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The exclusive properties of β-cyclodextrin (β-CD) combined with its harmless characters making it as an interesting and potential carbon adsorbent for water pollutants removal via adsorption. This work was aimed at evaluating the kinetics and isotherm parameters of methylene blue dye adsorption onto β-CD polymers. The carbon polymers were prepared by citric acid cross-linking, followed by post-treatment with sodium p-toluenesulfinate. The adsorbents were characterized using TGA, BET and FTIR. The adsorption of methylene blue was studied at varying concentrations (5–300 mg/L) and contact times (10–2880 min), and the kinetics and isotherm models were employed to describe the adsorption data. The post-treated carbon polymer exhibits a greater specific surface of 16.6 m2/g. The maximum adsorption of methylene blue by cross-linked and post-treated β-CD adsorbents are 263 and 227 mg/g, respectively. The kinetics data fitted well into pseudo-first order model, indicating physical adsorption. The Boyd’s model showed that film diffusion may be the controlling mechanism. The equilibrium data of methylene blue adsorption for the two β-CD polymers obeyed Langmuir model. To conclude, β-CD is a promising adsorbent candidate for the treatment of dye wastewater.

In the present study, an ion exchange membrane for thermostable alkaline protease separation from Bacillus subtilis was prepared via integration of hydroxyapatite from fish scales (FSHAp) and polye...

Membrane technology is important in industrial wastewater and water treatment. Recently, the polymeric membrane technology is widely chosen in these applications. However, they are lowtemperature ranges, low corrosion resistance, and low lifespan. Thus, researchers are actively trying to develop a better membrane technology such as natural clay ceramic membrane due to their excellent in chemical, mechanical and thermal resistance, high-pressure application and long lifespan. This detailed review compiles through the literature of current scientific research over the last ten years. Its highlights the key findings of factors in the fabrication of natural clay ceramic membrane that contributed to its properties. This review article presented an outline of the advantages, disadvantages, and how to overcome the disadvantages, structure, and preparation of ceramic membrane, including method, raw materials, drying and sintering temperature. The review confirmed that the sintering temperature, the composition of raw materials and pore-forming agent are significantly enhanced the mechanical strength and porosity of the natural clay ceramic membrane. However, further development and modification of the natural clay ceramic membrane technology and their applications to treat different environmental pollutants is still necessary.

The present work was aimed to evaluate the performance of low-cost activated carbon from coffee residue for Bisphenol A removal. Coffee residue was activated using phosphoric acid and iron (III) chloride. The resultant activated carbons were characterized for textural properties, surface chemistry and surface morphology. The results show that AC-CoR I (H3PO4-activated coffee residue carbon) exhibits high surface area of 1030 m2/g and mesopore size of 2.13 nm, favourable for Bisphenol A removal at 105 mg/g. The adsorption data fitted well with the pseudo-second-order and Langmuir models. In conclusion, coffee residue is a promising precursor of activated carbon for wastewater treatment.

Study region Five mountain rivers (Rasau, Congkak, Sekayu, Nal, and Lata Payung) in Malaysia. Study focus Stability of mountain rivers is essential to maintain the natural landscape of fluvial morphology amid climate variability and anthropogenic stresses. However, rapid assessment tools for characterizing the channel stability of mountain river systems are lacking. In this study, a River Morphologic Stability Index (RMSI) is developed and used to evaluate the stability of 32 cross-sections in five mountain rivers in Malaysia. The performance of this index is compared with that of five conventional indexes. New hydrological insights for the region The analysis indicates that ten crucial parameters (and their weightages) are key to represent the dynamic changes of river landscapes: channel form (0.16), channel dimension (0.14), substrate (0.13), channel pattern (0.12), bank slope (0.09), bank erosion (0.08), channel adjustment (0.08), artificial feature and structure (0.07), degree of constriction (0.07), and vegetative cover (0.06). These parameters formed the basis of the development of RMSI. For each parameter, its ratings and weightages were defined to differentiate between the excellent and worst river conditions. The final RMSI score was grouped into four categories: highly stable (0 %–25 %), moderately stable (26 %–50 %), moderately unstable (51 %–75 %), and extremely unstable (76 %–100 %). Results indicated that 22 of all the 32 cross-sections concerned were within the ‘very stable’ category.

