oxide (rGO) layer in the underlying polyethersulfone (PES) microfiltration membrane is a crucial step towards developing a high-performance membrane for water purification applications. In the present study, we modified the surface of a PES microfiltration membrane with plasma treatment (PT) carried out at different times (2, 10, and 20 min). We studied the effect of PT on the adhesion, stability, and performance of the synthesized GO/rGO-PES membranes.

Porous AlO-CNT Nanocomposite Membrane Produced by Spark Plasma Sintering with Tailored Microstructure and Properties for Water Treatment.

Ceramic-based nanocomposite membranes are gaining great attention in various applications, such as water treatment; gas separation; oil and gas, amid their superior fouling resistance and remarkable chemical/thermal stability. Here, we report for the first time the use of spark plasma sintering (SPS) process to fabricate a porous alumina-carbon nanotubes (AlO-CNT) nanocomposite membrane for water treatment. The challenge is this work is to achieve a balance between the amount of porosity, desired for a high water flux, and the membrane strength level, required to resist the applied pressure during a water flow experiment.

Tribological Characterization of Micron-/Nano-Sized WC-9%Co Cemented Carbides Prepared by Spark Plasma Sintering at Elevated Temperatures.

The present study investigates the high temperature tribological performance of spark plasma sintered, nano- and micron-sized tungsten carbide (WC) bonded by 9 wt.% cobalt (Co). The composites were fabricated using a two-step procedure of mixing followed by spark plasma sintering (SPS).

A Novel PAN-GO-SiO₂ Hybrid Membrane for Separating Oil and Water from Emulsified Mixture.

In this article, we report the development of a polyacrylonitrile-graphene oxide-silicon dioxide (PAN-GO-SiO₂) hybrid membrane for separation of oil and water from their emulsified mixture. The membrane was successfully fabricated using a one-step electrospinning process. GO and SiO₂ nanofillers were added in PAN in different concentrations to determine the optimized composition for the PAN-GO-SiO₂ hybrid membrane.

Surface modification of carbon nanotubes with copper oxide nanoparticles for heat transfer enhancement of nanofluids.

Over the last few years, nanoparticles have been used as thermal enhancement agents in many heat transfer based fluids to improve the thermal conductivity of the fluids. Recently, many experiments have been carried out to prepare different types of nanofluids (NFs) showing a tremendous increase in thermal conductivity of the base fluids with the addition of a small amount of nanoparticles. However, little experimental work has been proposed to calculate the flow behaviour and heat transfer of nanofluids and the exact mechanism for the increase in effective thermal conductivity in heat exchangers.

Enhanced water transport and salt rejection through hydrophobic zeolite pores.

The potential of improvements to reverse osmosis (RO) desalination by incorporating porous nanostructured materials such as zeolites into the selective layer in the membrane has spurred substantial research efforts over the past decade. However, because of the lack of methods to probe transport across these materials, it is still unclear which pore size or internal surface chemistry is optimal for maximizing permeability and salt rejection. We developed a platform to measure the transport of water and salt across a single layer of zeolite crystals, elucidating the effects of internal wettability on water and salt transport through the ≈5.

Water and Solute Transport Governed by Tunable Pore Size Distributions in Nanoporous Graphene Membranes.

Nanoporous graphene has the potential to advance membrane separations by offering high selectivity with minimal resistance to flow, but how mass transport depends on the structure of pores in this atomically thin membrane is poorly understood. Here, we investigate the relationship between tunable pore creation using ion bombardment and oxygen plasma etching, the resulting pore size distributions, and the consequent water and solute transport. Through tuning of the pore creation process, we demonstrate nanofiltration membranes that reject small molecules but offer high permeance to water or monovalent ions.

Novel Aluminum Oxide-Impregnated Carbon Nanotube Membrane for the Removal of Cadmium from Aqueous Solution.

An aluminum oxide-impregnated carbon nanotube (CNT-Al₂O₃) membrane was developed via a novel approach and used in the removal of toxic metal cadmium ions, Cd(II). The membrane did not require any binder to hold the carbon nanotubes (CNTs) together. Instead, the Al₂O₃ particles impregnated on the surface of the CNTs were sintered together during heating at 1400 °C.

Synthesis of Graphene Based Membranes: Effect of Substrate Surface Properties on Monolayer Graphene Transfer.

