Rice Husk Nanosilica Research Articles

Grafting of cinchonine onto rice husk nanosilica and its potential application in the synthesis of 2‐arylideneindan‐1,3‐diones and 2‐arylidene-5,5-dimethyl-1,3-cyclohexanedione

In this study, an eco-friendly and green procedure for Knoevenagel condensation reaction of aromatic aldehydes with indan-1,3-dione and dimedone was reported utilizing a rice husk silica‐anchored cinchonine nanocomposite as a heterogeneous catalyst in aqueous media. Without the need for an additional surfactant, rice husk was utilized as a raw material to create nanosilica. Through the grafting of 3-mercaptopropyl) trimethoxysilane, the rice husk nanosilica was modified. Next, azobisisobutylonitrile initiator was used to trigger the thiol-ene free radical interaction of the SH groups with the Cinchonine's alkene function. The morphology and structure of the nano SiO2-S-cinchonine were characterized using fourier transform infrared spectra, field emission scanning electron microscope, and energy-dispersive X-ray spectroscopy. The catalytic activity of the nanocomposite was investigated in the synthesis of 2-arylideneindan-1,3-diones and 2-arylidene-5,5-dimethyl-1,3-cyclohexanedione through an aqueous medium at 80 °C by the Knoevenagel condensation reaction. The advantages of this method are simple methodology, high yields, easy work-up, and green solvent.

Growth Response and Production of Rice (Oryza Sativa L.) Plant Study of Planting Distance and Concentration of Rice Husk Nanosilica Fertilizer

Growth Response and Production of Rice (Oryza Sativa L.) Plant Study of Planting Distance and Concentration of Rice Husk Nanosilica Fertilizer

Synthesis of Rice Husk Nanosilica using the Hydrothermal Method

Synthesis of rice husk nanosilica was carried out using hydrothermal methods at various temperatures and times and their characteristics. The stages of synthesis include sample preparation, nanosilica synthesis, and characteristics. The reaction temperature variations used are 120°C, 150°C, and 180°C, and the reaction time is 2 hours, 4 hours, and 6 hours then titrated using sulfuric acid until it reaches pH 7-8. XRF analysis results showed silica (SiO2) content of rice husk ash at 98.31%. Synthesized nanosilica has the largest particle size of 27.44 nm at a temperature of 180°C for 6 hours and the smallest size of 15.40 nm at a reaction temperature of 120°C and a reaction time of 6 hours. The nanosilica produced is multiphase, which is cristobalite, quartz, and coesite phases.

Removal of chromium from tannery wastewater by rice husk ash nanosilica

AbstractA study on the removal of hexavalent chromium by adsorption of rice husk nanosilica was attempted. The usage of chromium causes immense pollution as it is used in the leather industry, metal finishing, electroplating, and chromate preparations. To understand the adsorption capacity and its behavior, as well as the adsorption potential of rice husk nanosilica, the effluent used in this experiment is tannery wastewater. The experiment was conducted in tannery industrial wastewater using nanosilica extracted from rice husks ash for various pH, contact time, and adsorbent dosages. The result shows 88.3% chromium removal using rice husk ash nanosilica (RHANS) at pH 4, 1.75 mg adsorbent dosage, and 50 min of contact time. Removal of chromium by this method was a more economical and alternative process. RHANS was selected due to its source availability and antimicrobial properties.

Highly adsorptive protein inorganic nanohybrid of Moringa seeds protein and rice husk nanosilica for effective adsorption of pharmaceutical contaminants

