Sponge Surface Research Articles

Preparation of temperature-responsive smart sponge and its application in oil-water separation and dye adsorption

At present, researchers are committed to studying new intelligent response materials to deal with severe water pollution problems. Using PU sponge as the substrate, dopamine was first modified to construct a rough surface while introducing active groups. The monomer N-isopropylacrylamide (NIPAM) and itaconic acid (IA) were grafted and polymerized onto the polydopamine coating on the sponge surface by vinyltrimethoxysilane (VTMS). The obtained DINA-PU sponge has good temperature response and switchable wettability characteristics, and has good adsorption-desorption cycle function. Moreover, a micro-filtration device was designed to separate heavy (light) oil-water mixtures. The separation efficiency can reach more than 95% and 99% for heavy and light oil-water, respectively. In addition, the adsorption capacity of the material for methylene blue (MB) can reach 660mg·g-1. The separation efficiency in the oil-water separation-dye adsorption integrated separation experiment can reach more than 99%.

Preparation of superhydrophobic polyurethane sponge with photodegradation function and study on its oil-water separation performance

The surface of tetrapod-shaped zinc oxide whiskers (T-ZnOw) was hydrophobized by the sol-gel method, and then loaded onto the surface of polyurethane sponge by dip-curing method to prepare a superhydrophobic polyurethane sponge with photodegradation function. When the mass ratio of superhydrophobic tetrapod-shaped zinc oxide whiskers (ST-ZnOw) and polydimethylsiloxane (PDMS) was 0.5:1, the water contact angle of the sponge was 157.5°. After being soaked in acid and alkali corrosion solution, rubbed with sandpaper and heat treated, the sponge can still maintain excellent hydrophobic properties. The adsorption capacity for different oils and organic solvents is 12 to 35 times of its own mass. After repeated extrusion-oil absorption experiments, it can still maintain its good adsorption capacity and high hydrophobicity, showing excellent reusability. The continuous oil-water separation efficiency of the material for different oils and organic solvents is above 95%, and the separation efficiency for the emulsion prepared with span80 content of 0.1wt% is 99.84%. At the same time, the prepared material can degrade the organic dye methylene blue under ultraviolet light, with a degradation rate of 99.35%, showing excellent potential for degrading organic pollutants.

Methods of Thermal Energy Storage by Using Smart Heat Pumps

Abstract To address energy problems in thermodynamic installations, the authors of the paper propose a working methodology in which the determining role of the exergetic aspects of the processes is especially emphasized. One of these energy problems, addressed in many papers in recent years, is of particular importance in the fight to reduce chemical and thermal pollution of the environment: the problem of storing excess energy and energy from renewable or residual sources. Approaching this issue as well from this point of view, the authors propose a series of solutions by which they seek to use the most of the exergy extracted from the available energy sources. The solutions proposed here are based on the use of an own invention, the isothermalizer, a particularly powerful tool, able to bring highly effective solutions to many of the problems that concern researchers determined to create a cleaner planet. Designers and users of thermodynamic systems now have the possibility of an initial choice and subsequent changes (with the change of external conditions), of their energy and exergetic efficiency, as well as the possibility of calculating the material and energy costs necessary to achieve the proposed objective. In any gas compression/expansion problem, the energy efficiency is established precisely, by choosing the isothermal speed of the process (so of the isothermal temperature), and the power density, by choosing the total surface of the thermal sponge, the flow rate and the mode of distribution of the cooling agent. As the isothermalizer is equipped with a processor that controls and modifies the isothermal speed in such a way that the exergy consumption is optimized, the energy storage processes become processes of extracting thermal energy from a tank and transferring it to another tank, a process accompanied by consumption/supply of mechanical energy.

