SiOH Groups Research Articles

Poly(cyclohexylsilsesquioxane)-Based Hydrophilic Thermoset-Resistant Deep-Ultraviolet-Transparent Glasses with Low Melting Temperatures.

Silsesquioxane (SQ)-based glasses with low melting temperatures were prepared by the cosolvent-free (solventless) hydrolytic polycondensation of organotrimethoxysilanes with cyclopentyl (c-Pe) and cyclohexyl (c-Hx) groups. Copolymers consisting of phenylsilsesquioxane (Ph-SQ) units and c-Pe-SQ units [poly(Ph-co-c-Pe-SQ)] or c-Hx-SQ units [poly(Ph-co-c-Hx-SQ)] were melted at 140 °C and formed clear glasses. The glasses prepared by this method contained many residual SiOH groups and exhibited high adhesive strength to microscope glass plates, metals, and several polymers. The glass-transition temperature of poly(c-Hx-SQ) was lower than that of poly(Ph-SQ) by only a small margin, whereas that of poly(c-Pe-SQ) was much lower. The poly(c-Hx-SQ)-based glasses were stiff at room temperature and transparent in the deep-ultraviolet spectral region (≲300 nm). They formed fragile melts with kinetic fragility parameters as high as ∼0.8. The melts of poly(c-Hx-SQ) and poly(c-Hx-co-Et-SQ) exhibited better resistance to thermal curing than that of poly(Ph-SQ) and maintained thermoplasticity even after heat treatment at 200 °C for 6 h.

Improvement of surface insulating performance for polytetrafluoroethylene film by atmospheric pressure plasma deposition

The surface flashover phenomenon across a vacuum-dielectric interface severely limits the service life and operational reliability of high voltage electrical equipment. Surface modification by atmospheric pressure plasma treatment is a promising method to improve the surface insulating performance of polymers. In order to explore the mechanism of plasma processing on the vacuum flashover characteristics of polymer materials, atmospheric pressure plasma deposition was used to treat polytetrafluoroethylene (PTFE) film. The surface parameters under different processing conditions, such as surface chemical composition, surface resistivity, surface charge decay and trap distribution, were tested and analyzed. The space charge distribution of PTFE and the flashover voltage in vacuum were measured. The results show that Si–O–Si and Si–OH groups are introduced on the surface of PTFE, and the characteristic peaks of PTFE are gradually weakened with the increase of processing time. The surface trap density increases and more traps with lower energy level arise with longer processing time. The plasma deposition changes the space charge distribution in PTFE body, and leads to positive charge accumulation inside the sample. The flashover field strength respectively increases by 15% and 70% in direct current (DC) voltage and microsecond pulse voltage after plasma deposition. The rapid dissipation of surface charge is the main reason for pulse flashover voltage enhancement, while the increase of surface leakage current due to lower surface resistivity and space charge accumulation in PTFE body make the DC flashover voltage reach the saturation point. Therefore the surface insulating and body performance of polymer materials after plasma modification processing should be considered comprehensively based on different applications.

Simultaneous improvement of interfacial bonding and thermal resistance of carbonaceous fiber/silicone composite coatings modified with aniline-methyl-triethoxysilane

Mechanical properties and thermal resistance reinforcement were achieved by a one-step dipping method, in which an aniline-methyl-triethoxysilane (AMT) coupling agent was grafted onto the carbonaceous fiber (CF) to fabricate CF/silicone resin (SR) composite coatings. Micromorphology and structure analysis of carbonaceous fibers showed that the AMT modification increase the roughness and the uniformity on the fiber surface, resulting in the link between AMT and fiber surface, and the polysiloxane formation by polymerization between the Si-OH groups. The AMT modification of the fiber surface introduced the AMT with a disordered structure on the fiber surface and improved the compatibility between CFs and SR. Mechanical testing showed that the tensile strength and elongation rate of the coating containing CF modified with 1wt%AMT coupling agent was increased by 45.32 % and 19.07 % compared with that of the unmodified one, respectively. The reinforcing mechanism revealed that the AMT modification improved interfacial bonding and mechanical riveting. Besides, the thermogravimetric analysis (TGA) analysis showed that the siloxane layer crosslinked at a high temperature, which was conducive to improving the thermal resistance for the long-term stability of the composite coatings. This special treatment provides an idea for simultaneously improving the mechanical properties and thermal resistance of silicone composites.

