Bleaching Clay Research Articles

Study of the thermal stability of spent bleaching clay-based geopolymer with waste polypropylene plastic aggregates

This study incorporated polypropylene (PP) plastic waste into the spent bleaching clay (SBC)-based geopolymer as aggregates, aiming to address pollution from plastic and edible oil industry waste while promoting a transition into circular economy of repurposing waste. The geopolymer mixture paste, containing PP plastic aggregates in different mass ratios (SBC:PP = 1:0.4, 1:0.6, 1:0.8, and 1:1) is oven cured at 60 °C and 80 °C for 8 h followed by 7 days of room temperature curing. Thermal properties of PP-SBC-based geopolymer mortars with varying compositions of PP plastic were assessed using Thermogravimetric Analysis (TGA) and Differential Scanning Calorimetry (DSC). The TGA results revealed that the geopolymer's thermal stability within the temperature range of 620 °C–700 °C improved with an increase in PP plastic aggregate content, up to an optimal amount of 1:08 PPSBCG sample ratio of SBC to PP cured at oven temperature of 80 °C has been chosen as the representative sample for further discussion based on analysis result of ATR-FTIR spectroscopy and BET analysis. Beyond this amount, a reverse trend was observed. The DSC analysis revealed that incorporating PP plastic aggregates reduced its thermal stability towards the melting reaction but improved its thermal insulation properties. However, this effect was observed only up to a composition of PP plastic relative to SBC of 0.6, beyond this threshold, a reverse trend was observed. In addition to TGA and DSC, the geopolymer samples were characterized using Attenuated Total Reflectance - Fourier Transform Infrared (ATR-FTIR) spectroscopy and N2 Brunauer-Emmett-Teller (BET) analysis. This study proved that the addition of high heat-resistant PP plastic into the geopolymer system increased the thermal stability of geopolymers, but only up to a certain optimal quantity. Excessive PP plastic resulted in a reverse trend due to significant effect of weakened interfacial bonding between the geopolymer matrix.

Influence of acid and thermal treatment on regeneration of spent bleaching clay and conversion of residual oil to biodiesel

ABSTRACT Spent bleaching clay (SBC) is a hazardous waste produced by vegetable oil refining industries. SBC contains a residual oil (RO) with a lot of organic and inorganic impurities and its disposal leads to severe environmental consequences. In this study, SBC regeneration by extraction, acid modification and pyrolysis under various conditions and biodiesel production were studied. The GC-MS of the extracted RO shows that the fatty acid content is in conformity with crude oil and is appropriate for biodiesel production. FTIR was recorded in order to evaluate the main functional groups of fresh-, spent-, regenerated bleaching clay. The specific surface area (SSA) of fresh bleaching clay (FBC) (166.1 ± 1.7 m2/g) was lower than regenerated bleaching clay (RBC) one. The highest SSA (252.1 ± 1.7 m2/g) was revealed by pyrolysis at 550°C and activation with 10% sulfuric acid. Subsequent increase in the acid concentration and temperature of pyrolysis caused a decrease in the SSA. The heavy metals concentration in RBC was lower than the limits for activated bleaching clay in the National Food Safety Standard. Hence, RBC effectively copes with heavy metal removal. The peroxide, anisidine, acid values and oxidation stability of oil bleached with RBC are comparable to the FBC. Implications: The disposal of spent bleaching clay from vegetable oil refining industries has been recognized as a significant environmental issue. After adsorbing the impurities, spent bleaching clay becomes contaminated with a high concentration of organic and inorganic substances, including residual oils, fatty acids, phospholipids, and potentially toxic heavy metals. This makes spent bleaching clay a hazardous waste and improper disposal can lead to severe environmental consequences. Due to the potential environmental harm caused by spent bleaching clay disposal, it is crucial for vegetable oil refining industries to adopt proper waste management practices. Overall, the proper management and disposal of spent bleaching clay is essential to prevent environmental contamination and safeguard human health.

