Chemical Binder Research Articles

Self-adhesive fiberboards fabricated from waste bamboo powder through biological pretreatment

Using renewable and sustainable agricultural and forestry wastes to produce bio-based materials is an effective approach for significantly reducing the environmental pollution caused by petroleum-based materials such as plastics and chemical fibers. This research aims to develop a cleaning process for large-scale production of high-performance green bio-based materials without the use of any chemical binders. The mechanical properties of self-adhesive fiberboards are improved through pretreatment with white rot fungi. By pretreating bamboo powder with biological factors like sugars and laccase produced by white rot fungi under high temperature and pressure, lignin-active molecules are formed on the surface. These active molecules can reconstruct chemical bonds between multi-fiber materials, thereby exhibiting biological adhesion. The reconfiguration of lignin molecules on the material's surface also helps prevent rapid water penetration. After biological pretreatment, the surface of bamboo powder forms a concave-convex structure, effectively increasing the area of biological adhesion during hot-pressing conditions. Compared to regular bamboo powder control samples, bio-pretreated fiberboards showed an increase in modulus of rupture (MOR) by 83.33 % and modulus of elasticity (MOE) by 100.79 %. In contrast to traditional fossil-based adhesive synthetic materials, the findings of this study circumvent the emission of harmful volatiles from chemical adhesives while effectively substituting petroleum-based synthetic materials that necessitate diverse chemical additives, which are in alignment with the principles of environmental protection and sustainable development.

Highly Active Nano-Porous Thin-Films for Water Electrolysis Using an Automated Print Technology Based on Spark Ablation

Accelerating hydrogen (H2) deployment via renewable electricity is a key G7 strategy for sustainable transitions in hard-to-decarbonize sectors (e.g., circular-plastics, -steel, -fertilizers,shipping, and aviation) therefore, Alkaline (AWE) and Polymer Electrolyte Membrane water electrolysis (PEMWE) play a crucial role amongst low-temperature power-to-X technologies for establishing a hydrogen network. Assuming all hydrogen will be green by 2030 (with ca. 150 million metric tons), a significant increase in electrolyser capacity to 3,000 gigawatts is necessary, given the current capacity of 0.3 gigawatts. However, the adoption of electrolysers faces a bottleneck due to scarce platinum group materials (PGMs) used as catalyst, specifically Iridium and Platinum. The commercial PGM loading per membrane electrode assembly (MEA) is at 3 mg/cm2, requiring substantial efforts to redesign electrocatalyst materials through a nano-architecture, necessitating a thousandfold increase in surface area (µm to nm scale) and a tenfold reduction in mass loading (mg to µg). The realization of this objective is conceivable through innovative surface engineering and manufacturing techniques, exemplified by. VSPARTICLE is actively advancing its manufacturing technology for green H2, bridging academia and industry . We developed a unique nano-printing technology which utilizes spark ablation for generating nano-porous electrocatalyst thin films across diverse elements and alloys. Unlike traditional methods, it eliminates the need for chemical precursors or binders, reducing waste and extra pre- / post-process steps. The VSP-P1 nano-printer serves as a crucial R&D tool for dry-synthesis, enabling both the production of complex electrocatalyst layers and also sample arrays high-throughput screening. This accelerates the discovery of new catalysts, fostering the creation and application of novel nanomaterials in specialized setups. Our oral presentation will unveil the latest findings concerning oxygen evolution electrodes, employing Ir-based and Ni-based catalysts produced through the innovative VSP-P1 nano-printing technology, which exhibit notable activity in acidic and alkaline water electrolysis, respectively, even at low loadings, such as 0.4 mg/cm2. Therefore, our oral presentation aims to show the latest findings on accelerated electrocatalysts discovery concerning oxygen evolution reaction (OER) produced through the innovative VSP-P1 nano-printing technology. In parallel to comprehensive flow-cell experiments, meticulous control tests and characterization techniques (XRD, XRF, HR-SEM) on proxy samples were conducted, leveraging the versatility of VSP-P1 to create identical nano-porous films on various substrates such as Si-wafer, conductive glass, and glassy carbon disks. The scalability of this dry manufacturing process, coupled with the rapid iteration capability for tuning material parameters and test-beds, promises a tenfold acceleration in electrocatalyst utilization. In summary, this presentation intends to reveal a methodology that not only shows an efficient strategy for catalyst utilization through nano-printed layers, but also shortens the time required to bring novel materials to market. Figure 1

