Papers by Keyword: Bentonite

Abstract: The original Java bentonite has been improved by a new method of multi-step impregnation using over-concentrated ammonium under nature temperature. The achieved materials were characterized using SEM-EDX, XRD, FTIR, and BET analysis and then applied in cationic dye adsorption. The specific case in peak XRD analysis of ammonium impregnation was detected at 18°, and the spectra at 532.3 and 470.6 cm^-1 of the FTIR analysis were detected as the ammonium vibration and oscillation bending. Surface structure analysis from SEM-EDX showed the smooth and expanded material achieved, supported by surface area analysis of BET, which described the increase of surface area materials from 61.791, 73.089, and 178.710 m²/g for the bent, bent-Na, and bent-NH, respectively. The highest adsorption capacity on bentonite impregnated by ammonium was achieved at 526.316 mg/g and 128.205 mg/g for rhodamine B and malachite green, respectively. The adsorption mechanism was feasible in endothermic and fitted to pseudo-second-order and Langmuir isotherm adsorption model. The new method of ammonium impregnation on bentonite successfully improved the adsorption ability.

Abstract: This paper presents the regression model for predicting the maximum dry density (MDD) and optimum moisture content (OMC) for sedimentary residual soil mixed with bentonite. The empirical models were developed in accordance with the statistical validity steps and conditions. The laboratories were conducted to determine the physical properties of mixed samples with bentonite such as Atterberg limit and particle size distribution. Meanwhile the compaction testing was performed on the mixed soil samples with bentonite to determine the MDD and OMC values at different compaction energies. The data obtained from laboratories and secondary data were used to develop an empirical model. The results showed there is significant relationship between the particle size, compaction energy and bentonite content to the OMC. Meanwhile there is a relationship between the OMC, bentonite content and compaction energy to the MDD. Reasonably good regression coefficients are obtained in case of both model which R² = 82% for MDD model and R² = 72% for OMC model. Meanwhile the determination coefficient and mean square error (MSE) for validated model between predicted model and empirical model were given R² = 89.5% with MSE = 0.065% for MDD model and R² = 79.5% with MSE = 5.9% for OMC model. Therefore, the models developed present a good predicting for MDD and OMC values.

Abstract: Plastic industry development has increased the amount of plastic waste, including LDPE plastic film, therefore LDPE waste processing becomes essential, such as thermal or catalytic cracking. Cracking is the breakdown of complex hydrocarbons into simple and commercial hydrocarbons (C₃-C₄₀). The catalytic cracking is preferred due to lower temperatures, which is 200-300°C instead of 500-700°C. In this study, catalyst selection, acid impregnation of catalyst, catalyst loading (wt%), N₂-gas-purging, feed-to-solvent weight-ratio, temperature, and reaction time were studied to determine the most suitable process condition to obtain the highest liquid fraction. In this study, the catalytic cracking was conducted at 20 bar with kerosene as solvent, with and without N₂-gas-purging at several temperatures (265 and 295°C), solvent-to-feed weight-ratios (5:1 and 4:1), catalyst types (bentonite, SiO₂ and ZSM-5), catalyst loading (wt%) (1.0wt%; 5.0wt%; 7.0wt%; 9.0wt%; 10.0wt%), and reaction time (1-3 hours). The best results were with N₂-gas-purging using 10.0wt%-bentonite in (5:1) solvent-to-feed weight-ratio for 1 hour at 295^οC produced 54.9wt% of liquid fraction and without N₂-gas-purging at 265°C produced 54.5wt% of liquid fraction, indicating the possibility of N₂-gas-purging exclusion in future studies. Additionally, this study has promoted bentonite as a potentially viable catalyst for LDPE plastic waste catalytic cracking.

Abstract: The goal of this study was to investigate the effect of varied proportions of silica/M-BNT/BNT on the curing properties of natural rubber (NR) composites. Thirteen ternary-filled NR composites and a control sample were prepared in this study based on a third degree – simplex lattice mixture design of experiment. It was observed that high loading of silica has a retarding effect on vulcanization rate due to the presence of silanol groups on its surface. Replacement of silica with BNT led to a big reduction in scorch time and increase in vulcanization rate due to the presence of metallic oxides acting as co-activators. The addition of the organoclay M-BNT to silica and BNT resulted to shorter scorch time, an increase in vulcanization rate, and a decrease in minimum and maximum torques improving the processability of the rubber composite. The kinetic model was able to demonstrate the vulcanization behavior of the rubber composites as supported by the very high coefficient of determination (R²) values for all samples. The generated contour plots for maximum torque (M_H), minimum torque (M_L), scorch time (t_S1), cure rate index (CRI), induction time (t_i) and rate constant (k₁) were able to display the trends observed in the experimental values.

Abstract: Thermoplastic starch film (TPSF) and hybrid thermoplastic starch film (HTPSF) were stored for 3 months to study the effect of aging on the mechanical properties and crystalline structure of the starch biopolymer. The alteration of the mechanical properties and crystalline structure of the films were analyzed through tensile test and differential scanning calorimetry (DSC) analysis. The incorporation of the hybrid filler (microcrystalline cellulose + nanobentonite) in the HTPSF has effectively prevented retrogradation happen in the starch structure. In contrary, the TPSF showed high degree of retrogradation resulted in significant decrement in elongation at break which was not observed in the HTPSF after 3 months of aging test.