At present, heavy metal pollution is a major environmental concern and the adsorption technique is a potent method for removal of these heavy metals from wastewater. Activated carbon is one of the best adsorbents for metal ions removal but it is sometimes restricted due to high cost and problems with regeneration hamper large scale application. Low cost adsorbent is alternatively being introduced to replace activated carbon since it is available in large quantity, renewable and inexpensive. Hence, Pennisetum purpureum (elephant grass) was investigated for its potential in cadmium ions removal. The adsorbent was characterized by Fourier Transforms Infrared Spectroscopy (FT-IR), Scanning Electron Microscopy (SEM), Brunauer–Emmett–Teller (BET) and Barrett–Joyner–Halenda (BJH) analyses. The effects of pH (1 to 5), initial metal ion concentration (5 to 25 mg/L), contact time (10 to 60 minutes) and adsorbent dosage (0.2 to 1.0 g) on cadmium ions removal were conducted by batch adsorption experiments. In this study, the FT-IR results demonstrated that the functional groups for untreated and nitric acid-treated P. purpureum mainly consisted of carbonyl, carboxyl, hydroxyl and amine groups which are able to bind with positively charged cadmium ions. SEM micrographs have proven that nitric acid modification would remove the surface impurities of P. purpureum, which increased the surface roughness, produced deep, open pores and better pore size distribution. From the BET and BJH analyses, the treated P. purpureum was mesoporous, had larger surface area and pore volume compared to untreated P. purpureum. The best pH, adsorbent dosage and contact time were pH 4, 0.6 g and 30 minutes, respectively. The highest removal percentage of cadmium ions for both untreated and treated P. purpureum were 92% and 98% correspondingly. The results shown strengthened the fact that both biosorbents have great potential in cadmium ions removal.

Casuarina equisetifolia empty fruit has been utilized as activated carbon material because it is abundantly available in nature. The fruit was activated by metals hydroxide, namely potassium hydroxide and sodium hydroxide for dyes adsorption. The present work was aimed to evaluate the adsorption properties of activated carbons towards cationic dye (methylene blue) and anionic dye (congo red). Results show that KOH activation yields activated carbon with excellent maximum adsorption capacities of 614 mg/g and 340 mg/g for methylene blue and congo red, respectively. The adsorption data were analysed using isotherm and kinetic models and displayed a good regression with Langmuir and pseudo-second-order kinetic models.

Palm oil mill effluent (POME) is highly polluted wastewater that is to the environment if discharged directly to water source without proper treatment. Thus, a highly efficient treatment with reasonable cost is needed. This study reports the coagulation treatment of POME using integrated copperas and calcium hydroxide. The properties of copperas were determined using scanning electron microscopy (SEM), Fourier transform infrared (FTIR), X-ray diffraction (XRD), and X-ray fluorescence (XRF). Coagulation was conducted using jar test experiments for various coagulant formulations and dosages (1000–5000 mg/L), initial pH (4–10), stirring speed (100–300 rpm), and sedimentation time (30–180 min). The characterisation results show that copperas has a compact gel network structure with strong O–H stretching and monoclinic crystal structure. The effectiveness of integrated copperas and calcium hydroxide (Ca(OH)2) with the formulation of 80:20 removed 77.6%, 73.4%, and 57.0% of turbidity, colour, and chemical oxygen demand (COD), respectively. Furthermore, the integration of copperas and Ca(OH)2 produced heavier flocs (ferric hydroxide), which improved gravity settling. The coagulation equilibrium analysis shows that the Langmuir model best described the anaerobic POME sample as the process exhibited monolayer adsorption. The results of this study show that copperas with the aid of Ca(OH)2 demonstrated high potential in the removal of those parameters from POME with acceptable final pH for discharge. The utilisation of this by-product as a coagulant in effluent treatment can unlock the potential of copperas for wider applications, improve its marketability, and reduce gypsum waste generation from the TiO2 industry.