Mixed-mode cationic exchange paper combined with direct infusion mass spectrometry, a sustainable approach to determine opioids in biosamples

Direct infusion mass spectrometry (DI-MS/MS) allows the rapid analysis of samples and minimizes solvent usage by avoiding chromatographic separation. However, it is prone to ion suppression due to matrix effects, especially when biosamples are processed. In this context, sample preparation appears as the perfect complement to get proper analytical results. In this article, a novel and sustainable planar sorptive phase containing mixed-mode cationic exchange (MCX) particles is presented to overcome the limitations of DI-MS/MS in bioanalysis. The new phase uses cellulose paper as a natural substrate over which the particles can be retained using polyacrylonitrile (PAN) as the chemical binder. The high porosity of the cellulose substrate simplifies the synthesis since a straightforward dip-coating technique can be applied. For this purpose, MCX particles are initially dispersed in a PAN solution prepared in N,N-Dimethylformamide. A segment of paper is later introduced into the slurry, and the evaporation of the solvent leaves a film of PAN-MCX composite over the paper, where the particles are entrapped but accessible for the analyte's isolation. The resulting MCX-paper has been evaluated for the extraction of selected opioids (codeine, methadone, morphine, naloxone, oxycodone, and tramadol) from saliva and urine samples and their determination by direct infusion tandem mass spectrometry. Working at the optimized conditions, the limits of detection were in the low μg L−1 range. The precision, expressed as relative standard deviation, was better than 12 % under intra-day and inter-day conditions. The accuracy, expressed as relative recoveries, provides values in the ranges 89–113 % and 74–121% for saliva and urine, respectively. The method was finally applied to analyze saliva and urine samples collected from patients under codeine treatment.

Sustainable development of pavement base stabilization using future road base material (FROBM)

Sustainable road construction has emerged as a critical issue in assessing natural resources and urban development. With the rapid expansion of pavement networks to meet growing traffic demands, road base construction relies heavily on the consumption of natural aggregates and Ordinary Portland Cement (OPC) through the cement-treated base (CTB) technique. This practice contributes to the global warming and greenhouse gas (GHG) emissions associated with road construction. This study investigated a novel road base material, Future Road Base Material (FROBM), which emphasizes both eco-friendliness and economic advantages. Fine crushed rock (FCR) served as the parent aggregate and was modified with a chemical binder comprising 4% of the FCR weight. The proposed sustainable cementitious material, functioning as a non-OPC binder, incorporated fly ash and hydrated limestone as pozzolanic materials, along with sodium hydroxide (NaOH) as an alkali additive. An asphalt emulsion (AE) was employed as a special additive to enhance crucial pavement engineering properties. Through life cycle analysis (LCA), the construction activities and material acquisition of each stabilized base technique were evaluated in terms of project costs and carbon footprints. The non-OPC binder offered sufficient compressive strength for a stabilized base course. Furthermore, the addition of AE improved the elastic modulus and modulus of rupture of the non-OPC binder-stabilized mixture. Utilizing a non-OPC binder and AE in the base layer provides advantages in terms of construction cost and environmental impact. Although the costs increased slightly, the GHG emissions were reduced by approximately 30% compared to conventional base materials, with equivalent functionality and service life for road construction. The proposed stabilizing agent reduced the operational processes and demand for natural aggregates compared with the unbound FCR base course. Road-base stabilization using a non-OPC binder and AE represents an innovative approach to mitigate waste in coal mining and power plant industries by transitioning to a cleaner product. The concept of the FROBM serves as a valuable guideline for the development of future sustainable pavement materials.