The present study aims to investigate adsorption characteristics and mechanisms of Moringa (MO) seeds protein on nanosilica rice husk and their applications in removal of pharmaceutical residues including the fluoroquinolone antibiotic levofloxacin (LFX) and the nonsteroidal anti-inflammatory drug diclofenac (DCF) in aquatic environment. Molecular weight of MO protein was determined by gel-permeation chromatography (GPC) method while its amino acids were quantified by high performance liquid chromatography (HPLC). The number-(Mn) and weight-average molecular weights (Mw) of MO protein were 1.53 × 104 and 1.61 × 104 g/mol, respectively. Different effective conditions on adsorption protein on nanosilica including contact time, pH, adsorbent dosage, and ionic strength were systematically optimized and found to be 180 min, 10, 10 mg/mL and 1 mM KCl, respectively. The surface charge change by zeta potential, surface modification by Fourier-transform infrared spectroscopy (FT-IR) and adsorption isotherms demonstrated that protein adsorption on nanosilica was governed by both electrostatic and non-electrostatic interactions. Application of protein functionalized nanosilica (ProFNS) in LFX and DCF removal were also thoroughly studied. The selected conditions for LFX and DCF removal using ProFNS were 1 mM KCl for both LFX and DCF; pH 8 and pH 6; contact time 90 and 120 min, and adsorption dosage 10 and 5 mg/ml for LFX and DCF, respectively. Adsorption isotherms of protein on nanosilica as well as LFX and DCF onto ProFNS at different ionic strengths were reasonably fitted by the two-step model while a pseudo-second-order model could fit adsorption kinetic well. The removal of LFX and DCF using ProFNS significantly increased from 51.51% to 87.35%, and 7.97%–50.02%, respectively. High adsorption capacities of 75.75 mg/g for LFX and 59.52 mg/g for DCF, indicate that ProFNS is a great performance for pharmaceutical residues removal in water environment.

Efficacy of Rice Husk Nanosilica as A Caries Treatment (Dentin Hydroxyapatite and Antimicrobial Analysis).

Rice husk nanosilica has a porous, amorphous structure with a silica (SiO2) surface. Silica interacts with calcium ions to form hydroxyapatite and can induce the formation of reactive oxygen species (ROS), which harm microorganisms. This research determines the effect of rice husk nanosilica on the increase in dentin hydroxyapatite and its antimicrobial effects against Streptococcus mutans. We divided 27 dental cavity samples into three groups (n = 9). Group 1: normal dentin, Group 2: demineralized dentin, Group 3: demineralized dentin treated with rice husk nanosilica. The samples were analyzed using X-ray diffraction (XRD) to evaluate the formation of dentin hydroxyapatite. To analyze the viability of S. mutans after exposure to 2% nanosilica rice husk, we conducted an antimicrobial MTT assay. The Kruskal-Wallis test evaluates the formation of dentin hydroxyapatite, and the t-test evaluates the viability of S. mutans. There was an increase in the amount of dentin hydroxyapatite after the application of rice husk nanosilica compared with the control group (normal dentin), and 2% rice husk nanosilica had an antimicrobial effect (p < 0.005) in the group exposed to it. Rice husk nanosilica can induce the formation of dentin hydroxyapatite and has antimicrobial effects.

The Effectiveness of Adding Rice Husk Nanosilica to the Flexural Strength of Opaque Porcelain Coatings on Metal Ceramic Dental Crowns

Background. Failure of dentures that are unable to withstand flexural forces is often a major problem in the use of metal-ceramic crowns. The use of rice husk nano-silica powder has been extensively researched in dentistry because of its ability to improve mechanical properties. This study aims to determine the effectiveness of nano-silica particles from rice husks on the flexural strength of the opaque layer on Co-Cr metal-ceramic crowns.&#x0D; Methods. The type of research is experimental laboratories in vitro with posttest only control group design. The research samples were rectangular Co-Cr metal and porcelain plated on top of the metal center totaling 25 samples which were divided into 5 treatment groups. Flexural strength measurement with three-point bending at UTM. Data were analyzed by independent T-test and way ANOVA.&#x0D; Results. flexural strength of Co-Cr metal ceramic crown with the addition of 0.25% rice husk silica; 0.5%; 0.75%.1% in the opaque layer is 70.431±4.168; 84.093±2.852; 100,672±4,182 and 115,092±3,821, respectively.&#x0D; Conclusion. There is an increase in the flexural strength of metal ceramic crowns with the addition of 0.25% silica; 0.5%; 0.75%,1% on opaque coating.