Nowadays, amount of aquaculture wastewater produced in Malaysia is increasing due to the development of aquaculture. The ineffectiveness of conventional wastewater treatment will cause the present of some contaminants such as suspended solids, organic nitrogen and phosphorus in aquaculture effluent. Membrane technology is used to solve this problem. However, the membrane characteristics will affect the effectiveness of the membrane in removing the contaminants. Therefore, this study was proposed to determine the effect of sintering temperature on the characteristics and performance of ceramic membrane. The materials used to fabricate the ceramic membranes in this study were natural clay, sawdust, sodium silicate and polyethylene glycols (PEG). The ceramic membrane was fabricated by using slip casting and sintering process. The four different sintering temperatures (800, 900, 1000 and 1100°C) were used to fabricate ceramic membrane. The increased in sintering temperature has reduced the porosity (47.13% - 40.66%) but increased the density (0.89 -1.06) and mechanical strength (19.99MPa – 23.37MPa) of ceramic membrane respectively. The SEM results shown that the ceramic membranes formed were defect free. The pure water permeation of the ceramic membranes is directly proportional to filtration pressure applied which ranged from 0.5 bar to 3 bar. All the ceramic membranes were applied for aquaculture effluent treatment. The optimum sintering temperature was 1000°C which the ceramic membrane produced at this sintering temperature showed the highest removal of total suspended solids (98.91%) and turbidity (94.24%).

Evaporation time is one of the important membrane fabrication parameter that can be manipulated in order to produce the desired membrane morphology in ultrafiltration (UF) separation process. The morphology of UF membrane has a significant effect on structural properties and performance of UF membrane. In this study, flat sheet asymmetric polysulfone/cellulose acetate phthalate/polyvinylpyrrolidone (PSf/CAP/PVP) blend membranes were prepared at different evaporation time in the range of 0 to 20 s to investigate its effect on the morphological structures of the blend membranes. The morphological structure of these blend membranes were characterized by using Scanning Electron Microscopy (SEM). The results showed that in the absence of evaporation time, the morphology of blend membrane consits of open finger-like structure and microvoids. Introduction of evaporation time period between 5 to 10 s, produced spongy blend membranes with less finger-like structure. Further increment of evaporation time between 15 to 20s, formed incomplete dense structure with small microvoids PSf/CAP/PVP blend membranes.

Landfill gas (LFG) is a mixture of gases mainly CH4 and CO2 which are the most problematic of the greenhouse gases (GHGs) due primarily to their highest rate of accumulation in the environment. These two main GHGs are emitted from most landfills in developing countries. As a mitigation measure, the gases can be collected and utilized as renewable energy source. This research therefore aimed at planning the utilization of LFG for renewable energy production using linear programing approach executed in general algebraic modeling system (GAMS) and applied to Seelong landfill in Johor, Malaysia as the case study. GAMS (the optimizer) selects the most profitable LFG utilization technology from a number of options such as: gas engine, gas turbine and steam turbine for electricity or combined heat and power production; steam boiler for steam production; direct LFG distribution to residences/industries as substitutes to natural gas. The results from the optimizer gave a maximum profit of USD2.54 million per year. This included revenues from product sale and carbon credit. The results also revealed that GHG reduction of about 9,000 tons CO2eq were accomplished, and thus this is environmentally and economically beneficial environmentally (in terms of carbon credit). Furthermore, the optimization results revealed that steam turbine running on low grade LFG is the most feasible option in terms of profitability and environmental consideration. This approach can be applied to any sanitary landfill as a means of simultaneously curbing GHG emission and generating revenue.