Mats Made from Recycled Tyre Rubber and Polyurethane for Improving Growth Performance in Buffalo Farms

This study focuses on anti-trauma mats designed for buffaloes’ comfort, using as raw materials rubber powder from end-of-life tyres (ELTs) and an isocyanate-based polyurethane resin binder. The first part of the study focused on mat formulation. Whilst it was possible to select a unique combination of raw materials and design features, it was necessary to investigate the relationship between three critical parameters affecting mat consistency and therefore buffalo comfort: binder quantity, mat thickness, and desired final mat density (bulk). In order to quantitatively assess the variation in hardness, various combinations were investigated within well-defined ranges based on the relevant literature. The results obtained from nine selected combinations indicate that increases in the three critical parameters do not induce a real phase transition in the final product consistency, although the hardness suggests an increasing trend. The mats consistently exhibited a moderately soft/hard consistency, offering environmental benefits in terms of increased rubber usage and potentially reduced chemical binder, depending on the desired thickness. The selected mixture showed excellent resistance to heavy chemical loads, suggesting reliability for frequent cleaning operations. The second part of the study involved field trials of the mats with calves. This involved monitoring their weight gain and appetite levels over a 90-day period. The results showed excellent growth performance compared to uncoated grids (i.e., weight gain was approximately 20% higher at the end of the observation period); this was similar to that achieved with the use of straw bedding. However, compared to straw bedding, the mats (i) exhibit long-term durability, with no signs of wear from washing or trampling over the months of the trial, (ii) allow for quick and efficient cleaning, and (iii) enable companies to save on labour, material (straw), and waste disposal costs, while maintaining (or even improving) the same welfare levels associated with the use of straw.

Copper sulfides agglomeration using a novel lab-scale granulator: Integrated evaluation of bonding, leaching and mechanical behavior

The ore agglomerations could ameliorate intra-particle pore network, homogenize flow paths, and improve leaching efficiency of heap leaching. This paper innovatively develops a novel ore granulator with adjustable inclined angle and rolling speed. To comprehensively evaluate granulation procedure, the effects of physical (crushed feeds particle size distribution, rolling speed, inclined angle), chemical (binder type, curing time) and biological factors (bacterial concentration) on bonding performance of crushed feeds are analyzed. The objective of this paper is to obtain the optimal granulation conditions by studying the influence of various factors on the bonding ability, strength, and stability of granulated ores, in order to improve the pore structure of the heap leaching system, and increase the leaching rate of the ore. The results show that well-shaped agglomeration (WAs) does improve minerals leaching efficiency, and the uniaxial compressive strength of WAs is positively related to curing time, binder concentration, inclined angle, and rolling speed. The excessive lower or higher rolling speed is not suitable to get a higher extraction rate due to undesirable disintegration or compaction. The higher concentration (0.5–10 %) sulfuric acid solution could obviously increase WAs strength from 32.6 KPa to 48.3 KPa. The organic binders such as polyacrylamide are benefit for powders bonding and increase the compressive strength, but does not good for the desirable leaching reaction rate. The bacterial pre-adding has no significant positive influence on bonding and leaching efficiency. Relied on the 3D response surface, the preferred preparing condition is: 78.9 rpm rolling speed, 30° inclined angle, 7-days curing time and 9.3 % H2SO4 solution. Future studies should focus on exploring the intrinsic correlation between the various factors and evaluating the granulating and leaching effects from the perspective of chemical detection and leaching bacteria.

Turning Waste into Treasure: The Full Technological Process and Product Performance Characterization of Flushable Wet Wipes Prepared from Corn Stalk.

