GROWTH OF CARBON NANOTUBES USING THERMAL CATALYTIC CHEMICAL VAPOR DEPOSITION OF C2H2 OVER FE-CO CATALYSTS

This paper describes the influence of a Fe-Co catalyst on growth of carbon nanotubes (CNTs) by catalytic chemical vapour deposition of acetylene and nitrogen gases. Ferrum-Cobalt supported with alumina or zeolite was used as a catalyst. Comparison of the various types of the Fe-catalyst (Co, Al, and Zeolite) leads to the conclusion that Co-catalyst is suitable for producing multi wall carbon nanotubes (MWCNTs) and combination of Fe and Co provide a good condition to the catalytic growth of CNTs. Prepared samples were analysed by Raman spectroscopy (RS) and scanning electron microscopy (SEM)

Microalgae for Stabilizing Biogas Production from Cassava Starch Wastewater

The rapid growing of Indonesian population is emerging several critical national issues i.e. energy, food, environmental, water, transportation, as well as law and human right. As an agricultural country, Indonesia has abundant of biomass wastes such as agricultural wastes include the cassava starch wastes. The problem is that the effluent from cassava starch factories is released directly into the river before properly treatment. It has been a great source of pollution and has caused environmental problems to the nearby rural population. The possible alternative to solve the problem is by converting waste to energy biogas in the biodigester. The main problem of the biogas production of cassava starch effluent is acid forming-bacteria quickly produced acid resulting significantly in declining pH below the neutral pH and diminishing growth of methane bacteria. Hence, the only one of the method to cover this problem is by adding microalgae as biostabilisator of pH. Microalgae can also be used as purifier agent to absorb CO2.The general objective of this research project was to develop an integrated process of biogas production and purification from cassava starch effluent by using biostabilisator agent microalgae. This study has been focused on the used of urea, ruminant, yeast, microalgae, the treatment of gelled and ungelled feed for biogas production, pH control during biogas production using buffer Na2CO3, and feeding management in the semi-continuous process of biogas production. The result can be concluded as follows: i) The biogas production increased after cassava starch effluent and yeast was added, ii) Biogas production with microalgae and cassava starch effluent, yeast, ruminant bacteria, and urea were 726.43 ml/g total solid, iii) Biogas production without microalgae was 189 ml/g total solid

CO2 removal from biogas using carbon nanotubes mixed matrix membranes

A new type of mixed matrix membrane consisting of polyethersulfone (PES) and carbon nanotubes (CNTs) is prepared for biogas purification application. PES mixed matrix membrane with and without modification of carbon nanotubes were prepared by a dry/wet phase inversion technique using a pneumatically membrane casting machine system. The modified carbon nanotubes were prepared by treating the carbon nanotubes with chemical modification using acid treatment to allow PES chains to be grafted on carbon nanotubes surface. The results from the FESEM, DSC and FTIR analysis confirmed that chemical modification on carbon nanotubes surface had taken place. Meanwhile, the nanogaps in the interface of polymer and carbon nanotubes were appeared in the PES mixed matrix membrane with unmodified of carbon nanotubes. The modified carbon nanotubes mixed matrix membrane increases the mechanical properties and the permeability of all gases. For PESmodified carbon nanotubes mixed matrix membrane the maximum selectivity achieved for CO2/CH4 is 23.5

POLYIMIDE-ZEOLITE MIXED MATRIX MEMBRANE (MMM) FOR BIOGAS PURIFICATION

Biogas has being become significant potential as an alternative energy source due to the limitation of energy from fossil. In this study, a new type of mixed matrix membrane (MMM) consisting of polyimide-zeolite was synthesized and characterized for biogas purification. The MMM consists of medium concentration of polymer (20 %wt polyimide), 80 % N-Methyl-2-pyrrolidone (NMP) and 25 % zeolite 4A in total solid were prepared by a dry/wet phase inversion technique. The fabricated MMM was characterized using SEM and gas permeation. Post treatment coating procedure was also conducted. The research showed that surface coating by 3 % silicone rubber toward MMM PI 20 % gave the significant effect to improve membrane selectivity. The ideal selectivity for CO2/CH4 separation increased from 0.99 for before coating to 7.9 after coating for PI-Zeolite MMM, respectively. The results suggest that PI-Zeolite MMM with good post treatment procedure will increase the membrane selectivity and permeability with more saver polymer requirement as well as energy saving due to low energy for mixing

Performance Evaluation of of Sulfonated Poly (ether ether ketone) with Charged Surface modifying Macromolecule Membrane in Direct Methanol Fuel Cell

This study focuses on the modification of sulfonated poly(ether ether ketone) (SPEEK) membrane for direct methanol fuel cell application. The modification of SPEEK membrane was attempted by blending charged surface modifying macromolecule (cSMM). The modified membrane was compared with commercial membrane for direct methanol fuel cell (DMFC) application. Thermal and mechanical stability of the blended membrane were slightly reduced from the SPEEK membrane but still higher than the Nafion 112 membrane. The blend membrane was found to be promising for DMFC applications because of its lower methanol diffusivity (2.75×10−7 cm2 s−1) and higher proton conductivity (6.4×10−3 S cm−1), than the SPEEK membrane. The DMFC application testing results was also exhibited that during charging process, the SPEEK membrane could produced the voltage similar with the Nafion membrane. Keywords: Fuel cell membrane, Nafion Membrane, Direct methanol fuel cell; Proton exchange membrane; Sulfonated poly(ether ether ketone

Foam Behaviour of An Aqueous Solution of Piperazine- N-Methyldiethanolamine (MDEA) Blend as A Function of The Type of Impurities and Concentrations

This study focuses on the effect of impurities in the natural gas stream on the characteristic of foam behaviour in the blended piperazine and MDEA solution. Hydrocarbon liquids, Iron Sulphide, Sodium Chloride, Acetic Acid, Methanol and Polyethylene Glycol were used as the impurities. The results indicated that the type of impurities determined the foam formation of the amine solution. The concentration of piperazine-MDEA blends also enhanced to the increasing of the foam height of blended piperazine-MDEA. Iron sulfide, hydrocarbon and sodium chloride are the impurities which apparently contributed to the high foaming tendency of the solutions. At the same concentration of the impurities, iron sulfide appeared as the most influential contaminant to the foam formation, which promoted the highest foamability in any concentrations of the blend piperazine-MDEA

The Uses of Carbon Nanotubes Mixed Matrix Membranes (MMM) for Biogas Purification

A new type of mixed matrix membrane consisting of polyethersulfone (PES) and carbon nanotubes (CNTs) is prepared for biogas purification application. PES mixed matrix membrane with and without modification of carbon nanotubes were prepared by a dry/wet phase inversion technique using a pneumatically membrane casting machine system. The modified carbon nanotubes were prepared by treating the carbon nanotubes with chemical modification using acid treatment to allow PES chains to be grafted on carbon nanotubes surface. The results from the FESEM, DSC and FTIR analysis confirmed that chemical modification on carbon nanotubes surface had taken place. Meanwhile, the nanogaps in the interface of polymer and carbon nanotubes were appeared in the PES mixed matrix membrane with unmodified of carbon nanotubes. The modified carbon nanotubes mixed matrix membrane increases the mechanical properties and the permeability of all gases. For PES-modified carbon nanotubes mixed matrix membrane the maximum selectivity achieved for CO2/CH4 is 23.54