Riwandi Sihombing

Composition of size exclusion fractions of swamp water humic and fulvic acids as measured by solid state NMR and pyrolysis-gas chromatography-mass spectrometry

Abstract Organics from Neranie swamp water, collected from the Myall Lakes district, New South Wales, Australia, have been fractionated by gel permeation chromatography and analysed by 13C nuclear magnetic resonance (NMR) spectroscopy and pyrolysis-gas chromatography-mass spectrometry (py-GC-MS). The results from these techniques demonstrate that: (1) low ( M w daltons ) and high ( M w > 74,830 daltons ) weight average molecular weight humic acid fractions have aliphatic chains which are relatively unbranched compared to those humic acids fractions of intermediate molecular weight. (2) Alcoholic carbon, mainly as carbohydrates, is more predominant in the highest weight average molecular weight material, and carboxylic carbon is more predominant in molecules with M w 2800–8270 daltons. (3) If it is assumed that CP/MAS NMR data are at least semi-quantitative, polyoxyethers or unsaturated ethers account for as much as one half of the oxygen in humic low molecular weight ( M w daltons ) materials. (4) Lignin related components of the fractions concentrate in the region M w = 74,830−27,930 daltons . If there are not multiple lignin sources, these data indicate that lignin degradation is somewhat selective about weak links. (5) The fulvic acids are more homogeneous, with different molecular weight fractions having similar structures.

Synthesis of porous activated carbon from petroleum sludge using mesoporous silica template

Porous activated carbon (PAC) was synthesized using hard template method from petroleum sludge waste categorized as toxic waste, using mesoporous MCM-41 as silica template. This sludge waste consists of very high carbon content due to the processing and separation’s by-product of crude oil and natural gas from the flowing fluids released from the reservoir. The properties of sludge waste was characterized by FTIR to identify the functional group, XRD to determine the crystal structure, SEM-EDX and CS analyzer to perform elemental analysis, as well as determination of moisture content and ash content. The properties of PAC were studied by analyzing the pore size and volume using BET method, and elemental analysis using SEM-EDX and CS analyzer. The elemental analysis results showed that sludge waste consists of 47.10% carbon, indicated it is potential to be converted into activated carbon. The functional group analysis results indicated that sludge waste consists of some functional groups such as hydroxyl, ...

Modification of natural zeolite from Bayat with tandem acid-base treatments and cobalt (II) impregnation

Natural zeolite was modified using tandem acid-based treaments in order to create a mesoporous zeolite. Themesoporous zeolite was then characterized using XRD, FTIR, EDX, and AAS. The XRD patterns showed that the structure of zeolite mostly was clinoptilolite. After subjected to the tandem treatment, no significant change in the XRD patterns wasobserved. This indicates that the structure of zeolite is intact. However, the FTIR analysis shows that the wave number of functional groups in the zeolite were shifted after subjected to tandem acid-base treatment, compared to the one of the raw material. However the main functional groups of zeolites still exist after tandem acid-base treatment.The EDX analysis showed that the Si/Al ratio was increased after acid treatments (in average, approximately 1.5 times). In contrast, the Si/Al ratio was decreased from 4.50 to 4.13 after basic treatment. The mesoporous zeolite then was modified further with cobalt (II)-impregnation using incipient wetness method with varia...

Photodegradation study of TiO2-organoclay modified acetate cellulose bioplastic

Biodegradable cellulose acetate films have been synthesized using TiO2 modified organobentonite as nanofiller. The aim of titania addition is to add photocatalyst to the biocomposite, so it has self-photodegradation properties. Organobentonite was prepared from Tapanuli bentonite, previously purification and Na+-exchanged, modified with cationic surfactant hexadceyltrimethylammonium bromide (HDTMABr). The composition of bioplastic cellulose acetate was 7 wt.% organobentonite and certain amount of TiO2 (0 wt.%, 1 wt.%, 3 wt.%, 5 wt.%, 10 wt.%) of the total composite weight. Fabrication of nanocomposite film was carried out using acetone as solvent and through solvent casting method. FTIR analysis showed the intercalation with surfactant was successfully carried out, indicated by new absorption band at 2636 cm-1 and 2569 cm-1. Nanocomposite application in photodegradation test was carried out under direct sunlight irradiation, UV light, and without irradiation for thirty days. It is found that the greater the amount of TiO2 added into the composites, the more weight loss occurred due to photodegredation. Percent weight loss in the UV light irradiation are 4.02%, 13.45%, 18.66%, 22.35%, 27.86%, respectively for (TiO2 0 wt.%, 1 wt.%, 3 wt.%, 5 wt.%, 10 wt.%). While for bioplastic irradiated by direct sunlight, the weight loss was 2.15%, 8.49%, 13.85%, 14.70%, 15.02%, respectively. In contrast, without irradiation, the weight reduction of bioplastic was insignificant. The results indicate that the addition of TiO2 to the composition of bioplastic has given the ability of self-photodegradation to the composite.