The effect of rice husk nanosilica hydroxyl compound on dentin biomineralization.

Rice husk nanosilica contains hydroxyl for dentin remineralization. The aim of this study was to analyze and correlate the ability of rice husk nanosilica to induce hydroxyapatite dentin. The detachment of hydroxyl from rice husk nanosilica was analyzed using the sol–gel and pyrolysis methods with Fourier transform infrared spectroscopy. Subsequently, exposing of the demineralized dentin to rice husk nanosilica was performed for a comparison. The formation of hydroxyapatite on dentin was analyzed using X-ray diffraction. The amount of hydroxyl released from the two methods was then correlated with the hydroxyapatite that formed at the dentin. The extraction of hydroxyl on rice husk nanosilica with two methods was the same. Analysis of the amount of hydroxyapatite dentin with both the methods corresponds to each other. The correlation test obtains the value of R = 0.656. Rice husk nanosilica has a similar capability to release hydroxyl compound and form hydroxyapatite dentin using two methods. The creation of hydroxyapatite dentin is not only caused by the exposure of rice husk nanosilica but also owing to other factors that might reinforce the process of hydroxyapatite formation.

Efficacy of Rice Husk Nanosilica as a Caries Treatment (Dentin Hydroxyapatite and Antimicrobial Analysis)

Introduction: Rice husk nanosilica has a porous, amorphous structure with a surface containing silica (SiO2). Silica interacts with calcium ions to form hydroxyapatite and can induce the formation of reactive oxygen species (ROS), which harm microorganisms. Aims: To determine the effect of rice husk nanosilica on the increase in dentin hydroxyapatite and its antimicrobial effects against S. Mutans. Methods: Nine dental cavity samples were divided into 3 groups: group 1, normal dentin; group 2, demineralised dentin and group 3, demineralised dentin treated with rice husk nanosilica. The samples were analysed using XRD to evaluate the formation of dentin hydroxyapatite, and the results were statistically evaluated using the Kruskal-Wallis test. An antimicrobial test was conducted using an MTT assay to analyse the viability of S. mutans after exposure to 2% nanosilica rice husk, and the results were statistically evaluated using a t-test. Results: There was an increase in the amount of dentin hydroxyapatite after the application of rice husk nanosilica compared with the control group (normal dentin), and 2% rice husk nanosilica had an antimicrobial effect (p<0.005) in the group exposed to it. Conclusion: Rice husk nanosilica can induce the formation of dentin hydroxyapatite and has antimicrobial effects. Funding Information: The author would like to thank Universitas Indonesia for funding this research through PUTI Grant with contract number BA-631/UN2.RST/PPM.00.03.01/2021. Declaration of Interests: None to declare. Ethics Approval Statement: This research has obtained ethical approval No. 123/Ethical Approval/FKGUI/XI/201.

Luminescent properties of Eu3+-doped silica nanophosphors derived from rice husk

Rice husk nanosilica (RH-SiO2) doped with europium (RH-SiO2: Eu3+) was produced by the sol-gel method. X-ray Diffraction patterns show amorphous silica with increased crystallinity as the concentration of Eu increases. Phase transformation occurred with the addition of Eu3+ ion due to the presence of oxygen vacancy as well as strain in the lattice imposed by the larger size of the dopant ion in the lattice. The quartz structure emerged at a relative low concentration (1 mol%) and increased with Eu3+ content and at 3 mol% doping, the cristabolite phase emerged. No Eu3+ phase was observed. Scanning Electron Microscopy review agglomerates of nano-sized particles and Transmission Electron Microscopy show dispersed spherical nanoparticles measuring an average size of 35 nm. Fourier Transform Infra-red spectroscopy confirms the presence of SiO2. The surface area of the nanophosphor measured by Brunauer-Emmett-Teller is 189.64 m2/g. Photoluminescence (PL) analysis shows Eu3+ ion transitions leading to red emission. The asymmetry ratio and Judd-Ofelt intensity parameters indicate a low symmetry environment for the Eu3+ in the RH-SiO2 nanophosphors. The Ω2 values increase with increasing Eu3+ concentration, suggesting an increase in structural deformation or transformation of SiO2. The International Commission on Illumination (CIE) chromaticity coordinates values are close to the national television standard committee (NTSC) standards for red phosphors, which confirms the suitability of these red nanophosphors for display applications.