Hybrid amphiphilic janus PDMS sponge enabling electrical sensing of organic solvents

Porous materials exhibit exceptional suitability for underwater pollutant purification through selective absorption of water and oil. However, most reported porous materials designed for oil absorption, removal, and reuse lack the selectivity necessary to distinguish between different types of organic solvents. In this study, a sponge-based sensor that is responsive to and capable of distinguishing changes in resistance induced by physical deformation of the conductive layer is presented. The sensor is a Janus-structured porous PDMS sponge fabricated using sugar cube templates. The solvent-absorbing section features 300 µm pores to maximize absorption relative to its volume. The resistance-sensing section was created with 600 µm pores and PDMS mixed with the surfactant Triton X-100 (TX-100) to enhance hydrophilicity, allowing for low-cost dip coating with a water-dispersible conductive polymer poly(3,4-ethylenedioxythiophene) polystyrene sulfonate (PEDOT:PSS). Detecting the physical changes in the PEDOT:PSS film on the sponge surface allowed distinguishing responses to physical stimuli. Analyzing the trends in resistance changes under physical stimuli and in polar/nonpolar solvents, conductivity change mechanisms are proposed. The type of organic solvent absorbed by the sponge can be differentiated using these mechanisms.

Preparation of a superhydrophilic and superoleophobic sponge for continuous oil/water and oil/oil separation

Oily wastewater produced from various industries and oil spills has posed serious threats to the environment and human health. Promisingly, superwetting materials emerge as great candidates for efficient oil/water separation. In this work, a superhydrophilic-superoleophobic melamine sponge was prepared using a facile immersion method. Methyltrimethoxysilane (MTMS) was used as a binder, which combined fluorosurfactant (FS-50) and TiO2 onto the sponge surface. The coated sponge displayed a water contact angle of 0° and an oil contact angle of 154.5°. Accordingly, it exhibited absorption capacities of above 86 g/g for water and under 1 g/g for oils. Based on its selective permeability and 3D porous structures, the coated sponge could continuously separate various immiscible oil/water mixtures and oil-in-water emulsions with separation efficiencies larger than 99.4 % and 98.7 %, respectively. Notably, the superhydrophilic-superoleophobic sponge was extended to present opposite wettability towards polar and nonpolar liquids. Consequently, it achieved continuous separation of immiscible oil/oil mixtures, with separation efficiency over 99.1 %. Additionally, the coated sponge displayed excellent reusability, great mechanical stability against compression and abrasion, and stable separation performance for various harsh oil/water mixtures. The study presented a promising separation candidate for future applications in oily wastewater treatment and other liquid/liquid separation fields.

Inside-out templating: A strategy to decorate helical carbon nanotubes and 2D MoS2 on ethyl cellulose sponge for enhanced oil adsorption and oil/water separation

Ethyl cellulose (EC)-based composite sponges were developed for oil spillage treatment. The EC sponge surface was decorated with helical carbon nanotubes (HCNTs) and molybdenum disulfide (MoS2) (1 phr) using the inside-out sugar templating method. The inside surface of a sugar cube was coated with HCNTs and MoS2. After filling the sugar cube pores with EC and the subsequent sugar leaching, the decorating materials presented on the sponge surface. The EC/HCNT/MoS2 sponge had a high level of oil removal based on its adsorption capacity (41.68 g/g), cycled adsorption (∼75–79 %), separation flux efficiency (∼85–95 %), and efficiency in oil/water emulsion separation (92–94 %). The sponge maintained adsorption capacity in acidic, basic, and salty conditions, adsorbed oil under water, and functioned as an oil/water separator in a continuous pump-assisted system. The compressive stress and Young's modulus of the EC sponge increased following its decoration using HCNTs and MoS2. The composite sponge was robust based on cycled compression and was thermally stable up to ∼120 οC. Based on the eco-friendliness of EC, the low loading of HCNTs and MoS2, and sponge versatility, the developed EC/HCNT/MoS2 sponge should be good candidate for use in sustainable oil adsorption and separation applications.

Enhanced superhydrophobic melamine sponge with bimetal organic framework for simultaneous oil-water separation and microplastic removal