The study focuses on hydrogen production via glycerol steam reforming over copper and nickel loaded on HZSM-5 zeolite based catalyst. The catalysts were prepared by using different loading amount of copper (0-10wt%) and nickel (0-10wt%) on HZSM-5 zeolite catalysts through wet impregnation method and was characterized by X-Ray Diffraction (XRD). The performances of catalysts were evaluated in terms of glycerol conversion and hydrogen production at 500°C using 6:1 of water to glycerol molar ratio (WGMR) in a tubular fixed bed reactor. All the catalysts had achieved more than 85% of glycerol conversion except that of 5%Cu loaded on HZSM-5 catalyst. The addition of nickel into 5% Cu/HZSM-5 catalyst had increased the hydrogen yield. Similar trend was observed when copper was added into Ni/HZSM-5 catalyst but using copper loaded on HZSM-5 alone was unable to produce hydrogen compared to using nickel catalyst alone. It showed that copper acted as a promoter for hydrogen production. It was established that a 5wt% of Cu with 10wt% of Ni loaded on HZSM-5 catalyst showed significant improvement in terms of hydrogen yield and gaseous product compositions at selected operating conditions.

Rheological factor such as shear rate during membrane fabrication process has an effect on properties, structures and performance of membranes. Flat sheet asymmetric PSf/CAP blend membranes were prepared using an automatic casting machine at different shear rates in the range of 42.0 to 201.0 s-1. Results showed that increasing the shear rate from 42.0 to105 s-1has increased the molecular orientation and thickness which then reduces the water content, porosity and pure water flux of PSf/CAP blend membranes. However, further increasing the shear rate beyond 105 s-1has resulted in an increase in the water content of PSf/CAP blend membranes.

Rheological factor such as shear rate during membrane fabrication process has an effect on structural properties and performance of membranes. Flat sheet asymmetric polysulfone/cellulose acetate phthalate/polyvinylpyrrolidone (PSf/CAP/PVP) blend membranes were prepared by using an automatic casting machine at different shear rates in the range of 42.0 to 210.0 s-1. The blend membranes prepared at different shear rate were characterized in terms of its structural properties (molecular weight cut-off (MWCO) and average pore size) and performance (proteins separation). The results showed that increasing the shear rate from 42.0 to105 s-1 has decreased MWCO and average pore size of the blend membranes which then reduced protein solution permeate fluxes and increased proteins rejection of PSf/CAP/PVP blend membranes. However, further increasing the shear rate to 210.0 s-1 has resulted in an increase in MWCO and average pore size and consequently increased protein solution permeate flux but decreased proteins rejection.

It is well known that membrane with hydrophobic property is a fouling membrane. Polysulfone (PSf) membrane has hydrophobic characteristic was blended with a hydrophilic polymer, cellulose acetate phthalate (CAP) in order to increase hydrophilicity property of pure PSf membrane. In this study, membrane casting solutions containing 17 wt% of polymer was prepared via wet phase inversion process. The pure PSf membrane was coded as PC-0. PSf/CAP blend membranes with blend composition of 95/5, 90/10, 85/15 and 80/20 wt% of total polymer concentration in the membrane casting solutions were marked as PC-5, PC-10, PC-15 and PC-20 respectively. All of the membranes were characterized in terms of pure water flux and permeability coefficient in order to study their hydrophilicity properties. The investigated results shows that increased of CAP composition in PSf blend membranes has increased pure water flux, permeability coefficient and porosity of the blend membrane which in turn formed membrane with anti-fouling property.

Dielectric properties of materials play a significant role in design of microwave assisted processing system. This paper is focused on the dielectric properties of ε-caprolactone (ε-cap) which is the monomer for the biodegradable polymer, Poly (ε-caprolactone) (PCL). The dielectric properties of ε-cap were measured across a wide range of frequencies (0.1 GHz5.0 GHz) and temperatures (20-150oC). Then the measured dielectric properties data was modelled using Debye model in order to relate quantitatively the dielectric properties to microwave heating mechanisms. The analysis carried out gives a clear picture of interaction of ε-cap with microwave energy and its heating mechanism in microwave assisted polymerisation process. This study concluded that microwave heating mechanism of the ε-cap in the measured range may be dominated by the dipole reorientation.