ZSM-5@ceramic foam composite catalyst derived from spent bleaching clay for continuous pyrolysis of waste oil to produce monocyclic aromatic hydrocarbons

Spent bleaching clay, a solid waste generated during the refining process of vegetable oils, lacks an efficient treatment solution. In this study, spent bleaching clay was innovatively employed to fabricate ceramic foams. The thermal stability analysis, microstructure, and crystal phase composition of the ceramic foams were characterized by TG-DSC, SEM, and XRD. An investigation into the influence of Al2O3 content on the ceramic foams was conducted. Results showed that, as the Al2O3 content increased from 15 wt% to 30 wt%, there was a noticeable decrease in bulk density and linear shrinkage, accompanied by an increase in compressive strength. Additionally, the ceramic foams were used as catalyst supports, to synthesize ZSM-5@ceramic foam composite catalysts for pyrolysis of waste oil. The open pores of the ZSCF catalyst not only reduced diffusion path length but also facilitated the exposure of more acid sites, thereby increasing the utilization efficiency of ZSM-5 zeolite. This, in turn, engendered a significant enhancement in monocyclic aromatic hydrocarbons content from 39.15 % (ZSM-5 powder catalyst) to 78.96 %. Besides, a larger support pore size and a thicker ZSM-5 zeolite coating layer led to an increase in monocyclic aromatic hydrocarbons content. As the time on stream was extended to 56 min, the monocyclic aromatic hydrocarbon content obtained with the composite catalyst remained 12.41 % higher than that of the ZSM-5 powder catalyst. These findings validate the potential of the composite catalyst. In essence, this study advances the utilization of spent bleaching clay and introduces a novel concept for ceramic foam fabrication. Furthermore, it contributes to the scaling up of catalytic pyrolysis technology.

High-power ultrasound bleaching technique for canola oil (Brassica napus L.): Pigments removal and quality parameters

Canola seeds (Brassica napus L.) are among the most commonly used seeds in Mexico for vegetable oil production. This is based on the high yield and content of polyunsaturated and monounsaturated fatty acids. During oil bleaching, it is important to maintain fatty acids in their cis configuration because of the health concerns associated with trans-fatty acid consumption. In this sense, the industrial processing parameters employed for this purpose present some limitations, such as high temperatures and long times, which may change the cis configuration to trans. In addition, the amount of bleaching clay employed for this process could be a source of contamination because it is disposed of after treatment. Therefore, the aim of this study was to develop a bleaching process for canola oil using high-power ultrasound (US). US processing was applied to nine treatments with different processing times (60, 75, and 90 min), clay percentages (1, 2, and 3%), and temperatures (60 and 80 °C) to determine the concentrations of chlorophyll a and b (µg chlo/100 g oil), carotenes (µg β-carotene/100 g oil), color (L*, a*, b*, C*, and h°), iodine value (g I2/100 g oil), and finally carrying out a spectroscopic analysis (ATR-FTIR and Raman). A conventional bleaching treatment (100 °C for 180 min, 3% bleaching clay) was used as a control. The results revealed that US treatments with 2% clay at 60 °C for 60 and 90 min eliminated most of the chlorophyll compounds (98%). However, in terms of carotenes reduction, these identical treatments exhibited a similar tendency to that of the control (approximately 30% decrease). These findings also affected the sample color, in which US treatments revealed chromatic coordinates that indicated yellow tones with chroma values that were more intense than those in the control samples. In terms of the iodine value, such treatments fulfilled the international standards for vegetable oils (90–100 g I2/100 g oil). Finally, the spectroscopic study revealed no trans configurations or the presence of different chemical compounds after US treatment, because neither of them presented typical peaks for those molecular configurations. In this regard, US can be a useful methodology for bleaching vegetable oils, helping to reduce time, and bleaching clay with similar pigment reduction results.