As a daily consumable, wet wipes are mostly synthetic fibers, which are incinerated or landfilled after use. The nanoplastics generated during this process will lead to environmental pollution. The application of flushable wet wipes, which are dispersible and fully degradable, is of great significance. The main raw material for flushable wipes is wood pulp, which has a long growth cycle and high cost. Corn is widely planted and has a short growth cycle. Currently most corn stalk is treated by incineration, which produces a lot of smoke that pollutes the environment. Therefore, using corn stalk as the raw material for flushable wet wipes, replacing wood pulp, is both cost-effective and environmentally friendly. In this study, aiming at industrial production, we explored the full process of producing flushable wet wipes from corn stalk to pulp board, then to the final wipes. The corn stalk was treated using alkali and a bleaching agent to obtain corn stalk pulp, which was then made into pulp board through the nonwoven wet-laid process. The optimal parameters for the alkali treatment and bleaching were obtained. The properties of the corn stalk pulp board were compared with the commercial wood pulp board. Further, we mixed the corn stalk pulp with Lyocell fiber to prepare wet-laid webs, which were then bonded using a chemical binder poloxamer. Then, the evenness of the web, mechanical properties, absorption, and dispersibility of the flushable wipes were characterized. Results showed that the pulp obtained using the optimal treatment process has a high yield and better whiteness. The properties of the corn stalk pulp board are comparable with the commercial wood pulp board, which can therefore potentially be replaced by the corn stalk board prepared in our study. The prepared flushable wet wipes had good evenness and their water absorption rate was more than 600%. The mechanical strength in dry and wet states achieved 595.94 N/m and 179.00 N/m, respectively. Most importantly, the wet wipes can completely disperse under the standardized testing method. A good balance of dispersibility and wet strength of the wet wipes was achieved.

Self‐Shaping Monolithic Reticular Materials: Ingredients for Success

AbstractReticular materials are one of the more promising tools that humankind has developed to address the required energy transition. Despite their great potential showcased in the last decade, their use is so far mainly confined to the laboratory bench due to drawbacks derived from their powdery morphology. Unlike zeolites and activated carbons, the challenges in shaping and densification of reticular materials hamper their full implementation in the industry. Hence, strategies for shaping and integrating these materials need to be prioritized. Most of the existing strategies rely on applying mechanical pressure and adding chemical binders, but these approaches, although useful for shaping, diminish their final adsorption capacities and do not bring their theoretical, predicted performance. On the other hand, obtaining self‐shaped, dense bodies—so‐called monoliths—arises as a very promising and scalable alternative. Sol–gel monoliths are still scarce in the scientific literature despite their outstanding performance, particularly in terms of volumetric adsorption capacity. This review intends to help expand this scope by offering a rational guide on the self‐shaping of dense monoliths for reticular materials, as well as a complete revision of the state‐of‐the‐art in the field.

PHYSICAL CHARACTERIZATION OF STARCH-COTTON FIBER COMPOSITE SHEETS

Biobased materials had been identified as replacements for materials produced with chemical binders. Panels made from starch-cotton fiber waste composite materials fit perfectly into the category of biobased materials. The aim of this study was to measure the physical properties of starch-cotton fiber composite sheets. For sheets manufactured in 300x300x100mm3, the density and dimensional stability properties (water content, absorption rate, dimensional and volumetric swelling) were calculated. Density was determined in accordance with NF EN 323. Swellings were determined in accordance with EN 317. Water content was measured in accordance with EN 322. The sheets were manufactured with starch/water and starch/cotton fiber mass ratios respectfully equal to 0.25 and 1. We obtained an average water content of 4.27% and an absolute densityγs =1.13g/cm3. The average absorption coefficient measured was 62.88%. The measurement of dimensional variations showed that the panels underwent little deformation in the length and width directions. The average was 2%. In the thickness direction, on the other hand, dimensional variation was very high. This averaged 44%. The latter reflects the porosity of the material.

Systems-level analyses of protein-protein interaction network dysfunctions via epichaperomics identify cancer-specific mechanisms of stress adaptation

Systems-level assessments of protein-protein interaction (PPI) network dysfunctions are currently out-of-reach because approaches enabling proteome-wide identification, analysis, and modulation of context-specific PPI changes in native (unengineered) cells and tissues are lacking. Herein, we take advantage of chemical binders of maladaptive scaffolding structures termed epichaperomes and develop an epichaperome-based ‘omics platform, epichaperomics, to identify PPI alterations in disease. We provide multiple lines of evidence, at both biochemical and functional levels, demonstrating the importance of these probes to identify and study PPI network dysfunctions and provide mechanistically and therapeutically relevant proteome-wide insights. As proof-of-principle, we derive systems-level insight into PPI dysfunctions of cancer cells which enabled the discovery of a context-dependent mechanism by which cancer cells enhance the fitness of mitotic protein networks. Importantly, our systems levels analyses support the use of epichaperome chemical binders as therapeutic strategies aimed at normalizing PPI networks.

