Kimia organologam

Dalam Buku ini pembaca diperkenalkan dengan satu cabang ilmu kimia organologam iaitu kimia bagi sebatian yang mengandungi unsur logam yang berikatan terus dengan atom karbon pada ligan. Bidang ini mengaitkan dua bidang kimia iaitu kimia tak organik dan kimia organik yang mana ilmu pengetahuan dalam kedua-dua bidang diperlukan untuk memahami dengan lebih jelas bidang ini. Tajuk-tajuk meliputi pengenalan asas kepada sebatian organologam yang meliputi latar belakang, penamaan, pengkelasan sebatian organologam. Seterusnya penyediaan, struktur dan tindak balas beberapa sebatian organologam terpilih dikemukakan. Akhir sekali pembaca didedahkan kepada sebatian organologam dalam industri yang berkaitan dengan kehidupan kita seharian dalam menangani masalah dalam bidang pertanian, penternakan, pengawetan kayu, perubatan dan sebagainya. Penulis mengharapkan dengan terbitnya buku ini, dapat menambahkan bilangan buku dalam Bahasa Melayu peringkat tinggi di pasaran bagi kegunaan pelajar-pelajar tahun tiga di Universiti

Optimization and characterization of exo-polygalacturonase by Aspergillus niger cultured via solid state fermentation

Polygalacturonases represent an important member of pectinases group of enzymes with immense industrial applications. The activity of exo-polygalacturonase produced by Aspergillus niger was studied in solid state fermentation (SSF) using Nephrolepis biserrata leaves as substrate. Central composite design (CCD) was used to optimize four significant variables resulted from the screening process that has been initially analyzed for the production of exo-polygalacturonase which are incubation time, temperature, concentration of pectin and moisture content. The optimum exo-polygalacturonase production obtained was 54.64 U/g at 120 hours of incubation time, temperature at 340C, 5.0 g/L of pectin concentration and 75.26% of moisture content. For partial characterization of exo-polygalacturonase, the optimum temperature and pH were obtained at 50°C and pH 4.0, respectively. SDS-PAGE analysis showed that molecular weight of exo-polygalacturonase were 35 and 71 kDa. This study has revealed a significant production of exo-polygalacturonase by A. niger under SSF using cheap and easily available substrate and thus could found immense potential application in industrial sectors and biotechnology

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

Tailoring the surface properties of carbon nitride incorporated thin film nanocomposite membrane for forward osmosis desalination

Thin film nanocomposite (TFN) membranes incorporated with carbon nitride (CN) or protonated CN (pCN) were fabricated for forward osmosis (FO) desalination. The CN and pCN were incorporated within the polyamide (PA) layer which was supported by pCN incorporated polysulfone (PSf) substrate to form the TFN membrane. It was found that the presence of pCN in the substrate has favourably altered the intrinsic properties and affected the formation of PA layer. The physico-chemical characterizations indicated that the presence of both CN and pCN enhanced the surface hydrophilicity but reduced the surface negativity of the PA layer. These features have resulted in the improved water transport and salt rejective ability. As a result, CN-pCN-TFN membranes exhibited improved water permeability by about 70% (0.67 L/m2 h bar) compared to TFC membrane while maintaining salt rejection of 94.5%. CN-pCN-TFN also exhibited better anti-fouling property compared to TFC in which the flux decline was only half of that of TFC membrane during the 9 -h antifouling test. This work demonstrates the feasibility of using functional CN and pCN to independently tailor the substrate and PA layer properties of the TFN membrane, hence improving the desalination performances of the membrane

Nanocomposite ultrafiltration membranes incorporated with zeolite and carbon nanotubes for enhanced water separation

The objective of this work is to develop a new class of nanocomposite ultrafiltration (UF) membranes with excellent solute rejection rate and superior water flux using zeolitic imidazolate framework-8 (ZIF-8) and multi-walled carbon nanotubes (MWCNTs). The effect of ZIF-8 and MWCNTs loadings on the properties of polyvinyldifluoride (PVDF)-based membrane were investigated by introducing respective nanomaterial into the polymer dope solution. Prior to filtration tests, all the membranes were characterized using several important analytical instruments, i.e., SEM-EDX and contact angle analyzer. The addition of the nanoparticles into the membrane matrix has found to increase the membrane pore size and improve its hydrophilicity compared to the pristine membrane. The separation performance of membranes was determined with respect to pure water flux and rejections against bovine serum albumin (BSA) and humic acid (HA).The experimental findings indicated that the nanocomposite membranes in general demonstrated higher permeation flux and solute rejection compared to the pristine membrane and the use of ZIF-8 was reported to be better than that of MWCNTs in preparing nanocomposite UF membranes owing to its better flux and high percentage of solute rejection

