Incorporation Of Silica Research Articles

Crystal growth of hydrated calcium silicate synthesized from fly ash and lime milk at 100 °C

To maximize the high-value application of fly ash, this study investigates the incorporation of amorphous silica derived from fly ash as a silicon source and lime milk as a calcium source into microporous calcium silicate powders through dynamic hydrothermal synthesis at 100 °C for a duration of 2 h or less. The products were collected at various synthesis intervals and analyzed using X-ray diffraction (XRD), scanning electron microscopy (SEM), Fourier-transform infrared spectroscopy (FT-IR), and thermogravimetric differential scanning calorimetry (TG-DSC). Results indicate that microporous calcium silicate forms through a dynamic reaction that disrupts Si-O bonds, enhancing the mobility of silica-oxygen tetrahedra and generating H2SiO42−groups. Ca2+ ions also interact with these bonds, resulting in Q1 and Q2 forms of silica-oxygen tetrahedra. Phase transformation of calcium silicate at various intervals was noted, beginning with 3CaO·2SiO2·3H2O, shifting to 2CaO·3SiO2·2.5H2O, and finally to CaO·2SiO2·2H2O at 90 min. Thus, microporous calcium silicate evolves from an amorphous C-S-H gel into a crystalline form, featuring diverse calcium silicate minerals with calcium-silicon ratios and particle sizes between 10 and 20 μm, with sizes increasing until the 80-min.

Hybrid Effect of Metakaolin and Nano-Silica on Mechanical and Durability Parameters of Mortar

The incorporation of pozzolanic materials such as nano silica and metakaolin in cementitious materials has gained significant attention in recent years due to their potential to improve the mechanical and durability properties of cement-based composites. This thesis investigates the hybrid effect of nano silica and metakaolin on the mechanical and durability properties of cement mortar. The research work involved the preparation of cement mortar specimens with varying proportions of nano silica and metakaolin, which were then subjected to a series of mechanical and durability tests. The mechanical tests included compressive strength, while the durability tests included water absorption and elevated temperature test. The study showed that the addition of both nano silica and metakaolin to cement mortar resulted in a significant improvement in the mechanical properties of the mortar. Additionally, the hybrid effect of nano silica and metakaolin resulted in enhanced durability of the cement mortar, with a significant reduction in water absorption and improved temperature resistance. The findings of this study will have significant implications for the development of sustainable and durable cementitious materials. The use of pozzolanic materials such as nano silica and metakaolin can reduce the consumption of cement and the associated carbon footprint while also improving the durability and long-term performance of cement-based composites. Overall, this study suggests that the incorporation of nano silica and metakaolin can lead to significant improvements in the mechanical and durability properties of cement mortar, making it a promising material for use in various construction applications.

Graphene Oxide-Silica Green Hybrid Nanocomposites: Fabrication via Latex Mixing and Mechanical Properties Evaluation

ABSTRACT This study investigates the incorporation of sustainable self-assembled graphene oxide-nano silica (GO/NS) hybrid nanoparticles into the natural rubber latex matrix via latex mixing. The primary objective is to assess the synergistic impact of these nanofillers on the mechanical properties of natural rubber latex using both static and dynamic mechanical analysis. Results reveal significant enhancements in mechanical properties, with NRL GO/NS 2 exhibiting a remarkable 188% increase in tensile strength and NRL GO/NS 3 showing a substantial 107% increase. Furthermore, NRL GO/NS 3 demonstrates a 30% reduction in rolling resistance and a remarkable 200% improvement in wet grip, while NRL GO/NS 2 exhibits an 88% increase in wet grip and a 43% decrease in rolling resistance, suggesting potential fuel efficiency benefits. These advancements hold promise for various applications such as automotive tire manufacturing, biomedical devices, and the production of elastomeric goods.