Characterization of proteoglycan products of naturation of chitosan extraction liquid waste with sulfate ions

The process of naturation of chitosan extraction liquid waste into proteoglycans with various types of binders is an effort to make new materials / materials that are expected to provide benefits to increase livestock productivity. The new material (proteoglycan) is formed through a reaction mechanism that is highly dependent on the original component as well as additional components that function as receptors (inhibitors) or activators (triggers) for the formation / occurrence of molecular adhesion (chelating) to a core chain. In addition, the process of naturation of liquid waste is also an effort to manage or handle the environment from waste which if not handled can have a negative impact on the environment. This can happen because the denaturation of protein components or molecules contained in liquid waste becomes pollution due to the decay process. The purpose of the study was to obtain the character of proteoglycan quality as a result of the addition of various types of sulphate ion binders through measuring the digestibility and hematologic values of blood in broiler chickens. The study used experimental methods in the laboratory. The experimental design used was a Complete Randomized Design (6 X 4), with six treatments (3 types of chemical product binders and 3 types of biological product binders), which were repeated four times. The effect of the treatment was statistically tested by fingerprint analysis, and the difference between treatments was tested with the Duncan Multiple Distance Test. The research was carried out in two stages, namely the preparation stage (making proteoglycans with the addition of three types of sulphate ion binders), and the product quality testing stage. Product testing through measurement of digestibility (dry matter and protein) and hematologic (number of erythrocytes, leukocytes, and haematocrits) values of broiler blood. The results showed that liquid waste extracting chitosan from shrimp shells (both through chemical and biological processes) can be used as a source of making proteoglycans and can be used as a feed supplement in broiler chicken rations. Quality characteristics of proteoglycan products: good quality Proteoglycans of chemical and biological processes with potassium sulphate binders; Moderate quality chemical and biological process proteoglycans with ammonium sulphate binders, and biological process proteoglycans with sodium hydro sulphate binders; and Poor-quality Proteoglycan chemical process with sodium hydro sulphate binder. The number of erythrocytes, leukocytes and haematocrits blood of broiler chickens are normal for all types of products.

Effect of short carbon fibers on the thermal conductivities of Csf/AZ91D composites

Developing metal matrix composites with lightweight and high thermal conductivities (TCs) to realize high-efficiency thermal management is of great significance. Herein, a strategy for preparing short carbon fiber preform without any chemical binder through the application of vacuum filtration is proposed. High in-plane and nearly unaltered out-plane thermal conductive magnesium matrix composites with short carbon fibers have been prepared by the independently developed liquid-solid extrusion following the vacuum infiltration (LSEVI) technique. The in-plane TCs of the composites reaches 72.16 W·(m·K)−1, a 50.3% enhancement compared to the matrix. The microstructures of the carbon fibers and magnesium matrix before and after the fabrication processing are characterized using optical microscopy (OM), scanning electron microscopy (SEM), X-ray diffraction (XRD), and Raman spectroscopy (RS). The composites display attractive thermal properties and this work provides an efficient approach to prepare short fiber-related thermal conductive metal matrix composites with a refined thermal management capacity.

Room temperature synthesis of monolithic MIL-100(Fe) in aqueous solution for energy-efficient removal and recovery of aromatic volatile organic compounds.

