Synthesis and Characterization of Mesoporous Nanosilica Derived from Rice Husk Ash

Rice husk, an abundant agricultural byproduct, has garnered attention as a potential source of natural silica, a material with a myriad of applications. Natural silica is particularly attractive due to its low cost of production and safe handling. In this study, sodium silicate derived from rice husk ash was employed to create mesoporous nanosilica (MNS) via the sol-gel process. The extraction process commenced with the utilization of rice husk as a precursor for silica, capitalizing on its silica-rich composition. Fourier-transform infrared (FTIR) analysis was performed to ascertain the presence of Si-O-Si bonds within the synthesized MNS. This critical step confirmed the successful formation of silica-based materials. Subsequently, X-ray diffraction (XRD) analysis was employed, revealing a significant peak at 22 degrees, a clear indicator of the presence of crystalline silica. Examining the morphology of the MNS, field-emission scanning electron microscopy (FESEM) results showcased a smooth surface and spherical morphology. Additionally, high-resolution transmission electron microscopy (HR-TEM) was employed, revealing the presence of nanoparticles smaller than 100 nanometers, which is indicative of the mesoporous nature of the synthesized nanosilica. Characterization techniques, including FTIR, XRD, FESEM, and HR-TEM, provided compelling evidence of successful nanosilica extraction. The findings underscore the potential of utilizing agricultural waste products for the sustainable production of valuable materials like nanosilica, which holds promise in various industrial applications. This research not only contributes to the valorization of agricultural residues but also aligns with the pursuit of eco-friendly and cost-effective materials for a wide range of applications.

Green Nanotechnology: Harnessing Rice Husk Ash for Nano-Silica and Characterization Insights

In the form of nanoparticles, silica is a significant inorganic component of rice husk. Consequently, it is feasible to extract high purity amorphous silica nanoparticles by straightforward thermo-chemical processes. So, in this study, an eco-friendly chemical treatment method (Green Synthesis) was used to try and manufacture amorphous silica nanoparticles from rice husk ash. I had done synthesizing silica nanoparticle in Dept. of Soil Science and Agricultural chemistry, TNAU, Coimbatore in the year 2023 and the aim of this study is to characterize the silica nano particle and use it on agricultural crops. Selected region from X-ray diffraction analysis and Transmission Electron Microscopy, silica sample exhibited amorphous behaviour as seen in the electron diffraction patterns, whereas the Fourier-transform infrared Spectroscopy spectra primarily contained siloxane and silanol groups. Images obtained in Scanning Electron Microscopy (SEM) revealed the existence of primary nanoparticles with secondary microparticles, possibly as a result of their agglomeration. These silica nanoparticles can therefore be used in the fields of microelectronics, sensors, nano-additives and will be suitable on implication on agricultural crops.

Preparation of polypyrrole/nanosilica composite for solid-phase microextraction of bisphenol and phthalates migrated from containers to eye drops and injection solutions / 药物分析学报

This paper describes the electrodeposition of polyphosphate-doped polypyrrole/nanosilica nano-composite coating on steel wire for direct solid-phase microextraction of bisphenol A and five phthalates. We optimized influencing parameters on the extraction efficiency and morphology of the nanocomposite such as deposition potential, concentration of pyrrole and polyphosphate, deposition time and the nanosilica amount. Under the optimized conditions, characterization of the nanocomposite was inves-tigated by scanning electron microscopy and Fourier transform infra-red spectroscopy. Also, the factors related to the solid-phase microextraction method including desorption temperature and time, extrac-tion temperature and time, ionic strength and pH were studied in detail. Subsequently, the proposed method was validated by gas chromatography-mass spectrometry by thermal desorption and acceptable figures of merit were obtained. The linearity of the calibration curves was between 0.01 and 50 ng/mL with acceptable correlation coefficients (0.9956-0.9987) and limits of detection were in the range 0.002-0.01 ng/mL. Relative standard deviations in terms of intra-day and inter-day by five replicate analyses from aqueous solutions containing 0.1 ng/mL of target analytes were in the range 3.3％-5.4％ and 5％-7.1％, respectively. Fiber-to-fiber reproducibilities were measured for three different fibers prepared in the same conditions and the results were between 7.3％ and 9.8％. Also, extraction recoveries at two different concentrations were ≥96％. Finally, the suitability of the proposed method was demonstrated through its application to the analysis of some eye drops and injection solutions.