Achieving super dispersed metallic nickel nanoparticles over MCM-41 for highly active and stable hydrogenation of olefins and aromatics

Hydrogenation of olefins and aromatics is of significance for fuel processing and hydrogen storage, and developing nickel (Ni) catalyst highly active at low reaction temperature is the key to low the process cost. Herein we developed an ammonium citrate assisted impregnation method to fabricate loaded Ni catalyst (NiM-2) for hydrogenation. The Ni2+ species are anchored on the support MCM-41 strongly and evenly in form of Ni-citrate complex via the H-bonding between Si-OH group of MCM-41 and –COO- of citrate. During reduction, the carbon layerstemporarily formed by carbonization of citrate species inhibit the transfer and sintering of Ni species, and finally induces ultra-small metallic Ni nanoparticles after carbon layers slow decomposition by Ni species. Low coordination numbers and strong electron interaction between small metallic Ni nanoparticles and MCM-41 support upshift the d-band center of metallic Ni atoms. In hydrogenation, the small particle size and easier reduction for oxidized Ni species provide abundant active sites for reaction, and the upshifted d-band center induces strongly adsorption and activation of C = C bonds, which is confirmed for the first time in our work. As a result, the catalyst exhibits superior activity compared with reported and commercial Ni-based catalysts for hydrogenation of olefins and aromatics. Specifically, the catalyst with higher Ni loading (18%) exhibits good activity under room temperature and 0.1 MPa for hydrogenation of dicyclopentadiene and are comparable to Pd catalysts, making it as one of the best non-precious metal catalysts for hydrogenation reaction. And also, NiM-2 shows extremely high stability.

Unraveling the capture mechanism of gaseous As2O3 over H-ZSM-5 zeolite from coal-fired flue gas: Experimental and theoretical insights

Gaseous As2O3 discharged from coal-fired power plants results in severe detriments to the ecological environment. It is of great urgency to develop highly efficient As2O3 capture technology for reducing atmospheric arsenic contamination. Utilizing solid sorbents for gaseous As2O3 capture is a promising treatment for As2O3 capture. The zeolite of H-ZSM-5 was applied for As2O3 capture at high temperatures of 500–900 °C. Special attention was paid to clarifying its capture mechanism and identifying the influence of flue gas components via density functional theory (DFT) calculations and ab initio molecular dynamics (AIMD) simulations. Results revealed that due to high thermal stability with large specific areas, H-ZSM-5 demonstrated excellent arsenic capture at 500–900 °C. The captured arsenic consisted of As3+ and As5+ speciations, ascribed to As2O3 adsorption and oxidation. Moreover, As3+ and As5+ compounds were both through physisorption or chemisorption at 500–600 °C while dominant chemisorption at 700–900 °C. In particular, As3+ compounds were much more steadily fixed in products at all operating temperatures. Combining the characterization analysis and DFT calculations, it further verified that both Si–OH–Al groups and external Al species of H-ZSM-5 could chemisorb As2O3, and the latter exhibited much stronger affinities via orbital hybridization and electron transfer. The introduced O2 could facilitate As2O3 oxidation and fixation in H-ZSM-5, especially at a lower concentration of 2%. Additionally, H-ZSM-5 possessed great acid gas resistance for As2O3 capture under the concentration of NO or SO2 less than 500 ppm. AIMD simulations further identified that compared to NO and SO2, As2O3 was far more competitive and occupied the active sites of the Si–OH–Al groups and external Al species of H-ZSM-5. Overall, it demonstrated that H-ZSM-5 is a promising sorbent for As2O3 capture from coal-fired flue gas.