Abstract: The synthesis of acid-activated Al₂O₃-pillared bentonite as a solid acid catalyst has been completed. The pillarization process was carried out using the varying pf calcination time, mole OH/Al ratio, and mmol of Keggin/bentonite to determine the optimum total acidity. The higher the calcination time, (OH/Al) ratio, and suspension concentration, the greater the acidity of ​​the Al₂O₃-pillared bentonite. The optimum conditions were achieved at a calcination time of 20 minutes, a mol of (OH/Al) ratio of 2.2, and Keggin/bentonite of 10 mmol with a total acidity of 11.76 mmol gram ammonia and 2.44 mmol/gram pyridine. The pillared bentonite had a surface area of ​​154.64 m²/g and a pore diameter of 3.38 nm. The pillaring process was successfully increasing the basal spacing of natural bentonite from 14.77 to 17.78.

Abstract: The work is devoted to solving the current problem of increasing the level of environmental safety of treatment industrial wastewater of leather production from chromium ions (III) through the use of natural and modified bentonite. The investigation about the efficiency of purification of model solutions, which containe 1 g/dm³ of chromium ions and 0.75 g/dm³ of phosphate ions was carried out by the method of ideal displacement. In our research, we proposed a method of sequential adsorption, according to which phosphate ions are absorbed in the first stage and chromium ions are sequentially adsorbed in the second stage. Structural features of natural carbonate-rich and modified with chromium and phosphate ions bentonite clay have been studied. researched and analyzed.

Abstract: The main objective of this study was to evaluate the effect of soda ash (SA) and carboxy methyl cellulose (CMC) on the rheological of white bentonite collected from Boyolali, Indonesia (BWB). The first work was the determination of BWB composition with XRF and the study on the effect of SA on the swelling index. The second step was to study adding SA and CMC on viscosity at 600 and 300 rpm. Another rheological parameter (yield point to plastic viscosity ratio, μ_P/μ_V) was determined based on the viscosity data. The results showed that the BWB sample tended to be categorized as Ca-bentonite with a calcium oxide content of 0.70 wt.% and contained montmorillonite, quartz, and pyrophyllite. SA and CMC in BWB increased the interlayer space of the montmorillonite. The addition of 14 wt.% SA to the BWB sample showed the maximum swelling index of 10 mL/2 g. The optimal formula meeting API 13A specifications is BWB sample of 81.23 wt.%, soda ash 14 % (w/w), and CMC 4.77 wt.%. This product results in the viscosity at a reading of 600 rpm of 30 cP and the μ_P/μ_V ratio of 1.0. Therefore, the product is potential as a candidate material for drilling mud.

Abstract: Reinforcement of both fibrous and particulate materials can improve composite properties for various applications, such as biomedical applications. The alkali-treated kenaf fibers and (SiO2, bentonite, and CaCO3) microparticles 400 mesh in size reinforce the epoxy matrix for hybrid composites. The bending and impact properties of hybrid composites, as well as their water absorption, are compared. The hybrid composites were prepared in a compression mold using a hand lay-up technique at 100°C for 20 – 50 minutes consisting of 28 vol.% of short kenaf fibers ~5 mm in length, 2 vol.% of each type of microparticle, and 70 vol.% the epoxy resin. The flexural and impact properties of kenaf/silica/epoxy composite indicated the highest flexural strength (58.37±3.9 MPa), flexural modulus (4.68 ± 0.17 MPa), and impact strength (7.49 kJ/m²⁾. The addition of the microparticles reduced water absorption in the composites. The water absorption of kenaf/silica/epoxy composite appeared to be stable for immersion time near 216 hours. Other microparticle-filled composites did not show this pattern. The incorporation of silica microparticles to the kenaf/epoxy composite potentially enhanced the mechanical properties of the composite, with the expectation of using it to be developed for biomedical composite material.

Abstract: Polybutylene succinate (PBS) with bentonite was investigated for its rheological, thermal and water absorption properties. The bentonite (BTN) was modified with soybean oil (SBO) and lard oil (LO) (2:98 clay: oil % by weight) by mechanical stirring and ultrasonication. The composites were prepared using an internal mixer and processed by compression molding. Under the bentonite modification conditions, XRD showed that the bentonite layers were penetrated with edible oils into the small layers and the enhancement of d-spacing between the BTN-layers in the composites. A small platelet-like structure of the modified bentonite composites was observed by SEM micrographs. The increase in MFI of untreated bentonite displayed the viscosity of PBS involving the moisture and water molecules decreased the frictional force. In addition, the viscosity of composites between PBS and treated bentonite with LO represented in an increase of the MFI value. Regarding the thermal properties, the presence of bentonite could act as a nucleating agent for PBS at low content (1-2%). Moreover, the treated with edible oils of bentonite could increase the percentage crystallinity of PBS at higher bentonite content. The presence of bentonite tends to increase the water absorption behavior of PBS/bentonite composites.