Impact of Gamma Radiation and Rice Husk Nanosilica on the Physico-Mechanical Properties of Styrene Butadiene Rubber/Natural Rubber Blend

Silica is the major inorganic constituent of the rice husk. High-surface area amorphous silica, Extracted Nanosilica (ENS), was developed by washing out the rice husk, followed by combustion and finally chemically treated. ENS was characterized by FTIR, XRD and TEM techniques. Reinforcement of natural rubber (NR)/styrene butadiene rubber (SBR) blend with varying ratio of ENS, namely 5, 10 and 20 phr, and separately with 20 phr Hisil (commercial silica) was established. Vulcanization of the produced composites was applied by gamma irradiation at a total dose range from 50 to 200 kGy. The radiation-cured nanocomposites were examined via mechanical, physical and thermal investigations. The SEM micrographs affirmed the homogenous distribution of silica particles throughout the polymer matrices. The results ensured noticeable enhancement in the investigated properties of the nanocomposites.

Использование сжигаемых рисовых остатков для производства нанокремнезёма

The current uilization of rice straw and husk as a solid fuel or burning out in the open air creates a large amount of ash, which is still inefficiently used and causes environmental problems in countries that grow rice. Meanwhile, valuable organic silica dioxide can be obtained from these wastes for wide applications. Recently, the production of organic silica dioxide from various sources has attracted much attention in the world. This article presents the results of a study on the preparation of nanosilica from rice straw and rice husk of Vietnamese by a two-stage process. In the first stage, burn rice straw or rice husks with ash content of 92.4% and 92.2% respectively, were treated by sodium hydroxide solution and then filtered to obtain a dissolved sodium silicate. In the second stage, the silica gel was precipitated from a solution by hydrochloric acid or sulfuric acid, the precipitate was washed, dried and burned at 575 °C to obtain the nanosilica powder. It was found that the treatment with 25% NaOH at room temperature for 72 hours was optimal for extraction the maximum possible amount of silica from both types of silica sources. The highest yield of SiO2 is observed when 12% HCl and 30% H2SO4 were used, however, the maximum yield of SiO2 was achieved with using 12% HCl. The characterization of the nanosilica was carried out by SEM, EDS and XRD, which indicated the amorphous structure of obtained silica, which had particle diameter rang to 50 nanometers. The silica content of rice husk nanosilica powder was 54.8%, it was 60.2% for rice straw nanosilica.

White-light-emitting Dy3+-doped amorphous SiO2 nanophosphors derived from rice husk

