Ultrasound-assisted extraction (UAE) of phytochemicals with response surface methodology (RSM) in Curcuma xanthorrhiza

The genus Curcuma from the Zingiberaceae family consists of 80 species is widely recognized for its culinary and pharmaceutical application and has a significant effect on medicine, food, cosmetic industries, and economic. Considering an eco-friendly extraction method that provides the efficiency of the extraction, it is great of interest to explore the best optimum condition of parameters used in the extraction. This research is carried out to optimize the ultrasound-assisted extraction (UAE) of the extract from C. xanthorrhiza via Response Surface Methodology (RSM). Box-Behnken design (BBD) is used with three variables: extraction time (5-20 min), temperature (30-50°C) and liquid-solid ratio (6-10 mL/g). In the extracts, xanthorrhizol and curcumin are quantified using reversed-phase high-performance liquid chromatography combined with a diode array detector. The optimum condition of yield and concentration of xanthorrhizol are found at the extraction temperature of 50°C, time 20 minutes, and liquid-solid ratio8 mL/g. However, the optimum condition of curcumin is found at the extraction temperature 30°C, time 12.50 minutes, and 10 mL/g liquid-solid ratio. This research recommended that the ultrasound-assisted extraction method under specific parameters has favorable potential to be used in the extraction process which is useful for advanced research

Highly stable photocatalytic removal of paraquat dichloride using ZnO/TiO2 supported on PVC

This study presents on ZnO/TiO2 supported on PVC (ZnO/TiO2@PVC) in the photocatalytic removal of paraquat dichloride. The ZnO/TiO2@PVC was characterized using XRD, FESEM-EDX, FTIR, and AFM. Findings indicated that ZnO/TiO2@PVC allowed degradation of paraquat dichloride under UV irradiation by the rate of up to 73%. XRD pattern indicated the presence of both TiO2 (anatase) and ZnO (zincite) crystalline as well as PVC amorphous structures. FESEM and AFM results revealed the observed shape and surface of TiO2 interconnected nanowires with ZnO nanorods uniformly distributed according to EDX mapping. The reduced surface roughness was also shown in the supported photocatalyst. FTIR analysis clearly demonstrate the combined spectra of immobilised ZnO/TiO2 powder catalyst onto the PVC in the composite. Kinetic study of the degradation process was performed according to pseudofirst- order and the influence of ZnO/TiO2 coating onto PVC polymer and initial paraquat concentration were investigated on the treatment performance. Under optimized condition (pH = 7, PQ =20 mg/L and catalyst coating =15%), the stability and reusability of the supported catalyst was also evaluated over ten sequential treatment runs, and the catalyst maintain high reactivity. High recyclability of the ZnO/TiO2@PVC composites as catalyst in photodegradation processes are also reported in this study

Biodiesel production via transesterification of low grade cooking oil over heterostructure nano particles of ni/mg/al2o3 catalyst

Biodiesel which were synthesis from transesterification reaction in the present of heterogeneous base catalyst has been intensively studied over the last decades. This catalyst has an excellent result in producing high percentage conversions of biodiesel without further purification and cleaning process which contribute to the water pollution and high water content in biodiesel product. So, this study was conducted to synthesize and characterize series of heterostructure Ni/Mg/Al2O3 catalysts with different parameters to test their effectiveness towards the catalytic transesterification reaction. Series of Ni/Mg/Al2O3 catalysts were synthesized by wetness impregnation method supported on γ-alumina beads. Three parameters were studied include calcination temperatures, dopant ratios to base and numbers of alumina coating. The activity of the catalyst in transesterification reaction was evaluated at 65ºC of reaction temperature, 3 hours of reaction time, 6% w/w of catalyst loading and 1:24 molar ratio of oil to methanol. The potential catalyst was characterized by N2 Adsorption Analysis, TEM (BIO-TEM) and CO2-TPD. Meanwhile, the performance of the catalyst was evaluated using GC-FID. From the data obtained, Ni/Mg(20:80)/Al2O3 catalyst calcined at 800°C and three times alumina coating have the highest weak and moderate basic sites that contribute to the highest percentage conversion of low grade palm oil to biodiesel compared to others. Besides that, BIO-TEM result showed that the particle was non-homogeneous shape with a mixture of square sheet and one dimensional heterostructure nano-rod particles was observed. The data obtained from CO2-TPD and N2 Adsorption Analysis (NAA) prove that high basicity of the Ni/Mg(20:80)/Al2O3 catalyst (2.80 mmol/g) and high surface area (125 m2/g) had led to 78.53% of biodiesel conversion