Selective conversion of spent cracking catalyst to faujasite-structured zeolites

Current recycling strategies for spent catalyst in Fluid Catalytic Cracking (FCC) focus on valuable rare-earth elements (REE) and sometimes include a reuse of spent materials by down-cycling, which hinders a circular economy. Herein, a new procedure for the selective conversion of spent FCC catalysts to FAU-type zeolite without secondary crystalline phases such as sodalite, zeolite P or zeolite A is reported. The steps include a leaching process of REE, followed by thermal activation with sodium hydroxide and acid treatment to get an aluminum-rich feed. The synthesis of FAU-type zeolites with varying Si/Al ratios uses the aluminum-rich catalyst feed and commercial water glass. The experiments show that incorporation of silicate from water glass into the zeolite structure is limited to zeolite products with Si/Al ratio ≤ 2.0. It indicates a flocculation of silicates in higher concentration in competition to the crystallization process of FAU-type zeolites. This is reinforced by the resulting crystals, covered and surrounded with small particles with morphology of silica. Moreover, a clear differentiation between zeolite Y and zeolite X is possible from materials properties with the definite evidence of a mixed phase. The kinetics of feed dissolution and incorporation of impurities, alumina and silica are controlled by the pre-treatment temperature, duration and silicon source. This enables flexible adjustment of the aluminum re-use from spent FCC catalyst, the amount of foreign elements (Fe, Ni, V), phase purity, Si/Al ratio, specific surface area and thermal stability of the final zeolite product. Structural and textural data of the resulting zeolites reveals high crystallinity > 80 %, Si/Al ratios of 1.6–2.0, and specific surface areas up to 780 m2/g.

Optimizing Synergistic Silica–Zinc Oxide Coating for Enhanced Flammability Resistance in Cotton Protective Clothing

This study reports process optimization studies of silica and zinc oxide-based flame-retardant (FR) coatings on cotton fabric for protective clothing and enhanced flammability properties. The experiments were designed by central composite design (CCD) using response surface methodology (RSM) to assess the synergistic protective effects of silica and zinc oxide FR coating. These prepared sols were coated on cotton fabrics by a simple dip dry cure process. The resulting FR-finished fabrics were characterized by SEM, mechanical properties, flame retardancy, and air permeability. SEM results confirmed the homogenous spreading of particles on cotton fabrics. From TGA results, it was noticed that the incorporation of silica and ZnO in the prepared nano-sols results in improved thermal stability of the FR-finished fabrics. These sol–gel-treated FR cotton fabrics showed excellent comfort properties, which shows their suitability for fire-retardant protective clothing. RSM analysis proved that the predicted values are in good agreement with the experimental values since R2 values for time to ignite, flame spread time, and air permeability were greater than 0.90. The optimized concentration of silica and ZnO in FR-finished fabrics was found to be 0.302% and 0.353%, respectively, which was further confirmed by confirmatory experiments. The optimization analysis successfully optimized the process for synergistic coating of silica and zinc oxide nanoparticles for enhanced flammability properties of FR cotton fabric for protective clothing.

Factors Affecting Silica/Cellulose Nanocomposite Prepared via the Sol-Gel Technique: A Review.

Cellulose/silica nanocomposites, synthesised through the sol-gel technique, have garnered significant attention for their unique properties and diverse applications. The distinctive characteristics of these nanocomposites are influenced by a range of factors, including the cellulose-to-silica ratio, precursor concentration, pH, catalysts, solvent selection, temperature, processing techniques, and agitation. These variables play a pivotal role in determining the nanocomposites' structure, morphology, and mechanical properties, facilitating tailoring for specific applications. Studies by Raabe et al. and Barud et al. demonstrated well-deposited silica nanoparticles within the interstitial spaces of cellulosic fibres, achieved through TEOS precursor hydrolysis and the subsequent condensation of hydroxyl groups on the cellulose fibre surface. The introduction of TEOS established a robust affinity between the inorganic filler and the polymer matrix, emphasising the substantial impact of TEOS concentration on the size and morphology of silica nanoparticles in the final composites. The successful functionalisation of cellulose fibres with the TEOS precursor via the sol-gel method was reported, resulting in reduced water uptake and enhanced mechanical strength due to the strong chemical interaction between silica and cellulose. In research conducted by Feng et al., the silica/cellulose composite exhibited reduced weight loss compared to the pristine cellulose matrix, with the integration of silica leading to an elevated temperature of composite degradation. Additionally, Ahmad et al. investigated the effects of silica addition to cellulose acetate (CA) and polyethylene glycol membranes, noting an increase in Young's modulus, tensile strength, and elongation at break with silica incorporation. However, concentrations exceeding 4% (w/v) resulted in significant phase separations, leading to a decline in mechanical properties.