Green and sustainable nanoformulation of tebuconazole based on capsules of bionanocomposites halloysite/alginate

In this work, the synthesis of bionanocomposites based on halloysite/alginate with the fungicide tebuconazole (Tbz), as an active ingredient and its application as nanoformulation, was studied. The resultant nanoformulations were friendly to the environment and can be an alternative to increase the yiel of agricultural fields. To achieve this, the surface of the halloysite (Hal) was modified by the adsorption of five surfactants (one cationic and four nonionic) to obtain an organophilic organohalloysites (OHal). Adsorption isotherms and FTIR characterization demonstrated that OHal was obtained due to hydrogen bonding interactions between the nonionic surfactants and the Si-OH and Al-OH groups of the Hal, as well as due to cation exchange with the cationic surfactant. The Tbz was encapsulated in the OHal by adsorption. The mass of Tbz adsorbed was 6.73, 2.92, 4.41, 2.19, and 1.86 mg/g for the OHal with Span 20, Span 80, Tween 80, Tween 85, and HDTMA, respectively. This demonstrated that the surfactants with the highest uptake capacity in OHal have the lowest HLB (hydrophilic–lipophilic balance). The release kinetics of Tbz in the OHal occurred rapidly (approximately in 2 days), regardless of the surfactant type. Once encapsulated the Tbz with the alginate, the release time occurred between 5 and 15 days, decreasing the released quantity between 50 and 75%, evidencing a slow release and greater kinetics control. The confrontation of nanoformulations vs. Fusarium spp. delayed the fungus growth, like commercial tebuconazole does, corroborating the antifungal effect of the material, even though the nanopesticide synthesized in this work has 20 times less Tbz.

Preparation of coal fly ash supported high-temperature SCR catalyst by a novel alkali-acid combined activation

Coal fly ash (CFA) is an alternative carrier of selective catalytic reduction (SCR) catalyst, but its reactivity is usually poor. Herein, the alkali-acid combined activation was proposed to prepare the CFA-supported high-temperature SCR catalyst. The results revealed that 1.2 g/gCFA of NaOH and 0.6 g/gCFA of H2SO4 was the optimal CFA activation condition. The NaOH first destroyed the quartz crystal over the CFA, generating the Si-OH groups. Subsequently, H2SO4 enhanced the extraction of aluminates and enriched the acid sites, which promoted the standard SCR. Besides, the generated porous fragments facilitated the dispersion of Fe3+ species and improved the fast SCR.

Flexible All-Inorganic Perovskite Photodetector with a Combined Soft-Hard Layer Produced by Ligand Cross-Linking.

Although perovskite nanocrystals have attracted considerable interests as emerging semiconductors in optoelectronic devices, design and fabrication of a deformable structure with high stability and flexibility while meeting the charge transport requirements remain a huge challenge. Herein, a combined soft-hard strategy is demonstrated to fabricate intrinsically flexible all-inorganic perovskite layers for photodetection via ligand cross-linking. Perfluorodecyltrichlorosilane (FDTS) is employed as the capping ligand and passivating agent bound to the CsPbBr3 surface via Pb-F and Br-F interactions. The SiCl head groups of FDTS are hydrolyzed to produce SiOH groups which subsequently condense to form the SiOSi network. The CsPbBr3 @FDTS nanocrystals (NCs) are monodispersed cubes with an average particle size of 13.03nm and exhibit excellent optical stability. Furthermore, the residual hydroxyl groups on the surface of the CsPbBr3 @FDTS render the NCs tightly packed and cross-linked to each other to form a dense and elastic CsPbBr3 @FDTS film with soft and hard components. The photodetector based on the flexible CsPbBr3 @FDTS film exhibits outstanding mechanical flexibility and robust stability after 5000 bending cycles.