Utilization of used bleaching clay in pellet fuel production with torrefied oil palm fronds

Torrefaction oil palm fronds was studied as a renewable biomass resource for efficient and sustainable pellet fuel production. Employing microwave heating during torrefaction, the process optimized the conditions to enhance the fuel properties. At 300 °C for 40 minutes, the torrefied oil palm fronds exhibited a remarkable rise in net calorific value to 23 MJ/kg, accompanied by a substantial increase in fixed carbon content to 46%. These enhancements signify a significant boost in energy content and carbon richness, which is crucial for cleaner and greener energy solutions. Comparing pellet fuels derived from raw and torrefied biomass, a striking difference in calorific values was observed. While raw biomass pellets reached 12.24 MJ/kg, their torrefied counterparts achieved an impressive 18.40 MJ/kg. This undeniable advantage highlights the effectiveness of torrefaction in elevating energy output. To optimize the composition of the pellet fuel, an ideal mass proportion of torrefied oil palm fronds and used bleaching clay was identified as 70:30. This blend resulted in the highest recorded calorific value, further endorsing the viability of the approach. In conclusion, torrefaction at 300 °C for 40 minutes proved to be a potent technique for enhancing oil palm fronds as a valuable source of pellet fuel. These findings underscore its potential to revolutionize renewable energy production, promoting sustainability and mitigating environmental impact.

Development of productive pseudocapsulated compound feeds for rainbow trout grown in the Central Federal District of the Russian Federation

The decrease in catch of valuable fish species from natural water bodies is compensated by their intensive cultivation in artificial conditions. In order to realize the main task of trout farms associated with obtaining marketable products in the shortest possible period of time, artificial feed is used as a source of food. A economically feasible alternative source of raw materials is the products of plant origin. In the process of production of oil and fat products at various stages, numerous fat wastes and by-products are formed, wich have fodder value and are not used as feeding facilities in industrial scale. This is especially frue for fat processing (soapstock of Light oil, fatty bleaching clays, dezodoration chases, phosphatides, calcium salts of fatty acids), as well as waste oils in combination with fat processing waste. On the base of studying the classical technology of producing mixed fodders for valuable fish species and eliminating its drawbacks the technology of pseudocapsulated mixed fodders for salmon fish grown in the CFD of Russia Federation with given fodder value and a line for its realization is suggested. The best way to bring fats and vitamins contained in them to valuable fish species is to feed them as a part of mixed fodders. At present, however, it is difficult to increase the level of fat in feed on the existing Russian fats supply lines, since most plants can include up to 10% of fat in the bulk feed line. Therefore, the development of mixing formulations and techniques for valuable fish breeds using sturgeon fish with more than 10% fat in it as an addition of fat oily wastes such as epaulettes and phosphates is not only of scientific interest. In the course of studies optimization encapsulated optimal feeds for program "Feed Optima Expert" pseudorainbow trout were also developed. As a result, close results were obtained in terms of the rate of growth of trout, the development, conversion of feed and viability in comparison with the best feed counterparts on the Russian market.

Effect of bleaching with different clay on the final composition of post-fermentation corn oil with high content of β-sitosterol

Bleaching of oils is a stage of refining, and for post-fermentation corn oil, it is a novel issue intended to pretreat the corn oil for downstream refining processes. As a result of the completed research, which used a selection of available bleaching clays at 2 g/100g, post-fermentation corn oil with an improved quality was produced. The oil featured a reduced peroxide number and a lower content of carotenoid dyes. The oil after bleaching was found to have increased oxidation stability without any change discovered in the composition of fatty acids. From this research, it was observed that the 5σ-avenasterol levels were reduced, which affected the total phytosterol content and the reduction of oil colour on the Lovibond scale. The colour strength was considerably reduced by the bleaching process, to a level which varied with the specific bleaching clay. The content of the predominant β-sitosterol did not change significantly and remained at 700 mg/100 g. Optimum processing results were achieved by using the Tonsil 4120 AFF bleaching clay with an addition of activated carbon, and using the Supreme 112FF bleaching clay without activated carbon.