Powerful Protein Nanoreservoirs Based on Stellate Mesoporous Silica Embedded in Composite Hydrogels: From Burst Release to Retention

AbstractIn the biomaterials field, one major issue with hydrogels (HGs) loaded with active therapeutics is the spontaneous leaking of the cargo occurring rapidly, usually over several hours. However, biological processes involved in regenerative medicine would require to have a sustained drug delivery lasting over weeks/months or be triggered only when a specific biochemical stimulus (enzymatic, cellular, or antimicrobial) is applied. In this work, this challenge is addressed by demonstrating that the spontaneous protein release from an agarose HG (used as model HG) can be partially or totally blocked by the incorporation of stellate mesoporous silica (STMS) nanoparticles (NPs, ≈150 ± 28 nm size, 15 nm pore) within the HG. It is shown here that the porous silica NPs act as sub‐micrometer size reservoirs ensuring precise level retention simply by playing on the amount of STMS embedded in the HG. Further, this effect is shown for various proteins demonstrating the versatility of this concept.

Preparation of high-performance materials based on carbon nanofibers and analysis of mechanical properties at room and high temperatures

The shortcomings of conventional building materials, such as inadequate tensile strength and fire resistance, have been significantly exacerbated with the emergence of complex and diverse engineering practices. However, the current research on high-performance building materials is still in its nascent stage. Therefore, our study aims to investigate the potential improvements in the mechanical properties of building materials through the incorporation of carbon fiber and nano silica. Specifically, we focus on assessing the mechanical properties of these modified materials at both room and elevated temperatures. Our experimental results demonstrate a notable enhancement in compressive strength. At room temperature, the H2 group exhibited a 15.1% increase in compressive strength, while the H5 group experienced a 7.3% increase. Notably, the compressive strength of the H7 group reached its highest value at 47.13 MPa. Additionally, the H2 group displayed the highest bending strength at 5.18 MPa. Our electron scanning microscopy analysis revealed the uniform dispersion of carbon fibers within the building materials, without any clumping. This suggests that when the dosage of Carbon Fiber reaches 0.6% of the mass of building materials, it can be uniformly dispersed within the mixture. We have also evaluated the performance of the modified materials under high temperatures. It was observed that the prefabricated building materials group experienced a 65% reduction in compressive strength when subjected to 800 °C. Conversely, the carbon fiber building materials exhibited a compressive strength loss of over 62%. Overall, the carbon fiber building materials outperformed the standard building materials under high temperature conditions, with significantly higher compressive strength. Moreover, the modified materials demonstrated an improvement in the residual splitting strength, ranging from 26% to 37% when exposed to temperatures over 800 °C. These findings indicate a substantial enhancement in the mechanical properties of the proposed modified materials. In conclusion, the incorporation of carbon fiber and nano silica into the building materials resulted in substantial improvements in their mechanical properties. These modified materials hold great potential for practical construction projects, offering higher performance and enhanced durability.

Effect of silica type, content, and silanization on the curing, mechanical and energy dissipation properties of poly (epichlorohydrin-co-ethylene oxide-co-allyl glycidyl ether) elastomers

This work aimed to determine the effect of unmodified raw silicas and modified silicas with silane coupling agents on the curing, mechanical, and energy dissipation properties of poly (epichlorohydrin-co-ethylene oxide-co-allyl glycidyl ether) based elastomers. The modified silicas utilized include Coupsil 6109, Coupsil 8113, and Coupsil VP6411, while the unmodified silicas are Ultrasil VN2 and VN3. Adding modified silicas increased the optimum curing time and decreased the cure rate index up to a silica content of 20 phr. However, the cure rate index increased with the addition of 40 phr silica. Mechanical testing of the compounds highlighted the impact of silica addition on the reinforcement of the rubber matrix. The incorporation of silica resulted in enhanced mechanical properties, including increased tensile strength, elongation at break, and elastic modulus. The compression behavior of the vulcanized compounds is also analyzed. The results show that the modified silicas with silane coupling agents exhibit lower relative hysteresis loss than the unmodified silicas, highlighting their potential for reducing energy dissipation and improving mechanical efficiency. Additionally, the storage modulus (G') values of the unmodified silicas (VN2 and VN3) are higher than those of the silanized silicas. However, in compounds prepared with 20 phr silica, the differences in storage modulus (G') between the modified and unmodified silicas are minor. Overall, the findings highlight the influence of modified silicas with silane coupling agents and unmodified silicas on the properties of PECH elastomer, providing insights into optimizing silica content for desired material characteristics.