The escalating problem of oily wastewater and microplastic pollution poses a significant threat to our environment. Addressing this challenge has been hampered by the lack of sustainable materials capable of handling multiple pollutants effectively. However, this research introduces a groundbreaking approach for designing a superhydrophobic composite sponge, MS@ZnCo-ZIF@HDTMS. Utilizing a straightforward layer-by-layer self-assembly strategy, this work achieved the robust integration of bimetallic organic framework (ZnCo-ZIF) onto the sponge surface. This integration was facilitated by the adhesive and ion exchange properties of polydopamine (PDA), thereby constructing intricate micro- and nanocomposite structures. The immense specific surface area of ZnCo-ZIF offered numerous absorption sites for the assembly of PDA and hexadecyltrimethoxysilane (HDTMS). Remarkably, the composite sponge exhibits superhydrophobic and superoleophilic properties, demonstrating exceptional oil absorption capacities ranging from 55 g/g to 96 g/g, even after enduring 50 cycles. Moreover, MS@ZnCo-ZIF@HDTMS possesses remarkable mechanical and chemical stability. Its gravity-driven oil-water separation capabilities are noteworthy, achieving a permeate flux of 10,000 L m-2 h-1 and a removal rate of up to 99.2 %. Crucially, the superhydrophobic nature of the composite sponge, coupled with capillary effect, Van der Waals forces, hydrogen bonding, and other interactions, enables MS@ZnCo-ZIF@HDTMS to capture a diverse range of microplastics from water relatively swiftly. Therefore, this work not only provides effective candidates for the sustainable treatment of oil and microplastics in water but also opens new avenues for the restoration of aquatic environments.

Directional self-assembly of octavinyl polyhedral oligomeric silsesquioxane on the surface of melamine sponge: Establishing hydrophobic surfaces to improve oil–water separation performance

The continuous increase in industrial organic pollutants has seriously contaminated the natural environment, posing a threat to natural ecosystems and human survival. The preparation of hydrophobic materials with corrosion resistance is crucial for the efficient treatment of emulsified oil–water mixtures in industrial wastewater.Octavinyl polyhedral oligomeric silsesquioxane-coated melamine foam (OV-POSS@MF), possessing hydrophobic properties, was synthesized through a two-step process: initially, a sulfhydryl layer was built up on the surface of the melamine foam, followed by the subsequent assembly of octavinyl POSS onto the melamine foam's surface via a free radical polymerization reaction between sulfhydryl groups and vinyl moieties. OV-POSS@MF achieves a static water contact angle of 141°, demonstrating its pronounced hydrophobic nature. Moreover, the corrosion resistance, adsorption capacity, oil–water separation efficiency, deformation resistance, and flame retardancy of OV-POSS@MF were thoroughly examined. The results indicate that OV-POSS@MF exhibits strong corrosion resistance and maintains good hydrophobicity even after prolonged exposure to highly acidic and alkaline conditions. Notably, OV-POSS@MF possesses the capability to efficiently and rapidly separate emulsified oil–water mixtures. Furthermore, it retains excellent hydrophobicity even after undergoing up to 100 consecutive compressions or distortions, highlighting its remarkable mechanical resilience. Additionally, OV-POSS@MF demonstrates superior flame retardant properties compared to unmodified melamine foam (MF).

Facile construction of multifunctional 3D smart MOF-based polyurethane sponges with photocatalytic ability for efficient separation of oil-in-water emulsions and co-existing organic pollutant

Water resources are increasingly being damaged by human activities, and it is crucial to deal effectively with polluted water resources. Due to the diversity of pollution sources (oil, organic dyes, and other complex pollutants), it makes sense to develop a material that can handle these pollutants simultaneously. In this article, we construct a simple and fast method to fabricate multifunctional superhydrophobic polyurethane sponges (PU). A superhydrophobic composite coating constructed from ZIF-8, polydimethylsiloxane (PDMS), and stearic acid (SA) was attached to the surface of the polyurethane sponge by a simple impregnation method. Through the above process, we have successfully integrated oil–water separation, photocatalysis, and superhydrophobicity into a polyurethane sponge. The results showed that the PDMS/SA/ZIF-8 polyurethane sponge (PSZPU) had a high hydrophobicity angle (162.9 ± 1.1°). In addition, PSZPU maintains high oil–water separation performance (mean value of separation efficiency > 94.24 %) and superhydrophobicity after oil–water separation cycling tests and a series of harsh environmental tests in acidic and alkaline solutions, high temperatures, abrasion, and UV aging irradiation. Overall, the creation of PSZPU provides a new application for superhydrophobic sponges in water resource treatment.