PHYSICAL AND CHEMICAL PROPERTIES OF BLEACHING CLAY

The paper presents the study results of physicochemical properties of used (fatty) bleaching clay after using it at an oil extraction plant to purify vegetable oil from colored substances. In the studies X-ray phase, IK-spectral, granulometric, electron microscopic analyzes were used. The original and fattened heat-treated at 300 °C and 350 °C сlay was studied. It was revealed that the studied clay is monomineral with a predominance of the montmorillonite component and quartz is present as an impurity. Laser granulometric analysis of the studied clay samples showed that the bleaching clay particles in their bulk have a size not exceeding 100-200 μm and a porous highly developed surface. The specific surface area (Ssp) determined by the BET method on a TriStar II 3020 unit manufactured by Micromeritics (US) is 32 m2/g. Studies of the bleaching clay sorption properties showed that the sorption capacity determined under static conditions for the original clay by Ni2+ ions is 0.25 mmol/g. And for the fired clay it is 0.428 mmol/g, which is 1.7 times higher compared to the original clay. This, apparently, can be explained by an increase in the specific surface area and porosity during heat treatment. Analysis of micrographs obtained using a high-resolution scanning electron microscope TESCAN MIRA3 LMU (Czech Republic) showed that the bleaching clay structure consists of a porous inert material, and its porosity and roughness increase as a result of heat treatment. The IR study of clay samples has shown that during the heat treatment of used greased bleached clay, its structural features change: the destruction of triglycerides of fatty acids and other organic compounds present in the oil after bleaching occurs. For citation: Sverguzova S.V., Shaikhiev I.G., Sapronova Zh.A., Lupandina N.S., Voronina Yu.S., Gafarov R.R. Physical and chemical properties of bleaching clay. ChemChemTech [Izv. Vyssh. Uchebn. Zaved. Khim. Khim. Tekhnol.]. 2023. V. 66. N 6. P. 76-84. DOI: 10.6060/ivkkt.20236606.6780.

Performance of bleaching clays in dechlorophyllisation of microalgal oil: A comparative study

While clay has been extensively studied for its ability to remove chlorophyll from vegetable oil, its effects and suitability on microalgae oil have received far less attention. In this study, three different clay types are evaluated and compared for their ability to dechlorophyllise microalgae oil. The clays involved are kaolinite, Fuller’s earth and bentonite clay which are activated by acid treatment. Bentonite clay is found to remove chlorophyll effectively (76.04%) than kaolinite and Fuller’s earth due to the presence of porous materials that facilitate adsorption. Additionally, the conditions of high temperature (79.69%) and ultrasound treatment (84.24%) demonstrate satisfactory chlorophyll removal efficiency. Another promising finding is that chlorophyll can be adsorbed on the clays without affecting the lipid composition in the microalgae extract significantly. Spent bleaching clay disposal is a growing issue that poses an environmental burden. Reusing bleaching clay can lower expenses and increase oil recovery. In a single sequential run, using spent bentonite clay yields the outcomes comparable to those of virgin bentonite clay. This finding offers a useful green and environmentally friendly approach to remove chlorophyll from microalgae oil feedstock.

Lignin and spent bleaching clay into mono-aromatic hydrocarbons by a cascade dual catalytic pyrolysis system: Critical role of spent bleaching clay

In the present study, a cascade dual catalytic system was used for the co-pyrolysis of lignin with spent bleaching clay (SBC) to efficiently produce mono-aromatic hydrocarbon (MAHs). The cascade dual catalytic system is composed of calcined SBC (CSBC) and HZSM-5. In this system, SBC not only acts as a hydrogen donor and catalyst in the co-pyrolysis process, but is also used as a primary catalyst in the cascade dual catalytic system after recycling the pyrolysis residues. The effects of different influencing factors (i.e., temperature, CSBC-to-HZSM-5 ratio, and raw materials-to-catalyst ratio) on the system were explored. It was observed that, when the temperature was 550 °C, the CSBC-to-HZSM-5 ratio was 1:1, and when the raw materials-to-catalyst ratio was 1:2, the highest bio-oil yield was 21.35 wt%. The relative MAHs content in bio-oil was 73.34 %, whereas the relative polycyclic aromatic hydrocarbons (PAHs) content was 23.01 %. Meanwhile, the introduction of CSBC inhibited the generation of graphite-like coke as indicated by HZSM-5. This study realizes the full resource utilization of spent bleaching clay and reveals the environmental hazards caused by spent bleaching clay and lignin waste.