Investigation on the physicochemical properties of poly (ethylene-co-vinyl acetate)/mesoporous silica nanocomposites: Effects of content and surface functionalization

In this study, poly (ethylene-co-vinyl acetate)/mesoporous silica EVA/SBA-15 nanocomposites, containing 0.5, 1.5, and 2.5 wt% of unfunctionalized and functionalized SBA-15 were prepared by melt blending in an internal mixer. Mesoporous silica was synthesized through the sol-gel method and modified by hexadecyltrimethoxysilane (HDTMS). Several characterizations were performed; including Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), mechanical properties, dynamic mechanical analysis (DMA), and dielectric study to characterize the physicochemical properties of elaborated materials. The results revealed the successful synthesis and functionalization of mesoporous silica, as confirmed by the FTIR and SEM. The crystallinity of the nanocomposites decreased and the elastic modulus increased with the incorporation of the mesoporous silica. Measurement of tensile properties shows that the tensile strength of the nanocomposite content of 1.5 wt% F-SBA-15 is 17.2% is higher as compared to pure EVA. DMA analysis validates the improvement in mechanical properties of the EVA/SBA-15 samples. SEM images displayed well-dispersed F-SBA-15 nanoparticles and enhanced interfacial adhesion between the phases. TGA indicates the enhancement of the thermal stability of nanocomposites as compared with the pure EVA matrix. The surface functionalization presented an approach to preparing nanocomposites with enhanced thermal stability and a low dielectric constant.

Impact of triethanolamine on the hydration of Portland cement in the presence of high pozzolanic activity supplementary cementitious materials

Triethanolamine (TEA) is a widely employed cement accelerator that has been demonstrated to have a favorable impact on the early strength of cement at moderate dosing levels, while having a slight or negative impact on the later strength. This study systematically investigates the hydration pattern and strength development of Portland cement systems with the incorporation of fly ash microspheres and silica fume at a dosage of 0.02 % triethanolamine. The results proved that the addition of TEA had a positive impact on the early strength of the pure Portland cement system, while the later strength was reduced. However, the presence of high pozzolanic activity supplementary cementitious materials (SCMs) altered this reduction and even reversed it, resulting in an increase in strength. Specifically, TEA inhibits the crystallization nucleation growth of hydration products through complexation, resulting in the inhibition of the hydration of silicate minerals. The nucleation effect of silica fume, however, eliminates this inhibition and promotes the hydration of all minerals. Moreover, the presence of SCMs leads to the formation of more amorphous calcium hydroxide (CH) due to the demand of pozzolanic reaction, and the addition of TEA promotes the formation of amorphous CH, effectively lowering the reaction threshold of the pozzolanic reaction and facilitating it. The results confirm that the interaction of the complexation reaction of TEA with the pozzolanic reaction provides a beneficial complement to cement strength development.

Study on the Crystallization Behavior of Neodymium Rare-Earth Butadiene Rubber Blends and Its Effect on Dynamic Mechanical Properties.