Synthesis of ZSM−5 zeolite using Bayat natural zeolite as silica and alumina source

Zeolite ZSM-5 has been successfully synthesized from natural zeolite Bayat without further purification. The silica and alumina source are taken from the natural zeolite through submolten depolimerization method. Ludox 40% was used as additional silica source to reach Si/Al ratio of 32 in the starting gel and tetrapropylammonium hydroxide (TPAOH) was used as a structure directing agent (SDA). Synthesis was carried out hydrothermally with aging and crystallization temperature at 150°C. The as-synthesized zeolite was characterized with XRD, FTIR and SEM-EDX. The XRD patterns of the resulted synthesis showed diffraction peaks at 2θ = 7.9°-8.8° (doublet peaks) and diffraction peaks at 2θ = 22°-25° (triplet peaks) which are characteristic for ZSM-5 structure. The SEM image showed that the ZSM-5 zeolite from Bayat natural zeolite had morphology of hexagonal crystalls with some debris of impurities. The elemental analysis using EDX gave Si/Al molar ratio of 18.5.

Synthesis and characterization of mesoporous Co/ZSM5 catalyst and activity study on transesterification reaction

The early development of biodiesel production process has used basic homogeneous catalyst such as NaOH or KOH in methanol or ethanol. Hence, nowadays a lot of heterogeneous catalysts have been developed in transesterification reaction for triglyceride conversion, usually vegetable oil, to Fatty Acid Methyl Esters (FAME), the main component of biodiesel. In this work, the heterogeneous catalyst used is mesoporous Co/ZSM5 zeolite. The initial mesoporous NaZSM5 zeolite is synthesized by using double template methods with tetra propy lammonium hydroxide (TPAOH) as structure directing agent and poly dialil methyl ammonium chloride (PDDA) as mesoporous template. The cobalt (Co) species was introduced to zeolite through impregnation with incipient wetness. The result of characterization on ZSM-5 and Co/ZSM5 show that the structure of as-synthesized zeolite is ZSM5 (XRD pattern), the Si/Al ratio is 12.98 and the Co loaded are 2.53 (w/w)%. The mesoporous Co/ZSM5 catalyst activity test was carried out in transesterification reaction, in which the Crude Palm Oil (CPO) as substrate was mixed with methanol in the present of zeolite catalyst (10% substrate) to be converted to FAME. The reaction was set at 95 °C and the reaction time was varied from 0 to 8 hours. The product was then measured and analyzed with GC-FID. The conversion of CPO to FAME using Co/ZSM5 as catalyst is still inferior compared to basic catalyst. However, when the catalyst was applied for the transesterification process with commercial cooking oil, the yield of FAME reached 41.87 (w/w)%.

Modification of cellulose acetate nanocomposite with TiO2-organoclay as nanofiller and its self-photodegradation study

Nanocomposite cellulose acetate has been synthesized using organoclay nanofiller modified with TiO2. Tapanuli bentonite was previously subjected to purification and sodium exchangeprocesses, then modified with TiO2,that was added as much as 0%, 1%, 3%, 5%, and 10% weight of the total composite. FTIR analysis showed intercalation with Hexadecyl Ammonium Bromide (HDTMABr) surfactant was successfully carried out, indicated by new absorption bands at 2636 cm−1 and 2569 cm−1. XRD diffractogram shows the increase in basal spasing on the modification of bentonite from 15.7 A to 19.7 A after modification. Fabrication of nanocomposite film was carried out using acetone as solvent and through solvent casting method. Nanocomposite application in photodegradation test was carried out under direct sunlight irradiation, UV light, and without irradiation for six days. It is found that the greater the amount of TiO2 in the composites, the more weight loss occured, due to photodegredation. Percent weight loss in the UV li...