Flexible Sponge Surface Enhances Raman Scattering (SERS) Substrate with Patterned Superwettability for Ultrasensitive Pesticide Detection

Flexible Sponge Surface Enhances Raman Scattering (SERS) Substrate with Patterned Superwettability for Ultrasensitive Pesticide Detection

Robust nanoparticles growth in the interior of porous sponges for efficient dye adsorption and emulsion separation

Emulsified oils and dye contaminants already pose a huge threat to global ecosystems and human health. It is a significant research topic to develop efficient, rapid, versatile methods for emulsion separation and dye adsorption. The membrane material modified with common methods only modified the outer surface of the membrane, while the interior is hardly fully decorated. In this investigation, a solvent exchange method was used to in situ grow nanoparticles in the interior of a porous sponge. These nanoparticles were obtained with polyethyleneimine, gallic acid, and tannic acid via Michael addition and Schiff base reaction. The prepared nanoparticle-coated sponges provided efficient separation of dyes, emulsions, and complex contaminants. The separation efficiency of the dye reached 99.49%, and the separation efficiency of the emulsion was as high as 99.87% with a flux of 11140.3 L m−2 h−1. Furthermore, the maximum adsorption capacity reached 486.8 mg g−1 for cationic dyes and 182.1 mg g−1 for anionic dyes. More importantly, the nanoparticles were highly robust on the surface of the porous sponge, and the modified sponge could have long-term applications in hazardous environments. Overall, it is envisioned that the nanoparticles-modified porous sponge exhibited considerable potential for emulsion and dye wastewater treatment.

Preliminary Study and Use of Design of Dusto Cleaner for Black Board

Even if we lead to the digital platform traditional chalk and board is an integral part of the education life. Blackboards and chalk pieces are used in almost every educational field in the world. Cleaning the board using a duster is essential for continuing the writing process and this involves rubbing a sponge surface against the board surface. This cleans the board but also creates a fine dispersion and particles of chalk powder around the atmosphere nearer the board, which is certain to be inhaled by the teachers, and in many cases, students who occupy seats near the blackboard suffer some inhalation problems. The work also stated that teachers were at the maximum risk of inhaling the chalk dust and may suffer from respiratory diseases. Key Words: Blackboard, chalk, duster, respiratory, diseases

High-Density Microporous Drainage-Integrating Sheath Flow Generator for Streamlining Microfluidic Cell Sorting Systems.

Tremendous efforts have been made to develop practical and efficient microfluidic cell and particle sorting systems; however, there are technological limitations in terms of system complexity and low operability. Here, we propose a sheath flow generator that can dramatically simplify operational procedures and enhance the usability of microfluidic cell sorters. The device utilizes an embedded polydimethylsiloxane (PDMS) sponge with interconnected micropores, which is in direct contact with microchannels and seamlessly integrated into the microfluidic platform. The high-density micropores on the sponge surface facilitated fluid drainage, and the drained fluid was used as the sheath flow for downstream cell sorting processes. To fabricate the integrated device, a new process for sponge-embedded substrates was developed through the accumulation, incorporation, and dissolution of PMMA microparticles as sacrificial porogens. The effects of the microchannel geometry and flow velocity on the sheath flow generation were investigated. Furthermore, an asymmetric lattice-shaped microchannel network for cell/particle sorting was connected to the sheath flow generator in series, and the sorting performances of model particles, blood cells, and spiked tumor cells were investigated. The sheath flow generation technique developed in this study is expected to streamline conventional microfluidic cell-sorting systems as it dramatically improves versatility and operability.

Superhydrophobic Co-MOF-based sponge for efficient oil-water separation utilizing photothermal effect