Utilizing neodymium-based butadiene rubber as a baseline, this study examines the effect of eco-friendly aromatic TDAE oil, fillers, and crosslinking reactions on neodymium-based rare-earth butadiene rubber (Nd-BR) crystallization behavior. The findings suggest that TDAE oil hinders crystallization, resulting in decreased crystallization temperatures and heightened activation energies (Ea). The crystallization activation energies for 20 parts per hundreds of rubber (PHR) and 37.5 PHR oil stand at -116.8 kJ/mol and -48.1 kJ/mol, respectively, surpassing the -264.3 kJ/mol of the unadulterated rubber. Fillers act as nucleating agents, hastening crystallization, which in turn elevates crystallization temperatures and diminishes Ea. In samples containing 20 PHR and 37.5 PHR oil, the incorporation of carbon black and silica brought the Ea down to -224.9 kJ/mol and -239.1 kJ/mol, respectively. Crosslinking considerably restricts molecular motion and crystallization potential. In the examined conditions, butadiene rubber containing 37.5 PHR oil displayed no crystallization following crosslinking, albeit crystallization was discernible with filler inclusion. Simultaneously, the crystallinity level sharply declined, manifesting cold crystallization behavior. The crosslinking process elevates Ea, while the equilibrium melting point (Tm0) noticeably diminishes. For instance, the Tm0 of pure Nd-BR is approximately -0.135 °C. When blended with carbon black and silica, the Tm0 values are -3.13 °C and -5.23 °C, respectively. After vulcanization, these values decrease to -21.6 °C and -10.16 °C. Evaluating the isothermal crystallization kinetics of diverse materials via the Avrami equation revealed that both the oil and crosslinking process can bring about a decrease in n values, with the Avrami index n for various samples oscillating between 1.5 and 2.5. Assessing the dynamic mechanical attributes of different specimens reveals that Nd-BR crystallization notably curtails its glass transition, marked by a modulus shift in the transition domain and a decrement in loss factor. The modulus in the rubbery state also witnesses a substantial augmentation.

Comparative Analysis of Pre and Post Mix Methods for Nano Silica Incorporation in Concrete: A Study on Mechanical Property Enhancement

Comparative Analysis of Pre and Post Mix Methods for Nano Silica Incorporation in Concrete: A Study on Mechanical Property Enhancement

Design Strategy of the MnOx Catalyst for SCR of NO with NH3: Mechanism of Lead Poisoning and Improvement Method.

The conventional Mn-based catalysts suffer from lead toxicity and require other transition-metal oxides to enhance their resistance in the selective catalytic reduction of NOx with ammonia (NH3-SCR). Herein, we found that the incorporation of inert silica into pure MnOx effectively improved the Pb resistance. The NOx conversion of the MnOx-SiO2-Pb catalyst was nearly 55% higher than that of the MnOx-Pb catalyst, exhibiting enhanced activity at lower temperatures (150-225 °C). To reveal the essential roles at the molecular level, the types and numbers of surface acidity, nitrate species, and catalytic cycle were established through experimental analysis and theoretical calculations of catalysts. The presence of PbCl2 occupied the active Mn sites, resulting in an obvious decline in the Brønsted acid sites (B-NH4+) and the oxidation performance, and the NH3-SCR cycle was energetically less favorable on the MnOx-Pb catalyst. Conversely, SiO2 played a crucial role in preserving the activity of Mn sites on the MnOx-SiO2-Pb catalyst by preferentially bonding with PbCl2, generating more active intermediates. Significantly, this work provided mechanistic insights into the role of SiO2 in regulating the surface acidity, oxidation performance, and stability of active Mn sites, which is helpful for the design of Mn-based catalysts with high Pb resistance for the NH3-SCR reaction.

Effects of amorphous silica on mechanical contribution of coarse aggregates in UHPC: From micromechanics to mesoscale fracture and macroscopic strength

Despite the enhancement of amorphous silica on Ultra-High Performance Concrete (UHPC), the influence of amorphous silicas on the mechanical contribution of coarse aggregates (CA) in UHPC from the perspective of multiscale is still unclear. Herein, the mechanical contribution of CA owing to the incorporation of silica with different morphology (i.e. nano-silica and silica fume) is studied from micromechanics to mesoscale fracture and macroscopic strength. The results show that, on the premise of guarantee flowability, silica fume generates more C–S–H but more microcracks owing to the higher content, while nano-silica results in a higher percentage of high-density C–S–H. The fracture across CA in pure tensile cracking is controlled by the competition between high-density C–S–H content and microcracks, whereas, the fracture across CA in pure shear cracking is governed by microstructure compactness. That is, the high-density C–S–H benefits more the fracture of CA in the case of tensile condition, while the microstructure compactness benefits more the fracture of CA in the case of shear condition. Consequently, in terms of the macroscopic strength, silica fume benefits more the mechanical contribution of CA in compressive loading because of the denser microstructure, while nano-silica is more beneficial to that in flexural loading owing to the higher content of high-density C–S–H.