A computational and experimental investigation of TEOS-treated graphene oxide-PVA interaction: Molecular dynamics simulation and COSMO-RS insights

This research investigates the effect of tetraethyl orthosilicate TEOS on the interaction mechanism in the hybrid polyvinyl alcohol (PVA)/graphene oxide (GO) material. PVA, PVA/Go, and PVA/GO-SiO2 are produced by the solution casting method. The TEOS treated GO is confirmed by FTIR and also suggests that PVA is chemically bonded to GO-SiO2. XRD results reveal that the crystallinity of PVA is significantly reduced with the addition of TEOS as it becomes completely amorphous and shows that the GO has a full exfoliation in the matrix. However, thermogravimetric analysis indicates that the incorporation of GO improves the thermal stability of PVA by reducing its mass-loss rate upon heating. Theoretical molecular dynamic simulations indicate that the addition of SiO2 could significantly improve the binding interaction energies from 14387 kcal/mol to 15039 kcal/mol for 6PVA/3GO and 6PVA/3GO-3SiO2 systems, respectively. These simulations also highlight the occurrence of a hydrogen bonding between PVA and GO oxygen groups and PVA and Si-OH groups. The Conductor-like Screening Model for Real Solvents (COSMO-RS) study shows the intermediary role played by SiO2, which increases the compatibility between PVA and GO. The theoretical blend study also led to the conclusion that the three molecules could be mixed over the entire temperature range. Overall, these results suggest that TEOS can be successfully employed for the functionalization of PVA/GO hybrid materials, as it strengthens the interaction of the organic and inorganic phases.

Unusual Acid Sites in LSX Zeolite: Formation Features and Physico-Chemical Properties

The advanced approach for the preparation of the NH4 form of highly crystalline LSX zeolite under gentle drying conditions (40 °C, membrane pump dynamic vacuum) is discussed. Decationization of this form at moderate temperatures led to the formation of Brønsted acid sites (BASs), whose concentration and strength were characterized by IR spectroscopy. It was found that a maximum concentration of three BASs per unit cell can be achieved at 200 °C prior to the initiation of zeolite structure degradation. The proton affinity of BASs is unusual, and aspires 1240 kJ/mol, which is significantly higher compared to faujasites with higher moduli. The increase in temperature of the heat treatment (up to 300 °C) resulted in thermal decomposition of BASs and the manifestation of amorphous phase with corresponding Lewis acid sites (LASs) as well as terminal Si-OH groups. Both the destruction of BASs and formation of the LAS-containing amorphous phase are the key reasons for the significant decrease in the adsorption capacity in the micropore region revealed for the sample decationized at 300 °C.

Comparative assessment of formation pathways and adsorption behavior reveals the role of NaOH of MgO-modified diatomite on phosphate recovery

The phosphate adsorption behavior on MgO-modified diatomite has been routinely investigated. Batch experiments tend to show that the addition of NaOH during preparation largely promoted adsorption performance, but comparative studies of MgO-modified diatomite with and without NaOH (MODH and MOD) based on morphology, composition, functional groups, isoelectric points and adsorption behavior have not been reported. We demonstrated that NaOH can etch the structure of MODH and promote the migration of phosphate to active sites, which allowed MODH to have a faster adsorption rate, superior environmental adaptability, adsorption selectivity and regeneration performance. The phosphate adsorption ability was enhanced from 96.73 (MOD) to 197.4 mg P/g (MODH) under optimum conditions. Furthermore, the partially hydrolyzed Si-OH group reacted with Mg-OH via a hydrolytic condensation reaction to form a new Si-O-Mg bond. Intraparticle diffusion, electrostatic attraction and surface complexation may be the main modes of phosphate adsorption by MOD, while the MODH surface mainly relied on the synergy of chemical precipitation and electrostatic attraction due to the abundant MgO adsorptive sites. Indeed, the present study provides a new understanding of the microscopic analysis of sample differences.