Effectively addressing crude oil spills remains a global challenge due to its high viscosity and limited flow characteristics. In this study, we successfully prepared a modified sponge (PCP@MS) by embedding the photothermal material of Co-HHTP and coating the melamine sponge (MS) with low-surface-energy polydimethylsiloxane (PDMS). The PCP@MS exhibited outstanding hydrophobicity with WCA of 160.2° and high oil absorption capacity of 59–107 g/g. The PCP@MS showed high separation efficiency of 99.2% for various oil-water mixtures, along with notable self-cleaning properties and mechanical stability. The internal micro-nano hierarchical structure on the sponge surface significantly enhanced light absorption, synergizing with the photo-thermal conversion properties of Co-HHTP, enabled PCP@MS to achieve a surface temperature of 109.2 °C under 1.0 solar light within 300 s. With the aid of solar radiation, PCP@MS is able to heat up quickly and successfully lowering the viscosity of the surrounding crude oil, resulting in an oil recovery rate of 8.76 g/min. Density functional theory (DFT) calculation results revealed that Co-HHTP featured a zero-gap band structure, rendering advantageous electronic properties for full-wavelength light absorption. This in situ solar-heated absorbent design is poised to advance the practical application of viscous oil spill cleanup and recovery.

Simple synthesis of floating Fe2O3/Luffa catalysts for the photo-Fenton degradation of methyl orange at near neutral pH

Although widely used in the textile industry, methyl orange is considered one of the most toxic dyes, which have negative impacts on the aquatic environment and needs to be removed from water bodies. Hence, the present paper reports the synthesis of new floating photo-Fenton catalysts based on the immobilization of Fe2O3 nanoparticles on the surface of Luffa sponges for the oxalate-induced-degradation of methyl orange. The floating catalytic sponges were prepared through a simple precipitation method followed by a reflux heating process and then characterized by field emission scanning electron microscopy, X-ray diffraction, atomic absorption spectrometry, and nitrogen adsorption-desorption experiments. According to the experimental results, methyl orange was effectively degraded over our floating catalytic sponges underlight illumination at near neutral pH. The catalytic activity was also found to be enhanced with the increase in crystallinity of Fe2O3 nanoparticles, which can be achieved by the reflux heating. Besides, owing to the floating feature, these sponges are easily separated from the solution, thereby not forming a secondary source of pollution for water

Fabrication of Adsorbent Using Nano-Sized Lignocellulosic Biochar Coated on Luffa Aegyptiaca Sponge to Remove Heavy Metal Chromium VI

Eliminating heavy metal Cr (VI) in liquids is challenging. Developing adsorbents using sustainable, cheap, and biodegradable materials is still a concern. Therefore, this study aims to synthesize a heavy metal adsorbent by transforming forest residue into nano-sized lignocellulose biochar. This nano-sized lignocellulosic biochar, with the assistance of chitosan and alginate, was coated onto the Luffa aegyptiaca sponge surface to complete the structure of the proposed heavy metal adsorbent. This adsorbent is easy to apply in adsorbing heavy metals, is durable, and can be reused. The adsorbent products were characterized to observe the functional groups by Fourier Transform Infrared (FTIR) and surface morphology by Scanning Electron Microscopy (SEM). The adsorbents were also experimented with contact times of 120 and 1200 minutes in the adsorption process. The decrease in heavy metal concentration was analyzed by Atomic Absorption Spectroscopy (AAS). Scanning Electron Microscopy with Energy Dispersive X-ray spectroscopy (SEM-EDX) observed the adsorbent surface that has absorbed heavy metal ions. FTIR characterization of surface functional groups showed the presence of hydrogen, aliphatic C-H group, C=C aromatic ring, carboxyl groups, and carbonate ion, capable of binding heavy metal Cr (VI). The morphology of the adsorbent coated on luffa showed that the adsorbent was well attached. The results of the adsorption process showed a decrease in Cr (VI) concentration, with adsorption efficiency reaching 94% for 1200 min and adsorption capacity of 0.36 mg/g. SEM-EDX results validated the attachment of Cr (VI) heavy metal ions to the adsorbent surface.

Superhydrophilic and oleophobic sponges prepared based on Mussel-Inspired chemistry for efficient oil-water separation.

Superhydrophilic/oleophobic materials are considered to be the best materials for achieving oil-water separation, but their preparation is difficult and the existing methods are not universal. In this paper, a two-step modification strategy was used to prepare superhydrophilic/oleophobic sponges by adjusting the polar and nonpolar components of the materials using mussel-inspired chemistry. While remaining superhydrophilic, the modified sponge surface has a maximum contact angle of 135° with different oils in air. The modified sponge exhibited superoleophobicity in water, and the contact angle of oil could reach more than 150°. In addition, the modified sponges were also reusable, chemically stable, and mechanically durable. Its oil-water separation flux was up to 24900 Lm-2 h-1 bar-1 , and the separation efficiency was above 97 %. We believe that this method will provide an environmentally friendly and efficient way to prepare the superhydrophilic/oleophobic materials.