Synthesis of Graphene Oxide-Coated Mesoporous Silica with Cetyltrimethylammonium Bromide (CTAB) Template for Methylene Blue Adsorption

The synthesis of graphene oxide-coated mesoporous silica (MS_GO) with the template surfactant (Cetyltrimethylammonium Bromide) CTAB has been carried out. The effect of combining mesoporous silica and graphene oxide was studied by knowing the bonds, functional groups and crystalline structures. Functional groups C=O and C=C were formed at wave numbers 1,722, 1,617 and 1,647 cm−1, respectively, as a characteristic of GO compounds. XRD data showed that MS_GO has a more amorphous structure than graphite and GO due to the incorporation of silica onto the graphene oxide surface. The MS_GO synthesis was also applied as an adsorbent for methylene blue dye in water. The adsorption results showed that MS_GO was more effective than pure GO. The percent adorption efficiency (R %) of MS_GO against 10 ppm methylene blue was 93.1 % while that of pure GO was 91.5 %. The addition of mesoporous silica to graphene oxide makes MS_GO adsorbent more effective in adsorption dyes than pure GO, this is supported by the larger total surface area of BET MS_GO was 161.066 m2·g−1, while that of pure GO was 103.818 m2·g−1. HIGHLIGHTS Preparation of graphene oxide from graphite by the modified hummer method Mesoporous silica is synthesized with Graphene Oxide (GO) and occupies between GO layers in the GO interlayer space CTAB is used as a template and forms pores in the synthesis of layered Mesoporous Silica-Graphene Oxide (MS_GO) Graphene Oxide-Coated Mesoporous Silica will be applied for adsorption of methylene blue dye in water. The adsorption efficiency (% R) of GO against methylene blue is lower than % R of MS_GO against methylene blue GRAPHICAL ABSTRACT

Polypropylene Nanocomposites Attained by In Situ Polymerization Using SBA-15 Particles as Support for Metallocene Catalysts: Effect of Molecular Weight and Tacticity on Crystalline Details, Phase Transitions and Rheological Behavior.

In this study, nanocomposites based on polypropylene are synthesized by the in situ polymerization of propene in the presence of mesoporous SBA-15 silica, which acts as a carrier of the catalytic system (zirconocene as catalyst and methylaluminoxane as cocatalyst). The protocol for the immobilization and attainment of hybrid SBA-15 particles involves a pre-stage of contact between the catalyst with cocatalyst before their final functionalization. Two zirconocene catalysts are tested in order to attain materials with different microstructural characteristics, molar masses and regioregularities of chains. Some polypropylene chains are able to be accommodated within the silica mesostructure of these composites. Thus, an endothermic event of small intensity appears during heating calorimetric experiments at approximately 105 °C. The existence of these polypropylene crystals, confined within the nanometric channels of silica, is corroborated by SAXS measurements obtained via the change in the intensity and position of the first-order diffraction of SBA-15. The incorporation of silica also has a very significant effect on the rheological response of the resultant materials, leading to important variations in various magnitudes, such as the shear storage modulus, viscosity and δ angle, when a comparison is established with the corresponding neat iPP matrices. Rheological percolation is reached, thus demonstrating the role of SBA-15 particles as filler, in addition to the supporting role that they exert during the polymerizations.