Bioconversion of starch to maltooligosaccharides (MOS) by the reaction of maltogenic amylase

Maltogenic amylase is one of the significant enzymes in oligosaccharides synthesis. Its ability to utilise multiple substrates and catalyse hydrolysis and transglycosylation reactions simultaneously makes it a unique biocatalyst. The catalysis could be exploited in many ways to obtain oligosaccharides of different lengths and various modified sugars. Nonetheless, one of the major drawbacks of substrate hydrolysis to produce oligosaccharides is the low production of MOS with higher degree of polymerisation. To address this issue, reaction parameter optimisation was performed via one-factor-at-a-time (OFAT) approach on the production of MOS from soluble starch hydrolysis using maltogenic amylase from Bacillus lehensis G1 (MAG1). Optimisation of MAG1 loading, soluble starch loading, temperature, time and pH resulted in the production of 84.87 mg/g MOS with polymerisation degree of 3 to 7 compared to that of 51.60 mg/g obtained before the optimisation process, which recorded 1.64-fold increment. Among all parameters, soluble starch loading gave the most significant impact on the MOS production as the reaction equilibrium is highly affected by substrate concentration. The occurrence of MOS with polymerisation degree of 4 and above, which resulted from starch hydrolysis further confirms the endo-type of MAG1. Because starch is an abundant and inexpensive source of carbohydrate in the world, this study provides a cost-effective MOS production process which is highly relevant for industry

The effect of noble metals on catalytic methanation reaction over supported Mn/Ni oxide based catalysts

Carbon dioxide (CO2) in sour natural gas can be removed using green technology via catalytic methanation reaction by converting CO2 to methane (CH4) gas. Using waste to wealth concept, production of CH4 would increase as well as creating environmental friendly approach for the purification of natural gas. In this research, a series of alumina supported manganese-nickel oxide based catalysts doped with noble metals such as ruthenium and palladium were prepared by wetness impregnation method. The prepared catalysts were run catalytic screening process using in-house built micro reactor coupled with Fourier Transform Infra Red (FTIR) spectroscopy to study the percentage CO2 conversion and CH4 formation analyzed by GC. Ru/Mn/Ni(5:35:60)/Al2O3 calcined at 1000°C was found to be the potential catalyst which gave 99.74% of CO2 conversion and 72.36% of CH4 formation at 400°C reaction temperature. XRD diffractogram illustrated that the supported catalyst was in polycrystalline with some amorphous state at 1000°C calcination temperature with the presence of NiO as active site. According to FESEM micrographs, both fresh and used catalysts displayed spherical shape with small particle sizes in agglomerated and aggregated mixture. Nitrogen Adsorption analysis revealed that both catalysts were in mesoporous structures with BET surface area in the range of 46-60m2/g. All the impurities have been removed at 1000°C calcination temperature as presented by FTIR, TGA-DTA and EDX data

Catalytic oxidative desulfurization of Malaysian diesel utilizing palm kernel shell activated carbon supported cerium/iron oxide