Construction and screening of spin-crossover-sponge materials based on iron(II)-triazole coordination polymers.

Iron(II)-triazole coordination polymers have attracted considerable interest for their synthetic versatility, which allows tuning their spin-crossover (SCO) properties. Embedding SCO solid particles in sponge matrices is a simple, powerful, and generic approach to construct processable SCO materials. Here, we have studied a series of magnetic frameworks based on partial ligand substitution by using different chemical mixtures of two organic ligands, yielding four isostructural coordination polymers. The integration of the hygroscopic SCO material has endowed the composite sponge with the ability to capture moisture under ambient conditions. In particular, not only does a spin-crossover transition during absorption occur, but also a color variation has been achieved by varying humidity. The consequences of cooperativity and the exposed surface of the composite sponge on the spin transition were evaluated and the most promising materials among them were screened. This work provides guiding significance for the fabrication and practical application of spin-crossover-sponge materials.

Super-hydrophilic LaCoO3/g-C3N4 nanocomposite coated beauty sponge for solar-driven seawater desalination with simultaneous volatile organic compound removal.

Interfacial solar steam generation (ISSG) is emerging as a promising, environment-friendly solution for fulfilling freshwater and energy demands. However, a critical challenge for ISSG lies in the presence of harmful volatile organic compounds (VOCs) in the feedwater which are co-evaporated with water, leading to more enriched concentration in condensed water. Herein, lanthanum cobaltate-graphitic carbon nitride (LaCoO3/g-C3N4, LCO/g-CN) nanocomposite decorated beauty sponge (LCO/g-CN@BS) is proposed as an efficient photothermal/photocatalytic material for solar-driven seawater desalination and simultaneous VOC degradation. The hydrophobic surface of the beauty sponge after LCO/g-CN coating becomes super-hydrophilic, ensuring sufficient water supply and our LCO/g-CN@BS delivers an evaporation rate of 1.94 kg m-2 h-1 under 1 sun irradiation. This LCO/g-CN@BS shows excellent seawater desalination capacity with a self-cleaning ability when employed for saltwater purification for a salt (NaCl) concentration as high as 15 wt%. Moreover, fast photocarrier transfer between LCO and g-CN leads to enhanced photocatalytic degradation of over 90% of phenol simultaneously, which is about 60% for only an LCO-based beauty sponge. This work presents a promising approach to combining novel nanocomposites with microporous structures for efficient solar desalination, offering simultaneous VOC degradation.

A Janus Gelatin Sponge with a Procoagulant Nanoparticle-Embedded Surface for Coagulopathic Hemostasis.

Apart from the wide and safe application of natural polymer-based hemostatic materials/devices, it is still desirable to develop new types of hemostatic materials that can achieve both potent coagulopathic hemostasis and a facile preparation process. In this work, one Janus gelatin sponge (J-ZGS) is readily constructed for both coagulation-dependent and coagulopathic hemostasis by embedding zein nanoparticles on the surface of a self-prepared gelatin sponge (S-GS): zein nanoparticles were facilely prepared by an antisolvent method to achieve procoagulant blood-material interactions, while S-GS was prepared by freeze-drying a foaming gelatin solution. Due to the distinct secondary structure, the optimal zein nanoparticles possessed a higher in vitro hemostatic property than the pristine zein powder and other nanoparticles, the underlying mechanism of which was revealed as the superior RBC/platelet adhesion property in the presence/absence of plasma proteins. Compared with S-GS and a commercial gelatin sponge, J-ZGS achieved a significantly higher in vitro hemostatic property and similarly good blood compatibility/cytocompatibility. Moreover, in vivo artery-injury models confirmed the outstanding hemostatic performance of J-ZGS under both coagulation-dependent and coagulopathic conditions. Our work offers an appealing approach for developing potent hemostatic sponges from natural polymer-based nanoparticles that could be further extended to versatile hemostatic materials for coagulopathic hemostasis.