This research reports on the synthesis and characterization of white-light-emitting rice husk nano-silica doped with dysprosium ion (SiO2:Dy3+). The synthesis was carried out via the sol–gel method. Scanning electron microscopy and transmission electron microscopy show agglomerated particles. X-ray diffraction analysis shows all samples have amorphous structure. Diffuse reflectance analysis shows absorption band of the host SiO2 and 6H15/2 → 4I9/2 + 4G9/2, 6P7/2, 4I11/2, 4F7/2, 4G11/2, 4I15/2, 4F9/2, and 6F3/2 transitions of Dy3+ ions. Photoluminescence excitation spectra of the nanophosphors display both the host band as well as the intra-configurational transition lines of Dy3+ in the 250–500-nm range. Photoluminescence emission obtained at 275- and 350-nm excitation wavelengths shows two dominant emission lines assigned to the $$^{4}{{\text{F}}_{{\raise0.5ex\hbox{$\scriptstyle 9$}\kern-0.1em/\kern-0.15em\lower0.25ex\hbox{$\scriptstyle 2$}}}}\, \to {\,^6}{{\text{H}}_{{\raise0.5ex\hbox{$\scriptstyle {15}$}\kern-0.1em/\kern-0.15em\lower0.25ex\hbox{$\scriptstyle 2$}}}}$$ (blue) and $$^{4}{{\text{F}}_{{\raise0.5ex\hbox{$\scriptstyle 9$}\kern-0.1em/\kern-0.15em\lower0.25ex\hbox{$\scriptstyle 2$}}}}\, \to {\,^4}{{\text{H}}_{{\raise0.5ex\hbox{$\scriptstyle {13}$}\kern-0.1em/\kern-0.15em\lower0.25ex\hbox{$\scriptstyle 2$}}}}$$ (yellow) transitions of the Dy3+ ion. The International Commission on Illumination (CIE) chromaticity coordinate diagrams display white light with correlated color temperature (CCT) between 4868 and 6256 K (cold white light). These results show that SiO2:Dy3+ derived from rice husk has the potential for applications in white-light-emitting diodes (WLEDS) and other lighting technologies.

A novel and highly efficient photocatalytic degradation of malachite green dye via surface modified polyacrylonitrile nanofibers/biogenic silica composite nanofibers

In this work surface modified polyacrylonitrile nanofibers/biogenic silica composites were investigated for their promising and efficient photocatalytic degradation of malachite green (MG) dye. This photocatalyst was based on polyacrylonitrile (PAN) nanofibers fabricated using electrospinning technique, then crosslinked with two kinds of biogenic silica, diatomite and rice husk nanosilica. The photocatalytic activities of MG dye were compared for the two biogenic silica. The prepared membranes was analyzed using SEM, TEM, EDAX, FTIR, and XRD techniques. The photocatalysis performance investigations of malachite green were carried out under visible light illumination in aqueous solutions. Moreover, several factors affecting the degradation were studied including; dye concentration, solution pH, and irradiation time. The results indicated that the investigated composite nanofibers have excellent photodegradation performance for Malachite green. The highest photodegradation efficiency of the MG was obtained at pH 7 and it is relatively a very fast process.

Enhancement of polyethersulfone (PES) membrane performance by modification with rice husk nanosilica for removal of organic matter in water

This paper reports the effects of rice husk nanosilica addition on the performance of polyethersulfone (PES) membrane. Polyethersulfone membrane (PES) was fabricated by using N-methyl-2-pyrolidone (NMP) as a solvent and rice husk nanosilica as a modifying agent. The influence of the rice husk nanosilica additive on the characteristics and performance of the membrane has been studied. Scanning Electron Microscopy (SEM) analysis confirmed that the manufactured membrane has an asymmetric morphological structure consisting of two layers. The upper part of the membrane is a thin layer, meanwhile in the bottom side is a porous layer. The addition of 5% nanosilica resulting a PES membrane to have a bigger porous than that of pristine PES. The pure water flux of nanosilica-modified membranes were greater in comparison to the pure water flux of unmodified PES membrane. The performance of all membranes were evaluated on humic acid removal. The highest selectivity was showcased by pure PES membrane. The introduction of rice husk nanosilica additive to the membrane declined the selectivity of the membrane to humic acid in the feed solution. This is caused by the pores enlargement and enhanced hydrophilicity of the membrane after modification with rice husk biosilica.