Characteristic of praseodymium oxide doped manganese/ruthenium catalyst in methanation: effect calcination temperature

Methanation reaction using carbon dioxide gas is one of favorable green technology to form methane gas by converting carbon dioxide in the presence of hydrogen. This technology needs the catalyst to achieve a higher catalytic activity. Therefore, a catalyst of Ru/Mn/Pr (5:30:65)/Al2O3 (RMP, 5:30:60) was prepared via wetness impregnation method and investigated on the effect of calcination temperatures with respect to catalytic performance using FTIR analysis. The RMP (5:30:60) catalyst calcined at 800oC was chosen as an excel catalyst with 96.9% of CO2 conversion and 45.1% CH4 formation at 350oC reaction temperature. From the EDX mapping, it can be observed that the distribution of all element is homogeneous at 800oC except Ru, O and Al at 900oC and 1000oC calcination temperature. The image from FESEM also shows the presence of some crystal shape on the catalyst surface. From the FTIR analysis, the peaks stretching and bending mode of O-H bonding decreased when the calcination temperature increased

Investigation of active species in methanation reaction over cerium based loading

A series of cerium oxide based catalyst has been studied by various cerium loadings that calcined at 1000oC using wet impregnation method. The potential Ru/Mn/Ce (5:35:60) /Al2O3 catalyst calcined at 1000oC was characterized using XRD, XPS, and BET analyses. As could be observed from the XRD analysis, at Ce ratio of 55% and 65%, both revealed the presence of RuO2 with tetragonal phase and intense, sharper peaks indicating to high crystallinity and in line with lower surface area, 50.95 m2/g in BET analysis. Meanwhile, CeO2 (cubic phase) and MnO2 (tetragonal phase) were also observed for 55%, 60%, and 65%, respectively. However, the presence of Al2O3 with rhombohedral phase at 55% and 65% was revealed as an inhibitor which decreased the CO2 conversion. The presence of active species on Ru/Mn/Ce (5:35:60) /Al2O3 catalyst has been confirmed using XPS analysis with the deconvolation peaks belonged to Ce4+ with the formation of CeO2 compound and Mn4+ for MnO2. The product formed in catalytic methanation was proposed to be H2O and CH3OH from GC and HPLC analysis

Biochemical and physical characterization of immobilized Candida rugosa lipase on metal oxide hybrid support

Enzyme immobilization on inorganic materials is gaining more attention with the potential characteristics of high-surface-area-to-volume ratios, increasing the efficiency of enzyme loading on the support. Metal oxide hybrid support was prepared by a wetness impregnation of five metal precursors, including CaO, CuO, MgO, NiO, and ZnO, on Al2O3 and used as a support for the immobilization of Candida rugosa lipase (CRL) by adsorption. Maximum activity recovery (70.6%) and immobilization efficiency (63.2%) were obtained after optimization of five parameters using response surface methodology (RSM) by Box–Behnken design (BBD). The biochemical properties of immobilized CRL showed high thermostability up to 70 °C and a wide range in pH stability (pH 4–10). TGA-DTA and FTIR analysis were conducted, verifying thermo-decomposition of lipase and the presence of an amide bond. FESEM-EDX showed the homogeneous distribution and high dispersion of magnesium and CRL on MgO-Al2O3, while a nitrogen adsorption–desorption study confirmed MgO-Al2O3 as a mesoporous material. CRL/MgO-Al2O3 can be reused for up to 12 cycles and it demonstrated high tolerance in solvents (ethanol, isopropanol, methanol, and tert-butanol) compared to free CRL

Effectiveness of Ru/Mg/Ce supported on alumina catalyst for direct conversion of syngas to methane: Tailoring activity and physicochemical studies

The century of urbanisation and industrialisation had a great impact on the environment due to the rapid growth of the flue gas sectors. Thus, green technology is enforced to convert carbon dioxide (CO2) gas into methane (CH4) gas as an alternative fuel in electricity generation, particularly coal and natural gas sources. Cerium (Ce) was recognised as one of the most basic and unique redox characteristics utilised in the promising methanation reaction among catalysts used. The trimetallic catalyst used in this work was prepared with Ce as the based catalyst and ruthenium/magnesium (Ru/Mg) as the impregnated metal. Response surface methodology projected the CO2 conversion to be less than 0.3% of the experimental value of 78.82% using the indicated parameters of 593 °C calcination temperature and 61 wt.% ratios. Ru/Mg/Ce/Al2O3 catalyst with 60 wt.% of Ce loading calcined at 600 °C produced 58.08% of CH4. The characterisation results revealed that CeO2, Mg(Al2O4), and RuO2 species were the active species for CO2 methanation selectivity, as observed in XRD and XPS analyses. The mesoporous structure and particle agglomeration resulted in a surface area of 147 m2/g