The removal and recovery of volatile organic compounds (VOCs) are widely used in many industrials. Unfortunately, most conventional porous materials not only have low VOCs uptake, but also need to be regenerated at relatively high temperature. Metal-organic frameworks (MOFs) have great potential for the removal and recovery of VOCs as their record-breaking gas adsorption capacity, easy regeneration, tunable pore structure and functional groups. Whereas, powdered MOFs are hardly implemented in industrial fields owing to their low bulk density and high pressure drop. Exploring a green method to prepare granular MOFs for the removal and recovery of VOCs is still a challenge. Herein, we report the room temperature green synthesis of a stable Fe-based MOF monolith by using water as the solvent without applying high pressure and chemical binders. The static and dynamic experiments show that the optimized centimeter-scale monolith has high porosity and mechanical strength, and exhibits much better adsorption performance for representative aromatic VOCs (benzene, toluene and p-xylene), than commercial activated carbon and activated carbon fiber under the same conditions. Remarkably, as-synthesized monolith can be rapidly regenerated at lower temperature. These results clearly demonstrate the advantages of MOF monoliths in removing and recovering VOCs, and also provide new insight into the effects of drying temperature, washing and centrifugation procedures on MOF shaping.

ПЕРСПЕКТИВЫ ПРИМЕНЕНИЯ ПРОМЫШЛЕННЫХ ОТХОДОВ ДЛЯ ПОВЫШЕНИЯ ДОЛГОВЕЧНОСТИ И ОГНЕУПОРНОСТИ ЖАРОСТОЙКИХ БЕТОНОВ

The article analyzes recycling of industrial waste. The main direction of construction production development is the use of new materials, reduction of material intensity, providing mechanization and industrialization of construction, increasing the operational characteristics of products and structures, the implementation of wasteless technologies in building materials at the expense of industrial waste and pollution reduction. It is important to produce concretes and mortars with enhanced physical and thermal properties for linings of thermal units operating in difficult operating conditions (high temperature, aggressive environment, contact of lining material with gases, metal melts and fluxes). Heat-resistant concretes are used in ferrous and non-ferrous metallurgy, chemical and oil refining, petrochemical, power, machine building, pulp and paper industry, in building materials The introduction of heat-resistant concrete by using new structural elements for thermal units, the most appropriate from the thermal and technological side, which is not feasible when using piece ceramic refractories. Components of heat-resistant concretes - fine grind additives and aggregates are usually made of expensive materials (chamotte, mullite, chromite, magnesite, zircon, etc.). The production of additives requires energy-intensive milling and sieving operations, which complicate and increase the cost of aggregate production technology. The replacement of scarce and expensive components by local materials and the development of technology for obtaining heat-resistant concrete on chemical binders using non-deficient materials, especially industrial waste is an important task. The prospects of using alumina-containing wastes as additives in heat-resistant concretes, which allows increasing durability and refractoriness of construction materials. The used fine-dispersed catalyst IM-2201, which is used in petrochemistry and is an alumina-chromium waste, was studied. The composition and properties of this waste and the change in the properties of concrete with the introduction of additives have been studied. It was shown that the properties of concrete change after the introduction of alumina-chromium waste in a given amount (5, 10 and 15%). Their average density, thermal strength and other properties are increased. The improvement of physical and thermal characteristics depends on the structure and new formation in the obtained samples. Concrete samples were analyzed using petrographic method and it was shown that the addition of aluminochrome waste contributes to densification of the structure due to filling the pore space with glassy mass and newly formed crystals in the cementitious mass.

Multifunctional Nanoparticles as High-Efficient Targeted Hypericin System for Theranostic Melanoma

Biotin, spermine, and folic acid were covalently linked to the F127 copolymer to obtain a new drug delivery system designed for HY-loaded PDT treatment against B16F10 cells. Chemical structures and binders quantification were performed by spectroscopy and spectrophotometric techniques (1NMR, HABA/Avidin reagent, fluorescamine assay). Critical micelle concentration, critical micelle temperature, size, polydispersity, and zeta potential indicate the hydrophobicity of the binders can influence the physicochemical parameters. Spermine-modified micelles showed fewer changes in their physical and chemical parameters than the F127 micelles without modification. Furthermore, zeta potential measurements suggest an increase in the physical stability of these carrier systems. The phototherapeutic potential was demonstrated using hypericin-loaded formulation against B16F10 cells, which shows that the combination of the binders on F127 copolymer micelles enhances the photosensitizer uptake and potentializes the photodynamic activity.