Catalytic co-pyrolysis of lignin and spent bleaching clay via binder-modified HZSM-5: Evolution of coke composition

In this present study, the composite catalysts were synthesized by agglomeration method using HZSM-5 and calcined spent bleaching clay (CSBC) for lignin with spent bleaching clay (SBC) co-pyrolysis vapors upgrading. The coke characteristics were investigated by NH3-TPD, FTIR, N2 adsorption-desorption, XRD, TGA, Raman, and UV–vis. The results showed that the addition of CSBC could convert the graphite-like coke of HZSM-5 into oxygenated coke, which was beneficial to the regeneration of the catalysts. The skeletal structure of the catalysts was not severely broken by the coke, but there were different degrees of deterioration of the pore structure and acidity (mainly strong acids). The composition of soluble coke (coke precursors) was analyzed by FTIR, GC-MS and HPLC. The soluble coke adsorbed on the catalyst was dominated by long-chain alkanes and oxygenated aromatic compounds. These compounds would continuously polymerize on the acidic sites of HZSM-5 to produce graphite-like coke. The modulation of HZSM-5 by CSBC could inhibit this process. This result explained the binder modification to improve the MAHs selectivity and catalyst stability from the side. This study provides a feasible direction for the modification of zeolite catalysts in the future.

Catalytic pyrolysis of spent bleaching clay for its regeneration and simultaneously producing aromatic hydrocarbons

This study was focused on the value-increment of spent bleaching clay (SBC) to produce aromatic hydrocarbons and regenerated bleaching clay (RBC) via ex-situ catalytic pyrolysis with HZSM-5. The catalytic pyrolysis experiments were conducted to clarify the regulatory functions of pyrolytic temperature and SBC-to-HZSM-5 ratio (S/H) on the product distribution and aromatics generation. The adsorbed oil in SBC could be decomposed almost completely at 450 °C. The optimum aromatics yield of 3.49 wt% was achieved at catalytic temperature of 600 °C and S/H of 15. The solid product obtained under this condition underwent calcination at 500 °C and acid treatment successively to prepare RBC. The treatment did not affect the montmorillonite structure of clay. The RBC possessed good porous structures with newly generated micropores. The specific surface area and pore volume of RBC reached 163.32 m2/g and 0.29 cm3/g, higher than those of 146.17 m2/g and 0.25 cm3/g of fresh activated bleaching clay (ABC), indicating the better adsorption performance of RBC.

Fast co-pyrolysis of lignin with spent bleaching clay into monocyclic aromatic hydrocarbons over a novel low-cost composite catalyst

Improving the anti-coking performance of catalyst during lignin-catalyzed pyrolysis without affecting the selectivity of the monocyclic aromatic hydrocarbons (MAHs) is a challenge. In this paper, a low-cost composite catalyst (CSHZ) was prepared using calcined spent bleaching clay (CSBC) as a binder for HZSM-5 to resolve the issue. In order to evaluate the performance of the composite catalyst, an ex-situ fast catalytic co-pyrolysis experiment was performed in a fixed-bed reaction system with lignin and spent bleaching clay (SBC) as raw materials. The impacts of the temperature, CSBC-to-HZSM-5 ratios, raw material-to-catalyst ratios, and cycle-regeneration times on MAHs distribution, are then studied. The selectivity of CSHZ11 (CSBS-to-HZSM-5 ratio of 1:1) for MAHs in bio-oil reached 78.02 % at 550 ℃ and the raw material-to-catalyst ratio of 1:1, which exceeded those of HZSM-5 alone by 19.12 %. After 3 reaction-regeneration cycles, the catalytic activity of CSHZ11 for MAHs was 71.11 % of fresh catalyst. The characterization (TEM, Py-IR, TGA, etc.) of the catalysts (fresh and discarded) revealed that the addition of CSBC regulated the acidity and pore channels of HZSM-5 and inhibited the formation of catalyst graphite-like coke. This study demonstrates the feasibility of using binder modification to improve the anti-coking performance of HZSM-5. It also serves as a reference for the integrated utilization of SBC and lignin.