Optimization and physicochemical studies of alumina supported samarium oxide based catalysts using artificial neural network in methanation reaction

Developed countries are increasing their demand for natural gas as it is an industrial requirement for fuel transportation. Most of modern society relies heavily on vehicles. However, the presence of CO2 gas has led to the categorization of sour natural gas which reduces the quality and price of natural gas. Therefore, the catalytic methanation technique was applied to convert carbon dioxide (CO2) to methane (CH4) gas and reduce the emissions of CO2 within the environment. In this study, samarium oxide supported on alumina doped with ruthenium and manganese was synthesized via wet impregnation. X-ray diffraction (XRD) analysis revealed samarium oxide, Sm2O3 and manganese oxide, MnO2 as an active species. The reduction temperature for active species was at a low reaction temperature, 268.2oC with medium basicity site as in Temperature Programme Reduction (TPR) and Temperature Programme Desorption (TPD) analyses. Field Emission Scanning Electron Microscopy (FESEM) analysis showed an agglomeration of particle size. The characterised potential catalyst of Ru/Mn/Sm (5:35:60)/Al2O3 (RMS 5:35:60) calcined at 1,000oC revealed 100% conversion of CO2 with 68.87% CH4 formation at the reaction temperature of 400oC. These results were verified by artificial neural network (ANN) with validation R2 of 0.99 indicating all modelling data are acceptable

Catalytic transesterification of coconut oil in biodiesel production: A review

Biodiesel is one of the renewable energy (RE) sources that has received much interest due to its promising properties. Recently, the use of coconut oil as biodiesel has caught the attention of many researchers. As a result, this paper presents a comprehensive overview of the current catalysts used to produce coconut oil biodiesel via the transesterification method

Nickel oxide doped noble metals supported catalysts for carbon dioxide methanation and desulfurization reactions

Malaysia has one of the most extensive natural gas pipeline networks in Asia. Using pipeline system, the gas will be channelled to the onshore station where the natural gas will undergo separation of acidic gases. Nowadays, the removal of toxic gases such as H2S and CO2 via chemical conversion attracted many researchers due to the effectiveness of the technique. In this research, new catalysts of high industrial impact that can catalyze the reactions of CO2 methanation and H2S desulfurization were developed. A series of catalysts based on nickel oxide doped with ruthenium, rhodium, palladium and platinum were prepared. Then, the best two catalysts were subjected to undergo several optimizations such as different calcination temperature of catalysts, calcinations temperature of alumina, different support materials, preparation method, reproducibility testing and regeneration testing. Pd/Ru/Ni (2:8:90)/Al2O3 and Rh/Ni (30:70)/Al2O3 catalysts exhibited the most potential catalysts resulted from the activity testing monitored by FTIR and GC. These catalysts were prepared using wetness impregnation technique, aging at 85oC and followed by calcination at 400oC. Both catalysts achieved 100% H2S desulfurization below 200oC. In the presence of H2S gas, only 3.64% CH4 was produced over Pd/Ru/Ni (2:8:90)/Al2O3 catalyst from 57.31% CO2 conversion, while 0.5% CH4 was obtained from 4.53% CO2 conversion over Rh/Ni (30:70)/Al2O3 at temperature of 400oC, respectively. However, the methane percentage increased to 39.73% for Pd/Ru/Ni (2:8:90)/Al2O3 catalyst from 52.95% CO2 conversion and 70.75% for Rh/Ni (30:70)/Al2O3 catalyst from 90.1% CO2 conversion during testing without flowing of H2S gas. Moreover, the XRD diffractogram showed that both catalysts are highly amorphous in structure with BET surface area in the range of 220-270 m2g-1. FESEM analysis indicated a rough surface morphology and non-homogeneous spherical shape with the smallest particles size in the range 40-115 nm for fresh Pd/Ru/Ni (2:8:90)/Al2O3 catalyst and formation of aggregates with rough surface morphology for fresh Rh/Ni (30:70)/Al2O3 catalyst. The elemental analysis performed by EDX confirmed the presence of Ni, Ru, Pd, Al and O in the Pd/Ru/Ni (2:8:90)/Al2O3 catalyst while, Ni, Rh, Al and O in the Rh/Ni (30:70)/Al2O3 catalyst. Characterization by FTIR and TGA-DTG revealed the existence of nitrate and hydroxyl ions on the catalysts surface