The experimental investigation on the geo-polymerization of water-based filtercake at the second interface of the oil-gas well

The quality of bond along the second interface of sandstone oil-gas well is of an utmost important in order to ensure long-term zonal isolation throughout the lifecycle of the well by preventing the potential leakage of hydrocarbon fluids. Attaining effective long-term zonal isolation for the lifetime of oil-gas wells depends on the sealing capacity at second interface (SI). Existence of untreated filtercake at SI acts as weak point of potential leakage of hydrocarbon. Different techniques were developed to improve the situation; however, it is still difficult to cleaned up completely by chemical washes and spacers. Therefore, it is imperious to develop a method that can make a filtercake which can provide an effective bonding between the formation and the cement sheath. The experimental work introduces a novel KN solution developed in the laboratory, simulated wellbore as sandstone formation under the wellbore simulated conditions.The results revealed that the samples treated with KN solution had higher shear bond strength over untreated samples. The bond quality increased with the increase of curing time (3, 7, 14, and 28 days). The improvement was due to geopolymerization of remained water-based filtercake took place which led to formation of cementitious material such as Calcium-Silicate-Hydrate (C–S–H) and FTIR analysis revealed the formation of cementitious material (Calcium-Silicate-Hydrate (C–S–H)) and other geopolymers like Calcium-Aluminium-Silicate-Hydrate (C-A-S-H) and Sodium-Aluminium-Silicate-Hydrate (N-A-S-H)) along the interface which filled the existed pores hence reducing porosity hence high strength of bond at high concentration to treated samples. The untreated samples were observed at low transmittance revealing the low content of inorganic geopolymers hence poor bond quality. Thick water-based filtercake films at second interface, which prevented the complete reaction of cement hydration between rock grains and cement slurry material to form a chemical binder at the interface.This technique is of an utmost important as compared to the other means of improving shear bong strength. This chemical solution tends to convert the clay material into cementitious product (geopolymers) which will enhance the bonding strength. In addition, the formed products are high durable as it can withstand harsh environmental conditions such as higher elevated temperature and salinity condition hence leading to remedial cost reduction.

Electrocatalytic reduction of nitrate by carbon encapsulated Cu-Fe electroactive nanocatalysts on Ni foam

Electrocatalytic denitrification is an attractive and effective method for complete elimination of nitrate (NO3–). However, its application is limited by the activity and stability of the electrocatalyst. In this work, a novel bimetallic electrode was synthesized, in which N-doped graphitized carbon sealed with Cu and Fe nanoparticles and immobilized them on nickel foam (CuFe NPs@NC/NF) without any chemical binder. The immobilized Cu-Fe nanoparticles not only facilitated the adsorption of the reactant but also enhanced the electron transfer between the cathode and NO3–, thus promoting the electrochemical reduction of NO3–. Therefore, the as-prepared electrode exhibited enhanced electrocatalytic activity for NO3– reduction. The composite electrode with the Cu/Fe molar ratio of 1:2 achieved the highest NO3– removal (79.4 %) and the lowest energy consumption (0.0023 kW h mg−1). Furthermore, the composite electrode had a robust NO3– removal capacity under various conditions. Benefitting from the electrochlorination on the anode, this electrochemical system achieved nitrogen (N2) selectivity of 94.0 %. Moreover, CuFe NPs@NC/NF exhibited good stability after 15 cycles, which should be attributed to the graphitized carbon layer. This study confirmed that CuFe NPs@NC/NF electrode is a promising and inexpensive electrode with long-term stability for electrocatalytic denitrification.

Experimental study on modification of water-based filtercake to improve the bonding strength at the wellbore cement-formation interface