Methane gas obtained from coal sources can be classified into two categories i.e Coal Bed Methane (CBM) and Underground Coal Gasification (UCG) gases. The Industry today often neglects the importance of capturing the UCG as important source of methane potential besides the surface gasification potential. This research will evaluate on the new resource estimation of methane as reserves with application of new technological advances in exploitation. As an analysis, the UCG energy return is significantly higher than that of CBM. Both CBM and UCG output gas can be liquefied, or used as a direct feedstock to local power stations. The CO2 generated from UCG process may be used for Enhanced Coal Bed Methane (ECBM) process because of more adsorption capacity than methane, may lead to additional methane potential. Deeper coal seams may be targeted for CBM, followed by UCG for additional resources in the form of coal gas. A depleted CBM area may be targeted for UCG with some modification on the well profile. Developing an integrated and centrally controlled approach to exploit the coal resources in which, the appropriate extraction methodology should be identified for each particular target coal-seam or groups of coal seam. It is important to strategize the sequencing of energy extraction methods to provide an optimal balance between the energy delivery for sustainable future and its true socio-economic value. As from this analysis, with 245.6 acres of coal, estimated gas can be produced is 3.25 TSCF which is 101 BSCF is coming from CBM, 3.14 TSCF from UCG and another 14.45 BSCF is from ECBM.

Combustion study of municipal solid waste combustion in a pilot scale fluidized bed combustor had been carried out. The work was aimed at demonstrating sustainable combustion of municipal solid waste by employing operating parameters gained from previous studies. The primary and secondary air factor used were AF = 0.8 and AF = 0.6 respectively. The fluidization number was 5Umf and both in-bed and freeboard region temperature distributions were monitored continuously. Results on the combustion studies revealed that the initial bed temperature could be sustained due to high thermal capacity of sand but later dropped due to problem related to the mixing of bulky and heterogeneous components of municipal solid waste and sand.

Preparation of Alpinia galanga agro waste-high density polyethylene (HDPE) composites involved the addition of eco degradant and polyethylene-g-maleic anhydride (PE-g-MA). The Alpinia galanga agro waste fibers at 3, 6, 10 and 15 wt% were compounded in an internal mixer with the addition of 5 wt% MA-g-PE and eco degradant. The composite specimens were prepared using an injection molding machine. The results show that the maximum tensile strength of 33 MPa was obtained for sodium hydroxide (NaOH) & 3-aminopropyltriethoxysilane (3-APE) treated fiber composites with eco degradant and MA-g-PE at 15 wt% fiber loading compared to that of pristine HDPE (28 MPa). All the treated composites show an improvement in tensile strength. This indicates that the treatments using NaOH&3-APE and p-toluenesulfonic acid (PTSA) with addition of eco degradant and PE-g-MA improved adhesion between Alpinia galanga fiber and HDPE matrix. The Scanning Electron Microscopy (SEM) micrographs show the presence of a improved interaction between treated Alpinia galanga fibers and HDPE matrix with the addition of eco degradant and MA-g-PE. Thermal stability of composites was also improved for composites with treated fibers.

Polysulfone (PSf) membrane is catogorized as hydrophobic membrane that easily fouled during membrane operation process. The presence of second hydrophilic polymer which added into membrane casting solutions plays a crucial role in adjusting the membrane properties. This hydrophilic polymer was employed in hydrophobic polymer membranes in order to improve hydrophilicity and performance as well as formed antifouling ultrafiltration (UF) membranes. In this study, a hydrophilic polymer, cellulose acetate phthalate (CAP) was added into polysulfone (PSf) membrane casting solutions by blending technique to produce PSf/CAP blend membranes. Flat sheet asymmetric PSf/CAP blend membranes were prepared by wet phase inversion method. The results revealed that an increase in CAP increased the hydrophilicity properties of PSf/CAP blend membranes compared to pure PSf membrane. The significant changes in size and numbers of microvoids and macrovoids in the morphological structures of PSf/CAP blend membranes were due to CAP promote the instantaneous liquid-liquid demixing during phase inversion process.