Experimental Investigation on E-Waste Concrete with Silicafume

Electronic waste, commonly referred to as "E-waste," is any electronic device that is no longer useful or has reached the end of its useful life. This can include computers, smartphones, tablets, televisions, refrigerators, and other household appliances, as well as industrial equipment and medical devices. Many electronic devices contain hazardous materials such as lead, mercury, cadmium, and brominated flame retardants, which can be harmful to human health and the environment if not disposed of properly. Improper disposal of e-waste can lead to environmental pollution, as well as health problems for those who are exposed to the hazardous materials and is passing severe toxic waste issues to the human beings and the environment. E-waste is a growing problem worldwide, as electronic devices become more common and quickly become obsolete due to advances in technology. Recycling and proper disposal of e-waste is becoming increasingly important as more electronic devices. From then literature review it is inferred that the E waste was added to the concrete by partial replacement of Fine Aggregates. Recommended dosage of E waste as partial replacement of coarse aggregate was 10 % concrete. Minimum studies were carried out as a partial replacement of fine aggregates. To recommend the optimum percentage of E waste as replacement of fine aggregate. No effective method to prevent the leaching of toxic components from E waste concrete. The Compressive Strength, Split-Tensile strength, Rebound Number, UPV test and Durability tests was carried. Therefore, by incorporation of Silica Fume the mechanical properties such as Compressive strength and Tensile strength are improved. The increase in the % of E- waste decreases the density and hence E-waste concrete can be adopted for light weight construction. The quality of E-waste concrete improved by the incorporation of Silica Fume. which is evident from the rebound hammer and Ultrasonic Pulse velocity results. And also Durability Test results. The Optimum % of E-waste was found to be 5%. Overall, the combination of E-waste and Undensified Silica Fume develop a sustainable concrete which can prevent the unnecessary dumping of E-waste and act as a light weight concrete.

High early strength-high performance concrete produced with combination of ultra-fine slag and ultra-fine silica: Influence on fresh, mechanical, shrinkage and durability properties with microstructural investigation

This study relates to High early strength- High Performance concrete (HPC) produced with incorporation of Ultra-fine Slag (UFS) and Ultra-fine Silica (UFSi). Compressive Strength development was studied from an early period of 14–15 h of casting up to 180 days. The variations in workability and its retention levels after 60 min of mix preparation were recorded. Elastic modulus, compressive strain behaviour, flexural parameters, early age shrinkage and few durability properties were measured for resulting optimal concrete mixes. Modifications induced at microstructural level were assessed by Scanning Electron Microscopy (SEM) and Nanoindentation tests. Incorporation of UFS and UFSi resulted in reduction of fresh properties beyond certain addition percentages. Usage of UFS as part replacement to GGBS in HPC mixes showed considerable improvement with regards to mechanical and durability aspects. Incorporation of UFSi was evaluated to prominently improve early age strength of concrete in combination with UFS at optimal quantities, while moderately improving other mechanical properties. Early age shrinkage induced stress levels and the brittleness of concrete were observed to increase with use of selected admixtures under multiple blend system. Improvement in the microstructure was observed with denser hydrated matrix offering enhanced homogeneity and better bonding with aggregates. Increase in strength governing hydration phases was evidenced for optimal addition of UFS and UFSi. Durability behaviour was significantly enhanced for combination of UFS and UFSi owing to microstructural improvement through pore refinement.

Evaluation of Crosslinking Degree on the Integral Membrane by using Rice Husk Ash (RHA)

Rice husk ash (RHA) is a waste product from the harvesting and processing of rice that contains a high quantity of silica, approximately 95% after combustion. Membrane technology is being developed to remove impurities like heavy metals and dyes as the natural environment deteriorates and water supplies become scarce. Many researchers and developers are now adopting this type of technology. However, it has various drawbacks such as being costly and easily being fouled during the separation process. Therefor e, matrix modification of the membrane should be carried out to mitigate these problems. The incorporation of fillers from biomass materials is one of the ways. This research aims to demonstrate the significant effect of incorporating the extracted silica from rice husk ash (RHA) in a polymer-based membrane from a blend of Polyvinyl alcohol/chitosan/polysulfone on the membrane characteristics and antifouling properties. The membranes were prepared by using a phase inversion technique by the incorporation of silica from rice husk ash (RHA) at various concentrations such as 5 wt.%, 7.5 wt.%, and 10 wt.% with a fixed amount of the polymer blends. The results showed that the integral membrane M4 with 10wt.% silica has the best hydrophilicity properties and possesses excellent antifouling properties, which were portrayed through the greater value of pure water flux (PWF) of 20.38 L/m2.h and the highest flux recovery ratio of 76.32%. This study has proven the potential utilization of ricehusk ash to enhance the membrane properties for industrial wastewater treatment.