A Comparison of the Effects of Silica and Hydroxyapatite Nanoparticles on Poly(ε-caprolactone)-Poly(ethylene glycol)-Poly(ε-caprolactone)/Chitosan Nanofibrous Scaffolds for Bone Tissue Engineering

BACKGROUND: The major challenge of tissue engineering is to develop constructions with suitable properties which would mimic the natural extracellular matrix to induce the proliferation and differentiation of cells. Poly(ε-caprolactone)-poly(ethylene glycol)-poly(ε-caprolactone) (PCL-PEG-PCL, PCEC), chitosan (CS), nano-silica (n-SiO₂) and nano-hydroxyapatite (n-HA) are biomaterials successfully applied for the preparation of 3D structures appropriate for tissue engineering. METHODS: We evaluated the effect of n-HA and n-SiO₂ incorporated PCEC-CS nanofibers on physical properties and osteogenic differentiation of human dental pulp stem cells (hDPSCs). Fourier transform infrared spectroscopy, field emission scanning electron microscope, transmission electron microscope, thermogravimetric analysis, contact angle and mechanical test were applied to evaluate the physicochemical properties of nanofibers. Cell adhesion and proliferation of hDPSCs and their osteoblastic differentiation on nanofibers were assessed using MTT assay, DAPI staining, alizarin red S staining, and QRT-PCR assay. RESULTS: All the samples demonstrated bead-less morphologies with an average diameter in the range of 190–260 nm. The mechanical test studies showed that scaffolds incorporated with n-HA had a higher tensile strength than ones incorporated with n-SiO₂. While the hydrophilicity of n-SiO₂ incorporated PCEC-CS nanofibers was higher than that of samples enriched with n-HA. Cell adhesion and proliferation studies showed that n-HA incorporated nanofibers were slightly superior to n-SiO₂ incorporated ones. Alizarin red S staining and QRT-PCR analysis confirmed the osteogenic differentiation of hDPSCs on PCEC-CS nanofibers incorporated with n-HA and n-SiO₂. CONCLUSION: Compared to other groups, PCEC-CS nanofibers incorporated with 15 wt% n-HA were able to support more cell adhesion and differentiation, thus are better candidates for bone tissue engineering applications.

Study on the Effect of Hydrophilic/Hydrophobic Nano-silica with Different Adding Amount on the Stability of Glycyrrhetinic Acid Lipo-emulsion / 中国药房

OBJECTIVE:To study the effect of hydrophilic/hydrophobic nano-silica with different adding amount on the stabili-ty of lipo-emulsion. METHODS:Glycyrrhetinic acid lipo-emulsion 4 mL was taken,respectively adding into 0.5%,1.0%,1.5%(m/m,the same below) hydrophilic nSiO2,and 0.4%,0.75,1.0% hydrophobic nSiO2,incubating 2 h in 30 ℃ water;the same batch of Glycyrrhetinic acid lipo-emulsion was treated as blank control. The forms were observed under electron microscopy after treatment,absorbance value was determined,the stability parameter (KE) was calculated according to the absorbance value,then the adding amount of nSiO2 was optimized,3 batches of preparations was prepared,and the verification test was conducted. RE-SULTS:The spherical structure was Glycyrrhetinic acid lipo-emulsion in the electron microscopy,the substance wrapping its sur-face white ring (fully wrapped) or semi-circular structure (not fully wrapped) was nSiO2. KE of hydrophilic nSiO2 were 4.66%, 5.01% and -2.08%,and KE of hydrophobic nSiO2 were 3.02%,4.51% and 7.24%. The optimized adding amount of hydrophilic nSiO2 was 0.2%,0.3% and 0.4%,hydrophobic nSiO2 was 0.1%,0.2% and 0.3%;KE were 6.19%,3.05%,7.84%,8.42%, 2.41%,2.93%,respectively. The optimal adding amount was 0.3% hydrophilic nSiO2 and 0.2% hydrophobic nSiO2;the 3 batches of preparation showed the optimum stability in its own adding amount. CONCLUSIONS:Both hydrophilic and hydrophobic nSiO2 can improve the stability of Glycyrrhetinic acid lipo-emulsion,and preferably 0.3%,0.2%.

Modification study of cyanoacrylate medical adhesive / 医疗卫生装备

Objective To perform modification study of cyanoacrylate (CA) medical adhesive and to select the optimal mo-difying material and the best ratio.Methods Carboxylic multi-walled carbon nanotubes (MWCNTs-COOH), multi-walled carbon nanotubes (MWCNTs), hydrophobic nano-silica, nitrile rubber, epoxy resin and polymethyl methacrylate (PMMA) were used to modify 5% triclosan/cyanoacrylate antimicrobial adhesive respectively. The bond strength, toughness and viscosity of the modified adhesive were examined in different concentrations.Results 0.064% MWCNTs-COOH, 6% nano-silica, 4% nitrile rubber and 6.4% epoxy resin all had good effects in strength modification. The bond strength were (14.71±1.48)MPa, (14.03±1.92)MPa, (14.6±1.78)MPa and (14.05±1.46)MPa respectively. 8% nano-silica had the lowest Tg of (1.1±0.24)℃ and the strongest viscosity of (15 536.68±28.4)cP. When the nano-silica concentration was 8%, the compound was very viscous and sticky. When the antimicrobial adhesive modified with 6% nano-silica, the bond strength was (14.03±1.92)MPa, the Tg was (3.6±0.68)℃, and the viscosity was (5 278.87±31.68)cP.Conclusion 6% nano-silica is the best modifying material, and has the optimal effect of modification.