Existing technique of hydrodesulfurization (HDS) is no longer applicable in achieving Euro IV standard diesel due to the high operational cost, low efficiency and high operating temperature in hydrogen gas atmosphere. Due to these drawbacks, the utilization of the catalytic oxidative desulfurization (CODS) was introduced to complement the HDS process. In this study, the performance of activated carbon supported cerium and iron oxide catalysts were investigated using tert-butyl hydroperoxide (TBHP) as oxidizing agent and N,N-dimethylformamide (DMF) as extraction solvent. The effect of dopant ratio, calcination temperature, number of loading and desulfurization treatments were studied. The results showed that effective dopants ratio (% atomic weight) of Ce/Fe (80:20) prepared by wet impregnation method calcined at 400°C was the best catalyst in this study. Nitrogen adsorption/desorption measurement of CeO2/Fe2O3 (80:20)-AC exhibited the characteristic of microporous structure with Type 1 IUPAC isotherm. The micrograph of the field emission scanning electron microscopy (FESEM) illustrated an inhomogeneous distribution of various particle sizes composed of cerium and iron oxides as been proven by energy dispersive X-ray analysis (EDX) on the surface of prepared bimetallic oxides catalyst. The deep desulfurization of Malaysian commercial diesel fuel contained 440 ppm sulfur was achieved after oxidation with two cycle extraction process with 98% total sulfur removal to produce Green Diesel contained 8.8 ppm sulfur has been measured using GC-FPD. The results obtained has proven that CeO2/Fe2O3 (80:20)-AC can be used as potential catalyst for the removal of sulfur in the Malaysian diesel towards achieving the green diesel production

Binary metal oxides supported on gamma-Al2O3 for application in transesterification of low-grade cooking oil

Recently, the production of biodiesel has increased greatly due to the less harmful effects of this fuel towards the environment which is sourced from renewable materials compared to a conventional diesel. The series of solid base catalysts, binary metal oxide (Cu/Zn) were synthesized by the modified wet impregnation method supported on γ-Al2O3.The investigation of Cu/Zn/γ-Al2O3 catalyst on the calcination temperature, copper loading and number of alumina coatings had significantly affected the catalytic performance. The optimum conditions from experimental data were achieved with 10 wt.% of Cu loading of Cu/Zn/γ-Al2O3 catalyst calcined at 800°C with 3 times number of alumina coatings exhibited the highest fatty acid methyl ester (FAME) yields, 87.07% at mild reaction conditions (65°C, atmospheric pressure, 1:20 methanol-to-oil molar ratio, 10 wt.% of catalyst loading and 2 hours of reaction time). The physicochemical properties studied by BET surface area of Cu/Zn(10:90)/γ-Al2O3 catalyst calcined at 800°C which gave high surface area, 149.32 m2/g. FESEM-EDX analysis of Cu/Zn(10:90)/γ-Al2O3 catalyst indicated the amorphous in structure with undefined shapes and mixture of larger and smaller particles sizes. The production of biodiesel and the percentage conversion of FAME was analyzed by using GC-FID in the presence of methyl palmitate, cis-9-oleic acid methyl ester and methyl linoleate

Effect of calcium and iron doping over MoO3-PO4/Al2O3 catalyst in oxidative desulfurization of Malaysian diesel

The catalytic oxidative desulfurization (Cat-ODS) process has emerged as a new technology to achieve ultra-low sulfur levels in diesel fuels. The effect of calcium and iron dopant in MoO3-PO4/Al2O3 catalyst were tested on desulfurization reaction at ambient condition. The oxidizing reagent used was tert-butyl hydroperoxide (TBHP) and dimethylformamide (DMF) acted as an extraction solvent. A commercial Petronas diesel with 440 ppmw of total sulfur was employed to evaluate the elimination of sulfur compounds. The result obtained revealed that Fe/MoO3-PO4/Al2O3 catalyst gave superior performance towards desulfurization. The Fe/MoO3-PO4 catalyst was able to reduce the sulfur in commercial diesel from 440 to 79 ppmw with 82% of total sulfur removal while Ca/MoO3-PO4/Al2O3 catalyst only achieved 76% of sulfur removal. Ammonia temperature programme desorption (TPD) analyses showed that the Fe/MoO3-PO4/Al2O3 catalyst contained both strong and weak acid sites while field emission scanning electron microscopy (FESEM) micrograph illustrated well-dispersed homogeneous structure. The mechanistic study showed that it was depended on the type of dopant as the Fe/MoO3-PO4/Al2O3 catalyst tended to form sulfone in the oxidative desulfurization reaction meanwhile, the sulfoxide formation was dominated in the oxidative desulfurization reaction using Ca/MoO3-PO4(10:90)/ Al2O3 catalyst. The results obtained showed that Fe/MoO3-PO4(10:90)/Al2O3 catalyst can be used as a potential catalyst for the removal of sulfur in Malaysian diesel to achieve Euro IV diesel