In this work, we report the transfer of graphene onto eight commercial microfiltration substrates having different pore sizes and surface characteristics. Monolayer graphene grown on copper by the chemical vapor deposition (CVD) process was transferred by the pressing method over the target substrates, followed by wet etching of copper to obtain monolayer graphene/polymer membranes. Scanning electron microscopy (SEM), atomic force microscopy (AFM), and contact angle (CA) measurements were carried out to explore the graphene layer transferability.

Cadmium Removal from Contaminated Water Using Polyelectrolyte-Coated Industrial Waste Fly Ash.

Fly ash (FA) is a major industrial waste generated from power stations that add extra cost for proper disposal. Recent research efforts have consequently focused on developing ways to make use of FA in environmentally sound applications. This study, therefore, investigates the potential ability of raw fly ash (RFA) and polyelectrolyte-coated fly ash (PEFA) to remove cadmium (Cd) from polluted water.

A Comparative Study of Raw and Metal Oxide Impregnated Carbon Nanotubes for the Adsorption of Hexavalent Chromium from Aqueous Solution.

The present study reports the use of raw, iron oxide, and aluminum oxide impregnated carbon nanotubes (CNTs) for the adsorption of hexavalent chromium (Cr(VI)) ions from aqueous solution. The raw CNTs were impregnated with 1% and 10% loadings (weight %) of iron oxide and aluminum oxide nanoparticles using wet impregnation technique. The synthesized materials were characterized using scanning electron microscopy (SEM) and thermogravimetric analysis (TGA).

Porosimetry and packing morphology of vertically aligned carbon nanotube arrays via impedance spectroscopy.

Vertically aligned one-dimensional nanostructure arrays are promising in many applications such as electrochemical systems, solar cells, and electronics, taking advantage of high surface area per unit volume, nanometer length scale packing, and alignment leading to high conductivity. However, many devices need to optimize arrays for device performance by selecting an appropriate morphology. Developing a simple, non-invasive tool for understanding the role of pore volume distribution and interspacing would aid in the optimization of nanostructure morphologies in electrodes.

Nanofiltration across Defect-Sealed Nanoporous Monolayer Graphene.

Monolayer nanoporous graphene represents an ideal membrane for molecular separations, but its practical realization is impeded by leakage through defects in the ultrathin graphene. Here, we report a multiscale leakage-sealing process that exploits the nonpolar nature and impermeability of pristine graphene to selectively block defects, resulting in a centimeter-scale membrane that can separate two fluid reservoirs by an atomically thin layer of graphene. After introducing subnanometer pores in graphene, the membrane exhibited rejection of multivalent ions and small molecules and water flux consistent with prior molecular dynamics simulations.

Effect of hydrophilic defects on water transport in MFI zeolites.

The subnanometer pore structure of zeolites and other microporous materials has been proposed to act as a molecular sieve for various water separation technologies. However, due to the increased interaction between the solid and water in these nanoconfined spaces, it is unclear which type of interface, be it hydrophilic or hydrophobic, offers an advantageous medium for enhancing transport properties. In this work, we probe the role of hydrophilic defects on the transport of water inside the microporous hydrophobic MFI zeolite pore structure via combined sorption and high-pressure infiltration experiments.

Nanofluidic transport governed by the liquid/vapour interface.

Liquid/vapour interfaces govern the behaviour of a wide range of systems but remain poorly understood, leaving ample margin for the exploitation of intriguing functionalities for applications. Here, we systematically investigate the role of liquid/vapour interfaces in the transport of water across apposing liquid menisci in osmosis membranes comprising short hydrophobic nanopores that separate two fluid reservoirs. We show experimentally that mass transport is limited by molecular reflection from the liquid/vapour interface below a certain length scale, which depends on the transmission probability of water molecules across the nanopores and on the condensation probability of a water molecule incident on the liquid surface.

Selective ionic transport through tunable subnanometer pores in single-layer graphene membranes.

We report selective ionic transport through controlled, high-density, subnanometer diameter pores in macroscopic single-layer graphene membranes. Isolated, reactive defects were first introduced into the graphene lattice through ion bombardment and subsequently enlarged by oxidative etching into permeable pores with diameters of 0.40 ± 0.