Biodiesel derived from vegetable oils is renewable and environmentally friendly than those of petroleum diesel. Currently most of the biodiesel is produced using homogeneous catalysts which are corrosive and non-reusable, leading to an increased cost and causing environmental problems. Alternatively, heterogeneous catalysts are being considered over homogeneous catalysts. Trans-esterification of triacetin with methanol was studied over sulfated zirconia which was prepared with different concentrations of sulfuric acid. Liquid-phase reaction was performed at 60°C for 8 hours using a stirred batch reactor. IR-pyridine was used to characterize the acid sites concentration and strength of the solid catalyst. Conversion of triacetin was about 69% on sulfated zirconia modified with 2M sulfuric acid. The conversion of triacetin was improved due to an increased in the amount of acid sites. The acidity of the sulfated zirconia has significantly affected the catalytic activity in the trans-esterification of triacetin.

This paper is focused on the design of a bubbling fluidized bed gasifier (BFBG) for EFB briquette gasification. The annual production of palm oil in Malaysia generates large quantities of lignocellulosic biomass which can be converted into clean, sustainable energy for the future. Hence, the prospect of valorising palm waste using biomass gasifiers presents a viable option for energy production. The fluidized bed gasifier (FBG) is considered the most suitable reactor for biomass gasification due excellent mixing, efficient heat temperature control and tolerance for fuels. Consequently, the proposed design of the bubbling fluidized bed gasifier for EFB briquette gasification will consist of three main parts; feeding zone, gasification zone and the effluent gas zone for syngas production. The results of feedstock physicochemical properties such as bulk density, particle size, the bed hydrodynamic and fluidization parameters for gasification used in the design of the gasifier are presented in this paper.

Glycerol is the main by-product of biodiesel production and during the trans-esterification reaction, about 10 wt % of glycerol is produced. In this study, different amount of Ni was loaded on HZSM-5 and tested for the conversion of glycerol to hydrogen. The studies were also conducted at different reactor temperature of 450, 500, 550, 600 and 650°C respectively. The structural characterization of the catalyst was carried out using the XRD. It was found that, the addition of 15 wt % of nickel loaded on HZSM-5 shows the highest glycerol conversion of 98.54%. In addition, it produces the highest yield of hydrogen gas operated at reactor temperature of 600°C.

BACKGROUND: Membrane fouling in downstream processing has become a major obstacle in enzyme production. The use of a membrane with high surface hydrophilicity may be an acceptable way to overcome this problem. In this study, the effects of dip time on chitosan incorporation were investigated to produce a low fouling ultrafiltration membrane for trypsin separation. RESULT: Pristine ultrafiltration membrane with a polymer concentration of 15% was developed via phase inversion. Membrane surface modification was performed using chitosan solution with different dip times. Membranes with a 60-min dip time provided optimum trypsin transmission (about 91.8%). Such membranes have a high permeability coefficient (71 L m−2 h−1) and good porosity (about 89.6%). The hydrophilicity of this modified membrane was also improved by 50% compared with the native membrane, and its flux recovery was about 89.8%. The successful assembly of chitosan onto the membrane's surface was ascertained by ATR-FTIR and X-ray diffractometry (XRD). The morphology of this membrane was significantly different from that of native membrane. CONCLUSION: The experimental results show that membrane dip time exerts a significant influence on the self-assembly of chitosan particles onto the membrane's surface, and this process can be used to produce a potentially low-fouling UF membrane for trypsin separation. Copyright © 2012 Society of Chemical Industry

The aim of this study is to investigate the influence of different composition of cellulose acetate phtalate (CAP) on the membrane structural properties of polysulfone (PSf) membrane which in turn affect the separation performance of PSf/CAP blend membrane. The PSf/CAP blend membranes were prepared by using casting solutions contain 17 wt% of polymer via wet phase inversion process. The results showed that increasing the composition of CAP in PSf/CAP blend membranes increased molecular weight cut-off (MWCO), average pore size and pore density which then increased protein solution permeate fluxes but reduced proteins rejection of PSf/CAP blend membranes. Pure PSf membranehas the lowest membrane structural properties compared to blend membranes. This characteristic contributed to decrease in protein permeation flux and increase proteins rejection.