Microwave catalytic co-pyrolysis of low-density polyethylene and spent bleaching clay for monocyclic aromatic hydrocarbons

Combined with the fact that the poor heat transfer effect of low-density polyethylene (LDPE), the microwave absorption characteristics of spent bleaching clay (SBC) and the synergistic effect of co-pyrolysis, we conducted a study. In this study, microwave-assisted catalytic co-pyrolysis of SBC and LDPE was used to produce bio-oil rich in monocyclic aromatic hydrocarbons (MAHs). Then the conditions of co-pyrolysis, including pyrolysis temperature, catalytic temperature, the ratio of SBC/LDPE and catalytic mass were explored. The findings revealed that SBC and LDPE had a synergistic effect, SBC had microwave absorption characteristics, which could transfer heat to LDPE to improve heating rate. And the high H/Ceff of LDPE promoted the deoxidation of the SBC, which could optimize the quality of bio-oil. Compared with 43.69% for LDPE pyrolysis alone and 47.18% for SBC pyrolysis alone, the content of MAHs during co-pyrolysis was 54.92%. The optimum pyrolysis parameter was discovered at the pyrolysis temperature of 550 °C, 450 °C of catalytic temperature, 40:28.5 ratio of SBC to LDPE, 7 g of HZSM-5 mass, 69.89% of MAHs and 16.48% of Polycyclic aromatic hydrocarbons was obtained.

Hydrogen production from cotton stalk over Ni-La catalysts supported on spent bleaching clay via hydrothermal gasification

Cotton stalk was gasified to produce H2 with Ni-La based catalysts in subcritical and supercritical water. Approximately 90% H2 yield was obtained under optimized conditions (360 °C, 0.5 g Ni-La catalyst loading, 0.5 g biomass and 10 min) by an orthogonal design with Ni-La/spent bleaching clay (SBC) materials. In addition, the H2 yield of rice and wheat straw increased by 41.5 and 39.5 times, respectively at optimized conditions. It was found that the activity of Ni-La materials supported on SBC ash and Al2O3 was similar, with H2 yields of 108.3% and 115.1% at 380 °C, respectively in 5 min. SBC ash provided a high specific surface area (94.4 m2/g) for the Ni-La catalyst. La-promoted Ni/SBC (0.19 mmol/g) had a stronger acidity than Ni/SBC (0.16 mmol/g). Ni-La/SBC had a broad reduction peak, indicating the uniform dispersion of Ni on the support. Ni-La/SBC materials not only realized the reuse of SBC but also effectively promoted the hydrothermal gasification of agricultural wastes.

Co-pyrolysis of lignin and spent bleaching clay: Insight into the catalytic characteristic and hydrogen supply of spent bleaching clay

This study aimed to clarify the catalytic characteristic and hydrogen supply of spent bleaching clay (SBC) in the pyrolysis of corncob lignin. The effects of lignin doping ratio (0%, 25%, 50%, 75%, and 100%) and pyrolysis temperature (450 ℃, 550 ℃, and 650 ℃) on pyrolysis products were evaluated. The results of the kinetic analysis showed that when the lignin doping ratio was 75%, the activation energy was 51.753 kJ·mol−1, which was lower than that achieved in lignin-only pyrolysis. When the lignin doping ratio was 75% (550 ℃), the relative content of P-type phenols (methoxy-free phenols) was 23.08%, which reflected an increase of 34.23% relative to the theoretical value. Corncob lignin and SBC produced favorable synergistic effects during co-pyrolysis, which promoted the production of P-type phenols (synergistic effect reached 134.44%) and aromatic hydrocarbons (synergistic effect reached 36.98%) and the inhibition of various oxygenated compounds. Concurrently, the mechanism of the synergy between lignin and SBC during co-pyrolysis was proposed based on the experimental results. This study could provide basic research and theoretical reference for the resource utilization of lignin and SBC waste.

Disposal, regeneration and pyrolysis products characterization of spent bleaching clay from vegetable oil refinery in a fluidized bed pyrolyser