Enhanced gaseous acetone adsorption on montmorillonite by ball milling generated Si–OH and interlayer under synergistic modification with H2O2 and tetramethylammonium bromide

Montmorillonite (Mt) is a potential adsorbent for volatile organic vapor removal from contaminated soils because of its rich reserves and porous nature, but its inertia surface property has limited its application for polar compounds. In this study, modifications of Mt were carried out by high energy ball milling with H2O2 and tetramethylammonium bromide (TMAB) to obtain adsorbents with both high porosity and abundant Si–OH groups (BHTMt). The microporous structure produced by TMAB insertion as well as the silanol (Si–OH) groups formed by H2O2 oxidation improved the adsorption of acetone by the modified material. The adsorption capacity of BHTMt for acetone was increased by 80% compared to the original Mt. The effect of H2O2 dosage on the adsorption performance for gaseous acetone was investigated by dynamic adsorption experiments. The adsorption kinetic results demonstrated that the adsorption of acetone by the modified material was subject to both physical and chemical adsorption. Density functional theory calculations indicated that there was no obvious interaction between TMAB and acetone, and the materials adsorbed acetone mainly through hydrogen bonding interaction of Si–OH as well as pore filling effects.

Analysis of Coal Boiler Ash Content and Palm Shell Boiler Ash as a Cementitious Material in ECC Mortar

XRF characterization results showed that coal boiler ash contained SiO2 = 29.3%; Al2O3= 14%; Fe2O3= 30.9%; CaO= 18.3% and palm shell boiler ash containing SiO2 = 48.9%; Fe2O3= 3.42%; CaO= 13.8%. The FTIR test results show that the OH stretching vibration of the SiOH group absorbs in the regions 3676, 3597, 3462, and 3315 cm-1 at the peak of the coal boiler ash spectrum and 3614, 3502, 3365, and 3323 cm-1 at the peak of the palm shell boiler ash spectrum. From the ECC mortar FTIR test results, it can be seen that the functional group changes with the OH stretching vibration of the SiOH group absorbing in the 3387 cm-1 area. The results of the ECC mortar compressive strength test at 28 days increased with the addition of coal boiler ash up to 15% and palm shell boiler ash 10%, so the compressive strength was 59.30 MPa.

Nanoscale insights into the interfacial characteristics between calcium silicate hydrate and silica

The interfacial characteristics between cement paste and silica are far from being fully understood, especially from the nanoscale perspective. Herein, molecular models were used to provide comprehensive insights into the interfacial characteristics between calcium silicate hydrate (C-S-H, the main binding phase of cement paste) and silica. Chemically, various types of bonds existed at the interface, including H-bonds and Ca–O bonds, and proton (H+) exchange occurred between C-S-H and silica. An increase in the water content of C-S-H could depress the deprotonation of the Si-OH groups on the silica surface. Structurally, an atomic-level interfacial transition zone (ITZ) with a low density was identified, which was attributed to the rich presence of –OH groups at the C-S-H–silica interface. The water molecules and calcium ions in the ITZ diffused faster than those in the bulk C-S-H. Mechanically, the interfacial bond strength was inversely related to the water content of C-S-H, with the higher water content reducing the interfacial interactions. Under loading, the interfacial fracture underwent three stages: crack propagation, atomic chain bridging (responsible for the interfacial residual strength), and complete failure. These atomic-level findings provide hitherto unknown mechanisms of the interfacial interactions between cement paste and silica.