Evaluation of the therapeutic effects of rice husk nanosilica combined with platelet-derived growth factor in hepatic veno-occlusive disease

Veno-occlusive disease is an important pattern of hepatotoxicity associated with antineoplastic drugs. The study investigated the possible therapeutic effects of RHS nanoparticles combined with a PDGF on veno-occlusive disease (VOD) in liver elicited in rats with DAC. In this work, nanosilica (SiO2) was successfully prepared from rice husk, and its physicochemical characteristics were investigated using EDX, XRD, N2 adsorption-desorption isotherm, SEM, and TEM. Forty-eight male Sprague-Dawely rats were distributed into 6 groups, with 8 rats in each. The first group served as the control. In the second group, animals were infused with DAC (0.015 mg/kg; 1-3 days) by intraperitoneal injection (i.p.). In the third group, rats were injected i.p. with DAC, and then at 24 h following the last dose of DAC, received nano-RHS incorporated with PDGF twice a week for 4 weeks. In the fourth group, normal animals were injected with RHS. In the fifth group, normal rats received PDGF, and in the sixth group, normal rats received nano-RHS combined with PDGF. The prepared nanosilica showed type II adsorption isotherm characteristic for mesoporous materials with a specific surface area of 236 m2/g. TEM imaging confirmed the production of nanoparticles via the followed preparation procedure. Radical scavenging potential for nano-RHS was determined using two different in-vitro assays: DPPH, and ABTS radicals. The results of this work show that administration of nano-RHS combined with PDGF significantly reversed the oxidative stress effects of DAC as evidenced by a decrease in liver function. It can be concluded that the nano-RHS combined with PDGF is useful in preventing oxidative stress and hepatic VOD induced by chemotherapy such as DAC.

Effect of combining Al, Mg, Ce or La oxides to extracted rice husk nanosilica on the catalytic performance of NiO during COx-free hydrogen production via methane decomposition

Amorphous nanosilica powder was extracted from rice husk and used as a catalyst support as well as a starting material for the preparation of different binary oxides, i.e., SiO2Al2O3, SiO2MgO, SiO2CeO2 and SiO2La2O3. A series of supported nickel catalysts with the metal loading of 50 wt % were prepared by wet impregnation method and evaluated in methane decomposition to “COx-free” hydrogen production. The fresh and spent catalysts were extensively characterized by different techniques. Among the evaluated catalysts, both Ni/SiO2Al2O3 and Ni/SiO2La2O3 catalysts were the most active with an over-all H2 yield of ca. 80% at the initial period of the reaction. This distinguishable higher catalytic activity is mainly referred to the presence of free mobile surface NiO and/or that NiO fraction weakly interacted with the support easily reducible at low temperatures. The Ni/SiO2CeO2 catalyst has proven a great potential for application in the hydrogen production in terms of its catalytic stability. The formation of MgxNi(1−x)O solid solution caused the Ni/SiO2MgO catalyst to lose its activity and stability at a long reaction time. Various types of carbon materials were formed on the catalyst surface depending on the type of support used. TEM images of as-deposited carbon showed that multi-walled carbon nanotubes (MWCNTs) and graphene platelets were formed on Ni/SiO2, while only MWCNTs were deposited on all binary oxide supported Ni catalysts.

Effects of Rice Husk Nano-Silica and Methylcyclohexylphosphinate on the Thermal and Fire-Retardant Properties of Epoxy Resin

Effects of Rice Husk Nano-Silica and Methylcyclohexylphosphinate on the Thermal and Fire-Retardant Properties of Epoxy Resin

Rice husk ash nanosilica to inhibit human breast cancer cell line (3T3)

NaOH treatment on phase, purity and particle size of rice husk nanosilica were investigated employing alkaline-extraction–acid-precipitation method. Mild reaction at lower NaOH (1.5 N) revealed small and fine particles (600 nm) due to moderate reaction rate. Morphology of human breast cancer cell line (3T3) revealed that suggestive cell distress effects were more pronounced at 500 µg/ml silica dosages which are in agreement with cell viability decrease (~50 %). Among different silica dosages, 10 µg/ml was found to have highest cell viability (∼70 ± 2 %) capable of increasing dissolved oxygen level while viability was almost decreased to 27 ± 5 % due to toxic effect caused at higher SiO2 dosage and could be a potential candidate best suited for biomedical applications through development of sustainable materials.