Spent bleaching clay (SBC) is a by-product of edible oils refinery and inappropriate treatment has caused serious environmental pollution in the past decades. In this study, fluidized bed pyrolyser (FBP) was employed for oil recovery and regeneration of SBC. The oil recovery ratio (ORR) ranged from 24.8 to 60.2% at pyrolysis temperature of 400–700 °C, and reached the maximum at 600 °C. Pyrolysis oils (POs) were composed of carboxylic acids, alkanes, esters, aromatics, alkenes, alkynes and other oxygenated hydrocarbons, and the content of hydrocarbon compounds reached 73.9% in pyrolysis oil obtained at the pyrolysis temperature of 600 °C (PO600), which exhibited the potential for upgradation into green fuels and chemicals. The methylene blue (MB) adsorption value of pyrolysis char produced at pyrolysis temperature of 600 °C (PC600) reached maximum of 213.6 mg/g. While the decolorization ability of pyrolysis chars (PCs) increased with pyrolysis temperature, and pyrolysis char obtained at the pyrolysis temperature of 700 °C (PC700) reached maximum (i.e. 96.3%), close to that of virgin bleaching clay (VBC). FBP technology effectively improved the decolorization ability of SBC and achieved lower contents of heavy metals (Pb, Cd, Cr, Ni, Hg, and As) in PCs than national standards of VBC (GB 25571-2011), revealing the value of SBC regeneration through FBP technology. This study provided insights for utilization of SBC and the recovery of residual oil.

Dimethyl carbonate assisted catalytic esterification of palm fatty acid distillate using catalyst derived from spent bleaching clay

Herein, we utilized environmental waste products, palm fatty acid distillate (PFAD) and spent bleaching clay (SBC) from the palm oil refining industry as cheap feedstock and catalyst support, respectively, for glycerol-free biodiesel production. Dimethyl carbonate (DMC), regarded as a suitable environmental alternative to methanol in producing glycerol-free biodiesel, was used as the methylating agent. Reactions were carried out using a heterogeneous acid catalyst derived from SBC after calcination and sulphonation. The obtained solid acid catalyst was characterized using Fourier transform infrared spectroscopy (FT-IR), Thermogravimetric analysis (TGA), Field emission scanning electron microscopy (FESEM), Brunauer-Emmett-Teller (BET) and Energy dispersive X-ray (EDX) techniques. The experimental results revealed that the synthesized solid acid catalyst efficiently converted free fatty acids (FFA) present in PFAD to fatty acid methyl esters (FAMEs). The maximum conversion efficiency of 93.18% was obtained at optimum reaction conditions: catalyst amount 10 w/w%, reaction time 4 h, reaction temperature 100 °C and PFAD/DMC molar ratio 1:10. A mechanism for the esterification reaction between PFAD and DMC using the sulphonated SBC catalyst was also proposed. This study has established the esterification of PFAD experimentally with DMC using the synthesized sulphonated SBC catalyst.

Preparation, Characterization and Comparison of adsorbents from Kirfi kaolin clay with Commercial bleaching Clay

Several adsorbents were prepared by acid-activating Kirfi Kaolin clay sample obtained from Kirfi village in Bauchi state, Nigeria using sulfuric acid. The raw clay and the prepared adsorbents were characterized for their physical properties (pH, moisture content, apparent bulk density, and adsorptive power) and their chemical compositions, and compared with the properties of a commercial bleaching clay (CBC). Bleaching study was used to determine the adsorptive power of the raw clay as an adsorbent, the adsorbents prepared from the raw clay and the CBC while chemical composition was done using AAS and XRF. The result of compositional analyses showed that the silica content of 50.07% to 74.32% and alumina content of 4.42% to 10.96 were the major components of the raw clay, CBC and the prepared absorbents. The adsorbents prepared with 1 M and 2 M H2SO4 had compositions and physical properties that are similar to that of the CBC, and also has an adsorption powers (81.35% and 94.05% respectively) that are comparable to that of CBC (96.25%).

A novel bleaching approach: Microwave assisted sunflower oil bleaching and optimization

The factors affecting the microwave bleaching of sunflower oil and the interaction between them were investigated and optimized by response surface methodology using a three-factor five-level central composite rotatable design. Microwave power, time and the amount of bleaching clay were selected as independent variables studied in the range of 70-120 W, 2-15 min, and 0.01-0.5%. The dependent variables that measure the bleaching efficiency and oil quality were evaluated as hue angle, chroma and totox value. Optimization was carried out by minimizing totox and chroma and maximizing hue angle. Hue angle, chroma and totox were found as 96.91, 37.66 and 23.31 under optimal conditions. Optimal microwave bleaching was successfully performed by using less bleaching clay (0.4%) and a shorter time (8 min) compared to the current industrial application without any adverse effect on oil quality. Hence, microwave bleaching is thought to be an alternative method for the bleaching of edible oils.