Catalytic ozonation of hard COD in coking wastewater with Fe2O3/Al2O3-SiC: From catalyst design to industrial application

Development of robust, reactive, and inexpensive catalyst for pollutants abatement with catalytic ozonation is of great significance. Herein, the effect of a robust and easy-recovery catalyst, Fe2O3/Al2O3-SiC, for the catalytic ozonation of hardly biodegradable COD (hard COD) in coking wastewater had been explored. Al-O-Si bond formed on modified SiC through the substitution of hydrogen in surficial Si-OH groups by Al3+. The Lewis acid sites improved the adsorption of ozone and facilitated the formation of ·OH and O2·−. For coking wastewater treatment, the removal ratio of hard COD and the generation speed of hydroxyl radical (Rct) in the catalytic ozonation process were 71% and 253% higher than those in the ozonation group, respectively. Ozone utilization increased from 0.44 g COD removed/g O3 in the ozonation group to 1.42 g COD removed/g O3 in the Fe2O3/Al2O3-SiC catalytic ozonation group. In a full-scale application, Fe2O3/Al2O3-SiC catalytic ozonation decreased the consumption of O3 to 60 mg L−1 and decreased the operation cost by 50%. These results provided an approachable way for sharing the extraordinary capacity of ozone for contaminants remediation in industrial applications.

Titanium(IV) Surface Complexes Bearing Chelating Catecholato Ligands for Enhanced Band-Gap Reduction

Protonolysis reactions between dimethylamido titanium(IV) catecholate [Ti(CAT)(NMe2)2]2 and neopentanol or tris(tert-butoxy)silanol gave catecholato-bridged dimers [(Ti(CAT)(OCH2tBu)2)(HNMe2)]2 and [Ti(CAT){OSi(OtBu)3}2(HNMe2)2]2, respectively. Analogous reactions using the dimeric dimethylamido titanium(IV) (3,6-di-tert-butyl)catecholate [Ti(CATtBu2-3,6)(NMe2)2]2 yielded the monomeric Ti(CATtBu2-3,6)(OCH2tBu)2(HNMe2)2 and Ti(CATtBu2-3,6)[OSi(OtBu)3]2(HNMe2)2. The neopentoxide complex Ti(CATtBu2-3,6)(OCH2tBu)2(HNMe2)2 engaged in further protonolysis reactions with Si-OH groups and was consequentially used for grafting onto mesoporous silica KIT-6. Upon immobilization, the surface complex [Ti(CATtBu2-3,6)(OCH2tBu)2(HNMe2)2]@[KIT-6] retained the bidentate chelating geometry of the catecholato ligand. This convergent grafting strategy was compared with a sequential and an aqueous approach, which gave either a mixture of bidentate chelating species with a bipodally anchored Ti(IV) center along with other physisorbed surface species or not clearly identifiable surface species. Extension of the convergent and aqueous approaches to anatase mesoporous titania (m-TiO2) enabled optical and electronic investigations of the corresponding surface species, revealing that the band-gap reduction is more pronounced for the bidentate chelating species (convergent approach) than for that obtained via the aqueous approach. The applied methods include X-ray photoelectron spectroscopy, ultraviolet photoelectron spectroscopy, and solid-state UV/vis spectroscopy. The energy-level alignment for the surface species from the aqueous approach, calculated from experimental data, accounts for the well-known type II excitation mechanism, whereas the findings indicate a distinct excitation mechanism for the bidentate chelating surface species of the material [Ti(CATtBu2-3,6)(OCH2tBu)2(HNMe2)2]@[m-TiO2].

Chemical and Structural Comparison of Different Commercial Food Supplements for Silicon Uptake

Various food supplements for silicon uptake were compared in terms of their structures and chemical compositions. In particular, we analyzed the silanol group content, which can be an indicator of the uptake of the siliceous species in the human body. We analyzed the commercial products Original Silicea Balsam®, Flügge Siliceous Earth Powder, Pure Colloidal Silicon, and BioSil® by applying various methods such as FTIR, 29Si NMR, and TGA. The Si-OH group content of the samples containing pure silica was the highest for the Original Silicea Balsam followed by the Pure Colloidal Silicon. The siliceous earth powder revealed the lowest content of such groups and the densest structure. BioSil® contained a considerable concentration of organic molecules that stabilized orthosilicic acid. The study may help to understand the silicon uptake behavior of different food supplements depending on their chemical structure.