The objective of this experimental study is to improve the cementing bond quality of sandstone oil-gas well along the wellbore cement-formation interface (WCFI), so as to ensure long-term zonal isolation throughout the lifecycle of the well by using NSO solution as filtercake modifier which was developed in the laboratory. According to designed experimental method and API RP 10, the effectiveness of filtercake modifier (NSO) on the bonding strength at the WCFI was assessed by using designed simulated wellbore as sandstone formation. The experimental results indicated that the samples which were treated with NSO solution had higher bond strength over untreated samples. The strength generally increased with curing period as for treated samples, 0.198, 0.374, 0.433 and 0.473 MPa for 3, 7, 15, and 30 days respectively while for the untreated samples the bond strength were 0.050, 0.070, 0.81 and 0.100 MPa for the same period. The water-based filtercake modification techniques had significantly enhanced the bonding strength of WCFI by increasing rates above 296%. Improvement of bond strength to the treated sample was due to filtercake modification as a result of formation of cementitious material as revealed in FTIR spectral such as Calcium-Silicate-Hydrate (C–S–H) and other geopolymers like Calcium-Aluminium-Silicate-Hydrate (C-A-S-H) and Sodium-Aluminium-Silicate-Hydrate (N-A-S-H)) along the interface which filled the existed pores hence reducing porosity hence high strength of bond. The low transmittance value for the NSO treated samples revealed that there were more cementitious materials existing at the WCFI which led to improvement of bonding strength as compared to the untreated samples. The lower/poor bond strength for the untreated samples is due to existence of untreated, thick water-based filtercake films at WCFI, which prevented the complete hydration process between rock grains and cement slurry components to make chemical binder of cement slurry material and formation.

Thermophysical Properties of Sawdust and Coconut Coir Dust Incorporated Unfired Clay Blocks

Sawdust and coconut coir dust are agro-wastes/by-products which are suitable for use as raw materials to manufacture unfired clay blocks due to their excellent physical and mechanical properties. A limited number of studies have been conducted on the utilisation of these agro-wastes in clay block production, and they have mostly been devoted to investigating the physicomechanical properties, with less attention given to the thermal properties. Moreover, the majority of the studies have used chemical binders (cement and lime) in combination with agro-waste, thus increasing the carbon footprint and embodied energy of the samples. Furthermore, no research has been performed on the thermal performance of these agro-wastes when incorporated into clay blocks at the wall scale. Therefore, to address these limitations, the present study developed unfired clay blocks incorporating sawdust and coconut coir dust (0, 2.5, 5, and 7.5% by weight), without the use of chemical binders, and evaluated their thermal performance, both at the individual and wall scales. The experiments were divided into two phases. In the first phase, individual sample blocks was tested for basic thermal properties. Based on the results of the first phase, small walls with dimensions of 310 mm × 215 mm × 100 mm were built in the second phase, using the best performing mixture from each waste type, and these were assessed for thermal performance using an adapted hot box method. The thermal performance of the walls was evaluated by measuring the heat transfer rate from hot to cold environments and comparing the results to the reference wall. The results showed that thermal conductivity decreased from 0.36 W/mK for the reference sample, to 0.19 W/mK for the 7.5% coconut coir dust sample, and 0.21 W/mK for the 7.5% sawdust sample, indicating an improvement in thermal insulation. Furthermore, the coconut coir dust and sawdust sample walls showed a thermal resistance improvement of around 48% and 35%, respectively, over the reference sample wall. Consequently, the findings of this study will provide additional essential information that will help in assessing the prospective applications of sawdust and coconut coir dust as the insulating material for manufacturing unfired clay blocks.

Scavenger hunt: Searching for the optimal target material for low-level 210Pb accelerator mass spectrometry

The Centre of Excellence for Dark Matter Particle Physics aims to measure 210Pb (half-life of 22.2 years) in 1 kg of NaI via accelerator mass spectrometry (AMS) for the SABRE (Sodium iodide with Active Background REjection) South dark matter experiment. The first step is to find the optimal target material (chemical compound and binder) to produce the highest and most stable negative ion output. We initially studied the outputs from Pb3O4, PbO and PbF2 mixed 1:2 with Ag. The 208PbO2− and 208PbF3− currents were 0.5–1.2 μA with the procedural PbF2 compound performing slightly better. Based on these results, we explored the performance of PbF2 mixed with fluorinating agents such as AgF, AgF2 and SbF3 at different ratios. The 1:1 mixture was the best for all additives. The possibility of using either Fe (oxide/fluoride) or NaF as bulk material for the AMS target was also studied, however, none proved suitable.