Eco-friendly adsorbents were prepared from coastal plant, C. equisetifolia seeds treated with β-cyclodextrin (Rhusorbent) for the removal of dyes. The study was carried out to determine the effectiveness of Rhusorbent to remove common dyes such as malachite green (MG) and neutral red (NR) dyes from aqueous solutions in batch experiments. The commercial activated carbon (AC) was also used in this equilibrium absorption study which includes the effect of adsorbent dosage, initial dye concentration and contact time. The percentage of MG dye removal of about 92.4% and 88.4% was achieved for both Rhusorbent and AC respectively at concentration of 60mg/L and 0.4g absorbent. The equilibrium adsorption of about 91.1% and 79.1% was achieved for both Rhusorbent and AC respectively involving NR dye. The scanning electron micrographs of Rhusorbent show uneven and rough surface prompting evidence for the effective adsorption of MG and NR dyes on the surface of adsorbents. For both adsorption studies, Langmuir and Freundlich isotherm models fitted well the adsorption data involving both Rhusorbent and AC. C. equisetifolia seeds are a potential source for bio-inspired adsorbents for the removal of MG and NR dyes.

Mangkin zeolit HZSM–5 diubahsuai secara kaedah pertukaran ion berasid bagi menghasilkan mangkin zeolit Ga–HZSM–5. Aktiviti bermangkin bagi HZSM–5 dan Ga–HZSM–5 dikaji pada suhu tindak balas 800°C dan halaju ruang jaman masa (GHSV) 7500 jam–1. Mangkin HZSM–5 dan Ga–HZSM–5 dicirikan secara XRD, NMR, Penjerapan Nitrogen dan TPD. Hasil pencirian menunjukkan aluminium keluar dari kerangka asal. HZSM–5 yang mengandungi galium adalah mangkin yang lebih baik daripada mangkin zeolit HZSM–5 bagi menghasilkan cecair hidrokarbon. Kata kunci: Ga-HZSM-5; metana; pertukaran ion berasid; cecair hidrokarbon The HZSM–5 zeolite catalyst was modified by an acidic ion exchange method to produce the Ga–HZSM–5 zeolite catalyst. The catalytic activity of HZSM–5 and Ga–HZSM–5 were studied at reaction temperature of 800°C and gas hourly space velocities (GHSV) of 7500 hr–1. HZSM–5 and Ga–HZSM–5 catalysts were characterized by XRD, NMR, Nitrogen Adsorption and TPD. The characterization results revealed that aluminium was removed from the parent framework. Gallium loaded HZSM–5 is a better catalyst than HZSM–5 zeolite catalyst to produce liquid hydrocarbons. Key words: Ga-HZSM-5; methane; acidic ion exchange; liquid hydrocarbons

The direct conversion of methane to higher hydrocarbons either over metal catalyst or zeolite has not been successful so far in achieving the methane conversion with higher hydrocarbons selectivity within the economic range due to oxidation of the product. The present research aims at improving the performance of BZSM-5 catalyst with the addition of copper. Catalytic behaviours at different reaction conditions were investigated. Reaction temperature, oxygen concentration, copper loading and space velocity have been identified as the contributing factors in methane conversion and higher hydrocarbon selectivity. Methane conversion is favourable at higher temperatures which shows 78% conversion at 900 °C. The selectivity of C 5 + hydrocarbons increases from 650 °C up to 800 °C, but decreases slightly soon after. In methane conversion, the initial step involves an activation of methane to form CH 3 * free radicals via concerted actions between copper species and acid sites. CH 3 * radicals react in the gas phase to form C 2 + . The formation of CO x was derived from the secondary reaction of the CH 3 * radicals with metal oxide catalyst or complete combustion of C 2 + products. The formation of CO x was reduced at low oxygen concentration and short residence time.