Effect of pH on the Synthesis of Silica Sol-Gel Tetraethylorthosilicate-Trimethylchlorosilan (TEOS-TMCS)

Sol-gel synthesis of silica employing the co-precursor trimethylchlorosilane (TMCS) and the precursor tetraethylorthosilicate (TEOS) was accomplished. The purpose of this investigation was to ascertain how pH affected the properties of synthetic silica. The synthesized hydrophobic silica was characterized using FTIR, TGA, and GSA to determine the effect of pH adjustment on the functional group characters, thermal properties, and pore morphology. The ratio between TEOS/TMCS was fixed at 75:25 and varied the pH (4, 6, 7, 8, and 10) and the calcination temperature (without calcination, 300℃ and 500℃). FTIR analysis showed that the number of C-H and Si-OH groups in the xerogel decreased with increasing calcination temperature. Xerogel formed at pH 6 provides the highest thermal stability among other pHs. The results from the BET analysis revealed that changes in pH directly affect the physical characteristics of the surface, making the resulting gel network less rigid and more susceptible to shrinkage of pore volume and diameter in the atmosphere. Meanwhile, in an alkaline medium, continuous condensation will occur so that the pore diameter and volume decrease. The high pore diameter and volume imply that pH 7 is ideal for preparing xerogels.

Formulation body scrub from silica gel of palm oil shell (Elaeis Guineensis Jacq.)

Background: Oil palm shell is a waste of oil palm plants that can be used as a source of silica gel because it contains SiO2. This study aims to determine the oil palm shell silica gel can be used as an active ingredient in the manufacture of body scrubs.
 Method: This study uses active ingredients with various concentrations of 2,5%, 5%, and 10%. The process of making silica gel starts with ashing, washing, making a sodium silicate solution, and adding NaOH. The preparation test includes an organoleptic test, homogeneity test, pH test, dispersibility test, adhesion test, irritation test, dead skin cell removal test, and stability test. Results: From the results of this study, the SiO2 content of palm oil shell silica gel is as much as 43% with XRF testing, and XRD results at an angle of 2ϴ=22,93º. The FTIR results showed the presence of a Si-OH group at a wave number of 3439.08 cm -1, a Si-O-Si group at a wave number of 1020,34 cm -1, and a -OH group at a wave number of 806,25 cm -1. The preparations that have been made meet the physical evaluation of the preparations, namely in the form of semi-solid, white color, and smells of oleum citri. Each homogeneous preparation, pH with a value ranging from 4,7 to 6,5, does not irritate the skin, meets the requirements of the spreadability test and adhesion test, has poor stability because the pH value has increased and decreased, has a good keratin content value, and the stability test of the formula against temperature at pH showed significant results (p>0.05).
 Conclusion: This research concludes that palm oil shell silica gel can be formulated as an active ingredient in making body scrubs and has the effect of removing dead skin cells on the skin.

Facile preparation of hydrophobic Halloysite nanotubes (HNTs) for enhancement of organic solvent nanofiltration performance of polydimethylsiloxane (PDMS)-HNTs mixed matrix membrane

Depleting the alumina layer with acid treatment followed by a baking process was performed to generate Si-OH groups on HNTs. Facile hydrophobic modification with Trimethylsilyl chloride (TMCS) was carried out to generate organic nonpolar solvent dispersible HNTs. Baked hydrophobic modified HNTs embedded in polydimethylsiloxane (PDMS) and coated on the polyethersulfone (PES) support membrane ((PDMS/ BmHNTs) delivered an excellent OSN performance with a permeance of 3.75 L m−2 h−1 MPa−1 and 98.80% rejection in methanol/brilliant blue G (50 ppm) separation, which outperformed pristine PDMS, PDMS/RHNT, PDMS/nBmHNT membranes. The excellent performance of PDMS/ BmHNTs membranes was attributed to the high degree of modification which led to excellent interaction with the PDMS matrix.